ref: b3e4f911f42243bc77b5659e6f9184b349eb5b29
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 (
"encoding/json"
"fmt"
"image"
"image/color"
"image/draw"
_ "image/gif"
_ "image/png"
"io"
"io/ioutil"
"os"
"path"
"path/filepath"
"strings"
"sync"
"github.com/disintegration/gift"
"github.com/gohugoio/hugo/cache/filecache"
"github.com/gohugoio/hugo/resources/images/exif"
"github.com/gohugoio/hugo/resources/resource"
"github.com/pkg/errors"
_errors "github.com/pkg/errors"
"github.com/gohugoio/hugo/helpers"
"github.com/gohugoio/hugo/resources/images"
// Blind import for image.Decode
_ "golang.org/x/image/webp"
)
var (
_ resource.Image = (*imageResource)(nil)
_ resource.Source = (*imageResource)(nil)
_ resource.Cloner = (*imageResource)(nil)
)
// ImageResource represents an image resource.
type imageResource struct {
*images.Image
// When a image is processed in a chain, this holds the reference to the
// original (first).
root *imageResource
metaInit sync.Once
metaInitErr error
meta *imageMeta
baseResource
}
type imageMeta struct {
Exif *exif.Exif
}
func (i *imageResource) Exif() (*exif.Exif, error) {
return i.root.getExif()
}
func (i *imageResource) getExif() (*exif.Exif, error) {
i.metaInit.Do(func() {
supportsExif := i.Format == images.JPEG || i.Format == images.TIFF
if !supportsExif {
return
}
key := i.getImageMetaCacheTargetPath()
read := func(info filecache.ItemInfo, r io.ReadSeeker) error {
meta := &imageMeta{}
data, err := ioutil.ReadAll(r)
if err != nil {
return err
}
if err = json.Unmarshal(data, &meta); err != nil {
return err
}
i.meta = meta
return nil
}
create := func(info filecache.ItemInfo, w io.WriteCloser) (err error) {
f, err := i.root.ReadSeekCloser()
if err != nil {
i.metaInitErr = err
return
}
defer f.Close()
x, err := i.getSpec().imaging.DecodeExif(f)
if err != nil {
i.metaInitErr = err
return
}
i.meta = &imageMeta{Exif: x}
// Also write it to cache
enc := json.NewEncoder(w)
return enc.Encode(i.meta)
}
_, i.metaInitErr = i.getSpec().imageCache.fileCache.ReadOrCreate(key, read, create)
})
if i.metaInitErr != nil {
return nil, i.metaInitErr
}
return i.meta.Exif, nil
}
func (i *imageResource) Clone() resource.Resource {
gr := i.baseResource.Clone().(baseResource)
return &imageResource{
root: i.root,
Image: i.WithSpec(gr),
baseResource: gr,
}
}
func (i *imageResource) cloneWithUpdates(u *transformationUpdate) (baseResource, error) {
base, err := i.baseResource.cloneWithUpdates(u)
if err != nil {
return nil, err
}
var img *images.Image
if u.isContenChanged() {
img = i.WithSpec(base)
} else {
img = i.Image
}
return &imageResource{
root: i.root,
Image: img,
baseResource: base,
}, nil
}
// 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 *imageResource) Resize(spec string) (resource.Image, error) {
conf, err := i.decodeImageConfig("resize", spec)
if err != nil {
return nil, err
}
return i.doWithImageConfig(conf, func(src image.Image) (image.Image, error) {
return i.Proc.ApplyFiltersFromConfig(src, conf)
})
}
// Fit scales down the image using the specified resample filter to fit the specified
// maximum width and height.
func (i *imageResource) Fit(spec string) (resource.Image, error) {
conf, err := i.decodeImageConfig("fit", spec)
if err != nil {
return nil, err
}
return i.doWithImageConfig(conf, func(src image.Image) (image.Image, error) {
return i.Proc.ApplyFiltersFromConfig(src, conf)
})
}
// 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 *imageResource) Fill(spec string) (resource.Image, error) {
conf, err := i.decodeImageConfig("fill", spec)
if err != nil {
return nil, err
}
return i.doWithImageConfig(conf, func(src image.Image) (image.Image, error) {
return i.Proc.ApplyFiltersFromConfig(src, conf)
})
}
func (i *imageResource) Filter(filters ...interface{}) (resource.Image, error) {
conf := i.Proc.GetDefaultImageConfig("filter")
var gfilters []gift.Filter
for _, f := range filters {
gfilters = append(gfilters, images.ToFilters(f)...)
}
conf.Key = helpers.HashString(gfilters)
conf.TargetFormat = i.Format
return i.doWithImageConfig(conf, func(src image.Image) (image.Image, error) {
return i.Proc.Filter(src, gfilters...)
})
}
// 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 *imageResource) doWithImageConfig(conf images.ImageConfig, f func(src image.Image) (image.Image, error)) (resource.Image, error) {
img, err := i.getSpec().imageCache.getOrCreate(i, conf, func() (*imageResource, image.Image, error) {
imageProcSem <- true
defer func() {
<-imageProcSem
}()
errOp := conf.Action
errPath := i.getSourceFilename()
src, err := i.decodeSource()
if err != nil {
return nil, nil, &os.PathError{Op: errOp, Path: errPath, Err: err}
}
converted, err := f(src)
if err != nil {
return nil, nil, &os.PathError{Op: errOp, Path: errPath, Err: err}
}
hasAlpha := !images.IsOpaque(converted)
shouldFill := conf.BgColor != nil && hasAlpha
shouldFill = shouldFill || (!conf.TargetFormat.SupportsTransparency() && hasAlpha)
var bgColor color.Color
if shouldFill {
bgColor = conf.BgColor
if bgColor == nil {
bgColor = i.Proc.Cfg.BgColor
}
tmp := image.NewRGBA(converted.Bounds())
draw.Draw(tmp, tmp.Bounds(), image.NewUniform(bgColor), image.Point{}, draw.Src)
draw.Draw(tmp, tmp.Bounds(), converted, converted.Bounds().Min, draw.Over)
converted = tmp
}
if conf.TargetFormat == images.PNG {
// Apply the colour palette from the source
if paletted, ok := src.(*image.Paletted); ok {
palette := paletted.Palette
if bgColor != nil && len(palette) < 256 {
palette = images.AddColorToPalette(bgColor, palette)
} else if bgColor != nil {
images.ReplaceColorInPalette(bgColor, palette)
}
tmp := image.NewPaletted(converted.Bounds(), palette)
draw.FloydSteinberg.Draw(tmp, tmp.Bounds(), converted, converted.Bounds().Min)
converted = tmp
}
}
ci := i.clone(converted)
ci.setBasePath(conf)
ci.Format = conf.TargetFormat
ci.setMediaType(conf.TargetFormat.MediaType())
return ci, converted, nil
})
if err != nil {
if i.root != nil && i.root.getFileInfo() != nil {
return nil, errors.Wrapf(err, "image %q", i.root.getFileInfo().Meta().Filename())
}
}
return img, nil
}
func (i *imageResource) decodeImageConfig(action, spec string) (images.ImageConfig, error) {
conf, err := images.DecodeImageConfig(action, spec, i.Proc.Cfg.Cfg)
if err != nil {
return conf, err
}
// default to the source format
if conf.TargetFormat == 0 {
conf.TargetFormat = i.Format
}
if conf.Quality <= 0 && conf.TargetFormat.RequiresDefaultQuality() {
// We need a quality setting for all JPEGs
conf.Quality = i.Proc.Cfg.Cfg.Quality
}
if conf.BgColor == nil && conf.TargetFormat != i.Format {
if i.Format.SupportsTransparency() && !conf.TargetFormat.SupportsTransparency() {
conf.BgColor = i.Proc.Cfg.BgColor
conf.BgColorStr = i.Proc.Cfg.Cfg.BgColor
}
}
return conf, nil
}
func (i *imageResource) 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
}
func (i *imageResource) clone(img image.Image) *imageResource {
spec := i.baseResource.Clone().(baseResource)
var image *images.Image
if img != nil {
image = i.WithImage(img)
} else {
image = i.WithSpec(spec)
}
return &imageResource{
Image: image,
root: i.root,
baseResource: spec,
}
}
func (i *imageResource) setBasePath(conf images.ImageConfig) {
i.getResourcePaths().relTargetDirFile = i.relTargetPathFromConfig(conf)
}
func (i *imageResource) getImageMetaCacheTargetPath() string {
const imageMetaVersionNumber = 1 // Increment to invalidate the meta cache
cfg := i.getSpec().imaging.Cfg.Cfg
df := i.getResourcePaths().relTargetDirFile
if fi := i.getFileInfo(); fi != nil {
df.dir = filepath.Dir(fi.Meta().Path())
}
p1, _ := helpers.FileAndExt(df.file)
h, _ := i.hash()
idStr := helpers.HashString(h, i.size(), imageMetaVersionNumber, cfg)
return path.Join(df.dir, fmt.Sprintf("%s_%s.json", p1, idStr))
}
func (i *imageResource) relTargetPathFromConfig(conf images.ImageConfig) dirFile {
p1, p2 := helpers.FileAndExt(i.getResourcePaths().relTargetDirFile.file)
if conf.TargetFormat != i.Format {
p2 = conf.TargetFormat.DefaultExtension()
}
h, _ := i.hash()
idStr := fmt.Sprintf("_hu%s_%d", h, i.size())
// Do not change for no good reason.
const md5Threshold = 100
key := conf.GetKey(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.getResourcePaths().relTargetDirFile.dir,
file: fmt.Sprintf("%s%s_%s%s", p1, idStr, key, p2),
}
}