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Add Luminance to Color
To sort an image's colors from darkest to lightest, you can then do: ```handlebars {{ {{ $colorsByLuminance := sort $image.Colors "Luminance" }} ``` This uses the formula defined here: https://www.w3.org/TR/WCAG21/#dfn-relative-luminance Fixes #10450
This commit is contained in:
parent
74e9129568
commit
e197c7b29d
12 changed files with 204 additions and 39 deletions
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@ -123,6 +123,20 @@ func InSlicEqualFold(arr []string, el string) bool {
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return false
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}
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// ToString converts the given value to a string.
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// Note that this is a more strict version compared to cast.ToString,
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// as it will not try to convert numeric values to strings,
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// but only accept strings or fmt.Stringer.
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func ToString(v any) (string, bool) {
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switch vv := v.(type) {
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case string:
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return vv, true
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case fmt.Stringer:
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return vv.String(), true
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}
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return "", false
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}
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type Tuple struct {
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First string
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Second string
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@ -128,7 +128,7 @@ func (e *errorResource) Exif() *exif.ExifInfo {
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panic(e.ResourceError)
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}
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func (e *errorResource) Colors() ([]string, error) {
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func (e *errorResource) Colors() ([]images.Color, error) {
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panic(e.ResourceError)
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}
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@ -67,7 +67,7 @@ type imageResource struct {
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meta *imageMeta
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dominantColorInit sync.Once
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dominantColors []string
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dominantColors []images.Color
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baseResource
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}
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@ -143,7 +143,7 @@ func (i *imageResource) getExif() *exif.ExifInfo {
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// Colors returns a slice of the most dominant colors in an image
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// using a simple histogram method.
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func (i *imageResource) Colors() ([]string, error) {
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func (i *imageResource) Colors() ([]images.Color, error) {
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var err error
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i.dominantColorInit.Do(func() {
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var img image.Image
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@ -153,7 +153,7 @@ func (i *imageResource) Colors() ([]string, error) {
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}
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colors := color_extractor.ExtractColors(img)
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for _, c := range colors {
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i.dominantColors = append(i.dominantColors, images.ColorToHexString(c))
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i.dominantColors = append(i.dominantColors, images.ColorGoToColor(c))
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}
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})
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return i.dominantColors, nil
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@ -85,9 +85,16 @@ func TestImageTransformBasic(t *testing.T) {
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assertWidthHeight(c, img, w, h)
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}
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colors, err := image.Colors()
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gotColors, err := image.Colors()
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c.Assert(err, qt.IsNil)
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c.Assert(colors, qt.DeepEquals, []string{"#2d2f33", "#a49e93", "#d39e59", "#a76936", "#737a84", "#7c838b"})
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expectedColors := images.HexStringsToColors("#2d2f33", "#a49e93", "#d39e59", "#a76936", "#737a84", "#7c838b")
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c.Assert(len(gotColors), qt.Equals, len(expectedColors))
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for i := range gotColors {
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c1, c2 := gotColors[i], expectedColors[i]
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c.Assert(c1.ColorHex(), qt.Equals, c2.ColorHex())
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c.Assert(c1.ColorGo(), qt.DeepEquals, c2.ColorGo())
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c.Assert(c1.Luminance(), qt.Equals, c2.Luminance())
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}
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c.Assert(image.RelPermalink(), qt.Equals, "/a/sunset.jpg")
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c.Assert(image.ResourceType(), qt.Equals, "image")
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@ -445,6 +452,24 @@ func TestImageExif(t *testing.T) {
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getAndCheckExif(c, image)
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}
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func TestImageColorsLuminance(t *testing.T) {
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c := qt.New(t)
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_, image := fetchSunset(c)
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c.Assert(image, qt.Not(qt.IsNil))
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colors, err := image.Colors()
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c.Assert(err, qt.IsNil)
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c.Assert(len(colors), qt.Equals, 6)
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var prevLuminance float64
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for i, color := range colors {
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luminance := color.Luminance()
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c.Assert(err, qt.IsNil)
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c.Assert(luminance > 0, qt.IsTrue)
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c.Assert(luminance, qt.Not(qt.Equals), prevLuminance, qt.Commentf("i=%d", i))
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prevLuminance = luminance
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}
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}
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func BenchmarkImageExif(b *testing.B) {
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getImages := func(c *qt.C, b *testing.B, fs afero.Fs) []images.ImageResource {
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spec := newTestResourceSpec(specDescriptor{fs: fs, c: c})
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@ -16,10 +16,76 @@ package images
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import (
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"encoding/hex"
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"fmt"
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"hash/fnv"
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"image/color"
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"math"
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"strings"
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"github.com/gohugoio/hugo/common/hstrings"
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)
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type colorGoProvider interface {
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ColorGo() color.Color
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}
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type Color struct {
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// The color.
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color color.Color
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// The color prefixed with a #.
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hex string
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// The relative luminance of the color.
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luminance float64
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}
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// Luminance as defined by w3.org.
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// See https://www.w3.org/TR/WCAG21/#dfn-relative-luminance
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func (c Color) Luminance() float64 {
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return c.luminance
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}
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// ColorGo returns the color as a color.Color.
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// For internal use only.
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func (c Color) ColorGo() color.Color {
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return c.color
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}
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// ColorHex returns the color as a hex string prefixed with a #.
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func (c Color) ColorHex() string {
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return c.hex
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}
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// String returns the color as a hex string prefixed with a #.
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func (c Color) String() string {
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return c.hex
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}
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// For hashstructure. This struct is used in template func options
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// that needs to be able to hash a Color.
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// For internal use only.
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func (c Color) Hash() (uint64, error) {
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h := fnv.New64a()
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h.Write([]byte(c.hex))
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return h.Sum64(), nil
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}
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func (c *Color) init() error {
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c.hex = ColorGoToHexString(c.color)
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r, g, b, _ := c.color.RGBA()
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c.luminance = 0.2126*c.toSRGB(uint8(r)) + 0.7152*c.toSRGB(uint8(g)) + 0.0722*c.toSRGB(uint8(b))
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return nil
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}
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func (c Color) toSRGB(i uint8) float64 {
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v := float64(i) / 255
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if v <= 0.04045 {
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return v / 12.92
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} else {
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return math.Pow((v+0.055)/1.055, 2.4)
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}
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}
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// AddColorToPalette adds c as the first color in p if not already there.
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// Note that it does no additional checks, so callers must make sure
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// that the palette is valid for the relevant format.
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@ -45,14 +111,60 @@ func ReplaceColorInPalette(c color.Color, p color.Palette) {
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p[p.Index(c)] = c
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}
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// ColorToHexString converts a color to a hex string.
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func ColorToHexString(c color.Color) string {
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// ColorGoToHexString converts a color.Color to a hex string.
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func ColorGoToHexString(c color.Color) string {
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r, g, b, a := c.RGBA()
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rgba := color.RGBA{uint8(r), uint8(g), uint8(b), uint8(a)}
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return fmt.Sprintf("#%.2x%.2x%.2x", rgba.R, rgba.G, rgba.B)
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if rgba.A == 0xff {
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return fmt.Sprintf("#%.2x%.2x%.2x", rgba.R, rgba.G, rgba.B)
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}
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return fmt.Sprintf("#%.2x%.2x%.2x%.2x", rgba.R, rgba.G, rgba.B, rgba.A)
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}
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func hexStringToColor(s string) (color.Color, error) {
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// ColorGoToColor converts a color.Color to a Color.
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func ColorGoToColor(c color.Color) Color {
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cc := Color{color: c}
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if err := cc.init(); err != nil {
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panic(err)
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}
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return cc
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}
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func hexStringToColor(s string) Color {
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c, err := hexStringToColorGo(s)
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if err != nil {
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panic(err)
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}
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return ColorGoToColor(c)
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}
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// HexStringsToColors converts a slice of hex strings to a slice of Colors.
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func HexStringsToColors(s ...string) []Color {
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var colors []Color
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for _, v := range s {
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colors = append(colors, hexStringToColor(v))
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}
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return colors
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}
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func toColorGo(v any) (color.Color, bool, error) {
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switch vv := v.(type) {
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case colorGoProvider:
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return vv.ColorGo(), true, nil
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default:
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s, ok := hstrings.ToString(v)
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if !ok {
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return nil, false, nil
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}
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c, err := hexStringToColorGo(s)
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if err != nil {
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return nil, false, err
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}
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return c, true, nil
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}
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}
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func hexStringToColorGo(s string) (color.Color, error) {
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s = strings.TrimPrefix(s, "#")
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if len(s) != 3 && len(s) != 4 && len(s) != 6 && len(s) != 8 {
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@ -46,7 +46,7 @@ func TestHexStringToColor(t *testing.T) {
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c.Run(test.arg, func(c *qt.C) {
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c.Parallel()
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result, err := hexStringToColor(test.arg)
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result, err := hexStringToColorGo(test.arg)
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if b, ok := test.expect.(bool); ok && !b {
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c.Assert(err, qt.Not(qt.IsNil))
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@ -70,13 +70,18 @@ func TestColorToHexString(t *testing.T) {
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{color.White, "#ffffff"},
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{color.Black, "#000000"},
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{color.RGBA{R: 0x42, G: 0x87, B: 0xf5, A: 0xff}, "#4287f5"},
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// 50% opacity.
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// Note that the .Colors (dominant colors) received from the Image resource
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// will always have an alpha value of 0xff.
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{color.RGBA{R: 0x42, G: 0x87, B: 0xf5, A: 0x80}, "#4287f580"},
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} {
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test := test
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c.Run(test.expect, func(c *qt.C) {
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c.Parallel()
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result := ColorToHexString(test.arg)
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result := ColorGoToHexString(test.arg)
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c.Assert(result, qt.Equals, test.expect)
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})
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@ -91,9 +96,9 @@ func TestAddColorToPalette(t *testing.T) {
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c.Assert(AddColorToPalette(color.White, palette), qt.HasLen, 2)
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blue1, _ := hexStringToColor("34c3eb")
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blue2, _ := hexStringToColor("34c3eb")
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white, _ := hexStringToColor("fff")
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blue1, _ := hexStringToColorGo("34c3eb")
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blue2, _ := hexStringToColorGo("34c3eb")
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white, _ := hexStringToColorGo("fff")
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c.Assert(AddColorToPalette(white, palette), qt.HasLen, 2)
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c.Assert(AddColorToPalette(blue1, palette), qt.HasLen, 3)
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@ -104,10 +109,18 @@ func TestReplaceColorInPalette(t *testing.T) {
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c := qt.New(t)
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palette := color.Palette{color.White, color.Black}
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offWhite, _ := hexStringToColor("fcfcfc")
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offWhite, _ := hexStringToColorGo("fcfcfc")
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ReplaceColorInPalette(offWhite, palette)
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c.Assert(palette, qt.HasLen, 2)
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c.Assert(palette[0], qt.Equals, offWhite)
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}
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func TestColorLuminance(t *testing.T) {
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c := qt.New(t)
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c.Assert(hexStringToColor("#000000").Luminance(), qt.Equals, 0.0)
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c.Assert(hexStringToColor("#768a9a").Luminance(), qt.Equals, 0.24361603589088263)
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c.Assert(hexStringToColor("#d5bc9f").Luminance(), qt.Equals, 0.5261577672685374)
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c.Assert(hexStringToColor("#ffffff").Luminance(), qt.Equals, 1.0)
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}
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@ -171,7 +171,7 @@ func DecodeConfig(in map[string]any) (*config.ConfigNamespace[ImagingConfig, Ima
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return i, nil, err
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}
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i.BgColor, err = hexStringToColor(i.Imaging.BgColor)
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i.BgColor, err = hexStringToColorGo(i.Imaging.BgColor)
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if err != nil {
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return i, nil, err
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}
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@ -230,7 +230,7 @@ func DecodeImageConfig(action string, options []string, defaults *config.ConfigN
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c.Hint = hint
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} else if part[0] == '#' {
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c.BgColorStr = part[1:]
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c.BgColor, err = hexStringToColor(c.BgColorStr)
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c.BgColor, err = hexStringToColorGo(c.BgColorStr)
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if err != nil {
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return c, err
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}
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@ -424,7 +424,7 @@ type ImagingConfigInternal struct {
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func (i *ImagingConfigInternal) Compile(externalCfg *ImagingConfig) error {
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var err error
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i.BgColor, err = hexStringToColor(externalCfg.BgColor)
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i.BgColor, err = hexStringToColorGo(externalCfg.BgColor)
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if err != nil {
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return err
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}
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@ -132,7 +132,7 @@ func newImageConfig(action string, width, height, quality, rotate int, filter, a
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c.qualitySetForImage = quality != 75
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c.Rotate = rotate
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c.BgColorStr = bgColor
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c.BgColor, _ = hexStringToColor(bgColor)
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c.BgColor, _ = hexStringToColorGo(bgColor)
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if filter != "" {
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filter = strings.ToLower(filter)
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@ -1,4 +1,4 @@
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// Copyright 2019 The Hugo Authors. All rights reserved.
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// Copyright 2024 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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@ -65,7 +65,7 @@ func (*Filters) Opacity(opacity any) gift.Filter {
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func (*Filters) Text(text string, options ...any) gift.Filter {
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tf := textFilter{
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text: text,
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color: "#ffffff",
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color: color.White,
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size: 20,
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x: 10,
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y: 10,
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@ -78,7 +78,9 @@ func (*Filters) Text(text string, options ...any) gift.Filter {
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for option, v := range opt {
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switch option {
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case "color":
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tf.color = cast.ToString(v)
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if color, ok, _ := toColorGo(v); ok {
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tf.color = color
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}
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case "size":
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tf.size = cast.ToFloat64(v)
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case "x":
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@ -128,15 +130,14 @@ func (*Filters) Padding(args ...any) gift.Filter {
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var top, right, bottom, left int
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var ccolor color.Color = color.White // canvas color
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var err error
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_args := args // preserve original args for most stable hash
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if vcs, ok := (args[len(args)-1]).(string); ok {
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ccolor, err = hexStringToColor(vcs)
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if vcs, ok, err := toColorGo(args[len(args)-1]); ok || err != nil {
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if err != nil {
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panic("invalid canvas color: specify RGB or RGBA using hex notation")
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}
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ccolor = vcs
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args = args[:len(args)-1]
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if len(args) == 0 {
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panic("not enough arguments: provide one or more padding values using the CSS shorthand property syntax")
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@ -180,12 +181,11 @@ func (*Filters) Padding(args ...any) gift.Filter {
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// Dither creates a filter that dithers an image.
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func (*Filters) Dither(options ...any) gift.Filter {
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ditherOptions := struct {
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Colors []string
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Colors []any
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Method string
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Serpentine bool
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Strength float32
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}{
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Colors: []string{"000000ff", "ffffffff"},
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Method: "floydsteinberg",
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Serpentine: true,
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Strength: 1.0,
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@ -198,14 +198,18 @@ func (*Filters) Dither(options ...any) gift.Filter {
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}
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}
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if len(ditherOptions.Colors) == 0 {
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ditherOptions.Colors = []any{"000000ff", "ffffffff"}
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}
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if len(ditherOptions.Colors) < 2 {
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panic("palette must have at least two colors")
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}
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var palette []color.Color
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for _, c := range ditherOptions.Colors {
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cc, err := hexStringToColor(c)
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if err != nil {
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cc, ok, err := toColorGo(c)
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if !ok || err != nil {
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panic(fmt.Sprintf("%q is an invalid color: specify RGB or RGBA using hexadecimal notation", c))
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}
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palette = append(palette, cc)
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@ -63,7 +63,7 @@ type ImageResourceOps interface {
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// Colors returns a slice of the most dominant colors in an image
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// using a simple histogram method.
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Colors() ([]string, error)
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Colors() ([]Color, error)
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// For internal use.
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DecodeImage() (image.Image, error)
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@ -15,6 +15,7 @@ package images
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import (
|
||||
"image"
|
||||
"image/color"
|
||||
"image/draw"
|
||||
"io"
|
||||
"strings"
|
||||
|
@ -31,7 +32,8 @@ import (
|
|||
var _ gift.Filter = (*textFilter)(nil)
|
||||
|
||||
type textFilter struct {
|
||||
text, color string
|
||||
text string
|
||||
color color.Color
|
||||
x, y int
|
||||
size float64
|
||||
linespacing int
|
||||
|
@ -39,11 +41,6 @@ type textFilter struct {
|
|||
}
|
||||
|
||||
func (f textFilter) Draw(dst draw.Image, src image.Image, options *gift.Options) {
|
||||
color, err := hexStringToColor(f.color)
|
||||
if err != nil {
|
||||
panic(err)
|
||||
}
|
||||
|
||||
// Load and parse font
|
||||
ttf := goregular.TTF
|
||||
if f.fontSource != nil {
|
||||
|
@ -74,7 +71,7 @@ func (f textFilter) Draw(dst draw.Image, src image.Image, options *gift.Options)
|
|||
|
||||
d := font.Drawer{
|
||||
Dst: dst,
|
||||
Src: image.NewUniform(color),
|
||||
Src: image.NewUniform(f.color),
|
||||
Face: face,
|
||||
}
|
||||
|
||||
|
|
|
@ -263,7 +263,7 @@ func (r *resourceAdapter) Exif() *exif.ExifInfo {
|
|||
return r.getImageOps().Exif()
|
||||
}
|
||||
|
||||
func (r *resourceAdapter) Colors() ([]string, error) {
|
||||
func (r *resourceAdapter) Colors() ([]images.Color, error) {
|
||||
return r.getImageOps().Colors()
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue