photoprism/internal/thumb/create.go

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package thumb
import (
"errors"
"fmt"
"image"
"image/png"
"os"
"path"
"path/filepath"
"github.com/photoprism/photoprism/pkg/fs"
"github.com/disintegration/imaging"
)
func ResampleOptions(opts ...ResampleOption) (method ResampleOption, filter imaging.ResampleFilter, format fs.Type) {
method = ResampleFit
filter = imaging.Lanczos
format = fs.TypeJpeg
for _, option := range opts {
switch option {
case ResamplePng:
format = fs.TypePng
case ResampleNearestNeighbor:
filter = imaging.NearestNeighbor
case ResampleDefault:
filter = Algorithm.Filter()
case ResampleFillTopLeft:
method = ResampleFillTopLeft
case ResampleFillCenter:
method = ResampleFillCenter
case ResampleFillBottomRight:
method = ResampleFillBottomRight
case ResampleFit:
method = ResampleFit
case ResampleResize:
method = ResampleResize
default:
panic(fmt.Errorf("not a valid resample option: %d", option))
}
}
return method, filter, format
}
func Resample(img image.Image, width, height int, opts ...ResampleOption) (result image.Image) {
method, filter, _ := ResampleOptions(opts...)
if method == ResampleFit {
result = imaging.Fit(img, width, height, filter)
} else if method == ResampleFillCenter {
result = imaging.Fill(img, width, height, imaging.Center, filter)
} else if method == ResampleFillTopLeft {
result = imaging.Fill(img, width, height, imaging.TopLeft, filter)
} else if method == ResampleFillBottomRight {
result = imaging.Fill(img, width, height, imaging.BottomRight, filter)
} else if method == ResampleResize {
result = imaging.Resize(img, width, height, filter)
}
return result
}
func Postfix(width, height int, opts ...ResampleOption) (result string) {
method, _, format := ResampleOptions(opts...)
result = fmt.Sprintf("%dx%d_%s.%s", width, height, ResampleMethods[method], format)
return result
}
func Filename(hash string, thumbPath string, width, height int, opts ...ResampleOption) (filename string, err error) {
if width < 0 || width > MaxRenderSize {
return "", fmt.Errorf("thumbs: width exceeds limit (%d)", width)
}
if height < 0 || height > MaxRenderSize {
return "", fmt.Errorf("thumbs: height exceeds limit (%d)", height)
}
if len(hash) < 4 {
return "", fmt.Errorf("thumbs: file hash is empty or too short (\"%s\")", hash)
}
if len(thumbPath) == 0 {
return "", errors.New("thumbs: path is empty")
}
postfix := Postfix(width, height, opts...)
p := path.Join(thumbPath, hash[0:1], hash[1:2], hash[2:3])
if err := os.MkdirAll(p, os.ModePerm); err != nil {
return "", err
}
filename = fmt.Sprintf("%s/%s_%s", p, hash, postfix)
return filename, nil
}
func FromFile(imageFilename string, hash string, thumbPath string, width, height int, opts ...ResampleOption) (fileName string, err error) {
if len(hash) < 4 {
return "", fmt.Errorf("thumbs: file hash is empty or too short (\"%s\")", hash)
}
if len(imageFilename) < 4 {
return "", fmt.Errorf("thumbs: image filename is empty or too short (\"%s\")", imageFilename)
}
fileName, err = Filename(hash, thumbPath, width, height, opts...)
if err != nil {
log.Errorf("thumbs: can't determine filename (%s)", err)
return "", err
}
if fs.FileExists(fileName) {
return fileName, nil
}
img, err := imaging.Open(imageFilename, imaging.AutoOrientation(true))
if err != nil {
log.Errorf("can't open original: %s", err)
return "", err
}
if _, err := Create(img, fileName, width, height, opts...); err != nil {
return "", err
}
return fileName, nil
}
func Create(img image.Image, fileName string, width, height int, opts ...ResampleOption) (result image.Image, err error) {
if width < 0 || width > MaxRenderSize {
return img, fmt.Errorf("thumbs: width has an invalid value (%d)", width)
}
if height < 0 || height > MaxRenderSize {
return img, fmt.Errorf("thumbs: height has an invalid value (%d)", height)
}
result = Resample(img, width, height, opts...)
var saveOption imaging.EncodeOption
if filepath.Ext(fileName) == "."+string(fs.TypePng) {
saveOption = imaging.PNGCompressionLevel(png.DefaultCompression)
} else if width <= 150 && height <= 150 {
saveOption = imaging.JPEGQuality(JpegQualitySmall)
} else {
saveOption = imaging.JPEGQuality(JpegQuality)
}
err = imaging.Save(result, fileName, saveOption)
if err != nil {
log.Errorf("thumbs: failed to save %s", fileName)
return result, err
}
return result, nil
}