hugo/resources/image.go
J. Ansorg e5856e61d8 resources: Support output image format in image operations
The image format is defined as the image extension of the known formats,
excluding the dot.
All of 'img.Resize "600x jpeg"', 'img.Resize "600x jpg"',
and 'img.Resize "600x png"' are valid format definitions.
If the target format is defined in the operation definition string,
then the converted image will be stored in this format. Permalinks and
media type are updated correspondingly.
Unknown image extensions in the operation definition have not effect.

See #6298
2019-09-21 16:50:27 +02:00

376 lines
9.5 KiB
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/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/internal"
"github.com/gohugoio/hugo/resources/resource"
_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.Reader) 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 = internal.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) {
return 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}
}
if conf.TargetFormat == images.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
}
}
ci := i.clone(converted)
ci.setBasePath(conf)
ci.Format = conf.TargetFormat
ci.setMediaType(conf.TargetFormat.MediaType())
return ci, converted, nil
})
}
func (i *imageResource) decodeImageConfig(action, spec string) (images.ImageConfig, error) {
conf, err := images.DecodeImageConfig(action, spec, i.Proc.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.Quality
}
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
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 := internal.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),
}
}