更新

2026-09-03 08:38:17 +08:00
parent 6cd4f1b1db
commit 842990b0e7
1853 changed files with 278406 additions and 361 deletions
@@ -0,0 +1,83 @@
+package app
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/jpeg"
+	"io"
+
+	"github.com/disintegration/imaging"
+	_ "golang.org/x/image/webp"
+)
+
+const (
+	avatarDisplaySize   = 640
+	avatarThumbnailSize = 256
+	maxAvatarPixels     = 24_000_000
+)
+
+// Bound peak decoding memory on small servers. Do not queue decoded photos in
+// memory when multiple clients upload avatars at the same time.
+var avatarProcessing = make(chan struct{}, 1)
+var errAvatarBusy = errors.New("头像正在处理中，请稍后重试")
+
+type avatarImages struct {
+	Display, Thumbnail []byte
+	Width, Height      int
+}
+
+func createAvatarImages(ctx context.Context, source io.ReadSeeker) (avatarImages, error) {
+	select {
+	case avatarProcessing <- struct{}{}:
+		defer func() { <-avatarProcessing }()
+	default:
+		return avatarImages{}, errAvatarBusy
+	}
+	if err := ctx.Err(); err != nil {
+		return avatarImages{}, err
+	}
+	config, format, err := image.DecodeConfig(source)
+	if err != nil || (format != "jpeg" && format != "png" && format != "gif" && format != "webp") {
+		return avatarImages{}, errors.New("无法读取头像，请选择有效的 JPG、PNG、GIF 或 WebP 图片")
+	}
+	if config.Width <= 0 || config.Height <= 0 || config.Width > 16384 || config.Height > 16384 || int64(config.Width)*int64(config.Height) > maxAvatarPixels {
+		return avatarImages{}, errors.New("头像分辨率过大，请选择不超过 2400 万像素的图片")
+	}
+	if _, err = source.Seek(0, io.SeekStart); err != nil {
+		return avatarImages{}, err
+	}
+	// Orient phone photos before resizing. Re-encoding also removes EXIF/GPS
+	// from the display variants. Animated images use their first decoded frame.
+	src, err := imaging.Decode(source, imaging.AutoOrientation(true))
+	if err != nil {
+		return avatarImages{}, errors.New("头像文件损坏或格式暂不支持，请重新选择图片")
+	}
+	if err = ctx.Err(); err != nil {
+		return avatarImages{}, err
+	}
+	display := imaging.Fit(src, avatarDisplaySize, avatarDisplaySize, imaging.Lanczos)
+	thumbnail := imaging.Fit(display, avatarThumbnailSize, avatarThumbnailSize, imaging.Lanczos)
+	result := avatarImages{Width: display.Bounds().Dx(), Height: display.Bounds().Dy()}
+	if result.Display, err = avatarJPEG(display, 82); err != nil {
+		return avatarImages{}, err
+	}
+	if result.Thumbnail, err = avatarJPEG(thumbnail, 78); err != nil {
+		return avatarImages{}, err
+	}
+	_, err = source.Seek(0, io.SeekStart)
+	return result, err
+}
+
+func avatarJPEG(src image.Image, quality int) ([]byte, error) {
+	// Composite transparency onto white instead of producing black PNG edges.
+	opaque := image.NewRGBA(src.Bounds())
+	draw.Draw(opaque, opaque.Bounds(), image.NewUniform(color.White), image.Point{}, draw.Src)
+	draw.Draw(opaque, opaque.Bounds(), src, src.Bounds().Min, draw.Over)
+	var buffer bytes.Buffer
+	err := jpeg.Encode(&buffer, opaque, &jpeg.Options{Quality: quality})
+	return buffer.Bytes(), err
+}