refactor(thumb): new thumb pipeline model to generate thumb on-demand

pkg/thumb/builtin.go

@@ -0,0 +1,177 @@
+package thumb
+
+import (
+	"fmt"
+	"image"
+	"image/gif"
+	"image/jpeg"
+	"image/png"
+	"io"
+	"path/filepath"
+	"strings"
+
+	model "github.com/cloudreve/Cloudreve/v3/models"
+	"github.com/cloudreve/Cloudreve/v3/pkg/util"
+
+	//"github.com/nfnt/resize"
+	"golang.org/x/image/draw"
+)
+
+func init() {
+	RegisterGenerator(&Builtin{})
+}
+
+// Thumb 缩略图
+type Thumb struct {
+	src image.Image
+	ext string
+}
+
+// NewThumbFromFile 从文件数据获取新的Thumb对象，
+// 尝试通过文件名name解码图像
+func NewThumbFromFile(file io.Reader, name string) (*Thumb, error) {
+	ext := strings.ToLower(filepath.Ext(name))
+	// 无扩展名时
+	if len(ext) == 0 {
+		return nil, fmt.Errorf("unknown image format: %w", ErrPassThrough)
+	}
+
+	var err error
+	var img image.Image
+	switch ext[1:] {
+	case "jpg":
+		img, err = jpeg.Decode(file)
+	case "jpeg":
+		img, err = jpeg.Decode(file)
+	case "gif":
+		img, err = gif.Decode(file)
+	case "png":
+		img, err = png.Decode(file)
+	default:
+		return nil, fmt.Errorf("unknown image format: %w", ErrPassThrough)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return &Thumb{
+		src: img,
+		ext: ext[1:],
+	}, nil
+}
+
+// GetThumb 生成给定最大尺寸的缩略图
+func (image *Thumb) GetThumb(width, height uint) {
+	//image.src = resize.Thumbnail(width, height, image.src, resize.Lanczos3)
+	image.src = Thumbnail(width, height, image.src)
+}
+
+// GetSize 获取图像尺寸
+func (image *Thumb) GetSize() (int, int) {
+	b := image.src.Bounds()
+	return b.Max.X, b.Max.Y
+}
+
+// Save 保存图像到给定路径
+func (image *Thumb) Save(w io.Writer) (err error) {
+	switch model.GetSettingByNameWithDefault("thumb_encode_method", "jpg") {
+	case "png":
+		err = png.Encode(w, image.src)
+	default:
+		err = jpeg.Encode(w, image.src, &jpeg.Options{Quality: model.GetIntSetting("thumb_encode_quality", 85)})
+	}
+
+	return err
+
+}
+
+// Thumbnail will downscale provided image to max width and height preserving
+// original aspect ratio and using the interpolation function interp.
+// It will return original image, without processing it, if original sizes
+// are already smaller than provided constraints.
+func Thumbnail(maxWidth, maxHeight uint, img image.Image) image.Image {
+	origBounds := img.Bounds()
+	origWidth := uint(origBounds.Dx())
+	origHeight := uint(origBounds.Dy())
+	newWidth, newHeight := origWidth, origHeight
+
+	// Return original image if it have same or smaller size as constraints
+	if maxWidth >= origWidth && maxHeight >= origHeight {
+		return img
+	}
+
+	// Preserve aspect ratio
+	if origWidth > maxWidth {
+		newHeight = uint(origHeight * maxWidth / origWidth)
+		if newHeight < 1 {
+			newHeight = 1
+		}
+		newWidth = maxWidth
+	}
+
+	if newHeight > maxHeight {
+		newWidth = uint(newWidth * maxHeight / newHeight)
+		if newWidth < 1 {
+			newWidth = 1
+		}
+		newHeight = maxHeight
+	}
+	return Resize(newWidth, newHeight, img)
+}
+
+func Resize(newWidth, newHeight uint, img image.Image) image.Image {
+	// Set the expected size that you want:
+	dst := image.NewRGBA(image.Rect(0, 0, int(newWidth), int(newHeight)))
+	// Resize:
+	draw.BiLinear.Scale(dst, dst.Rect, img, img.Bounds(), draw.Src, nil)
+	return dst
+}
+
+// CreateAvatar 创建头像
+func (image *Thumb) CreateAvatar(uid uint) error {
+	// 读取头像相关设定
+	savePath := util.RelativePath(model.GetSettingByName("avatar_path"))
+	s := model.GetIntSetting("avatar_size_s", 50)
+	m := model.GetIntSetting("avatar_size_m", 130)
+	l := model.GetIntSetting("avatar_size_l", 200)
+
+	// 生成头像缩略图
+	src := image.src
+	for k, size := range []int{s, m, l} {
+		out, err := util.CreatNestedFile(filepath.Join(savePath, fmt.Sprintf("avatar_%d_%d.png", uid, k)))
+
+		if err != nil {
+			return err
+		}
+		defer out.Close()
+
+		image.src = Resize(uint(size), uint(size), src)
+		err = image.Save(out)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+
+}
+
+type Builtin struct{}
+
+func (b Builtin) Generate(file io.Reader, w io.Writer, name string, options map[string]string) error {
+	img, err := NewThumbFromFile(file, name)
+	if err != nil {
+		return err
+	}
+
+	img.GetThumb(thumbSize(options))
+	return img.Save(w)
+}
+
+func (b Builtin) Priority() int {
+	return 300
+}
+
+func (b Builtin) EnableFlag() string {
+	return "thumb_builtin_enabled"
+}