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Do not upscale inline thumbnails

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corrado.mulas
2026-10-04 10:54:21 +02:00
parent dd4b591f42
commit 3abaf71920
1 changed files with 13 additions and 2 deletions
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15
internal/render/render.go
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@@ -395,15 +395,26 @@ func (r *Renderer) renderThumbnail(ctx context.Context, workdir string, dpi int,
args := []string{ args := []string{
"-jpeg", "-jpegopt", "quality=82,progressive=n,optimize=y", "-jpeg", "-jpegopt", "quality=82,progressive=n,optimize=y",
"-r", strconv.Itoa(dpi), "-singlefile", "-f", "1", "-l", "1", "-r", strconv.Itoa(dpi), "-singlefile", "-f", "1", "-l", "1",
"-scale-to", strconv.Itoa(inlineThumbnailSide), pdfPath, base,
} }
if err := r.run(ctx, workdir, r.Pdftoppm, args...); err != nil { if err := r.run(ctx, workdir, r.Pdftoppm, append(args, pdfPath, base)...); err != nil {
return fmt.Errorf("render inline thumbnail: %w", err) return fmt.Errorf("render inline thumbnail: %w", err)
} }
width, height, err := imageSize(sourcePath) width, height, err := imageSize(sourcePath)
if err != nil { if err != nil {
return fmt.Errorf("inspect inline thumbnail: %w", err) return fmt.Errorf("inspect inline thumbnail: %w", err)
} }
// Only shrink oversized previews. pdftoppm's -scale-to also upscales
// small pages, which would unnecessarily enlarge short expressions.
if width > inlineThumbnailSide || height > inlineThumbnailSide {
scaledArgs := append(args, "-scale-to", strconv.Itoa(inlineThumbnailSide))
if err := r.run(ctx, workdir, r.Pdftoppm, append(scaledArgs, pdfPath, base)...); err != nil {
return fmt.Errorf("scale inline thumbnail: %w", err)
}
width, height, err = imageSize(sourcePath)
if err != nil {
return fmt.Errorf("inspect scaled inline thumbnail: %w", err)
}
}
if width > inlineThumbnailSide || height > inlineThumbnailSide { if width > inlineThumbnailSide || height > inlineThumbnailSide {
return fmt.Errorf("inline thumbnail is unexpectedly large: %dx%d", width, height) return fmt.Errorf("inline thumbnail is unexpectedly large: %dx%d", width, height)
} }