ref: 2d0b976efe9cb2da0b01e396392c622b077ddac7
author: Sigrid Haflínudóttir <ftrvxmtrx@gmail.com>
date: Thu Sep 3 14:53:59 EDT 2020
first
--- /dev/null
+++ b/.gitignore
@@ -1,0 +1,2 @@
+*.[678]
+[678].*
--- /dev/null
+++ b/README.md
@@ -1,0 +1,7 @@
+# img
+
+Some random image-related tools.
+
+## resample
+
+A faster drop-in replacement of `resample(1)` with some more features.
--- /dev/null
+++ b/mkfile
@@ -1,0 +1,12 @@
+</$objtype/mkfile
+
+MAN=/sys/man/1
+CFLAGS=$CFLAGS -p
+TARG=resample
+BIN=/$objtype/bin
+HFILES=stb_image_resize.h
+UPDATE=$HFILES
+
+default:V: all
+
+</sys/src/cmd/mkmany
--- /dev/null
+++ b/resample.c
@@ -1,0 +1,102 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+#define STB_IMAGE_RESIZE_IMPLEMENTATION
+#define STBIR_MALLOC(x,u) malloc(x)
+#define STBIR_FREE(x,u) free(x)
+#define STBIR_ASSERT(x) assert(x)
+#define NULL nil
+typedef uintptr size_t;
+#include "stb_image_resize.h"
+
+static char *filters[] = {+ [STBIR_FILTER_BOX] = "box",
+ [STBIR_FILTER_TRIANGLE] = "triangle",
+ [STBIR_FILTER_CUBICBSPLINE] = "cubicbspline",
+ [STBIR_FILTER_CATMULLROM] = "catmullrom",
+ [STBIR_FILTER_MITCHELL] = "mitchell",
+};
+
+static void
+usage(void)
+{+ fprint(2, "usage: %s [-x size] [-y size] [-f filter]\n", argv0);
+ exits("usage");+}
+
+void
+main(int argc, char **argv)
+{+ Memimage *a, *b;
+ u8int *in, *out;
+ char *flts, *s;
+ int n, w, h, bp;
+ int ow, oh, obp;
+ int wp, hp, f;
+
+ ow = oh = 0;
+ wp = hp = 0;
+ flts = filters[STBIR_FILTER_MITCHELL];
+ ARGBEGIN{+ case 'x':
+ s = EARGF(usage());
+ wp = (ow = atoi(s)) > 0 && s[strlen(s)-1] == '%';
+ break;
+ case 'y':
+ s = EARGF(usage());
+ hp = (oh = atoi(s)) > 0 && s[strlen(s)-1] == '%';
+ break;
+ case 'f':
+ flts = EARGF(usage());
+ break;
+ default:
+ usage();
+ }ARGEND
+
+ if(ow < 1 && oh < 1)
+ usage();
+ for(f = 0; f < nelem(filters) && (filters[f] == nil || strcmp(flts, filters[f]) != 0); f++);
+ if(f >= nelem(filters)){+ fprint(2, "invalid filter %s\n", flts);
+ exits("filter");+ }
+
+ memimageinit();
+ if((a = readmemimage(0)) == nil)
+ sysfatal("memory");+ if(a->chan != RGB24){+ if((b = allocmemimage(a->r, RGB24)) == nil)
+ sysfatal("memory");+ memimagedraw(b, a->r, a, ZP, nil, ZP, S);
+ freememimage(a);
+ a = b;
+ }
+ w = Dx(a->r);
+ h = Dy(a->r);
+ ow = wp ? w*ow/100.0 : w;
+ oh = hp ? h*oh/100.0 : h;
+ if(w < 1 || h < 1)
+ sysfatal("invalid size: %dx%d", ow, oh);+ bp = 3;
+ n = w*h*bp;
+ if((in = malloc(w*h*bp)) == nil)
+ sysfatal("%r");+ if(unloadmemimage(a, a->r, in, n) < 0)
+ sysfatal("%r");+ obp = 3;
+ if((out = malloc(ow*oh*obp)) == nil)
+ sysfatal("memory");+ stbir_resize_uint8_generic(
+ in, w, h, w*bp,
+ out, ow, oh, ow*obp,
+ 3, -1, 0,
+ STBIR_EDGE_CLAMP, STBIR_FILTER_CATMULLROM, STBIR_COLORSPACE_LINEAR,
+ NULL);
+ if((b = allocmemimage(Rect(0,0,ow,oh), RGB24)) == nil)
+ sysfatal("%r");+ loadmemimage(b, b->r, out, ow*oh*obp);
+ writememimage(1, b);
+
+ exits(nil);
+}
--- /dev/null
+++ b/stb_image_resize.h
@@ -1,0 +1,2616 @@
+/* stb_image_resize - v0.96 - public domain image resizing
+ by Jorge L Rodriguez (@VinoBS) - 2014
+ http://github.com/nothings/stb
+
+ Written with emphasis on usability, portability, and efficiency. (No
+ SIMD or threads, so it be easily outperformed by libs that use those.)
+ Only scaling and translation is supported, no rotations or shears.
+ Easy API downsamples w/Mitchell filter, upsamples w/cubic interpolation.
+
+ COMPILING & LINKING
+ In one C/C++ file that #includes this file, do this:
+ #define STB_IMAGE_RESIZE_IMPLEMENTATION
+ before the #include. That will create the implementation in that file.
+
+ QUICKSTART
+ stbir_resize_uint8( input_pixels , in_w , in_h , 0,
+ output_pixels, out_w, out_h, 0, num_channels)
+ stbir_resize_float(...)
+ stbir_resize_uint8_srgb( input_pixels , in_w , in_h , 0,
+ output_pixels, out_w, out_h, 0,
+ num_channels , alpha_chan , 0)
+ stbir_resize_uint8_srgb_edgemode(
+ input_pixels , in_w , in_h , 0,
+ output_pixels, out_w, out_h, 0,
+ num_channels , alpha_chan , 0, STBIR_EDGE_CLAMP)
+ // WRAP/REFLECT/ZERO
+
+ FULL API
+ See the "header file" section of the source for API documentation.
+
+ ADDITIONAL DOCUMENTATION
+
+ SRGB & FLOATING POINT REPRESENTATION
+ The sRGB functions presume IEEE floating point. If you do not have
+ IEEE floating point, define STBIR_NON_IEEE_FLOAT. This will use
+ a slower implementation.
+
+ MEMORY ALLOCATION
+ The resize functions here perform a single memory allocation using
+ malloc. To control the memory allocation, before the #include that
+ triggers the implementation, do:
+
+ #define STBIR_MALLOC(size,context) ...
+ #define STBIR_FREE(ptr,context) ...
+
+ Each resize function makes exactly one call to malloc/free, so to use
+ temp memory, store the temp memory in the context and return that.
+
+ ASSERT
+ Define STBIR_ASSERT(boolval) to override assert() and not use assert.h
+
+ OPTIMIZATION
+ Define STBIR_SATURATE_INT to compute clamp values in-range using
+ integer operations instead of float operations. This may be faster
+ on some platforms.
+
+ DEFAULT FILTERS
+ For functions which don't provide explicit control over what filters
+ to use, you can change the compile-time defaults with
+
+ #define STBIR_DEFAULT_FILTER_UPSAMPLE STBIR_FILTER_something
+ #define STBIR_DEFAULT_FILTER_DOWNSAMPLE STBIR_FILTER_something
+
+ See stbir_filter in the header-file section for the list of filters.
+
+ NEW FILTERS
+ A number of 1D filter kernels are used. For a list of
+ supported filters see the stbir_filter enum. To add a new filter,
+ write a filter function and add it to stbir__filter_info_table.
+
+ PROGRESS
+ For interactive use with slow resize operations, you can install
+ a progress-report callback:
+
+ #define STBIR_PROGRESS_REPORT(val) some_func(val)
+
+ The parameter val is a float which goes from 0 to 1 as progress is made.
+
+ For example:
+
+ static void my_progress_report(float progress);
+ #define STBIR_PROGRESS_REPORT(val) my_progress_report(val)
+
+ #define STB_IMAGE_RESIZE_IMPLEMENTATION
+ #include "stb_image_resize.h"
+
+ static void my_progress_report(float progress)
+ {+ printf("Progress: %f%%\n", progress*100);+ }
+
+ MAX CHANNELS
+ If your image has more than 64 channels, define STBIR_MAX_CHANNELS
+ to the max you'll have.
+
+ ALPHA CHANNEL
+ Most of the resizing functions provide the ability to control how
+ the alpha channel of an image is processed. The important things
+ to know about this:
+
+ 1. The best mathematically-behaved version of alpha to use is
+ called "premultiplied alpha", in which the other color channels
+ have had the alpha value multiplied in. If you use premultiplied
+ alpha, linear filtering (such as image resampling done by this
+ library, or performed in texture units on GPUs) does the "right
+ thing". While premultiplied alpha is standard in the movie CGI
+ industry, it is still uncommon in the videogame/real-time world.
+
+ If you linearly filter non-premultiplied alpha, strange effects
+ occur. (For example, the 50/50 average of 99% transparent bright green
+ and 1% transparent black produces 50% transparent dark green when
+ non-premultiplied, whereas premultiplied it produces 50%
+ transparent near-black. The former introduces green energy
+ that doesn't exist in the source image.)
+
+ 2. Artists should not edit premultiplied-alpha images; artists
+ want non-premultiplied alpha images. Thus, art tools generally output
+ non-premultiplied alpha images.
+
+ 3. You will get best results in most cases by converting images
+ to premultiplied alpha before processing them mathematically.
+
+ 4. If you pass the flag STBIR_FLAG_ALPHA_PREMULTIPLIED, the
+ resizer does not do anything special for the alpha channel;
+ it is resampled identically to other channels. This produces
+ the correct results for premultiplied-alpha images, but produces
+ less-than-ideal results for non-premultiplied-alpha images.
+
+ 5. If you do not pass the flag STBIR_FLAG_ALPHA_PREMULTIPLIED,
+ then the resizer weights the contribution of input pixels
+ based on their alpha values, or, equivalently, it multiplies
+ the alpha value into the color channels, resamples, then divides
+ by the resultant alpha value. Input pixels which have alpha=0 do
+ not contribute at all to output pixels unless _all_ of the input
+ pixels affecting that output pixel have alpha=0, in which case
+ the result for that pixel is the same as it would be without
+ STBIR_FLAG_ALPHA_PREMULTIPLIED. However, this is only true for
+ input images in integer formats. For input images in float format,
+ input pixels with alpha=0 have no effect, and output pixels
+ which have alpha=0 will be 0 in all channels. (For float images,
+ you can manually achieve the same result by adding a tiny epsilon
+ value to the alpha channel of every image, and then subtracting
+ or clamping it at the end.)
+
+ 6. You can suppress the behavior described in #5 and make
+ all-0-alpha pixels have 0 in all channels by #defining
+ STBIR_NO_ALPHA_EPSILON.
+
+ 7. You can separately control whether the alpha channel is
+ interpreted as linear or affected by the colorspace. By default
+ it is linear; you almost never want to apply the colorspace.
+ (For example, graphics hardware does not apply sRGB conversion
+ to the alpha channel.)
+
+ CONTRIBUTORS
+ Jorge L Rodriguez: Implementation
+ Sean Barrett: API design, optimizations
+ Aras Pranckevicius: bugfix
+ Nathan Reed: warning fixes
+
+ REVISIONS
+ 0.97 (2020-02-02) fixed warning
+ 0.96 (2019-03-04) fixed warnings
+ 0.95 (2017-07-23) fixed warnings
+ 0.94 (2017-03-18) fixed warnings
+ 0.93 (2017-03-03) fixed bug with certain combinations of heights
+ 0.92 (2017-01-02) fix integer overflow on large (>2GB) images
+ 0.91 (2016-04-02) fix warnings; fix handling of subpixel regions
+ 0.90 (2014-09-17) first released version
+
+ LICENSE
+ See end of file for license information.
+
+ TODO
+ Don't decode all of the image data when only processing a partial tile
+ Don't use full-width decode buffers when only processing a partial tile
+ When processing wide images, break processing into tiles so data fits in L1 cache
+ Installable filters?
+ Resize that respects alpha test coverage
+ (Reference code: FloatImage::alphaTestCoverage and FloatImage::scaleAlphaToCoverage:
+ https://code.google.com/p/nvidia-texture-tools/source/browse/trunk/src/nvimage/FloatImage.cpp )
+*/
+
+#ifndef STBIR_INCLUDE_STB_IMAGE_RESIZE_H
+#define STBIR_INCLUDE_STB_IMAGE_RESIZE_H
+
+typedef u8int stbir_uint8;
+typedef u16int stbir_uint16;
+typedef u32int stbir_uint32;
+
+#ifndef STBIRDEF
+#ifdef STB_IMAGE_RESIZE_STATIC
+#define STBIRDEF static
+#else
+#ifdef __cplusplus
+#define STBIRDEF extern "C"
+#else
+#define STBIRDEF extern
+#endif
+#endif
+#endif
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Easy-to-use API:
+//
+// * "input pixels" points to an array of image data with 'num_channels' channels (e.g. RGB=3, RGBA=4)
+// * input_w is input image width (x-axis), input_h is input image height (y-axis)
+// * stride is the offset between successive rows of image data in memory, in bytes. you can
+// specify 0 to mean packed continuously in memory
+// * alpha channel is treated identically to other channels.
+// * colorspace is linear or sRGB as specified by function name
+// * returned result is 1 for success or 0 in case of an error.
+// #define STBIR_ASSERT() to trigger an assert on parameter validation errors.
+// * Memory required grows approximately linearly with input and output size, but with
+// discontinuities at input_w == output_w and input_h == output_h.
+// * These functions use a "default" resampling filter defined at compile time. To change the filter,
+// you can change the compile-time defaults by #defining STBIR_DEFAULT_FILTER_UPSAMPLE
+// and STBIR_DEFAULT_FILTER_DOWNSAMPLE, or you can use the medium-complexity API.
+
+STBIRDEF int stbir_resize_uint8( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels);
+
+STBIRDEF int stbir_resize_float( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ float *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels);
+
+
+// The following functions interpret image data as gamma-corrected sRGB.
+// Specify STBIR_ALPHA_CHANNEL_NONE if you have no alpha channel,
+// or otherwise provide the index of the alpha channel. Flags value
+// of 0 will probably do the right thing if you're not sure what
+// the flags mean.
+
+#define STBIR_ALPHA_CHANNEL_NONE -1
+
+// Set this flag if your texture has premultiplied alpha. Otherwise, stbir will
+// use alpha-weighted resampling (effectively premultiplying, resampling,
+// then unpremultiplying).
+#define STBIR_FLAG_ALPHA_PREMULTIPLIED (1 << 0)
+// The specified alpha channel should be handled as gamma-corrected value even
+// when doing sRGB operations.
+#define STBIR_FLAG_ALPHA_USES_COLORSPACE (1 << 1)
+
+STBIRDEF int stbir_resize_uint8_srgb(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags);
+
+
+typedef enum
+{+ STBIR_EDGE_CLAMP = 1,
+ STBIR_EDGE_REFLECT = 2,
+ STBIR_EDGE_WRAP = 3,
+ STBIR_EDGE_ZERO = 4,
+} stbir_edge;
+
+// This function adds the ability to specify how requests to sample off the edge of the image are handled.
+STBIRDEF int stbir_resize_uint8_srgb_edgemode(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_wrap_mode);
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Medium-complexity API
+//
+// This extends the easy-to-use API as follows:
+//
+// * Alpha-channel can be processed separately
+// * If alpha_channel is not STBIR_ALPHA_CHANNEL_NONE
+// * Alpha channel will not be gamma corrected (unless flags&STBIR_FLAG_GAMMA_CORRECT)
+// * Filters will be weighted by alpha channel (unless flags&STBIR_FLAG_ALPHA_PREMULTIPLIED)
+// * Filter can be selected explicitly
+// * uint16 image type
+// * sRGB colorspace available for all types
+// * context parameter for passing to STBIR_MALLOC
+
+typedef enum
+{+ STBIR_FILTER_DEFAULT = 0, // use same filter type that easy-to-use API chooses
+ STBIR_FILTER_BOX = 1, // A trapezoid w/1-pixel wide ramps, same result as box for integer scale ratios
+ STBIR_FILTER_TRIANGLE = 2, // On upsampling, produces same results as bilinear texture filtering
+ STBIR_FILTER_CUBICBSPLINE = 3, // The cubic b-spline (aka Mitchell-Netrevalli with B=1,C=0), gaussian-esque
+ STBIR_FILTER_CATMULLROM = 4, // An interpolating cubic spline
+ STBIR_FILTER_MITCHELL = 5, // Mitchell-Netrevalli filter with B=1/3, C=1/3
+} stbir_filter;
+
+typedef enum
+{+ STBIR_COLORSPACE_LINEAR,
+ STBIR_COLORSPACE_SRGB,
+
+ STBIR_MAX_COLORSPACES,
+} stbir_colorspace;
+
+// The following functions are all identical except for the type of the image data
+
+STBIRDEF int stbir_resize_uint8_generic( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
+ void *alloc_context);
+
+STBIRDEF int stbir_resize_uint16_generic(const stbir_uint16 *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ stbir_uint16 *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
+ void *alloc_context);
+
+STBIRDEF int stbir_resize_float_generic( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ float *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
+ void *alloc_context);
+
+
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Full-complexity API
+//
+// This extends the medium API as follows:
+//
+// * uint32 image type
+// * not typesafe
+// * separate filter types for each axis
+// * separate edge modes for each axis
+// * can specify scale explicitly for subpixel correctness
+// * can specify image source tile using texture coordinates
+
+typedef enum
+{+ STBIR_TYPE_UINT8 ,
+ STBIR_TYPE_UINT16,
+ STBIR_TYPE_UINT32,
+ STBIR_TYPE_FLOAT ,
+
+ STBIR_MAX_TYPES
+} stbir_datatype;
+
+STBIRDEF int stbir_resize( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ stbir_datatype datatype,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
+ stbir_filter filter_horizontal, stbir_filter filter_vertical,
+ stbir_colorspace space, void *alloc_context);
+
+STBIRDEF int stbir_resize_subpixel(const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ stbir_datatype datatype,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
+ stbir_filter filter_horizontal, stbir_filter filter_vertical,
+ stbir_colorspace space, void *alloc_context,
+ float x_scale, float y_scale,
+ float x_offset, float y_offset);
+
+STBIRDEF int stbir_resize_region( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ stbir_datatype datatype,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
+ stbir_filter filter_horizontal, stbir_filter filter_vertical,
+ stbir_colorspace space, void *alloc_context,
+ float s0, float t0, float s1, float t1);
+// (s0, t0) & (s1, t1) are the top-left and bottom right corner (uv addressing style: [0, 1]x[0, 1]) of a region of the input image to use.
+
+//
+//
+//// end header file /////////////////////////////////////////////////////
+#endif // STBIR_INCLUDE_STB_IMAGE_RESIZE_H
+
+
+
+
+
+#ifdef STB_IMAGE_RESIZE_IMPLEMENTATION
+
+#ifndef STBIR_ASSERT
+#include <assert.h>
+#define STBIR_ASSERT(x) assert(x)
+#endif
+
+#ifndef STBIR_MALLOC
+#include <stdlib.h>
+// use comma operator to evaluate c, to avoid "unused parameter" warnings
+#define STBIR_MALLOC(size,c) ((void)(c), malloc(size))
+#define STBIR_FREE(ptr,c) ((void)(c), free(ptr))
+#endif
+
+#ifndef _MSC_VER
+#ifdef __cplusplus
+#define stbir__inline inline
+#else
+#define stbir__inline
+#endif
+#else
+#define stbir__inline __forceinline
+#endif
+
+
+// should produce compiler error if size is wrong
+typedef unsigned char stbir__validate_uint32[sizeof(stbir_uint32) == 4 ? 1 : -1];
+
+#define STBIR__NOTUSED(v) USED(v)
+
+#define STBIR__ARRAY_SIZE(a) nelem(a)
+
+#ifndef STBIR_DEFAULT_FILTER_UPSAMPLE
+#define STBIR_DEFAULT_FILTER_UPSAMPLE STBIR_FILTER_CATMULLROM
+#endif
+
+#ifndef STBIR_DEFAULT_FILTER_DOWNSAMPLE
+#define STBIR_DEFAULT_FILTER_DOWNSAMPLE STBIR_FILTER_MITCHELL
+#endif
+
+#ifndef STBIR_PROGRESS_REPORT
+#define STBIR_PROGRESS_REPORT(float_0_to_1)
+#endif
+
+#ifndef STBIR_MAX_CHANNELS
+#define STBIR_MAX_CHANNELS 64
+#endif
+
+#if STBIR_MAX_CHANNELS > 65536
+#error "Too many channels; STBIR_MAX_CHANNELS must be no more than 65536."
+// because we store the indices in 16-bit variables
+#endif
+
+// This value is added to alpha just before premultiplication to avoid
+// zeroing out color values. It is equivalent to 2^-80. If you don't want
+// that behavior (it may interfere if you have floating point images with
+// very small alpha values) then you can define STBIR_NO_ALPHA_EPSILON to
+// disable it.
+#ifndef STBIR_ALPHA_EPSILON
+#define STBIR_ALPHA_EPSILON ((float)1 / (1 << 20) / (1 << 20) / (1 << 20) / (1 << 20))
+#endif
+
+
+
+#ifdef _MSC_VER
+#define STBIR__UNUSED_PARAM(v) (void)(v)
+#else
+#define STBIR__UNUSED_PARAM(v) (void)sizeof(v)
+#endif
+
+// must match stbir_datatype
+static unsigned char stbir__type_size[] = {+ 1, // STBIR_TYPE_UINT8
+ 2, // STBIR_TYPE_UINT16
+ 4, // STBIR_TYPE_UINT32
+ 4, // STBIR_TYPE_FLOAT
+};
+
+// Kernel function centered at 0
+typedef float (stbir__kernel_fn)(float x, float scale);
+typedef float (stbir__support_fn)(float scale);
+
+typedef struct
+{+ stbir__kernel_fn* kernel;
+ stbir__support_fn* support;
+} stbir__filter_info;
+
+// When upsampling, the contributors are which source pixels contribute.
+// When downsampling, the contributors are which destination pixels are contributed to.
+typedef struct
+{+ int n0; // First contributing pixel
+ int n1; // Last contributing pixel
+} stbir__contributors;
+
+typedef struct
+{+ const void* input_data;
+ int input_w;
+ int input_h;
+ int input_stride_bytes;
+
+ void* output_data;
+ int output_w;
+ int output_h;
+ int output_stride_bytes;
+
+ float s0, t0, s1, t1;
+
+ float horizontal_shift; // Units: output pixels
+ float vertical_shift; // Units: output pixels
+ float horizontal_scale;
+ float vertical_scale;
+
+ int channels;
+ int alpha_channel;
+ stbir_uint32 flags;
+ stbir_datatype type;
+ stbir_filter horizontal_filter;
+ stbir_filter vertical_filter;
+ stbir_edge edge_horizontal;
+ stbir_edge edge_vertical;
+ stbir_colorspace colorspace;
+
+ stbir__contributors* horizontal_contributors;
+ float* horizontal_coefficients;
+
+ stbir__contributors* vertical_contributors;
+ float* vertical_coefficients;
+
+ int decode_buffer_pixels;
+ float* decode_buffer;
+
+ float* horizontal_buffer;
+
+ // cache these because ceil/floor are inexplicably showing up in profile
+ int horizontal_coefficient_width;
+ int vertical_coefficient_width;
+ int horizontal_filter_pixel_width;
+ int vertical_filter_pixel_width;
+ int horizontal_filter_pixel_margin;
+ int vertical_filter_pixel_margin;
+ int horizontal_num_contributors;
+ int vertical_num_contributors;
+
+ int ring_buffer_length_bytes; // The length of an individual entry in the ring buffer. The total number of ring buffers is stbir__get_filter_pixel_width(filter)
+ int ring_buffer_num_entries; // Total number of entries in the ring buffer.
+ int ring_buffer_first_scanline;
+ int ring_buffer_last_scanline;
+ int ring_buffer_begin_index; // first_scanline is at this index in the ring buffer
+ float* ring_buffer;
+
+ float* encode_buffer; // A temporary buffer to store floats so we don't lose precision while we do multiply-adds.
+
+ int horizontal_contributors_size;
+ int horizontal_coefficients_size;
+ int vertical_contributors_size;
+ int vertical_coefficients_size;
+ int decode_buffer_size;
+ int horizontal_buffer_size;
+ int ring_buffer_size;
+ int encode_buffer_size;
+} stbir__info;
+
+
+static const float stbir__max_uint8_as_float = 255.0f;
+static const float stbir__max_uint16_as_float = 65535.0f;
+static const double stbir__max_uint32_as_float = 4294967295.0;
+
+
+static stbir__inline int stbir__min(int a, int b)
+{+ return a < b ? a : b;
+}
+
+static stbir__inline float stbir__saturate(float x)
+{+ if (x < 0)
+ return 0;
+
+ if (x > 1)
+ return 1;
+
+ return x;
+}
+
+#ifdef STBIR_SATURATE_INT
+static stbir__inline stbir_uint8 stbir__saturate8(int x)
+{+ if ((unsigned int) x <= 255)
+ return x;
+
+ if (x < 0)
+ return 0;
+
+ return 255;
+}
+
+static stbir__inline stbir_uint16 stbir__saturate16(int x)
+{+ if ((unsigned int) x <= 65535)
+ return x;
+
+ if (x < 0)
+ return 0;
+
+ return 65535;
+}
+#endif
+
+static float stbir__srgb_uchar_to_linear_float[256] = {+ 0.000000f, 0.000304f, 0.000607f, 0.000911f, 0.001214f, 0.001518f, 0.001821f, 0.002125f, 0.002428f, 0.002732f, 0.003035f,
+ 0.003347f, 0.003677f, 0.004025f, 0.004391f, 0.004777f, 0.005182f, 0.005605f, 0.006049f, 0.006512f, 0.006995f, 0.007499f,
+ 0.008023f, 0.008568f, 0.009134f, 0.009721f, 0.010330f, 0.010960f, 0.011612f, 0.012286f, 0.012983f, 0.013702f, 0.014444f,
+ 0.015209f, 0.015996f, 0.016807f, 0.017642f, 0.018500f, 0.019382f, 0.020289f, 0.021219f, 0.022174f, 0.023153f, 0.024158f,
+ 0.025187f, 0.026241f, 0.027321f, 0.028426f, 0.029557f, 0.030713f, 0.031896f, 0.033105f, 0.034340f, 0.035601f, 0.036889f,
+ 0.038204f, 0.039546f, 0.040915f, 0.042311f, 0.043735f, 0.045186f, 0.046665f, 0.048172f, 0.049707f, 0.051269f, 0.052861f,
+ 0.054480f, 0.056128f, 0.057805f, 0.059511f, 0.061246f, 0.063010f, 0.064803f, 0.066626f, 0.068478f, 0.070360f, 0.072272f,
+ 0.074214f, 0.076185f, 0.078187f, 0.080220f, 0.082283f, 0.084376f, 0.086500f, 0.088656f, 0.090842f, 0.093059f, 0.095307f,
+ 0.097587f, 0.099899f, 0.102242f, 0.104616f, 0.107023f, 0.109462f, 0.111932f, 0.114435f, 0.116971f, 0.119538f, 0.122139f,
+ 0.124772f, 0.127438f, 0.130136f, 0.132868f, 0.135633f, 0.138432f, 0.141263f, 0.144128f, 0.147027f, 0.149960f, 0.152926f,
+ 0.155926f, 0.158961f, 0.162029f, 0.165132f, 0.168269f, 0.171441f, 0.174647f, 0.177888f, 0.181164f, 0.184475f, 0.187821f,
+ 0.191202f, 0.194618f, 0.198069f, 0.201556f, 0.205079f, 0.208637f, 0.212231f, 0.215861f, 0.219526f, 0.223228f, 0.226966f,
+ 0.230740f, 0.234551f, 0.238398f, 0.242281f, 0.246201f, 0.250158f, 0.254152f, 0.258183f, 0.262251f, 0.266356f, 0.270498f,
+ 0.274677f, 0.278894f, 0.283149f, 0.287441f, 0.291771f, 0.296138f, 0.300544f, 0.304987f, 0.309469f, 0.313989f, 0.318547f,
+ 0.323143f, 0.327778f, 0.332452f, 0.337164f, 0.341914f, 0.346704f, 0.351533f, 0.356400f, 0.361307f, 0.366253f, 0.371238f,
+ 0.376262f, 0.381326f, 0.386430f, 0.391573f, 0.396755f, 0.401978f, 0.407240f, 0.412543f, 0.417885f, 0.423268f, 0.428691f,
+ 0.434154f, 0.439657f, 0.445201f, 0.450786f, 0.456411f, 0.462077f, 0.467784f, 0.473532f, 0.479320f, 0.485150f, 0.491021f,
+ 0.496933f, 0.502887f, 0.508881f, 0.514918f, 0.520996f, 0.527115f, 0.533276f, 0.539480f, 0.545725f, 0.552011f, 0.558340f,
+ 0.564712f, 0.571125f, 0.577581f, 0.584078f, 0.590619f, 0.597202f, 0.603827f, 0.610496f, 0.617207f, 0.623960f, 0.630757f,
+ 0.637597f, 0.644480f, 0.651406f, 0.658375f, 0.665387f, 0.672443f, 0.679543f, 0.686685f, 0.693872f, 0.701102f, 0.708376f,
+ 0.715694f, 0.723055f, 0.730461f, 0.737911f, 0.745404f, 0.752942f, 0.760525f, 0.768151f, 0.775822f, 0.783538f, 0.791298f,
+ 0.799103f, 0.806952f, 0.814847f, 0.822786f, 0.830770f, 0.838799f, 0.846873f, 0.854993f, 0.863157f, 0.871367f, 0.879622f,
+ 0.887923f, 0.896269f, 0.904661f, 0.913099f, 0.921582f, 0.930111f, 0.938686f, 0.947307f, 0.955974f, 0.964686f, 0.973445f,
+ 0.982251f, 0.991102f, 1.0f
+};
+
+static float stbir__srgb_to_linear(float f)
+{+ if (f <= 0.04045f)
+ return f / 12.92f;
+ else
+ return (float)pow((f + 0.055f) / 1.055f, 2.4f);
+}
+
+static float stbir__linear_to_srgb(float f)
+{+ if (f <= 0.0031308f)
+ return f * 12.92f;
+ else
+ return 1.055f * (float)pow(f, 1 / 2.4f) - 0.055f;
+}
+
+#ifndef STBIR_NON_IEEE_FLOAT
+// From https://gist.github.com/rygorous/2203834
+
+typedef union
+{+ stbir_uint32 u;
+ float f;
+} stbir__FP32;
+
+static const stbir_uint32 fp32_to_srgb8_tab4[104] = {+ 0x0073000d, 0x007a000d, 0x0080000d, 0x0087000d, 0x008d000d, 0x0094000d, 0x009a000d, 0x00a1000d,
+ 0x00a7001a, 0x00b4001a, 0x00c1001a, 0x00ce001a, 0x00da001a, 0x00e7001a, 0x00f4001a, 0x0101001a,
+ 0x010e0033, 0x01280033, 0x01410033, 0x015b0033, 0x01750033, 0x018f0033, 0x01a80033, 0x01c20033,
+ 0x01dc0067, 0x020f0067, 0x02430067, 0x02760067, 0x02aa0067, 0x02dd0067, 0x03110067, 0x03440067,
+ 0x037800ce, 0x03df00ce, 0x044600ce, 0x04ad00ce, 0x051400ce, 0x057b00c5, 0x05dd00bc, 0x063b00b5,
+ 0x06970158, 0x07420142, 0x07e30130, 0x087b0120, 0x090b0112, 0x09940106, 0x0a1700fc, 0x0a9500f2,
+ 0x0b0f01cb, 0x0bf401ae, 0x0ccb0195, 0x0d950180, 0x0e56016e, 0x0f0d015e, 0x0fbc0150, 0x10630143,
+ 0x11070264, 0x1238023e, 0x1357021d, 0x14660201, 0x156601e9, 0x165a01d3, 0x174401c0, 0x182401af,
+ 0x18fe0331, 0x1a9602fe, 0x1c1502d2, 0x1d7e02ad, 0x1ed4028d, 0x201a0270, 0x21520256, 0x227d0240,
+ 0x239f0443, 0x25c003fe, 0x27bf03c4, 0x29a10392, 0x2b6a0367, 0x2d1d0341, 0x2ebe031f, 0x304d0300,
+ 0x31d105b0, 0x34a80555, 0x37520507, 0x39d504c5, 0x3c37048b, 0x3e7c0458, 0x40a8042a, 0x42bd0401,
+ 0x44c20798, 0x488e071e, 0x4c1c06b6, 0x4f76065d, 0x52a50610, 0x55ac05cc, 0x5892058f, 0x5b590559,
+ 0x5e0c0a23, 0x631c0980, 0x67db08f6, 0x6c55087f, 0x70940818, 0x74a007bd, 0x787d076c, 0x7c330723,
+};
+
+static stbir_uint8 stbir__linear_to_srgb_uchar(float in)
+{+ static const stbir__FP32 almostone = { 0x3f7fffff }; // 1-eps+ static const stbir__FP32 minval = { (127-13) << 23 };+ stbir_uint32 tab,bias,scale,t;
+ stbir__FP32 f;
+
+ // Clamp to [2^(-13), 1-eps]; these two values map to 0 and 1, respectively.
+ // The tests are carefully written so that NaNs map to 0, same as in the reference
+ // implementation.
+ if (!(in > minval.f)) // written this way to catch NaNs
+ in = minval.f;
+ if (in > almostone.f)
+ in = almostone.f;
+
+ // Do the table lookup and unpack bias, scale
+ f.f = in;
+ tab = fp32_to_srgb8_tab4[(f.u - minval.u) >> 20];
+ bias = (tab >> 16) << 9;
+ scale = tab & 0xffff;
+
+ // Grab next-highest mantissa bits and perform linear interpolation
+ t = (f.u >> 12) & 0xff;
+ return (unsigned char) ((bias + scale*t) >> 16);
+}
+
+#else
+// sRGB transition values, scaled by 1<<28
+static int stbir__srgb_offset_to_linear_scaled[256] =
+{+ 0, 40738, 122216, 203693, 285170, 366648, 448125, 529603,
+ 611080, 692557, 774035, 855852, 942009, 1033024, 1128971, 1229926,
+ 1335959, 1447142, 1563542, 1685229, 1812268, 1944725, 2082664, 2226148,
+ 2375238, 2529996, 2690481, 2856753, 3028870, 3206888, 3390865, 3580856,
+ 3776916, 3979100, 4187460, 4402049, 4622919, 4850123, 5083710, 5323731,
+ 5570236, 5823273, 6082892, 6349140, 6622065, 6901714, 7188133, 7481369,
+ 7781466, 8088471, 8402427, 8723380, 9051372, 9386448, 9728650, 10078021,
+ 10434603, 10798439, 11169569, 11548036, 11933879, 12327139, 12727857, 13136073,
+ 13551826, 13975156, 14406100, 14844697, 15290987, 15745007, 16206795, 16676389,
+ 17153826, 17639142, 18132374, 18633560, 19142734, 19659934, 20185196, 20718552,
+ 21260042, 21809696, 22367554, 22933648, 23508010, 24090680, 24681686, 25281066,
+ 25888850, 26505076, 27129772, 27762974, 28404716, 29055026, 29713942, 30381490,
+ 31057708, 31742624, 32436272, 33138682, 33849884, 34569912, 35298800, 36036568,
+ 36783260, 37538896, 38303512, 39077136, 39859796, 40651528, 41452360, 42262316,
+ 43081432, 43909732, 44747252, 45594016, 46450052, 47315392, 48190064, 49074096,
+ 49967516, 50870356, 51782636, 52704392, 53635648, 54576432, 55526772, 56486700,
+ 57456236, 58435408, 59424248, 60422780, 61431036, 62449032, 63476804, 64514376,
+ 65561776, 66619028, 67686160, 68763192, 69850160, 70947088, 72053992, 73170912,
+ 74297864, 75434880, 76581976, 77739184, 78906536, 80084040, 81271736, 82469648,
+ 83677792, 84896192, 86124888, 87363888, 88613232, 89872928, 91143016, 92423512,
+ 93714432, 95015816, 96327688, 97650056, 98982952, 100326408, 101680440, 103045072,
+ 104420320, 105806224, 107202800, 108610064, 110028048, 111456776, 112896264, 114346544,
+ 115807632, 117279552, 118762328, 120255976, 121760536, 123276016, 124802440, 126339832,
+ 127888216, 129447616, 131018048, 132599544, 134192112, 135795792, 137410592, 139036528,
+ 140673648, 142321952, 143981456, 145652208, 147334208, 149027488, 150732064, 152447968,
+ 154175200, 155913792, 157663776, 159425168, 161197984, 162982240, 164777968, 166585184,
+ 168403904, 170234160, 172075968, 173929344, 175794320, 177670896, 179559120, 181458992,
+ 183370528, 185293776, 187228736, 189175424, 191133888, 193104112, 195086128, 197079968,
+ 199085648, 201103184, 203132592, 205173888, 207227120, 209292272, 211369392, 213458480,
+ 215559568, 217672656, 219797792, 221934976, 224084240, 226245600, 228419056, 230604656,
+ 232802400, 235012320, 237234432, 239468736, 241715280, 243974080, 246245120, 248528464,
+ 250824112, 253132064, 255452368, 257785040, 260130080, 262487520, 264857376, 267239664,
+};
+
+static stbir_uint8 stbir__linear_to_srgb_uchar(float f)
+{+ int x = (int) (f * (1 << 28)); // has headroom so you don't need to clamp
+ int v = 0;
+ int i;
+
+ // Refine the guess with a short binary search.
+ i = v + 128; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
+ i = v + 64; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
+ i = v + 32; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
+ i = v + 16; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
+ i = v + 8; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
+ i = v + 4; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
+ i = v + 2; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
+ i = v + 1; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
+
+ return (stbir_uint8) v;
+}
+#endif
+
+static float stbir__filter_trapezoid(float x, float scale)
+{+ float halfscale = scale / 2;
+ float t = 0.5f + halfscale;
+ STBIR_ASSERT(scale <= 1);
+
+ x = (float)fabs(x);
+
+ if (x >= t)
+ return 0;
+ else
+ {+ float r = 0.5f - halfscale;
+ if (x <= r)
+ return 1;
+ else
+ return (t - x) / scale;
+ }
+}
+
+static float stbir__support_trapezoid(float scale)
+{+ STBIR_ASSERT(scale <= 1);
+ return 0.5f + scale / 2;
+}
+
+static float stbir__filter_triangle(float x, float s)
+{+ STBIR__UNUSED_PARAM(s);
+
+ x = (float)fabs(x);
+
+ if (x <= 1.0f)
+ return 1 - x;
+ else
+ return 0;
+}
+
+static float stbir__filter_cubic(float x, float s)
+{+ STBIR__UNUSED_PARAM(s);
+
+ x = (float)fabs(x);
+
+ if (x < 1.0f)
+ return (4 + x*x*(3*x - 6))/6;
+ else if (x < 2.0f)
+ return (8 + x*(-12 + x*(6 - x)))/6;
+
+ return (0.0f);
+}
+
+static float stbir__filter_catmullrom(float x, float s)
+{+ STBIR__UNUSED_PARAM(s);
+
+ x = (float)fabs(x);
+
+ if (x < 1.0f)
+ return 1 - x*x*(2.5f - 1.5f*x);
+ else if (x < 2.0f)
+ return 2 - x*(4 + x*(0.5f*x - 2.5f));
+
+ return (0.0f);
+}
+
+static float stbir__filter_mitchell(float x, float s)
+{+ STBIR__UNUSED_PARAM(s);
+
+ x = (float)fabs(x);
+
+ if (x < 1.0f)
+ return (16 + x*x*(21 * x - 36))/18;
+ else if (x < 2.0f)
+ return (32 + x*(-60 + x*(36 - 7*x)))/18;
+
+ return (0.0f);
+}
+
+static float stbir__support_zero(float s)
+{+ STBIR__UNUSED_PARAM(s);
+ return 0;
+}
+
+static float stbir__support_one(float s)
+{+ STBIR__UNUSED_PARAM(s);
+ return 1;
+}
+
+static float stbir__support_two(float s)
+{+ STBIR__UNUSED_PARAM(s);
+ return 2;
+}
+
+static stbir__filter_info stbir__filter_info_table[] = {+ { NULL, stbir__support_zero },+ { stbir__filter_trapezoid, stbir__support_trapezoid },+ { stbir__filter_triangle, stbir__support_one },+ { stbir__filter_cubic, stbir__support_two },+ { stbir__filter_catmullrom, stbir__support_two },+ { stbir__filter_mitchell, stbir__support_two },+};
+
+stbir__inline static int stbir__use_upsampling(float ratio)
+{+ return ratio > 1;
+}
+
+stbir__inline static int stbir__use_width_upsampling(stbir__info* stbir_info)
+{+ return stbir__use_upsampling(stbir_info->horizontal_scale);
+}
+
+stbir__inline static int stbir__use_height_upsampling(stbir__info* stbir_info)
+{+ return stbir__use_upsampling(stbir_info->vertical_scale);
+}
+
+// This is the maximum number of input samples that can affect an output sample
+// with the given filter
+static int stbir__get_filter_pixel_width(stbir_filter filter, float scale)
+{+ STBIR_ASSERT(filter != 0);
+ STBIR_ASSERT(filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
+
+ if (stbir__use_upsampling(scale))
+ return (int)ceil(stbir__filter_info_table[filter].support(1/scale) * 2);
+ else
+ return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2 / scale);
+}
+
+// This is how much to expand buffers to account for filters seeking outside
+// the image boundaries.
+static int stbir__get_filter_pixel_margin(stbir_filter filter, float scale)
+{+ return stbir__get_filter_pixel_width(filter, scale) / 2;
+}
+
+static int stbir__get_coefficient_width(stbir_filter filter, float scale)
+{+ if (stbir__use_upsampling(scale))
+ return (int)ceil(stbir__filter_info_table[filter].support(1 / scale) * 2);
+ else
+ return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2);
+}
+
+static int stbir__get_contributors(float scale, stbir_filter filter, int input_size, int output_size)
+{+ if (stbir__use_upsampling(scale))
+ return output_size;
+ else
+ return (input_size + stbir__get_filter_pixel_margin(filter, scale) * 2);
+}
+
+static int stbir__get_total_horizontal_coefficients(stbir__info* info)
+{+ return info->horizontal_num_contributors
+ * stbir__get_coefficient_width (info->horizontal_filter, info->horizontal_scale);
+}
+
+static int stbir__get_total_vertical_coefficients(stbir__info* info)
+{+ return info->vertical_num_contributors
+ * stbir__get_coefficient_width (info->vertical_filter, info->vertical_scale);
+}
+
+static stbir__contributors* stbir__get_contributor(stbir__contributors* contributors, int n)
+{+ return &contributors[n];
+}
+
+// For perf reasons this code is duplicated in stbir__resample_horizontal_upsample/downsample,
+// if you change it here change it there too.
+static float* stbir__get_coefficient(float* coefficients, stbir_filter filter, float scale, int n, int c)
+{+ int width = stbir__get_coefficient_width(filter, scale);
+ return &coefficients[width*n + c];
+}
+
+static int stbir__edge_wrap_slow(stbir_edge edge, int n, int max)
+{+ switch (edge)
+ {+ case STBIR_EDGE_ZERO:
+ return 0; // we'll decode the wrong pixel here, and then overwrite with 0s later
+
+ case STBIR_EDGE_CLAMP:
+ if (n < 0)
+ return 0;
+
+ if (n >= max)
+ return max - 1;
+
+ return n; // NOTREACHED
+
+ case STBIR_EDGE_REFLECT:
+ {+ if (n < 0)
+ {+ if (n < max)
+ return -n;
+ else
+ return max - 1;
+ }
+
+ if (n >= max)
+ {+ int max2 = max * 2;
+ if (n >= max2)
+ return 0;
+ else
+ return max2 - n - 1;
+ }
+
+ return n; // NOTREACHED
+ }
+
+ case STBIR_EDGE_WRAP:
+ if (n >= 0)
+ return (n % max);
+ else
+ {+ int m = (-n) % max;
+
+ if (m != 0)
+ m = max - m;
+
+ return (m);
+ }
+ // NOTREACHED
+
+ default:
+ STBIR_ASSERT(!"Unimplemented edge type");
+ return 0;
+ }
+}
+
+stbir__inline static int stbir__edge_wrap(stbir_edge edge, int n, int max)
+{+ // avoid per-pixel switch
+ if (n >= 0 && n < max)
+ return n;
+ return stbir__edge_wrap_slow(edge, n, max);
+}
+
+// What input pixels contribute to this output pixel?
+static void stbir__calculate_sample_range_upsample(int n, float out_filter_radius, float scale_ratio, float out_shift, int* in_first_pixel, int* in_last_pixel, float* in_center_of_out)
+{+ float out_pixel_center = (float)n + 0.5f;
+ float out_pixel_influence_lowerbound = out_pixel_center - out_filter_radius;
+ float out_pixel_influence_upperbound = out_pixel_center + out_filter_radius;
+
+ float in_pixel_influence_lowerbound = (out_pixel_influence_lowerbound + out_shift) / scale_ratio;
+ float in_pixel_influence_upperbound = (out_pixel_influence_upperbound + out_shift) / scale_ratio;
+
+ *in_center_of_out = (out_pixel_center + out_shift) / scale_ratio;
+ *in_first_pixel = (int)(floor(in_pixel_influence_lowerbound + 0.5));
+ *in_last_pixel = (int)(floor(in_pixel_influence_upperbound - 0.5));
+}
+
+// What output pixels does this input pixel contribute to?
+static void stbir__calculate_sample_range_downsample(int n, float in_pixels_radius, float scale_ratio, float out_shift, int* out_first_pixel, int* out_last_pixel, float* out_center_of_in)
+{+ float in_pixel_center = (float)n + 0.5f;
+ float in_pixel_influence_lowerbound = in_pixel_center - in_pixels_radius;
+ float in_pixel_influence_upperbound = in_pixel_center + in_pixels_radius;
+
+ float out_pixel_influence_lowerbound = in_pixel_influence_lowerbound * scale_ratio - out_shift;
+ float out_pixel_influence_upperbound = in_pixel_influence_upperbound * scale_ratio - out_shift;
+
+ *out_center_of_in = in_pixel_center * scale_ratio - out_shift;
+ *out_first_pixel = (int)(floor(out_pixel_influence_lowerbound + 0.5));
+ *out_last_pixel = (int)(floor(out_pixel_influence_upperbound - 0.5));
+}
+
+static void stbir__calculate_coefficients_upsample(stbir_filter filter, float scale, int in_first_pixel, int in_last_pixel, float in_center_of_out, stbir__contributors* contributor, float* coefficient_group)
+{+ int i;
+ float total_filter = 0;
+ float filter_scale;
+
+ STBIR_ASSERT(in_last_pixel - in_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(1/scale) * 2)); // Taken directly from stbir__get_coefficient_width() which we can't call because we don't know if we're horizontal or vertical.
+
+ contributor->n0 = in_first_pixel;
+ contributor->n1 = in_last_pixel;
+
+ STBIR_ASSERT(contributor->n1 >= contributor->n0);
+
+ for (i = 0; i <= in_last_pixel - in_first_pixel; i++)
+ {+ float in_pixel_center = (float)(i + in_first_pixel) + 0.5f;
+ coefficient_group[i] = stbir__filter_info_table[filter].kernel(in_center_of_out - in_pixel_center, 1 / scale);
+
+ // If the coefficient is zero, skip it. (Don't do the <0 check here, we want the influence of those outside pixels.)
+ if (i == 0 && !coefficient_group[i])
+ {+ contributor->n0 = ++in_first_pixel;
+ i--;
+ continue;
+ }
+
+ total_filter += coefficient_group[i];
+ }
+
+ STBIR_ASSERT(stbir__filter_info_table[filter].kernel((float)(in_last_pixel + 1) + 0.5f - in_center_of_out, 1/scale) == 0);
+
+ STBIR_ASSERT(total_filter > 0.9);
+ STBIR_ASSERT(total_filter < 1.1f); // Make sure it's not way off.
+
+ // Make sure the sum of all coefficients is 1.
+ filter_scale = 1 / total_filter;
+
+ for (i = 0; i <= in_last_pixel - in_first_pixel; i++)
+ coefficient_group[i] *= filter_scale;
+
+ for (i = in_last_pixel - in_first_pixel; i >= 0; i--)
+ {+ if (coefficient_group[i])
+ break;
+
+ // This line has no weight. We can skip it.
+ contributor->n1 = contributor->n0 + i - 1;
+ }
+}
+
+static void stbir__calculate_coefficients_downsample(stbir_filter filter, float scale_ratio, int out_first_pixel, int out_last_pixel, float out_center_of_in, stbir__contributors* contributor, float* coefficient_group)
+{+ int i;
+
+ STBIR_ASSERT(out_last_pixel - out_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(scale_ratio) * 2)); // Taken directly from stbir__get_coefficient_width() which we can't call because we don't know if we're horizontal or vertical.
+
+ contributor->n0 = out_first_pixel;
+ contributor->n1 = out_last_pixel;
+
+ STBIR_ASSERT(contributor->n1 >= contributor->n0);
+
+ for (i = 0; i <= out_last_pixel - out_first_pixel; i++)
+ {+ float out_pixel_center = (float)(i + out_first_pixel) + 0.5f;
+ float x = out_pixel_center - out_center_of_in;
+ coefficient_group[i] = stbir__filter_info_table[filter].kernel(x, scale_ratio) * scale_ratio;
+ }
+
+ STBIR_ASSERT(stbir__filter_info_table[filter].kernel((float)(out_last_pixel + 1) + 0.5f - out_center_of_in, scale_ratio) == 0);
+
+ for (i = out_last_pixel - out_first_pixel; i >= 0; i--)
+ {+ if (coefficient_group[i])
+ break;
+
+ // This line has no weight. We can skip it.
+ contributor->n1 = contributor->n0 + i - 1;
+ }
+}
+
+static void stbir__normalize_downsample_coefficients(stbir__contributors* contributors, float* coefficients, stbir_filter filter, float scale_ratio, int input_size, int output_size)
+{+ int num_contributors = stbir__get_contributors(scale_ratio, filter, input_size, output_size);
+ int num_coefficients = stbir__get_coefficient_width(filter, scale_ratio);
+ int i, j;
+ int skip;
+
+ for (i = 0; i < output_size; i++)
+ {+ float scale;
+ float total = 0;
+
+ for (j = 0; j < num_contributors; j++)
+ {+ if (i >= contributors[j].n0 && i <= contributors[j].n1)
+ {+ float coefficient = *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i - contributors[j].n0);
+ total += coefficient;
+ }
+ else if (i < contributors[j].n0)
+ break;
+ }
+
+ STBIR_ASSERT(total > 0.9f);
+ STBIR_ASSERT(total < 1.1f);
+
+ scale = 1 / total;
+
+ for (j = 0; j < num_contributors; j++)
+ {+ if (i >= contributors[j].n0 && i <= contributors[j].n1)
+ *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i - contributors[j].n0) *= scale;
+ else if (i < contributors[j].n0)
+ break;
+ }
+ }
+
+ // Optimize: Skip zero coefficients and contributions outside of image bounds.
+ // Do this after normalizing because normalization depends on the n0/n1 values.
+ for (j = 0; j < num_contributors; j++)
+ {+ int range, max, width;
+
+ skip = 0;
+ while (*stbir__get_coefficient(coefficients, filter, scale_ratio, j, skip) == 0)
+ skip++;
+
+ contributors[j].n0 += skip;
+
+ while (contributors[j].n0 < 0)
+ {+ contributors[j].n0++;
+ skip++;
+ }
+
+ range = contributors[j].n1 - contributors[j].n0 + 1;
+ max = stbir__min(num_coefficients, range);
+
+ width = stbir__get_coefficient_width(filter, scale_ratio);
+ for (i = 0; i < max; i++)
+ {+ if (i + skip >= width)
+ break;
+
+ *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i) = *stbir__get_coefficient(coefficients, filter, scale_ratio, j, i + skip);
+ }
+
+ continue;
+ }
+
+ // Using min to avoid writing into invalid pixels.
+ for (i = 0; i < num_contributors; i++)
+ contributors[i].n1 = stbir__min(contributors[i].n1, output_size - 1);
+}
+
+// Each scan line uses the same kernel values so we should calculate the kernel
+// values once and then we can use them for every scan line.
+static void stbir__calculate_filters(stbir__contributors* contributors, float* coefficients, stbir_filter filter, float scale_ratio, float shift, int input_size, int output_size)
+{+ int n;
+ int total_contributors = stbir__get_contributors(scale_ratio, filter, input_size, output_size);
+
+ if (stbir__use_upsampling(scale_ratio))
+ {+ float out_pixels_radius = stbir__filter_info_table[filter].support(1 / scale_ratio) * scale_ratio;
+
+ // Looping through out pixels
+ for (n = 0; n < total_contributors; n++)
+ {+ float in_center_of_out; // Center of the current out pixel in the in pixel space
+ int in_first_pixel, in_last_pixel;
+
+ stbir__calculate_sample_range_upsample(n, out_pixels_radius, scale_ratio, shift, &in_first_pixel, &in_last_pixel, &in_center_of_out);
+
+ stbir__calculate_coefficients_upsample(filter, scale_ratio, in_first_pixel, in_last_pixel, in_center_of_out, stbir__get_contributor(contributors, n), stbir__get_coefficient(coefficients, filter, scale_ratio, n, 0));
+ }
+ }
+ else
+ {+ float in_pixels_radius = stbir__filter_info_table[filter].support(scale_ratio) / scale_ratio;
+
+ // Looping through in pixels
+ for (n = 0; n < total_contributors; n++)
+ {+ float out_center_of_in; // Center of the current out pixel in the in pixel space
+ int out_first_pixel, out_last_pixel;
+ int n_adjusted = n - stbir__get_filter_pixel_margin(filter, scale_ratio);
+
+ stbir__calculate_sample_range_downsample(n_adjusted, in_pixels_radius, scale_ratio, shift, &out_first_pixel, &out_last_pixel, &out_center_of_in);
+
+ stbir__calculate_coefficients_downsample(filter, scale_ratio, out_first_pixel, out_last_pixel, out_center_of_in, stbir__get_contributor(contributors, n), stbir__get_coefficient(coefficients, filter, scale_ratio, n, 0));
+ }
+
+ stbir__normalize_downsample_coefficients(contributors, coefficients, filter, scale_ratio, input_size, output_size);
+ }
+}
+
+static float* stbir__get_decode_buffer(stbir__info* stbir_info)
+{+ // The 0 index of the decode buffer starts after the margin. This makes
+ // it okay to use negative indexes on the decode buffer.
+ return &stbir_info->decode_buffer[stbir_info->horizontal_filter_pixel_margin * stbir_info->channels];
+}
+
+#define STBIR__DECODE(type, colorspace) ((int)(type) * (STBIR_MAX_COLORSPACES) + (int)(colorspace))
+
+static void stbir__decode_scanline(stbir__info* stbir_info, int n)
+{+ int c;
+ int channels = stbir_info->channels;
+ int alpha_channel = stbir_info->alpha_channel;
+ int type = stbir_info->type;
+ int colorspace = stbir_info->colorspace;
+ int input_w = stbir_info->input_w;
+ size_t input_stride_bytes = stbir_info->input_stride_bytes;
+ float* decode_buffer = stbir__get_decode_buffer(stbir_info);
+ stbir_edge edge_horizontal = stbir_info->edge_horizontal;
+ stbir_edge edge_vertical = stbir_info->edge_vertical;
+ size_t in_buffer_row_offset = stbir__edge_wrap(edge_vertical, n, stbir_info->input_h) * input_stride_bytes;
+ const void* input_data = (char *) stbir_info->input_data + in_buffer_row_offset;
+ int max_x = input_w + stbir_info->horizontal_filter_pixel_margin;
+ int decode = STBIR__DECODE(type, colorspace);
+
+ int x = -stbir_info->horizontal_filter_pixel_margin;
+
+ // special handling for STBIR_EDGE_ZERO because it needs to return an item that doesn't appear in the input,
+ // and we want to avoid paying overhead on every pixel if not STBIR_EDGE_ZERO
+ if (edge_vertical == STBIR_EDGE_ZERO && (n < 0 || n >= stbir_info->input_h))
+ {+ for (; x < max_x; x++)
+ for (c = 0; c < channels; c++)
+ decode_buffer[x*channels + c] = 0;
+ return;
+ }
+
+ switch (decode)
+ {+ case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
+ for (; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+ int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
+ for (c = 0; c < channels; c++)
+ decode_buffer[decode_pixel_index + c] = ((float)((const unsigned char*)input_data)[input_pixel_index + c]) / stbir__max_uint8_as_float;
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
+ for (; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+ int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
+ for (c = 0; c < channels; c++)
+ decode_buffer[decode_pixel_index + c] = stbir__srgb_uchar_to_linear_float[((const unsigned char*)input_data)[input_pixel_index + c]];
+
+ if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned char*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint8_as_float;
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
+ for (; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+ int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
+ for (c = 0; c < channels; c++)
+ decode_buffer[decode_pixel_index + c] = ((float)((const unsigned short*)input_data)[input_pixel_index + c]) / stbir__max_uint16_as_float;
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
+ for (; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+ int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
+ for (c = 0; c < channels; c++)
+ decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear(((float)((const unsigned short*)input_data)[input_pixel_index + c]) / stbir__max_uint16_as_float);
+
+ if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned short*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint16_as_float;
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
+ for (; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+ int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
+ for (c = 0; c < channels; c++)
+ decode_buffer[decode_pixel_index + c] = (float)(((double)((const unsigned int*)input_data)[input_pixel_index + c]) / stbir__max_uint32_as_float);
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
+ for (; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+ int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
+ for (c = 0; c < channels; c++)
+ decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear((float)(((double)((const unsigned int*)input_data)[input_pixel_index + c]) / stbir__max_uint32_as_float));
+
+ if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ decode_buffer[decode_pixel_index + alpha_channel] = (float)(((double)((const unsigned int*)input_data)[input_pixel_index + alpha_channel]) / stbir__max_uint32_as_float);
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
+ for (; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+ int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
+ for (c = 0; c < channels; c++)
+ decode_buffer[decode_pixel_index + c] = ((const float*)input_data)[input_pixel_index + c];
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
+ for (; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+ int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
+ for (c = 0; c < channels; c++)
+ decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear(((const float*)input_data)[input_pixel_index + c]);
+
+ if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ decode_buffer[decode_pixel_index + alpha_channel] = ((const float*)input_data)[input_pixel_index + alpha_channel];
+ }
+
+ break;
+
+ default:
+ STBIR_ASSERT(!"Unknown type/colorspace/channels combination.");
+ break;
+ }
+
+ if (!(stbir_info->flags & STBIR_FLAG_ALPHA_PREMULTIPLIED))
+ {+ for (x = -stbir_info->horizontal_filter_pixel_margin; x < max_x; x++)
+ {+ int decode_pixel_index = x * channels;
+
+ // If the alpha value is 0 it will clobber the color values. Make sure it's not.
+ float alpha = decode_buffer[decode_pixel_index + alpha_channel];
+#ifndef STBIR_NO_ALPHA_EPSILON
+ if (stbir_info->type != STBIR_TYPE_FLOAT) {+ alpha += STBIR_ALPHA_EPSILON;
+ decode_buffer[decode_pixel_index + alpha_channel] = alpha;
+ }
+#endif
+ for (c = 0; c < channels; c++)
+ {+ if (c == alpha_channel)
+ continue;
+
+ decode_buffer[decode_pixel_index + c] *= alpha;
+ }
+ }
+ }
+
+ if (edge_horizontal == STBIR_EDGE_ZERO)
+ {+ for (x = -stbir_info->horizontal_filter_pixel_margin; x < 0; x++)
+ {+ for (c = 0; c < channels; c++)
+ decode_buffer[x*channels + c] = 0;
+ }
+ for (x = input_w; x < max_x; x++)
+ {+ for (c = 0; c < channels; c++)
+ decode_buffer[x*channels + c] = 0;
+ }
+ }
+}
+
+static float* stbir__get_ring_buffer_entry(float* ring_buffer, int index, int ring_buffer_length)
+{+ return &ring_buffer[index * ring_buffer_length];
+}
+
+static float* stbir__add_empty_ring_buffer_entry(stbir__info* stbir_info, int n)
+{+ int ring_buffer_index;
+ float* ring_buffer;
+
+ stbir_info->ring_buffer_last_scanline = n;
+
+ if (stbir_info->ring_buffer_begin_index < 0)
+ {+ ring_buffer_index = stbir_info->ring_buffer_begin_index = 0;
+ stbir_info->ring_buffer_first_scanline = n;
+ }
+ else
+ {+ ring_buffer_index = (stbir_info->ring_buffer_begin_index + (stbir_info->ring_buffer_last_scanline - stbir_info->ring_buffer_first_scanline)) % stbir_info->ring_buffer_num_entries;
+ STBIR_ASSERT(ring_buffer_index != stbir_info->ring_buffer_begin_index);
+ }
+
+ ring_buffer = stbir__get_ring_buffer_entry(stbir_info->ring_buffer, ring_buffer_index, stbir_info->ring_buffer_length_bytes / sizeof(float));
+ memset(ring_buffer, 0, stbir_info->ring_buffer_length_bytes);
+
+ return ring_buffer;
+}
+
+
+static void stbir__resample_horizontal_upsample(stbir__info* stbir_info, float* output_buffer)
+{+ int x, k;
+ int output_w = stbir_info->output_w;
+ int channels = stbir_info->channels;
+ float* decode_buffer = stbir__get_decode_buffer(stbir_info);
+ stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors;
+ float* horizontal_coefficients = stbir_info->horizontal_coefficients;
+ int coefficient_width = stbir_info->horizontal_coefficient_width;
+
+ for (x = 0; x < output_w; x++)
+ {+ int n0 = horizontal_contributors[x].n0;
+ int n1 = horizontal_contributors[x].n1;
+
+ int out_pixel_index = x * channels;
+ int coefficient_group = coefficient_width * x;
+ int coefficient_counter = 0;
+
+ STBIR_ASSERT(n1 >= n0);
+ STBIR_ASSERT(n0 >= -stbir_info->horizontal_filter_pixel_margin);
+ STBIR_ASSERT(n1 >= -stbir_info->horizontal_filter_pixel_margin);
+ STBIR_ASSERT(n0 < stbir_info->input_w + stbir_info->horizontal_filter_pixel_margin);
+ STBIR_ASSERT(n1 < stbir_info->input_w + stbir_info->horizontal_filter_pixel_margin);
+
+ switch (channels) {+ case 1:
+ for (k = n0; k <= n1; k++)
+ {+ int in_pixel_index = k * 1;
+ float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
+ STBIR_ASSERT(coefficient != 0);
+ output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
+ }
+ break;
+ case 2:
+ for (k = n0; k <= n1; k++)
+ {+ int in_pixel_index = k * 2;
+ float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
+ STBIR_ASSERT(coefficient != 0);
+ output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
+ output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
+ }
+ break;
+ case 3:
+ for (k = n0; k <= n1; k++)
+ {+ int in_pixel_index = k * 3;
+ float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
+ STBIR_ASSERT(coefficient != 0);
+ output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
+ output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
+ output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
+ }
+ break;
+ case 4:
+ for (k = n0; k <= n1; k++)
+ {+ int in_pixel_index = k * 4;
+ float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
+ STBIR_ASSERT(coefficient != 0);
+ output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
+ output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
+ output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
+ output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient;
+ }
+ break;
+ default:
+ for (k = n0; k <= n1; k++)
+ {+ int in_pixel_index = k * channels;
+ float coefficient = horizontal_coefficients[coefficient_group + coefficient_counter++];
+ int c;
+ STBIR_ASSERT(coefficient != 0);
+ for (c = 0; c < channels; c++)
+ output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
+ }
+ break;
+ }
+ }
+}
+
+static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, float* output_buffer)
+{+ int x, k;
+ int input_w = stbir_info->input_w;
+ int channels = stbir_info->channels;
+ float* decode_buffer = stbir__get_decode_buffer(stbir_info);
+ stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors;
+ float* horizontal_coefficients = stbir_info->horizontal_coefficients;
+ int coefficient_width = stbir_info->horizontal_coefficient_width;
+ int filter_pixel_margin = stbir_info->horizontal_filter_pixel_margin;
+ int max_x = input_w + filter_pixel_margin * 2;
+
+ STBIR_ASSERT(!stbir__use_width_upsampling(stbir_info));
+
+ switch (channels) {+ case 1:
+ for (x = 0; x < max_x; x++)
+ {+ int n0 = horizontal_contributors[x].n0;
+ int n1 = horizontal_contributors[x].n1;
+
+ int in_x = x - filter_pixel_margin;
+ int in_pixel_index = in_x * 1;
+ int max_n = n1;
+ int coefficient_group = coefficient_width * x;
+
+ for (k = n0; k <= max_n; k++)
+ {+ int out_pixel_index = k * 1;
+ float coefficient = horizontal_coefficients[coefficient_group + k - n0];
+ STBIR_ASSERT(coefficient != 0);
+ output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
+ }
+ }
+ break;
+
+ case 2:
+ for (x = 0; x < max_x; x++)
+ {+ int n0 = horizontal_contributors[x].n0;
+ int n1 = horizontal_contributors[x].n1;
+
+ int in_x = x - filter_pixel_margin;
+ int in_pixel_index = in_x * 2;
+ int max_n = n1;
+ int coefficient_group = coefficient_width * x;
+
+ for (k = n0; k <= max_n; k++)
+ {+ int out_pixel_index = k * 2;
+ float coefficient = horizontal_coefficients[coefficient_group + k - n0];
+ STBIR_ASSERT(coefficient != 0);
+ output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
+ output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
+ }
+ }
+ break;
+
+ case 3:
+ for (x = 0; x < max_x; x++)
+ {+ int n0 = horizontal_contributors[x].n0;
+ int n1 = horizontal_contributors[x].n1;
+
+ int in_x = x - filter_pixel_margin;
+ int in_pixel_index = in_x * 3;
+ int max_n = n1;
+ int coefficient_group = coefficient_width * x;
+
+ for (k = n0; k <= max_n; k++)
+ {+ int out_pixel_index = k * 3;
+ float coefficient = horizontal_coefficients[coefficient_group + k - n0];
+ STBIR_ASSERT(coefficient != 0);
+ output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
+ output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
+ output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
+ }
+ }
+ break;
+
+ case 4:
+ for (x = 0; x < max_x; x++)
+ {+ int n0 = horizontal_contributors[x].n0;
+ int n1 = horizontal_contributors[x].n1;
+
+ int in_x = x - filter_pixel_margin;
+ int in_pixel_index = in_x * 4;
+ int max_n = n1;
+ int coefficient_group = coefficient_width * x;
+
+ for (k = n0; k <= max_n; k++)
+ {+ int out_pixel_index = k * 4;
+ float coefficient = horizontal_coefficients[coefficient_group + k - n0];
+ STBIR_ASSERT(coefficient != 0);
+ output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
+ output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
+ output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
+ output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient;
+ }
+ }
+ break;
+
+ default:
+ for (x = 0; x < max_x; x++)
+ {+ int n0 = horizontal_contributors[x].n0;
+ int n1 = horizontal_contributors[x].n1;
+
+ int in_x = x - filter_pixel_margin;
+ int in_pixel_index = in_x * channels;
+ int max_n = n1;
+ int coefficient_group = coefficient_width * x;
+
+ for (k = n0; k <= max_n; k++)
+ {+ int c;
+ int out_pixel_index = k * channels;
+ float coefficient = horizontal_coefficients[coefficient_group + k - n0];
+ STBIR_ASSERT(coefficient != 0);
+ for (c = 0; c < channels; c++)
+ output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
+ }
+ }
+ break;
+ }
+}
+
+static void stbir__decode_and_resample_upsample(stbir__info* stbir_info, int n)
+{+ // Decode the nth scanline from the source image into the decode buffer.
+ stbir__decode_scanline(stbir_info, n);
+
+ // Now resample it into the ring buffer.
+ if (stbir__use_width_upsampling(stbir_info))
+ stbir__resample_horizontal_upsample(stbir_info, stbir__add_empty_ring_buffer_entry(stbir_info, n));
+ else
+ stbir__resample_horizontal_downsample(stbir_info, stbir__add_empty_ring_buffer_entry(stbir_info, n));
+
+ // Now it's sitting in the ring buffer ready to be used as source for the vertical sampling.
+}
+
+static void stbir__decode_and_resample_downsample(stbir__info* stbir_info, int n)
+{+ // Decode the nth scanline from the source image into the decode buffer.
+ stbir__decode_scanline(stbir_info, n);
+
+ memset(stbir_info->horizontal_buffer, 0, stbir_info->output_w * stbir_info->channels * sizeof(float));
+
+ // Now resample it into the horizontal buffer.
+ if (stbir__use_width_upsampling(stbir_info))
+ stbir__resample_horizontal_upsample(stbir_info, stbir_info->horizontal_buffer);
+ else
+ stbir__resample_horizontal_downsample(stbir_info, stbir_info->horizontal_buffer);
+
+ // Now it's sitting in the horizontal buffer ready to be distributed into the ring buffers.
+}
+
+// Get the specified scan line from the ring buffer.
+static float* stbir__get_ring_buffer_scanline(int get_scanline, float* ring_buffer, int begin_index, int first_scanline, int ring_buffer_num_entries, int ring_buffer_length)
+{+ int ring_buffer_index = (begin_index + (get_scanline - first_scanline)) % ring_buffer_num_entries;
+ return stbir__get_ring_buffer_entry(ring_buffer, ring_buffer_index, ring_buffer_length);
+}
+
+
+static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void *output_buffer, float *encode_buffer, int channels, int alpha_channel, int decode)
+{+ int x;
+ int n;
+ int num_nonalpha;
+ stbir_uint16 nonalpha[STBIR_MAX_CHANNELS];
+
+ if (!(stbir_info->flags&STBIR_FLAG_ALPHA_PREMULTIPLIED))
+ {+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ float alpha = encode_buffer[pixel_index + alpha_channel];
+ float reciprocal_alpha = alpha ? 1.0f / alpha : 0;
+
+ // unrolling this produced a 1% slowdown upscaling a large RGBA linear-space image on my machine - stb
+ for (n = 0; n < channels; n++)
+ if (n != alpha_channel)
+ encode_buffer[pixel_index + n] *= reciprocal_alpha;
+
+ // We added in a small epsilon to prevent the color channel from being deleted with zero alpha.
+ // Because we only add it for integer types, it will automatically be discarded on integer
+ // conversion, so we don't need to subtract it back out (which would be problematic for
+ // numeric precision reasons).
+ }
+ }
+
+ // build a table of all channels that need colorspace correction, so
+ // we don't perform colorspace correction on channels that don't need it.
+ for (x = 0, num_nonalpha = 0; x < channels; ++x)
+ {+ if (x != alpha_channel || (stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ {+ nonalpha[num_nonalpha++] = (stbir_uint16)x;
+ }
+ }
+
+ #define STBIR__ROUND_INT(f) ((int) ((f)+0.5))
+ #define STBIR__ROUND_UINT(f) ((stbir_uint32) ((f)+0.5))
+
+ #ifdef STBIR__SATURATE_INT
+ #define STBIR__ENCODE_LINEAR8(f) stbir__saturate8 (STBIR__ROUND_INT((f) * stbir__max_uint8_as_float ))
+ #define STBIR__ENCODE_LINEAR16(f) stbir__saturate16(STBIR__ROUND_INT((f) * stbir__max_uint16_as_float))
+ #else
+ #define STBIR__ENCODE_LINEAR8(f) (unsigned char ) STBIR__ROUND_INT(stbir__saturate(f) * stbir__max_uint8_as_float )
+ #define STBIR__ENCODE_LINEAR16(f) (unsigned short) STBIR__ROUND_INT(stbir__saturate(f) * stbir__max_uint16_as_float)
+ #endif
+
+ switch (decode)
+ {+ case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ for (n = 0; n < channels; n++)
+ {+ int index = pixel_index + n;
+ ((unsigned char*)output_buffer)[index] = STBIR__ENCODE_LINEAR8(encode_buffer[index]);
+ }
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ for (n = 0; n < num_nonalpha; n++)
+ {+ int index = pixel_index + nonalpha[n];
+ ((unsigned char*)output_buffer)[index] = stbir__linear_to_srgb_uchar(encode_buffer[index]);
+ }
+
+ if (!(stbir_info->flags & STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ ((unsigned char *)output_buffer)[pixel_index + alpha_channel] = STBIR__ENCODE_LINEAR8(encode_buffer[pixel_index+alpha_channel]);
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ for (n = 0; n < channels; n++)
+ {+ int index = pixel_index + n;
+ ((unsigned short*)output_buffer)[index] = STBIR__ENCODE_LINEAR16(encode_buffer[index]);
+ }
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ for (n = 0; n < num_nonalpha; n++)
+ {+ int index = pixel_index + nonalpha[n];
+ ((unsigned short*)output_buffer)[index] = (unsigned short)STBIR__ROUND_INT(stbir__linear_to_srgb(stbir__saturate(encode_buffer[index])) * stbir__max_uint16_as_float);
+ }
+
+ if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ ((unsigned short*)output_buffer)[pixel_index + alpha_channel] = STBIR__ENCODE_LINEAR16(encode_buffer[pixel_index + alpha_channel]);
+ }
+
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ for (n = 0; n < channels; n++)
+ {+ int index = pixel_index + n;
+ ((unsigned int*)output_buffer)[index] = (unsigned int)STBIR__ROUND_UINT(((double)stbir__saturate(encode_buffer[index])) * stbir__max_uint32_as_float);
+ }
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ for (n = 0; n < num_nonalpha; n++)
+ {+ int index = pixel_index + nonalpha[n];
+ ((unsigned int*)output_buffer)[index] = (unsigned int)STBIR__ROUND_UINT(((double)stbir__linear_to_srgb(stbir__saturate(encode_buffer[index]))) * stbir__max_uint32_as_float);
+ }
+
+ if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ ((unsigned int*)output_buffer)[pixel_index + alpha_channel] = (unsigned int)STBIR__ROUND_INT(((double)stbir__saturate(encode_buffer[pixel_index + alpha_channel])) * stbir__max_uint32_as_float);
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ for (n = 0; n < channels; n++)
+ {+ int index = pixel_index + n;
+ ((float*)output_buffer)[index] = encode_buffer[index];
+ }
+ }
+ break;
+
+ case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
+ for (x=0; x < num_pixels; ++x)
+ {+ int pixel_index = x*channels;
+
+ for (n = 0; n < num_nonalpha; n++)
+ {+ int index = pixel_index + nonalpha[n];
+ ((float*)output_buffer)[index] = stbir__linear_to_srgb(encode_buffer[index]);
+ }
+
+ if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
+ ((float*)output_buffer)[pixel_index + alpha_channel] = encode_buffer[pixel_index + alpha_channel];
+ }
+ break;
+
+ default:
+ STBIR_ASSERT(!"Unknown type/colorspace/channels combination.");
+ break;
+ }
+}
+
+static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n)
+{+ int x, k;
+ int output_w = stbir_info->output_w;
+ stbir__contributors* vertical_contributors = stbir_info->vertical_contributors;
+ float* vertical_coefficients = stbir_info->vertical_coefficients;
+ int channels = stbir_info->channels;
+ int alpha_channel = stbir_info->alpha_channel;
+ int type = stbir_info->type;
+ int colorspace = stbir_info->colorspace;
+ int ring_buffer_entries = stbir_info->ring_buffer_num_entries;
+ void* output_data = stbir_info->output_data;
+ float* encode_buffer = stbir_info->encode_buffer;
+ int decode = STBIR__DECODE(type, colorspace);
+ int coefficient_width = stbir_info->vertical_coefficient_width;
+ int coefficient_counter;
+ int contributor = n;
+
+ float* ring_buffer = stbir_info->ring_buffer;
+ int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index;
+ int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline;
+ int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
+
+ int n0,n1, output_row_start;
+ int coefficient_group = coefficient_width * contributor;
+
+ n0 = vertical_contributors[contributor].n0;
+ n1 = vertical_contributors[contributor].n1;
+
+ output_row_start = n * stbir_info->output_stride_bytes;
+
+ STBIR_ASSERT(stbir__use_height_upsampling(stbir_info));
+
+ memset(encode_buffer, 0, output_w * sizeof(float) * channels);
+
+ // I tried reblocking this for better cache usage of encode_buffer
+ // (using x_outer, k, x_inner), but it lost speed. -- stb
+
+ coefficient_counter = 0;
+ switch (channels) {+ case 1:
+ for (k = n0; k <= n1; k++)
+ {+ int coefficient_index = coefficient_counter++;
+ float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
+ float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
+ for (x = 0; x < output_w; ++x)
+ {+ int in_pixel_index = x * 1;
+ encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
+ }
+ }
+ break;
+ case 2:
+ for (k = n0; k <= n1; k++)
+ {+ int coefficient_index = coefficient_counter++;
+ float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
+ float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
+ for (x = 0; x < output_w; ++x)
+ {+ int in_pixel_index = x * 2;
+ encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
+ encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
+ }
+ }
+ break;
+ case 3:
+ for (k = n0; k <= n1; k++)
+ {+ int coefficient_index = coefficient_counter++;
+ float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
+ float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
+ for (x = 0; x < output_w; ++x)
+ {+ int in_pixel_index = x * 3;
+ encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
+ encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
+ encode_buffer[in_pixel_index + 2] += ring_buffer_entry[in_pixel_index + 2] * coefficient;
+ }
+ }
+ break;
+ case 4:
+ for (k = n0; k <= n1; k++)
+ {+ int coefficient_index = coefficient_counter++;
+ float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
+ float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
+ for (x = 0; x < output_w; ++x)
+ {+ int in_pixel_index = x * 4;
+ encode_buffer[in_pixel_index + 0] += ring_buffer_entry[in_pixel_index + 0] * coefficient;
+ encode_buffer[in_pixel_index + 1] += ring_buffer_entry[in_pixel_index + 1] * coefficient;
+ encode_buffer[in_pixel_index + 2] += ring_buffer_entry[in_pixel_index + 2] * coefficient;
+ encode_buffer[in_pixel_index + 3] += ring_buffer_entry[in_pixel_index + 3] * coefficient;
+ }
+ }
+ break;
+ default:
+ for (k = n0; k <= n1; k++)
+ {+ int coefficient_index = coefficient_counter++;
+ float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
+ float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
+ for (x = 0; x < output_w; ++x)
+ {+ int in_pixel_index = x * channels;
+ int c;
+ for (c = 0; c < channels; c++)
+ encode_buffer[in_pixel_index + c] += ring_buffer_entry[in_pixel_index + c] * coefficient;
+ }
+ }
+ break;
+ }
+ stbir__encode_scanline(stbir_info, output_w, (char *) output_data + output_row_start, encode_buffer, channels, alpha_channel, decode);
+}
+
+static void stbir__resample_vertical_downsample(stbir__info* stbir_info, int n)
+{+ int x, k;
+ int output_w = stbir_info->output_w;
+ stbir__contributors* vertical_contributors = stbir_info->vertical_contributors;
+ float* vertical_coefficients = stbir_info->vertical_coefficients;
+ int channels = stbir_info->channels;
+ int ring_buffer_entries = stbir_info->ring_buffer_num_entries;
+ float* horizontal_buffer = stbir_info->horizontal_buffer;
+ int coefficient_width = stbir_info->vertical_coefficient_width;
+ int contributor = n + stbir_info->vertical_filter_pixel_margin;
+
+ float* ring_buffer = stbir_info->ring_buffer;
+ int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index;
+ int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline;
+ int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
+ int n0,n1;
+
+ n0 = vertical_contributors[contributor].n0;
+ n1 = vertical_contributors[contributor].n1;
+
+ STBIR_ASSERT(!stbir__use_height_upsampling(stbir_info));
+
+ for (k = n0; k <= n1; k++)
+ {+ int coefficient_index = k - n0;
+ int coefficient_group = coefficient_width * contributor;
+ float coefficient = vertical_coefficients[coefficient_group + coefficient_index];
+
+ float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length);
+
+ switch (channels) {+ case 1:
+ for (x = 0; x < output_w; x++)
+ {+ int in_pixel_index = x * 1;
+ ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
+ }
+ break;
+ case 2:
+ for (x = 0; x < output_w; x++)
+ {+ int in_pixel_index = x * 2;
+ ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
+ ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
+ }
+ break;
+ case 3:
+ for (x = 0; x < output_w; x++)
+ {+ int in_pixel_index = x * 3;
+ ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
+ ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
+ ring_buffer_entry[in_pixel_index + 2] += horizontal_buffer[in_pixel_index + 2] * coefficient;
+ }
+ break;
+ case 4:
+ for (x = 0; x < output_w; x++)
+ {+ int in_pixel_index = x * 4;
+ ring_buffer_entry[in_pixel_index + 0] += horizontal_buffer[in_pixel_index + 0] * coefficient;
+ ring_buffer_entry[in_pixel_index + 1] += horizontal_buffer[in_pixel_index + 1] * coefficient;
+ ring_buffer_entry[in_pixel_index + 2] += horizontal_buffer[in_pixel_index + 2] * coefficient;
+ ring_buffer_entry[in_pixel_index + 3] += horizontal_buffer[in_pixel_index + 3] * coefficient;
+ }
+ break;
+ default:
+ for (x = 0; x < output_w; x++)
+ {+ int in_pixel_index = x * channels;
+
+ int c;
+ for (c = 0; c < channels; c++)
+ ring_buffer_entry[in_pixel_index + c] += horizontal_buffer[in_pixel_index + c] * coefficient;
+ }
+ break;
+ }
+ }
+}
+
+static void stbir__buffer_loop_upsample(stbir__info* stbir_info)
+{+ int y;
+ float scale_ratio = stbir_info->vertical_scale;
+ float out_scanlines_radius = stbir__filter_info_table[stbir_info->vertical_filter].support(1/scale_ratio) * scale_ratio;
+
+ STBIR_ASSERT(stbir__use_height_upsampling(stbir_info));
+
+ for (y = 0; y < stbir_info->output_h; y++)
+ {+ float in_center_of_out = 0; // Center of the current out scanline in the in scanline space
+ int in_first_scanline = 0, in_last_scanline = 0;
+
+ stbir__calculate_sample_range_upsample(y, out_scanlines_radius, scale_ratio, stbir_info->vertical_shift, &in_first_scanline, &in_last_scanline, &in_center_of_out);
+
+ STBIR_ASSERT(in_last_scanline - in_first_scanline + 1 <= stbir_info->ring_buffer_num_entries);
+
+ if (stbir_info->ring_buffer_begin_index >= 0)
+ {+ // Get rid of whatever we don't need anymore.
+ while (in_first_scanline > stbir_info->ring_buffer_first_scanline)
+ {+ if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline)
+ {+ // We just popped the last scanline off the ring buffer.
+ // Reset it to the empty state.
+ stbir_info->ring_buffer_begin_index = -1;
+ stbir_info->ring_buffer_first_scanline = 0;
+ stbir_info->ring_buffer_last_scanline = 0;
+ break;
+ }
+ else
+ {+ stbir_info->ring_buffer_first_scanline++;
+ stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries;
+ }
+ }
+ }
+
+ // Load in new ones.
+ if (stbir_info->ring_buffer_begin_index < 0)
+ stbir__decode_and_resample_upsample(stbir_info, in_first_scanline);
+
+ while (in_last_scanline > stbir_info->ring_buffer_last_scanline)
+ stbir__decode_and_resample_upsample(stbir_info, stbir_info->ring_buffer_last_scanline + 1);
+
+ // Now all buffers should be ready to write a row of vertical sampling.
+ stbir__resample_vertical_upsample(stbir_info, y);
+
+ STBIR_PROGRESS_REPORT((float)y / stbir_info->output_h);
+ }
+}
+
+static void stbir__empty_ring_buffer(stbir__info* stbir_info, int first_necessary_scanline)
+{+ int output_stride_bytes = stbir_info->output_stride_bytes;
+ int channels = stbir_info->channels;
+ int alpha_channel = stbir_info->alpha_channel;
+ int type = stbir_info->type;
+ int colorspace = stbir_info->colorspace;
+ int output_w = stbir_info->output_w;
+ void* output_data = stbir_info->output_data;
+ int decode = STBIR__DECODE(type, colorspace);
+
+ float* ring_buffer = stbir_info->ring_buffer;
+ int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
+
+ if (stbir_info->ring_buffer_begin_index >= 0)
+ {+ // Get rid of whatever we don't need anymore.
+ while (first_necessary_scanline > stbir_info->ring_buffer_first_scanline)
+ {+ if (stbir_info->ring_buffer_first_scanline >= 0 && stbir_info->ring_buffer_first_scanline < stbir_info->output_h)
+ {+ int output_row_start = stbir_info->ring_buffer_first_scanline * output_stride_bytes;
+ float* ring_buffer_entry = stbir__get_ring_buffer_entry(ring_buffer, stbir_info->ring_buffer_begin_index, ring_buffer_length);
+ stbir__encode_scanline(stbir_info, output_w, (char *) output_data + output_row_start, ring_buffer_entry, channels, alpha_channel, decode);
+ STBIR_PROGRESS_REPORT((float)stbir_info->ring_buffer_first_scanline / stbir_info->output_h);
+ }
+
+ if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline)
+ {+ // We just popped the last scanline off the ring buffer.
+ // Reset it to the empty state.
+ stbir_info->ring_buffer_begin_index = -1;
+ stbir_info->ring_buffer_first_scanline = 0;
+ stbir_info->ring_buffer_last_scanline = 0;
+ break;
+ }
+ else
+ {+ stbir_info->ring_buffer_first_scanline++;
+ stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries;
+ }
+ }
+ }
+}
+
+static void stbir__buffer_loop_downsample(stbir__info* stbir_info)
+{+ int y;
+ float scale_ratio = stbir_info->vertical_scale;
+ int output_h = stbir_info->output_h;
+ float in_pixels_radius = stbir__filter_info_table[stbir_info->vertical_filter].support(scale_ratio) / scale_ratio;
+ int pixel_margin = stbir_info->vertical_filter_pixel_margin;
+ int max_y = stbir_info->input_h + pixel_margin;
+
+ STBIR_ASSERT(!stbir__use_height_upsampling(stbir_info));
+
+ for (y = -pixel_margin; y < max_y; y++)
+ {+ float out_center_of_in; // Center of the current out scanline in the in scanline space
+ int out_first_scanline, out_last_scanline;
+
+ stbir__calculate_sample_range_downsample(y, in_pixels_radius, scale_ratio, stbir_info->vertical_shift, &out_first_scanline, &out_last_scanline, &out_center_of_in);
+
+ STBIR_ASSERT(out_last_scanline - out_first_scanline + 1 <= stbir_info->ring_buffer_num_entries);
+
+ if (out_last_scanline < 0 || out_first_scanline >= output_h)
+ continue;
+
+ stbir__empty_ring_buffer(stbir_info, out_first_scanline);
+
+ stbir__decode_and_resample_downsample(stbir_info, y);
+
+ // Load in new ones.
+ if (stbir_info->ring_buffer_begin_index < 0)
+ stbir__add_empty_ring_buffer_entry(stbir_info, out_first_scanline);
+
+ while (out_last_scanline > stbir_info->ring_buffer_last_scanline)
+ stbir__add_empty_ring_buffer_entry(stbir_info, stbir_info->ring_buffer_last_scanline + 1);
+
+ // Now the horizontal buffer is ready to write to all ring buffer rows.
+ stbir__resample_vertical_downsample(stbir_info, y);
+ }
+
+ stbir__empty_ring_buffer(stbir_info, stbir_info->output_h);
+}
+
+static void stbir__setup(stbir__info *info, int input_w, int input_h, int output_w, int output_h, int channels)
+{+ info->input_w = input_w;
+ info->input_h = input_h;
+ info->output_w = output_w;
+ info->output_h = output_h;
+ info->channels = channels;
+}
+
+static void stbir__calculate_transform(stbir__info *info, float s0, float t0, float s1, float t1, float *transform)
+{+ info->s0 = s0;
+ info->t0 = t0;
+ info->s1 = s1;
+ info->t1 = t1;
+
+ if (transform)
+ {+ info->horizontal_scale = transform[0];
+ info->vertical_scale = transform[1];
+ info->horizontal_shift = transform[2];
+ info->vertical_shift = transform[3];
+ }
+ else
+ {+ info->horizontal_scale = ((float)info->output_w / info->input_w) / (s1 - s0);
+ info->vertical_scale = ((float)info->output_h / info->input_h) / (t1 - t0);
+
+ info->horizontal_shift = s0 * info->output_w / (s1 - s0);
+ info->vertical_shift = t0 * info->output_h / (t1 - t0);
+ }
+}
+
+static void stbir__choose_filter(stbir__info *info, stbir_filter h_filter, stbir_filter v_filter)
+{+ if (h_filter == 0)
+ h_filter = stbir__use_upsampling(info->horizontal_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE;
+ if (v_filter == 0)
+ v_filter = stbir__use_upsampling(info->vertical_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE;
+ info->horizontal_filter = h_filter;
+ info->vertical_filter = v_filter;
+}
+
+static stbir_uint32 stbir__calculate_memory(stbir__info *info)
+{+ int pixel_margin = stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale);
+ int filter_height = stbir__get_filter_pixel_width(info->vertical_filter, info->vertical_scale);
+
+ info->horizontal_num_contributors = stbir__get_contributors(info->horizontal_scale, info->horizontal_filter, info->input_w, info->output_w);
+ info->vertical_num_contributors = stbir__get_contributors(info->vertical_scale , info->vertical_filter , info->input_h, info->output_h);
+
+ // One extra entry because floating point precision problems sometimes cause an extra to be necessary.
+ info->ring_buffer_num_entries = filter_height + 1;
+
+ info->horizontal_contributors_size = info->horizontal_num_contributors * sizeof(stbir__contributors);
+ info->horizontal_coefficients_size = stbir__get_total_horizontal_coefficients(info) * sizeof(float);
+ info->vertical_contributors_size = info->vertical_num_contributors * sizeof(stbir__contributors);
+ info->vertical_coefficients_size = stbir__get_total_vertical_coefficients(info) * sizeof(float);
+ info->decode_buffer_size = (info->input_w + pixel_margin * 2) * info->channels * sizeof(float);
+ info->horizontal_buffer_size = info->output_w * info->channels * sizeof(float);
+ info->ring_buffer_size = info->output_w * info->channels * info->ring_buffer_num_entries * sizeof(float);
+ info->encode_buffer_size = info->output_w * info->channels * sizeof(float);
+
+ STBIR_ASSERT(info->horizontal_filter != 0);
+ STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); // this now happens too late
+ STBIR_ASSERT(info->vertical_filter != 0);
+ STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); // this now happens too late
+
+ if (stbir__use_height_upsampling(info))
+ // The horizontal buffer is for when we're downsampling the height and we
+ // can't output the result of sampling the decode buffer directly into the
+ // ring buffers.
+ info->horizontal_buffer_size = 0;
+ else
+ // The encode buffer is to retain precision in the height upsampling method
+ // and isn't used when height downsampling.
+ info->encode_buffer_size = 0;
+
+ return info->horizontal_contributors_size + info->horizontal_coefficients_size
+ + info->vertical_contributors_size + info->vertical_coefficients_size
+ + info->decode_buffer_size + info->horizontal_buffer_size
+ + info->ring_buffer_size + info->encode_buffer_size;
+}
+
+static int stbir__resize_allocated(stbir__info *info,
+ const void* input_data, int input_stride_in_bytes,
+ void* output_data, int output_stride_in_bytes,
+ int alpha_channel, stbir_uint32 flags, stbir_datatype type,
+ stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace,
+ void* tempmem, size_t tempmem_size_in_bytes)
+{+ size_t memory_required = stbir__calculate_memory(info);
+
+ int width_stride_input = input_stride_in_bytes ? input_stride_in_bytes : info->channels * info->input_w * stbir__type_size[type];
+ int width_stride_output = output_stride_in_bytes ? output_stride_in_bytes : info->channels * info->output_w * stbir__type_size[type];
+
+#ifdef STBIR_DEBUG_OVERWRITE_TEST
+#define OVERWRITE_ARRAY_SIZE 8
+ unsigned char overwrite_output_before_pre[OVERWRITE_ARRAY_SIZE];
+ unsigned char overwrite_tempmem_before_pre[OVERWRITE_ARRAY_SIZE];
+ unsigned char overwrite_output_after_pre[OVERWRITE_ARRAY_SIZE];
+ unsigned char overwrite_tempmem_after_pre[OVERWRITE_ARRAY_SIZE];
+
+ size_t begin_forbidden = width_stride_output * (info->output_h - 1) + info->output_w * info->channels * stbir__type_size[type];
+ memcpy(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE);
+ memcpy(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE);
+ memcpy(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE);
+ memcpy(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE);
+#endif
+
+ STBIR_ASSERT(info->channels >= 0);
+ STBIR_ASSERT(info->channels <= STBIR_MAX_CHANNELS);
+
+ if (info->channels < 0 || info->channels > STBIR_MAX_CHANNELS)
+ return 0;
+
+ STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
+ STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
+
+ if (info->horizontal_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table))
+ return 0;
+ if (info->vertical_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table))
+ return 0;
+
+ if (alpha_channel < 0)
+ flags |= STBIR_FLAG_ALPHA_USES_COLORSPACE | STBIR_FLAG_ALPHA_PREMULTIPLIED;
+
+ if (!(flags&STBIR_FLAG_ALPHA_USES_COLORSPACE) || !(flags&STBIR_FLAG_ALPHA_PREMULTIPLIED)) {+ STBIR_ASSERT(alpha_channel >= 0 && alpha_channel < info->channels);
+ }
+
+ if (alpha_channel >= info->channels)
+ return 0;
+
+ STBIR_ASSERT(tempmem);
+
+ if (!tempmem)
+ return 0;
+
+ STBIR_ASSERT(tempmem_size_in_bytes >= memory_required);
+
+ if (tempmem_size_in_bytes < memory_required)
+ return 0;
+
+ memset(tempmem, 0, tempmem_size_in_bytes);
+
+ info->input_data = input_data;
+ info->input_stride_bytes = width_stride_input;
+
+ info->output_data = output_data;
+ info->output_stride_bytes = width_stride_output;
+
+ info->alpha_channel = alpha_channel;
+ info->flags = flags;
+ info->type = type;
+ info->edge_horizontal = edge_horizontal;
+ info->edge_vertical = edge_vertical;
+ info->colorspace = colorspace;
+
+ info->horizontal_coefficient_width = stbir__get_coefficient_width (info->horizontal_filter, info->horizontal_scale);
+ info->vertical_coefficient_width = stbir__get_coefficient_width (info->vertical_filter , info->vertical_scale );
+ info->horizontal_filter_pixel_width = stbir__get_filter_pixel_width (info->horizontal_filter, info->horizontal_scale);
+ info->vertical_filter_pixel_width = stbir__get_filter_pixel_width (info->vertical_filter , info->vertical_scale );
+ info->horizontal_filter_pixel_margin = stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale);
+ info->vertical_filter_pixel_margin = stbir__get_filter_pixel_margin(info->vertical_filter , info->vertical_scale );
+
+ info->ring_buffer_length_bytes = info->output_w * info->channels * sizeof(float);
+ info->decode_buffer_pixels = info->input_w + info->horizontal_filter_pixel_margin * 2;
+
+#define STBIR__NEXT_MEMPTR(current, newtype) (newtype*)(((unsigned char*)current) + current##_size)
+
+ info->horizontal_contributors = (stbir__contributors *) tempmem;
+ info->horizontal_coefficients = STBIR__NEXT_MEMPTR(info->horizontal_contributors, float);
+ info->vertical_contributors = STBIR__NEXT_MEMPTR(info->horizontal_coefficients, stbir__contributors);
+ info->vertical_coefficients = STBIR__NEXT_MEMPTR(info->vertical_contributors, float);
+ info->decode_buffer = STBIR__NEXT_MEMPTR(info->vertical_coefficients, float);
+
+ if (stbir__use_height_upsampling(info))
+ {+ info->horizontal_buffer = NULL;
+ info->ring_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float);
+ info->encode_buffer = STBIR__NEXT_MEMPTR(info->ring_buffer, float);
+
+ STBIR_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->encode_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
+ }
+ else
+ {+ info->horizontal_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float);
+ info->ring_buffer = STBIR__NEXT_MEMPTR(info->horizontal_buffer, float);
+ info->encode_buffer = NULL;
+
+ STBIR_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->ring_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
+ }
+
+#undef STBIR__NEXT_MEMPTR
+
+ // This signals that the ring buffer is empty
+ info->ring_buffer_begin_index = -1;
+
+ stbir__calculate_filters(info->horizontal_contributors, info->horizontal_coefficients, info->horizontal_filter, info->horizontal_scale, info->horizontal_shift, info->input_w, info->output_w);
+ stbir__calculate_filters(info->vertical_contributors, info->vertical_coefficients, info->vertical_filter, info->vertical_scale, info->vertical_shift, info->input_h, info->output_h);
+
+ STBIR_PROGRESS_REPORT(0);
+
+ if (stbir__use_height_upsampling(info))
+ stbir__buffer_loop_upsample(info);
+ else
+ stbir__buffer_loop_downsample(info);
+
+ STBIR_PROGRESS_REPORT(1);
+
+#ifdef STBIR_DEBUG_OVERWRITE_TEST
+ STBIR_ASSERT(memcmp(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0);
+ STBIR_ASSERT(memcmp(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE) == 0);
+ STBIR_ASSERT(memcmp(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0);
+ STBIR_ASSERT(memcmp(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE) == 0);
+#endif
+
+ return 1;
+}
+
+
+static int stbir__resize_arbitrary(
+ void *alloc_context,
+ const void* input_data, int input_w, int input_h, int input_stride_in_bytes,
+ void* output_data, int output_w, int output_h, int output_stride_in_bytes,
+ float s0, float t0, float s1, float t1, float *transform,
+ int channels, int alpha_channel, stbir_uint32 flags, stbir_datatype type,
+ stbir_filter h_filter, stbir_filter v_filter,
+ stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace)
+{+ stbir__info info;
+ int result;
+ size_t memory_required;
+ void* extra_memory;
+
+ stbir__setup(&info, input_w, input_h, output_w, output_h, channels);
+ stbir__calculate_transform(&info, s0,t0,s1,t1,transform);
+ stbir__choose_filter(&info, h_filter, v_filter);
+ memory_required = stbir__calculate_memory(&info);
+ extra_memory = STBIR_MALLOC(memory_required, alloc_context);
+ STBIR__NOTUSED(alloc_context);
+
+ if (!extra_memory)
+ return 0;
+
+ result = stbir__resize_allocated(&info, input_data, input_stride_in_bytes,
+ output_data, output_stride_in_bytes,
+ alpha_channel, flags, type,
+ edge_horizontal, edge_vertical,
+ colorspace, extra_memory, memory_required);
+
+ STBIR_FREE(extra_memory, alloc_context);
+
+ return result;
+}
+
+STBIRDEF int stbir_resize_uint8( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels)
+{+ return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,NULL,num_channels,-1,0, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
+ STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR);
+}
+
+STBIRDEF int stbir_resize_float( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ float *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels)
+{+ return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,NULL,num_channels,-1,0, STBIR_TYPE_FLOAT, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
+ STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR);
+}
+
+STBIRDEF int stbir_resize_uint8_srgb(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags)
+{+ return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
+ STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB);
+}
+
+STBIRDEF int stbir_resize_uint8_srgb_edgemode(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_wrap_mode)
+{+ return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
+ edge_wrap_mode, edge_wrap_mode, STBIR_COLORSPACE_SRGB);
+}
+
+STBIRDEF int stbir_resize_uint8_generic( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
+ void *alloc_context)
+{+ return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, filter, filter,
+ edge_wrap_mode, edge_wrap_mode, space);
+}
+
+STBIRDEF int stbir_resize_uint16_generic(const stbir_uint16 *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ stbir_uint16 *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
+ void *alloc_context)
+{+ return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT16, filter, filter,
+ edge_wrap_mode, edge_wrap_mode, space);
+}
+
+
+STBIRDEF int stbir_resize_float_generic( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ float *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
+ void *alloc_context)
+{+ return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_FLOAT, filter, filter,
+ edge_wrap_mode, edge_wrap_mode, space);
+}
+
+
+STBIRDEF int stbir_resize( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ stbir_datatype datatype,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
+ stbir_filter filter_horizontal, stbir_filter filter_vertical,
+ stbir_colorspace space, void *alloc_context)
+{+ return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,NULL,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
+ edge_mode_horizontal, edge_mode_vertical, space);
+}
+
+
+STBIRDEF int stbir_resize_subpixel(const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ stbir_datatype datatype,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
+ stbir_filter filter_horizontal, stbir_filter filter_vertical,
+ stbir_colorspace space, void *alloc_context,
+ float x_scale, float y_scale,
+ float x_offset, float y_offset)
+{+ float transform[4];
+ transform[0] = x_scale;
+ transform[1] = y_scale;
+ transform[2] = x_offset;
+ transform[3] = y_offset;
+ return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ 0,0,1,1,transform,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
+ edge_mode_horizontal, edge_mode_vertical, space);
+}
+
+STBIRDEF int stbir_resize_region( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
+ void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
+ stbir_datatype datatype,
+ int num_channels, int alpha_channel, int flags,
+ stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
+ stbir_filter filter_horizontal, stbir_filter filter_vertical,
+ stbir_colorspace space, void *alloc_context,
+ float s0, float t0, float s1, float t1)
+{+ return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
+ output_pixels, output_w, output_h, output_stride_in_bytes,
+ s0,t0,s1,t1,NULL,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
+ edge_mode_horizontal, edge_mode_vertical, space);
+}
+
+#endif // STB_IMAGE_RESIZE_IMPLEMENTATION
+
+/*
+------------------------------------------------------------------------------
+This software is available under 2 licenses -- choose whichever you prefer.
+------------------------------------------------------------------------------
+ALTERNATIVE A - MIT License
+Copyright (c) 2017 Sean Barrett
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+------------------------------------------------------------------------------
+ALTERNATIVE B - Public Domain (www.unlicense.org)
+This is free and unencumbered software released into the public domain.
+Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
+software, either in source code form or as a compiled binary, for any purpose,
+commercial or non-commercial, and by any means.
+In jurisdictions that recognize copyright laws, the author or authors of this
+software dedicate any and all copyright interest in the software to the public
+domain. We make this dedication for the benefit of the public at large and to
+the detriment of our heirs and successors. We intend this dedication to be an
+overt act of relinquishment in perpetuity of all present and future rights to
+this software under copyright law.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+------------------------------------------------------------------------------
+*/