ref: 35b21c71e5d9513a7c29ad4fc3efbbb0546a6e6a
parent: 36ee71714f5f84876cd3e9b479dbbd72a5124412
author: Werner Lemberg <wl@gnu.org>
date: Tue Jun 8 05:06:39 EDT 2021
[sdf] Make `make multi` work. * src/sdf/ftsdf.c: Include `ftbitmap.h`. * src/sdf/ftsdfcommon.h: Move function bodies to `ftsdfcommon.c`. Include `ftobjs.h` to get definitions of `FT_LOCAL` and friends. * src/sdf/ftsdfcommon.c: New file. * src/sdf/rules.mk, src/sdf/sdf.c: Updated.
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2021-06-08 Werner Lemberg <wl@gnu.org>
+
+ [sdf] Make `make multi` work.
+
+ * src/sdf/ftsdf.c: Include `ftbitmap.h`.
+
+ * src/sdf/ftsdfcommon.h: Move function bodies to `ftsdfcommon.c`.
+ Include `ftobjs.h` to get definitions of `FT_LOCAL` and friends.
+
+ * src/sdf/ftsdfcommon.c: New file.
+
+ * src/sdf/rules.mk, src/sdf/sdf.c: Updated.
+
2021-06-08 Anuj Verma <anujv@iitbhilai.ac.in>
[sdf] Use 8 bits for final SDF output instead of 16bits.
--- a/src/sdf/ftsdf.c
+++ b/src/sdf/ftsdf.c
@@ -22,6 +22,7 @@
#include <freetype/internal/ftdebug.h>
#include <freetype/ftoutln.h>
#include <freetype/fttrigon.h>
+#include <freetype/ftbitmap.h>
#include "ftsdf.h"
#include "ftsdferrs.h"
--- /dev/null
+++ b/src/sdf/ftsdfcommon.c
@@ -1,0 +1,147 @@
+/****************************************************************************
+ *
+ * ftsdfcommon.c
+ *
+ * Auxiliary data for Signed Distance Field support (body).
+ *
+ * Copyright (C) 2020-2021 by
+ * David Turner, Robert Wilhelm, and Werner Lemberg.
+ *
+ * Written by Anuj Verma.
+ *
+ * This file is part of the FreeType project, and may only be used,
+ * modified, and distributed under the terms of the FreeType project
+ * license, LICENSE.TXT. By continuing to use, modify, or distribute
+ * this file you indicate that you have read the license and
+ * understand and accept it fully.
+ *
+ */
+
+
+#include <ftsdf.h>
+#include <ftsdfcommon.h>
+
+
+ /**************************************************************************
+ *
+ * common functions
+ *
+ */
+
+ /*
+ * Original algorithm:
+ *
+ * https://github.com/chmike/fpsqrt
+ *
+ * Use this to compute the square root of a 16.16 fixed point number.
+ */
+ FT_LOCAL_DEF( FT_16D16 )
+ square_root( FT_16D16 val )
+ {+ FT_ULong t, q, b, r;
+
+
+ r = (FT_ULong)val;
+ b = 0x40000000L;
+ q = 0;
+
+ while ( b > 0x40L )
+ {+ t = q + b;
+
+ if ( r >= t )
+ {+ r -= t;
+ q = t + b;
+ }
+
+ r <<= 1;
+ b >>= 1;
+ }
+
+ q >>= 8;
+
+ return (FT_16D16)q;
+ }
+
+
+ /**************************************************************************
+ *
+ * format and sign manipulating functions
+ *
+ */
+
+ /*
+ * Convert 16.16 fixed point values to the desired output format.
+ * In this case we reduce 16.16 fixed point values to normalized
+ * 8-bit values.
+ *
+ * The `max_value` in the parameter is the maximum value in the
+ * distance field map and is equal to the spread. We normalize
+ * the distances using this value instead of computing the maximum
+ * value for the entire bitmap.
+ *
+ * You can use this function to map the 16.16 signed values to any
+ * format required. Do note that the output buffer is 8-bit, so only
+ * use an 8-bit format for `FT_SDFFormat`, or increase the buffer size in
+ * `ftsdfrend.c`.
+ */
+ FT_LOCAL_DEF( FT_SDFFormat )
+ map_fixed_to_sdf( FT_16D16 dist,
+ FT_16D16 max_value )
+ {+ FT_SDFFormat out;
+ FT_16D16 udist;
+
+
+ /* normalize the distance values */
+ dist = FT_DivFix( dist, max_value );
+
+ udist = dist < 0 ? -dist : dist;
+
+ /* Reduce the distance values to 8 bits. */
+ /* */
+ /* Since +1/-1 in 16.16 takes the 16th bit, we right-shift */
+ /* the number by 9 to make it fit into the 7-bit range. */
+ /* */
+ /* One bit is reserved for the sign. */
+ udist >>= 9;
+
+ /* Since `char` can only store a maximum positive value */
+ /* of 127 we need to make sure it does not wrap around and */
+ /* give a negative value. */
+ if ( dist > 0 && udist > 127 )
+ udist = 127;
+ if ( dist < 0 && udist > 128 )
+ udist = 128;
+
+ /* Output the data; negative values are from [0, 127] and positive */
+ /* from [128, 255]. One important thing is that negative values */
+ /* are inverted here, that means [0, 128] maps to [-128, 0] linearly. */
+ /* More on that in `freetype.h` near the documentation of */
+ /* `FT_RENDER_MODE_SDF`. */
+ out = dist < 0 ? 128 - (FT_SDFFormat)udist
+ : (FT_SDFFormat)udist + 128;
+
+ return out;
+ }
+
+
+ /*
+ * Invert the signed distance packed into the corresponding format.
+ * So if the values are negative they will become positive in the
+ * chosen format.
+ *
+ * [Note]: This function should only be used after converting the
+ * 16.16 signed distance values to `FT_SDFFormat`. If that
+ * conversion has not been done, then simply invert the sign
+ * and use the above function to pack the values.
+ */
+ FT_LOCAL_DEF( FT_SDFFormat )
+ invert_sign( FT_SDFFormat dist )
+ {+ return 255 - dist;
+ }
+
+
+/* END */
--- a/src/sdf/ftsdfcommon.h
+++ b/src/sdf/ftsdfcommon.h
@@ -2,7 +2,7 @@
*
* ftsdfcommon.h
*
- * Auxiliary data for Signed Distance Field support (specification only).
+ * Auxiliary data for Signed Distance Field support (specification).
*
* Copyright (C) 2020-2021 by
* David Turner, Robert Wilhelm, and Werner Lemberg.
@@ -30,7 +30,7 @@
#include <ft2build.h>
#include FT_CONFIG_CONFIG_H
-#include <freetype/freetype.h>
+#include <freetype/internal/ftobjs.h>
FT_BEGIN_HEADER
@@ -120,116 +120,15 @@
typedef FT_BBox FT_CBox; /* control box of a curve */
- /**************************************************************************
- *
- * common functions
- *
- */
+ FT_LOCAL( FT_16D16 )
+ square_root( FT_16D16 val );
- /*
- * Original algorithm:
- *
- * https://github.com/chmike/fpsqrt
- *
- * Use this to compute the square root of a 16.16 fixed point number.
- */
- static FT_16D16
- square_root( FT_16D16 val )
- {- FT_ULong t, q, b, r;
+ FT_LOCAL( FT_SDFFormat )
+ map_fixed_to_sdf( FT_16D16 dist,
+ FT_16D16 max_value );
-
- r = (FT_ULong)val;
- b = 0x40000000L;
- q = 0;
-
- while ( b > 0x40L )
- {- t = q + b;
-
- if ( r >= t )
- {- r -= t;
- q = t + b;
- }
-
- r <<= 1;
- b >>= 1;
- }
-
- q >>= 8;
-
- return (FT_16D16)q;
- }
-
- /**************************************************************************
- *
- * format and sign manipulating functions
- *
- */
-
- /*
- * Convert 16.16 fixed point value to the desired output format.
- * In this case we reduce 16.16 fixed point value to normalized
- * 8-bit values.
- * The `max_value` in the parameter is the maximum value in the
- * distance field map and is equal to the spread. We normalize
- * the distances using this value instead of computing the maximum
- * value for the entire bitmap.
- * You can use this function to map the 16.16 signed values to any
- * format required. Do note that the output buffer is 8-bit, so only
- * use 8-bit format for `FT_SDFFormat`, or increase buffer size in
- * `ftsdfrend.c`.
- */
- static FT_SDFFormat
- map_fixed_to_sdf( FT_16D16 dist, FT_16D16 max_value )
- {- FT_SDFFormat out;
- FT_16D16 udist;
-
-
- /* normalize the distance values */
- dist = FT_DivFix( dist, max_value );
-
- udist = dist < 0 ? -dist : dist;
-
- /* Reduce the distance values to 8 bits, +1/-1 in */
- /* 16.16 takes the 16th bit. So we right shift the */
- /* number by 9 to make it fit in the 7 bit range. */
- /* 1 bit is reserved for the sign. */
- udist >>= 9;
-
- /* Since char can only store max positive value */
- /* of 127 we need to make sure it does not wrap */
- /* around and give a negative value. */
- if ( dist > 0 && udist > 127 )
- udist = 127;
- if ( dist < 0 && udist > 128 )
- udist = 128;
-
- /* Output the data; negative values are from [0, 127] and positive */
- /* from [128, 255]. One important thing is that negative values */
- /* are inverted here, that means [0, 128] maps to [-128, 0] linearly. */
- /* More on that in `freetype.h` near `FT_RENDER_MODE_SDF` */
- out = dist < 0 ? 128 - (FT_SDFFormat)udist :
- (FT_SDFFormat)udist + 128;
- return out;
- }
-
- /*
- * Invert the signed distance packed into the corresponding format.
- * So if the values are negative they will become positive in the
- * chosen format.
- *
- * [Note]: This function should only be used after converting the
- * 16.16 signed distance values to `FT_SDFFormat`, if that
- * conversion has not been done, then simply invert the sign
- * and use the above function to pack the values.
- */
- static FT_SDFFormat
- invert_sign( FT_SDFFormat dist ) {- return 255 - dist;
- }
+ FT_LOCAL( FT_SDFFormat )
+ invert_sign( FT_SDFFormat dist );
FT_END_HEADER
--- a/src/sdf/rules.mk
+++ b/src/sdf/rules.mk
@@ -28,9 +28,10 @@
# sdf driver sources (i.e., C files)
#
-SDF_DRV_SRC := $(SDF_DIR)/ftsdfrend.c \
- $(SDF_DIR)/ftsdf.c \
- $(SDF_DIR)/ftbsdf.c
+SDF_DRV_SRC := $(SDF_DIR)/ftsdfrend.c \
+ $(SDF_DIR)/ftsdf.c \
+ $(SDF_DIR)/ftbsdf.c \
+ $(SDF_DIR)/ftsdfcommon.c
# sdf driver headers
--- a/src/sdf/sdf.c
+++ b/src/sdf/sdf.c
@@ -21,6 +21,7 @@
#define FT_MAKE_OPTION_SINGLE_OBJECT
#include "ftsdfrend.c"
+#include "ftsdfcommon.c"
#include "ftbsdf.c"
#include "ftsdf.c"