resource: Use Floyd-Steinberg dithering for PNGs

Fixes #4453
This commit is contained in:
Bjørn Erik Pedersen 2018-02-26 18:55:00 +01:00
parent 9f740b37cf
commit 13ea1e7c35
2 changed files with 3 additions and 3 deletions

View file

@ -80,7 +80,7 @@ var (
// Add or increment if changes to an image format's processing requires
// re-generation.
imageFormatsVersions = map[imaging.Format]int{
imaging.PNG: 1, // 1: Add proper palette handling
imaging.PNG: 2, // Floyd Steinberg dithering
}
// Increment to mark all processed images as stale. Only use when absolutely needed.
@ -266,7 +266,7 @@ func (i *Image) doWithImageConfig(action, spec string, f func(src image.Image, c
// Apply the colour palette from the source
if paletted, ok := src.(*image.Paletted); ok {
tmp := image.NewPaletted(converted.Bounds(), paletted.Palette)
draw.Src.Draw(tmp, tmp.Bounds(), converted, converted.Bounds().Min)
draw.FloydSteinberg.Draw(tmp, tmp.Bounds(), converted, converted.Bounds().Min)
converted = tmp
}
}

View file

@ -273,7 +273,7 @@ func TestImageResize8BitPNG(t *testing.T) {
resized, err := image.Resize("800x")
assert.NoError(err)
assert.Equal(imaging.PNG, resized.format)
assert.Equal("/a/gohugoio_hu0e1b9e4a4be4d6f86c7b37b9ccce3fbc_73886_800x0_resize_linear_1.png", resized.RelPermalink())
assert.Equal("/a/gohugoio_hu0e1b9e4a4be4d6f86c7b37b9ccce3fbc_73886_800x0_resize_linear_2.png", resized.RelPermalink())
assert.Equal(800, resized.Width())
}