ref: edc5c4741caaee36ba4d42b5947c195a3e02e6aa
dir: /resources/images/config.go/
// Copyright 2019 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package images
import (
"errors"
"fmt"
"image/color"
"strconv"
"strings"
"github.com/disintegration/gift"
"github.com/mitchellh/mapstructure"
)
const (
defaultJPEGQuality = 75
defaultResampleFilter = "box"
defaultBgColor = "ffffff"
)
var (
imageFormats = map[string]Format{
".jpg": JPEG,
".jpeg": JPEG,
".png": PNG,
".tif": TIFF,
".tiff": TIFF,
".bmp": BMP,
".gif": GIF,
}
// Add or increment if changes to an image format's processing requires
// re-generation.
imageFormatsVersions = map[Format]int{
PNG: 2, // Floyd Steinberg dithering
}
// Increment to mark all processed images as stale. Only use when absolutely needed.
// See the finer grained smartCropVersionNumber and imageFormatsVersions.
mainImageVersionNumber = 0
)
var anchorPositions = map[string]gift.Anchor{
strings.ToLower("Center"): gift.CenterAnchor,
strings.ToLower("TopLeft"): gift.TopLeftAnchor,
strings.ToLower("Top"): gift.TopAnchor,
strings.ToLower("TopRight"): gift.TopRightAnchor,
strings.ToLower("Left"): gift.LeftAnchor,
strings.ToLower("Right"): gift.RightAnchor,
strings.ToLower("BottomLeft"): gift.BottomLeftAnchor,
strings.ToLower("Bottom"): gift.BottomAnchor,
strings.ToLower("BottomRight"): gift.BottomRightAnchor,
}
var imageFilters = map[string]gift.Resampling{
strings.ToLower("NearestNeighbor"): gift.NearestNeighborResampling,
strings.ToLower("Box"): gift.BoxResampling,
strings.ToLower("Linear"): gift.LinearResampling,
strings.ToLower("Hermite"): hermiteResampling,
strings.ToLower("MitchellNetravali"): mitchellNetravaliResampling,
strings.ToLower("CatmullRom"): catmullRomResampling,
strings.ToLower("BSpline"): bSplineResampling,
strings.ToLower("Gaussian"): gaussianResampling,
strings.ToLower("Lanczos"): gift.LanczosResampling,
strings.ToLower("Hann"): hannResampling,
strings.ToLower("Hamming"): hammingResampling,
strings.ToLower("Blackman"): blackmanResampling,
strings.ToLower("Bartlett"): bartlettResampling,
strings.ToLower("Welch"): welchResampling,
strings.ToLower("Cosine"): cosineResampling,
}
func ImageFormatFromExt(ext string) (Format, bool) {
f, found := imageFormats[ext]
return f, found
}
func DecodeConfig(m map[string]interface{}) (ImagingConfig, error) {
var i Imaging
var ic ImagingConfig
if err := mapstructure.WeakDecode(m, &i); err != nil {
return ic, err
}
if i.Quality == 0 {
i.Quality = defaultJPEGQuality
} else if i.Quality < 0 || i.Quality > 100 {
return ic, errors.New("JPEG quality must be a number between 1 and 100")
}
if i.BgColor != "" {
i.BgColor = strings.TrimPrefix(i.BgColor, "#")
} else {
i.BgColor = defaultBgColor
}
var err error
ic.BgColor, err = hexStringToColor(i.BgColor)
if err != nil {
return ic, err
}
if i.Anchor == "" || strings.EqualFold(i.Anchor, smartCropIdentifier) {
i.Anchor = smartCropIdentifier
} else {
i.Anchor = strings.ToLower(i.Anchor)
if _, found := anchorPositions[i.Anchor]; !found {
return ic, errors.New("invalid anchor value in imaging config")
}
}
if i.ResampleFilter == "" {
i.ResampleFilter = defaultResampleFilter
} else {
filter := strings.ToLower(i.ResampleFilter)
_, found := imageFilters[filter]
if !found {
return ic, fmt.Errorf("%q is not a valid resample filter", filter)
}
i.ResampleFilter = filter
}
if strings.TrimSpace(i.Exif.IncludeFields) == "" && strings.TrimSpace(i.Exif.ExcludeFields) == "" {
// Don't change this for no good reason. Please don't.
i.Exif.ExcludeFields = "GPS|Exif|Exposure[M|P|B]|Contrast|Resolution|Sharp|JPEG|Metering|Sensing|Saturation|ColorSpace|Flash|WhiteBalance"
}
ic.Cfg = i
return ic, nil
}
func DecodeImageConfig(action, config string, defaults Imaging) (ImageConfig, error) {
var (
c ImageConfig
err error
)
c.Action = action
if config == "" {
return c, errors.New("image config cannot be empty")
}
parts := strings.Fields(config)
for _, part := range parts {
part = strings.ToLower(part)
if part == smartCropIdentifier {
c.AnchorStr = smartCropIdentifier
} else if pos, ok := anchorPositions[part]; ok {
c.Anchor = pos
c.AnchorStr = part
} else if filter, ok := imageFilters[part]; ok {
c.Filter = filter
c.FilterStr = part
} else if part[0] == '#' {
c.BgColorStr = part[1:]
c.BgColor, err = hexStringToColor(c.BgColorStr)
if err != nil {
return c, err
}
} else if part[0] == 'q' {
c.Quality, err = strconv.Atoi(part[1:])
if err != nil {
return c, err
}
if c.Quality < 1 || c.Quality > 100 {
return c, errors.New("quality ranges from 1 to 100 inclusive")
}
} else if part[0] == 'r' {
c.Rotate, err = strconv.Atoi(part[1:])
if err != nil {
return c, err
}
} else if strings.Contains(part, "x") {
widthHeight := strings.Split(part, "x")
if len(widthHeight) <= 2 {
first := widthHeight[0]
if first != "" {
c.Width, err = strconv.Atoi(first)
if err != nil {
return c, err
}
}
if len(widthHeight) == 2 {
second := widthHeight[1]
if second != "" {
c.Height, err = strconv.Atoi(second)
if err != nil {
return c, err
}
}
}
} else {
return c, errors.New("invalid image dimensions")
}
} else if f, ok := ImageFormatFromExt("." + part); ok {
c.TargetFormat = f
}
}
if c.Width == 0 && c.Height == 0 {
return c, errors.New("must provide Width or Height")
}
if c.FilterStr == "" {
c.FilterStr = defaults.ResampleFilter
c.Filter = imageFilters[c.FilterStr]
}
if c.AnchorStr == "" {
c.AnchorStr = defaults.Anchor
if !strings.EqualFold(c.AnchorStr, smartCropIdentifier) {
c.Anchor = anchorPositions[c.AnchorStr]
}
}
return c, nil
}
// ImageConfig holds configuration to create a new image from an existing one, resize etc.
type ImageConfig struct {
// This defines the output format of the output image. It defaults to the source format
TargetFormat Format
Action string
// If set, this will be used as the key in filenames etc.
Key string
// Quality ranges from 1 to 100 inclusive, higher is better.
// This is only relevant for JPEG images.
// Default is 75.
Quality int
// Rotate rotates an image by the given angle counter-clockwise.
// The rotation will be performed first.
Rotate int
// Used to fill any transparency.
// When set in site config, it's used when converting to a format that does
// not support transparency.
// When set per image operation, it's used even for formats that does support
// transparency.
BgColor color.Color
BgColorStr string
Width int
Height int
Filter gift.Resampling
FilterStr string
Anchor gift.Anchor
AnchorStr string
}
func (i ImageConfig) GetKey(format Format) string {
if i.Key != "" {
return i.Action + "_" + i.Key
}
k := strconv.Itoa(i.Width) + "x" + strconv.Itoa(i.Height)
if i.Action != "" {
k += "_" + i.Action
}
if i.Quality > 0 {
k += "_q" + strconv.Itoa(i.Quality)
}
if i.Rotate != 0 {
k += "_r" + strconv.Itoa(i.Rotate)
}
if i.BgColorStr != "" {
k += "_bg" + i.BgColorStr
}
anchor := i.AnchorStr
if anchor == smartCropIdentifier {
anchor = anchor + strconv.Itoa(smartCropVersionNumber)
}
k += "_" + i.FilterStr
if strings.EqualFold(i.Action, "fill") {
k += "_" + anchor
}
if v, ok := imageFormatsVersions[format]; ok {
k += "_" + strconv.Itoa(v)
}
if mainImageVersionNumber > 0 {
k += "_" + strconv.Itoa(mainImageVersionNumber)
}
return k
}
type ImagingConfig struct {
BgColor color.Color
// Config as provided by the user.
Cfg Imaging
}
// Imaging contains default image processing configuration. This will be fetched
// from site (or language) config.
type Imaging struct {
// Default image quality setting (1-100). Only used for JPEG images.
Quality int
// Resample filter to use in resize operations..
ResampleFilter string
// The anchor to use in Fill. Default is "smart", i.e. Smart Crop.
Anchor string
// Default color used in fill operations (e.g. "fff" for white).
BgColor string
Exif ExifConfig
}
type ExifConfig struct {
// Regexp matching the Exif fields you want from the (massive) set of Exif info
// available. As we cache this info to disk, this is for performance and
// disk space reasons more than anything.
// If you want it all, put ".*" in this config setting.
// Note that if neither this or ExcludeFields is set, Hugo will return a small
// default set.
IncludeFields string
// Regexp matching the Exif fields you want to exclude. This may be easier to use
// than IncludeFields above, depending on what you want.
ExcludeFields string
// Hugo extracts the "photo taken" date/time into .Date by default.
// Set this to true to turn it off.
DisableDate bool
// Hugo extracts the "photo taken where" (GPS latitude and longitude) into
// .Long and .Lat. Set this to true to turn it off.
DisableLatLong bool
}