Modify luminance calculation and extract related functions into single files (#24586)
Close #24508 Main changes: As discussed in the issue 1. Change luminance calculation function to use [Relative Luminance](https://www.w3.org/WAI/GL/wiki/Relative_luminance) 2. Move the luminance related functions into color.go/color.js 3. Add tests for both the files (Not sure if test cases are too many now) Before (tests included by `UseLightTextOnBackground` are labels started with `##`): https://try.gitea.io/HesterG/testrepo/labels After: <img width="1307" alt="Screen Shot 2023-05-08 at 13 37 55" src="https://user-images.githubusercontent.com/17645053/236742562-fdfc3a4d-2fab-466b-9613-96f2bf96b4bc.png"> <img width="1289" alt="Screen Shot 2023-05-08 at 13 38 06" src="https://user-images.githubusercontent.com/17645053/236742570-022db68e-cec0-43bb-888a-fc54f5332cc3.png"> <img width="1299" alt="Screen Shot 2023-05-08 at 13 38 20" src="https://user-images.githubusercontent.com/17645053/236742572-9af1de45-fb7f-460b-828d-ba25fae20f51.png"> --------- Co-authored-by: silverwind <me@silverwind.io> Co-authored-by: Giteabot <teabot@gitea.io>
This commit is contained in:
Hester Gong
GitHub
parent
0ca5adee16
commit
ea7954f069
@ -159,33 +159,6 @@ func (l *Label) BelongsToRepo() bool {
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return l.RepoID > 0
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}
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// Get color as RGB values in 0..255 range
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func (l *Label) ColorRGB() (float64, float64, float64, error) {
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color, err := strconv.ParseUint(l.Color[1:], 16, 64)
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if err != nil {
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return 0, 0, 0, err
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}
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r := float64(uint8(0xFF & (uint32(color) >> 16)))
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g := float64(uint8(0xFF & (uint32(color) >> 8)))
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b := float64(uint8(0xFF & uint32(color)))
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return r, g, b, nil
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}
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// Determine if label text should be light or dark to be readable on background color
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func (l *Label) UseLightTextColor() bool {
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if strings.HasPrefix(l.Color, "#") {
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if r, g, b, err := l.ColorRGB(); err == nil {
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// Perceived brightness from: https://www.w3.org/TR/AERT/#color-contrast
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// In the future WCAG 3 APCA may be a better solution
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brightness := (0.299*r + 0.587*g + 0.114*b) / 255
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return brightness < 0.35
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}
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}
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return false
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}
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// Return scope substring of label name, or empty string if none exists
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func (l *Label) ExclusiveScope() string {
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if !l.Exclusive {
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@ -22,15 +22,6 @@ func TestLabel_CalOpenIssues(t *testing.T) {
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assert.EqualValues(t, 2, label.NumOpenIssues)
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}
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func TestLabel_TextColor(t *testing.T) {
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assert.NoError(t, unittest.PrepareTestDatabase())
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label := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 1})
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assert.False(t, label.UseLightTextColor())
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label = unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 2})
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assert.True(t, label.UseLightTextColor())
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}
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func TestLabel_ExclusiveScope(t *testing.T) {
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assert.NoError(t, unittest.PrepareTestDatabase())
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label := unittest.AssertExistsAndLoadBean(t, &issues_model.Label{ID: 7})
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@ -20,6 +20,7 @@ import (
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"code.gitea.io/gitea/modules/markup"
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"code.gitea.io/gitea/modules/markup/markdown"
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"code.gitea.io/gitea/modules/setting"
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"code.gitea.io/gitea/modules/util"
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)
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// RenderCommitMessage renders commit message with XSS-safe and special links.
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@ -133,7 +134,9 @@ func RenderLabel(ctx context.Context, label *issues_model.Label) template.HTML {
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labelScope := label.ExclusiveScope()
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textColor := "#111"
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if label.UseLightTextColor() {
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r, g, b := util.HexToRBGColor(label.Color)
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// Determine if label text should be light or dark to be readable on background color
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if util.UseLightTextOnBackground(r, g, b) {
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textColor = "#eee"
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}
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@ -150,34 +153,30 @@ func RenderLabel(ctx context.Context, label *issues_model.Label) template.HTML {
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scopeText := RenderEmoji(ctx, labelScope)
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itemText := RenderEmoji(ctx, label.Name[len(labelScope)+1:])
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itemColor := label.Color
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scopeColor := label.Color
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if r, g, b, err := label.ColorRGB(); err == nil {
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// Make scope and item background colors slightly darker and lighter respectively.
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// More contrast needed with higher luminance, empirically tweaked.
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luminance := (0.299*r + 0.587*g + 0.114*b) / 255
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contrast := 0.01 + luminance*0.03
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// Ensure we add the same amount of contrast also near 0 and 1.
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darken := contrast + math.Max(luminance+contrast-1.0, 0.0)
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lighten := contrast + math.Max(contrast-luminance, 0.0)
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// Compute factor to keep RGB values proportional.
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darkenFactor := math.Max(luminance-darken, 0.0) / math.Max(luminance, 1.0/255.0)
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lightenFactor := math.Min(luminance+lighten, 1.0) / math.Max(luminance, 1.0/255.0)
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// Make scope and item background colors slightly darker and lighter respectively.
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// More contrast needed with higher luminance, empirically tweaked.
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luminance := util.GetLuminance(r, g, b)
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contrast := 0.01 + luminance*0.03
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// Ensure we add the same amount of contrast also near 0 and 1.
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darken := contrast + math.Max(luminance+contrast-1.0, 0.0)
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lighten := contrast + math.Max(contrast-luminance, 0.0)
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// Compute factor to keep RGB values proportional.
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darkenFactor := math.Max(luminance-darken, 0.0) / math.Max(luminance, 1.0/255.0)
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lightenFactor := math.Min(luminance+lighten, 1.0) / math.Max(luminance, 1.0/255.0)
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scopeBytes := []byte{
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uint8(math.Min(math.Round(r*darkenFactor), 255)),
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uint8(math.Min(math.Round(g*darkenFactor), 255)),
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uint8(math.Min(math.Round(b*darkenFactor), 255)),
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}
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itemBytes := []byte{
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uint8(math.Min(math.Round(r*lightenFactor), 255)),
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uint8(math.Min(math.Round(g*lightenFactor), 255)),
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uint8(math.Min(math.Round(b*lightenFactor), 255)),
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}
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itemColor = "#" + hex.EncodeToString(itemBytes)
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scopeColor = "#" + hex.EncodeToString(scopeBytes)
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scopeBytes := []byte{
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uint8(math.Min(math.Round(r*darkenFactor), 255)),
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uint8(math.Min(math.Round(g*darkenFactor), 255)),
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uint8(math.Min(math.Round(b*darkenFactor), 255)),
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}
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itemBytes := []byte{
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uint8(math.Min(math.Round(r*lightenFactor), 255)),
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uint8(math.Min(math.Round(g*lightenFactor), 255)),
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uint8(math.Min(math.Round(b*lightenFactor), 255)),
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}
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itemColor := "#" + hex.EncodeToString(itemBytes)
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scopeColor := "#" + hex.EncodeToString(scopeBytes)
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s := fmt.Sprintf("<span class='ui label scope-parent' title='%s'>"+
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"<div class='ui label scope-left' style='color: %s !important; background-color: %s !important'>%s</div>"+
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65
modules/util/color.go
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65
modules/util/color.go
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@ -0,0 +1,65 @@
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// Copyright 2023 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package util
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import (
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"fmt"
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"math"
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"strconv"
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"strings"
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)
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// Check similar implementation in web_src/js/utils/color.js and keep synchronization
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// Return R, G, B values defined in reletive luminance
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func getLuminanceRGB(channel float64) float64 {
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sRGB := channel / 255
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if sRGB <= 0.03928 {
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return sRGB / 12.92
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}
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return math.Pow((sRGB+0.055)/1.055, 2.4)
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}
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// Get color as RGB values in 0..255 range from the hex color string (with or without #)
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func HexToRBGColor(colorString string) (float64, float64, float64) {
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hexString := colorString
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if strings.HasPrefix(colorString, "#") {
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hexString = colorString[1:]
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}
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// only support transfer of rgb, rgba, rrggbb and rrggbbaa
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// if not in these formats, use default values 0, 0, 0
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if len(hexString) != 3 && len(hexString) != 4 && len(hexString) != 6 && len(hexString) != 8 {
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return 0, 0, 0
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}
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if len(hexString) == 3 || len(hexString) == 4 {
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hexString = fmt.Sprintf("%c%c%c%c%c%c", hexString[0], hexString[0], hexString[1], hexString[1], hexString[2], hexString[2])
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}
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if len(hexString) == 8 {
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hexString = hexString[0:6]
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}
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color, err := strconv.ParseUint(hexString, 16, 64)
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if err != nil {
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return 0, 0, 0
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}
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r := float64(uint8(0xFF & (uint32(color) >> 16)))
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g := float64(uint8(0xFF & (uint32(color) >> 8)))
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b := float64(uint8(0xFF & uint32(color)))
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return r, g, b
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}
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// return luminance given RGB channels
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// Reference from: https://www.w3.org/WAI/GL/wiki/Relative_luminance
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func GetLuminance(r, g, b float64) float64 {
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R := getLuminanceRGB(r)
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G := getLuminanceRGB(g)
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B := getLuminanceRGB(b)
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luminance := 0.2126*R + 0.7152*G + 0.0722*B
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return luminance
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}
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// Reference from: https://firsching.ch/github_labels.html
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// In the future WCAG 3 APCA may be a better solution.
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// Check if text should use light color based on RGB of background
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func UseLightTextOnBackground(r, g, b float64) bool {
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return GetLuminance(r, g, b) < 0.453
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}
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65
modules/util/color_test.go
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65
modules/util/color_test.go
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@ -0,0 +1,65 @@
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// Copyright 2023 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package util
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import (
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func Test_HexToRBGColor(t *testing.T) {
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cases := []struct {
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colorString string
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expectedR float64
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expectedG float64
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expectedB float64
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}{
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{"2b8685", 43, 134, 133},
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{"1e1", 17, 238, 17},
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{"#1e1", 17, 238, 17},
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{"1e16", 17, 238, 17},
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{"3bb6b3", 59, 182, 179},
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{"#3bb6b399", 59, 182, 179},
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{"#0", 0, 0, 0},
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{"#00000", 0, 0, 0},
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{"#1234567", 0, 0, 0},
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}
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for n, c := range cases {
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r, g, b := HexToRBGColor(c.colorString)
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assert.Equal(t, c.expectedR, r, "case %d: error R should match: expected %f, but get %f", n, c.expectedR, r)
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assert.Equal(t, c.expectedG, g, "case %d: error G should match: expected %f, but get %f", n, c.expectedG, g)
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assert.Equal(t, c.expectedB, b, "case %d: error B should match: expected %f, but get %f", n, c.expectedB, b)
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}
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}
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func Test_UseLightTextOnBackground(t *testing.T) {
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cases := []struct {
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r float64
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g float64
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b float64
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expected bool
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}{
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{215, 58, 74, true},
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{0, 117, 202, true},
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{207, 211, 215, false},
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{162, 238, 239, false},
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{112, 87, 255, true},
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{0, 134, 114, true},
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{228, 230, 105, false},
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{216, 118, 227, true},
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{255, 255, 255, false},
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{43, 134, 133, true},
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{43, 135, 134, true},
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{44, 135, 134, true},
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{59, 182, 179, true},
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{124, 114, 104, true},
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{126, 113, 108, true},
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{129, 112, 109, true},
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{128, 112, 112, true},
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}
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for n, c := range cases {
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result := UseLightTextOnBackground(c.r, c.g, c.b)
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assert.Equal(t, c.expected, result, "case %d: error should match", n)
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}
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}
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@ -26,7 +26,7 @@
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<script>
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import $ from 'jquery';
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import {SvgIcon} from '../svg.js';
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import {useLightTextOnBackground} from '../utils.js';
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import {useLightTextOnBackground, hexToRGBColor} from '../utils/color.js';
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const {appSubUrl, i18n} = window.config;
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@ -77,7 +77,8 @@ export default {
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labels() {
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return this.issue.labels.map((label) => {
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let textColor;
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if (useLightTextOnBackground(label.color)) {
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const [r, g, b] = hexToRGBColor(label.color);
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if (useLightTextOnBackground(r, g, b)) {
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textColor = '#eeeeee';
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} else {
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textColor = '#111111';
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@ -1,5 +1,5 @@
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import $ from 'jquery';
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import {useLightTextOnBackground} from '../utils.js';
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import {useLightTextOnBackground, hexToRGBColor} from '../utils/color.js';
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const {csrfToken} = window.config;
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@ -190,7 +190,8 @@ export function initRepoProject() {
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}
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function setLabelColor(label, color) {
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if (useLightTextOnBackground(color)) {
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const [r, g, b] = hexToRGBColor(color);
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if (useLightTextOnBackground(r, g, b)) {
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label.removeClass('dark-label').addClass('light-label');
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} else {
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label.removeClass('light-label').addClass('dark-label');
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@ -135,17 +135,3 @@ export function toAbsoluteUrl(url) {
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return `${window.location.origin}${url}`;
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}
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// determine if light or dark text color should be used on a given background color
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// NOTE: see models/issue_label.go for similar implementation
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export function useLightTextOnBackground(backgroundColor) {
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if (backgroundColor[0] === '#') {
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backgroundColor = backgroundColor.substring(1);
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}
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// Perceived brightness from: https://www.w3.org/TR/AERT/#color-contrast
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// In the future WCAG 3 APCA may be a better solution.
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const r = parseInt(backgroundColor.substring(0, 2), 16);
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const g = parseInt(backgroundColor.substring(2, 4), 16);
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const b = parseInt(backgroundColor.substring(4, 6), 16);
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const brightness = (0.299 * r + 0.587 * g + 0.114 * b) / 255;
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return brightness < 0.35;
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}
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42
web_src/js/utils/color.js
Normal file
42
web_src/js/utils/color.js
Normal file
@ -0,0 +1,42 @@
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// Check similar implementation in modules/util/color.go and keep synchronization
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// Return R, G, B values defined in reletive luminance
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function getLuminanceRGB(channel) {
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const sRGB = channel / 255;
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return (sRGB <= 0.03928) ? sRGB / 12.92 : ((sRGB + 0.055) / 1.055) ** 2.4;
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}
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// Reference from: https://www.w3.org/WAI/GL/wiki/Relative_luminance
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function getLuminance(r, g, b) {
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const R = getLuminanceRGB(r);
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const G = getLuminanceRGB(g);
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const B = getLuminanceRGB(b);
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return 0.2126 * R + 0.7152 * G + 0.0722 * B;
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}
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// Get color as RGB values in 0..255 range from the hex color string (with or without #)
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export function hexToRGBColor(backgroundColorStr) {
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let backgroundColor = backgroundColorStr;
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if (backgroundColorStr[0] === '#') {
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backgroundColor = backgroundColorStr.substring(1);
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}
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// only support transfer of rgb, rgba, rrggbb and rrggbbaa
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// if not in these formats, use default values 0, 0, 0
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if (![3, 4, 6, 8].includes(backgroundColor.length)) {
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return [0, 0, 0];
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}
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if ([3, 4].includes(backgroundColor.length)) {
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const [r, g, b] = backgroundColor;
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backgroundColor = `${r}${r}${g}${g}${b}${b}`;
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}
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const r = parseInt(backgroundColor.substring(0, 2), 16);
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const g = parseInt(backgroundColor.substring(2, 4), 16);
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const b = parseInt(backgroundColor.substring(4, 6), 16);
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return [r, g, b];
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}
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// Reference from: https://firsching.ch/github_labels.html
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// In the future WCAG 3 APCA may be a better solution.
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// Check if text should use light color based on RGB of background
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export function useLightTextOnBackground(r, g, b) {
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return getLuminance(r, g, b) < 0.453;
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}
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34
web_src/js/utils/color.test.js
Normal file
34
web_src/js/utils/color.test.js
Normal file
@ -0,0 +1,34 @@
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import {test, expect} from 'vitest';
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import {hexToRGBColor, useLightTextOnBackground} from './color.js';
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test('hexToRGBColor', () => {
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expect(hexToRGBColor('2b8685')).toEqual([43, 134, 133]);
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expect(hexToRGBColor('1e1')).toEqual([17, 238, 17]);
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expect(hexToRGBColor('#1e1')).toEqual([17, 238, 17]);
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expect(hexToRGBColor('1e16')).toEqual([17, 238, 17]);
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expect(hexToRGBColor('3bb6b3')).toEqual([59, 182, 179]);
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expect(hexToRGBColor('#3bb6b399')).toEqual([59, 182, 179]);
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expect(hexToRGBColor('#0')).toEqual([0, 0, 0]);
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expect(hexToRGBColor('#00000')).toEqual([0, 0, 0]);
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expect(hexToRGBColor('#1234567')).toEqual([0, 0, 0]);
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});
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test('useLightTextOnBackground', () => {
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expect(useLightTextOnBackground(215, 58, 74)).toBe(true);
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expect(useLightTextOnBackground(0, 117, 202)).toBe(true);
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expect(useLightTextOnBackground(207, 211, 215)).toBe(false);
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expect(useLightTextOnBackground(162, 238, 239)).toBe(false);
|
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expect(useLightTextOnBackground(112, 87, 255)).toBe(true);
|
||||
expect(useLightTextOnBackground(0, 134, 114)).toBe(true);
|
||||
expect(useLightTextOnBackground(228, 230, 105)).toBe(false);
|
||||
expect(useLightTextOnBackground(216, 118, 227)).toBe(true);
|
||||
expect(useLightTextOnBackground(255, 255, 255)).toBe(false);
|
||||
expect(useLightTextOnBackground(43, 134, 133)).toBe(true);
|
||||
expect(useLightTextOnBackground(43, 135, 134)).toBe(true);
|
||||
expect(useLightTextOnBackground(44, 135, 134)).toBe(true);
|
||||
expect(useLightTextOnBackground(59, 182, 179)).toBe(true);
|
||||
expect(useLightTextOnBackground(124, 114, 104)).toBe(true);
|
||||
expect(useLightTextOnBackground(126, 113, 108)).toBe(true);
|
||||
expect(useLightTextOnBackground(129, 112, 109)).toBe(true);
|
||||
expect(useLightTextOnBackground(128, 112, 112)).toBe(true);
|
||||
});
|
||||
Loading…
Reference in New Issue
Block a user