mirror of
https://github.com/Luzifer/gallery.git
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115 lines
2.2 KiB
Go
115 lines
2.2 KiB
Go
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package main
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import (
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"bytes"
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"fmt"
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"image"
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"io"
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"math"
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"os"
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"strconv"
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"strings"
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"github.com/disintegration/imaging"
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)
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const (
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imgQuality = 95
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)
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type transformFunc func(img image.Image, width int, height int, filter imaging.ResampleFilter) *image.NRGBA
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func noTransform(img image.Image, width int, height int, filter imaging.ResampleFilter) *image.NRGBA {
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return imaging.Clone(img)
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}
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type size struct {
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width int
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height int
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}
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func parseSize(s string) (size, error) {
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nums := strings.Split(s, "x")
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if len(nums) != 2 {
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return size{}, fmt.Errorf("Invalid size %q", s)
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}
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w, err := strconv.ParseInt(nums[0], 10, 64)
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if err != nil {
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return size{}, fmt.Errorf("Invalid size %q: %s", s, err)
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}
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h, err := strconv.ParseInt(nums[1], 10, 64)
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if err != nil {
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return size{}, fmt.Errorf("Invalid size %q: %s", s, err)
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}
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return size{
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width: int(w),
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height: int(h),
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}, nil
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}
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func scaleImage(path string) (thumbnail io.Reader, fullsize io.Reader, err error) {
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var img image.Image
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img, err = loadImage(path)
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if err != nil {
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return
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}
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thumbnail, err = generateThumbnail(img)
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if err != nil {
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return
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}
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fullsize, err = fitImage(img)
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return
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}
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func fitImage(img image.Image) (io.Reader, error) {
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s, err := parseSize(cfg.FullSize)
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if err != nil {
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return nil, err
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}
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origW, origH := img.Bounds().Max.X, img.Bounds().Max.Y
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scaleFactor := math.Max(float64(s.width)/float64(origW), float64(s.height)/float64(origH))
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var t transformFunc = noTransform
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if scaleFactor < 1 {
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t = imaging.Fit
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}
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return renderImage(img, s.width, s.height, t)
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}
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func generateThumbnail(img image.Image) (io.Reader, error) {
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s, err := parseSize(cfg.ThumbnailSize)
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if err != nil {
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return nil, err
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}
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return renderImage(img, s.width, s.height, imaging.Thumbnail)
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}
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func renderImage(img image.Image, w, h int, trans transformFunc) (io.Reader, error) {
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outImg := trans(img, w, h, imaging.Lanczos)
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buf := new(bytes.Buffer)
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if err := imaging.Encode(buf, outImg, imaging.JPEG, imaging.JPEGQuality(imgQuality)); err != nil {
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return nil, err
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}
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return buf, nil
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}
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func loadImage(path string) (image.Image, error) {
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fp, err := os.Open(path)
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if err != nil {
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return nil, err
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}
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defer fp.Close()
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return imaging.Decode(fp)
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}
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