ref: ea6816030081b2cffa6c0ae9ca5429a2c6fe2fa5
dir: /resources/image.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 resources
import (
"errors"
"fmt"
"image"
"image/color"
"image/draw"
"image/jpeg"
"io"
"os"
"strconv"
"strings"
"sync"
"github.com/gohugoio/hugo/resources/resource"
_errors "github.com/pkg/errors"
"github.com/disintegration/imaging"
"github.com/gohugoio/hugo/common/hugio"
"github.com/gohugoio/hugo/helpers"
"github.com/mitchellh/mapstructure"
// Blind import for image.Decode
_ "image/gif"
_ "image/png"
// Blind import for image.Decode
_ "golang.org/x/image/webp"
)
var (
_ resource.Resource = (*Image)(nil)
_ resource.Source = (*Image)(nil)
_ resource.Cloner = (*Image)(nil)
)
// 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 used. See https://github.com/disintegration/imaging
ResampleFilter string
// The anchor used in Fill. Default is "smart", i.e. Smart Crop.
Anchor string
}
const (
defaultJPEGQuality = 75
defaultResampleFilter = "box"
)
var (
imageFormats = map[string]imaging.Format{
".jpg": imaging.JPEG,
".jpeg": imaging.JPEG,
".png": imaging.PNG,
".tif": imaging.TIFF,
".tiff": imaging.TIFF,
".bmp": imaging.BMP,
".gif": imaging.GIF,
}
// Add or increment if changes to an image format's processing requires
// re-generation.
imageFormatsVersions = map[imaging.Format]int{
imaging.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]imaging.Anchor{
strings.ToLower("Center"): imaging.Center,
strings.ToLower("TopLeft"): imaging.TopLeft,
strings.ToLower("Top"): imaging.Top,
strings.ToLower("TopRight"): imaging.TopRight,
strings.ToLower("Left"): imaging.Left,
strings.ToLower("Right"): imaging.Right,
strings.ToLower("BottomLeft"): imaging.BottomLeft,
strings.ToLower("Bottom"): imaging.Bottom,
strings.ToLower("BottomRight"): imaging.BottomRight,
}
var imageFilters = map[string]imaging.ResampleFilter{
strings.ToLower("NearestNeighbor"): imaging.NearestNeighbor,
strings.ToLower("Box"): imaging.Box,
strings.ToLower("Linear"): imaging.Linear,
strings.ToLower("Hermite"): imaging.Hermite,
strings.ToLower("MitchellNetravali"): imaging.MitchellNetravali,
strings.ToLower("CatmullRom"): imaging.CatmullRom,
strings.ToLower("BSpline"): imaging.BSpline,
strings.ToLower("Gaussian"): imaging.Gaussian,
strings.ToLower("Lanczos"): imaging.Lanczos,
strings.ToLower("Hann"): imaging.Hann,
strings.ToLower("Hamming"): imaging.Hamming,
strings.ToLower("Blackman"): imaging.Blackman,
strings.ToLower("Bartlett"): imaging.Bartlett,
strings.ToLower("Welch"): imaging.Welch,
strings.ToLower("Cosine"): imaging.Cosine,
}
// Image represents an image resource.
type Image struct {
config image.Config
configInit sync.Once
configLoaded bool
imaging *Imaging
format imaging.Format
*genericResource
}
// Width returns i's width.
func (i *Image) Width() int {
i.initConfig()
return i.config.Width
}
// Height returns i's height.
func (i *Image) Height() int {
i.initConfig()
return i.config.Height
}
// WithNewBase implements the Cloner interface.
func (i *Image) WithNewBase(base string) resource.Resource {
return &Image{
imaging: i.imaging,
format: i.format,
genericResource: i.genericResource.WithNewBase(base).(*genericResource)}
}
// Resize resizes the image to the specified width and height using the specified resampling
// filter and returns the transformed image. If one of width or height is 0, the image aspect
// ratio is preserved.
func (i *Image) Resize(spec string) (*Image, error) {
return i.doWithImageConfig("resize", spec, func(src image.Image, conf imageConfig) (image.Image, error) {
return imaging.Resize(src, conf.Width, conf.Height, conf.Filter), nil
})
}
// Fit scales down the image using the specified resample filter to fit the specified
// maximum width and height.
func (i *Image) Fit(spec string) (*Image, error) {
return i.doWithImageConfig("fit", spec, func(src image.Image, conf imageConfig) (image.Image, error) {
return imaging.Fit(src, conf.Width, conf.Height, conf.Filter), nil
})
}
// Fill scales the image to the smallest possible size that will cover the specified dimensions,
// crops the resized image to the specified dimensions using the given anchor point.
// Space delimited config: 200x300 TopLeft
func (i *Image) Fill(spec string) (*Image, error) {
return i.doWithImageConfig("fill", spec, func(src image.Image, conf imageConfig) (image.Image, error) {
if conf.AnchorStr == smartCropIdentifier {
return smartCrop(src, conf.Width, conf.Height, conf.Anchor, conf.Filter)
}
return imaging.Fill(src, conf.Width, conf.Height, conf.Anchor, conf.Filter), nil
})
}
// Holds configuration to create a new image from an existing one, resize etc.
type imageConfig struct {
Action 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
Width int
Height int
Filter imaging.ResampleFilter
FilterStr string
Anchor imaging.Anchor
AnchorStr string
}
func (i *Image) isJPEG() bool {
name := strings.ToLower(i.relTargetDirFile.file)
return strings.HasSuffix(name, ".jpg") || strings.HasSuffix(name, ".jpeg")
}
// Serialize image processing. The imaging library spins up its own set of Go routines,
// so there is not much to gain from adding more load to the mix. That
// can even have negative effect in low resource scenarios.
// Note that this only effects the non-cached scenario. Once the processed
// image is written to disk, everything is fast, fast fast.
const imageProcWorkers = 1
var imageProcSem = make(chan bool, imageProcWorkers)
func (i *Image) doWithImageConfig(action, spec string, f func(src image.Image, conf imageConfig) (image.Image, error)) (*Image, error) {
conf, err := parseImageConfig(spec)
if err != nil {
return nil, err
}
conf.Action = action
if conf.Quality <= 0 && i.isJPEG() {
// We need a quality setting for all JPEGs
conf.Quality = i.imaging.Quality
}
if conf.FilterStr == "" {
conf.FilterStr = i.imaging.ResampleFilter
conf.Filter = imageFilters[conf.FilterStr]
}
if conf.AnchorStr == "" {
conf.AnchorStr = i.imaging.Anchor
if !strings.EqualFold(conf.AnchorStr, smartCropIdentifier) {
conf.Anchor = anchorPositions[conf.AnchorStr]
}
}
return i.spec.imageCache.getOrCreate(i, conf, func() (*Image, image.Image, error) {
imageProcSem <- true
defer func() {
<-imageProcSem
}()
ci := i.clone()
errOp := action
errPath := i.sourceFilename
ci.setBasePath(conf)
src, err := i.decodeSource()
if err != nil {
return nil, nil, &os.PathError{Op: errOp, Path: errPath, Err: err}
}
if conf.Rotate != 0 {
// Rotate it before any scaling to get the dimensions correct.
src = imaging.Rotate(src, float64(conf.Rotate), color.Transparent)
}
converted, err := f(src, conf)
if err != nil {
return ci, nil, &os.PathError{Op: errOp, Path: errPath, Err: err}
}
if i.format == imaging.PNG {
// Apply the colour palette from the source
if paletted, ok := src.(*image.Paletted); ok {
tmp := image.NewPaletted(converted.Bounds(), paletted.Palette)
draw.FloydSteinberg.Draw(tmp, tmp.Bounds(), converted, converted.Bounds().Min)
converted = tmp
}
}
b := converted.Bounds()
ci.config = image.Config{Width: b.Max.X, Height: b.Max.Y}
ci.configLoaded = true
return ci, converted, nil
})
}
func (i imageConfig) key(format imaging.Format) string {
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)
}
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
}
func newImageConfig(width, height, quality, rotate int, filter, anchor string) imageConfig {
var c imageConfig
c.Width = width
c.Height = height
c.Quality = quality
c.Rotate = rotate
if filter != "" {
filter = strings.ToLower(filter)
if v, ok := imageFilters[filter]; ok {
c.Filter = v
c.FilterStr = filter
}
}
if anchor != "" {
anchor = strings.ToLower(anchor)
if v, ok := anchorPositions[anchor]; ok {
c.Anchor = v
c.AnchorStr = anchor
}
}
return c
}
func parseImageConfig(config string) (imageConfig, error) {
var (
c imageConfig
err error
)
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] == '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")
}
}
}
if c.Width == 0 && c.Height == 0 {
return c, errors.New("must provide Width or Height")
}
return c, nil
}
func (i *Image) initConfig() error {
var err error
i.configInit.Do(func() {
if i.configLoaded {
return
}
var (
f hugio.ReadSeekCloser
config image.Config
)
f, err = i.ReadSeekCloser()
if err != nil {
return
}
defer f.Close()
config, _, err = image.DecodeConfig(f)
if err != nil {
return
}
i.config = config
})
if err != nil {
return _errors.Wrap(err, "failed to load image config")
}
return nil
}
func (i *Image) decodeSource() (image.Image, error) {
f, err := i.ReadSeekCloser()
if err != nil {
return nil, _errors.Wrap(err, "failed to open image for decode")
}
defer f.Close()
img, _, err := image.Decode(f)
return img, err
}
// returns an opened file or nil if nothing to write.
func (i *Image) openDestinationsForWriting() (io.WriteCloser, error) {
targetFilenames := i.targetFilenames()
var changedFilenames []string
// Fast path:
// This is a processed version of the original;
// check if it already existis at the destination.
for _, targetFilename := range targetFilenames {
if _, err := i.spec.BaseFs.PublishFs.Stat(targetFilename); err == nil {
continue
}
changedFilenames = append(changedFilenames, targetFilename)
}
if len(changedFilenames) == 0 {
return nil, nil
}
return helpers.OpenFilesForWriting(i.spec.BaseFs.PublishFs, changedFilenames...)
}
func (i *Image) encodeTo(conf imageConfig, img image.Image, w io.Writer) error {
switch i.format {
case imaging.JPEG:
var rgba *image.RGBA
quality := conf.Quality
if nrgba, ok := img.(*image.NRGBA); ok {
if nrgba.Opaque() {
rgba = &image.RGBA{
Pix: nrgba.Pix,
Stride: nrgba.Stride,
Rect: nrgba.Rect,
}
}
}
if rgba != nil {
return jpeg.Encode(w, rgba, &jpeg.Options{Quality: quality})
}
return jpeg.Encode(w, img, &jpeg.Options{Quality: quality})
default:
return imaging.Encode(w, img, i.format)
}
}
func (i *Image) clone() *Image {
g := *i.genericResource
g.resourceContent = &resourceContent{}
if g.publishOnce != nil {
g.publishOnce = &publishOnce{logger: g.publishOnce.logger}
}
return &Image{
imaging: i.imaging,
format: i.format,
genericResource: &g}
}
func (i *Image) setBasePath(conf imageConfig) {
i.relTargetDirFile = i.relTargetPathFromConfig(conf)
}
func (i *Image) relTargetPathFromConfig(conf imageConfig) dirFile {
p1, p2 := helpers.FileAndExt(i.relTargetDirFile.file)
idStr := fmt.Sprintf("_hu%s_%d", i.hash, i.osFileInfo.Size())
// Do not change for no good reason.
const md5Threshold = 100
key := conf.key(i.format)
// It is useful to have the key in clear text, but when nesting transforms, it
// can easily be too long to read, and maybe even too long
// for the different OSes to handle.
if len(p1)+len(idStr)+len(p2) > md5Threshold {
key = helpers.MD5String(p1 + key + p2)
huIdx := strings.Index(p1, "_hu")
if huIdx != -1 {
p1 = p1[:huIdx]
} else {
// This started out as a very long file name. Making it even longer
// could melt ice in the Arctic.
p1 = ""
}
} else if strings.Contains(p1, idStr) {
// On scaling an already scaled image, we get the file info from the original.
// Repeating the same info in the filename makes it stuttery for no good reason.
idStr = ""
}
return dirFile{
dir: i.relTargetDirFile.dir,
file: fmt.Sprintf("%s%s_%s%s", p1, idStr, key, p2),
}
}
func decodeImaging(m map[string]interface{}) (Imaging, error) {
var i Imaging
if err := mapstructure.WeakDecode(m, &i); err != nil {
return i, err
}
if i.Quality == 0 {
i.Quality = defaultJPEGQuality
} else if i.Quality < 0 || i.Quality > 100 {
return i, errors.New("JPEG quality must be a number between 1 and 100")
}
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 i, 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 i, fmt.Errorf("%q is not a valid resample filter", filter)
}
i.ResampleFilter = filter
}
return i, nil
}