diff options
author | Hester Gong <hestergong@gmail.com> | 2023-05-10 19:19:03 +0800 |
---|---|---|
committer | GitHub <noreply@github.com> | 2023-05-10 11:19:03 +0000 |
commit | ea7954f069bf8bcb87d520f8aab0a80b0768590d (patch) | |
tree | f5edc566c9dbafa3507ed8ef3ffaa32944f80797 /modules | |
parent | 0ca5adee16a9de0fb0bd410aa841eeeda3372e23 (diff) | |
download | gitea-ea7954f069bf8bcb87d520f8aab0a80b0768590d.tar.gz gitea-ea7954f069bf8bcb87d520f8aab0a80b0768590d.zip |
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>
Diffstat (limited to 'modules')
-rw-r--r-- | modules/templates/util_render.go | 57 | ||||
-rw-r--r-- | modules/util/color.go | 65 | ||||
-rw-r--r-- | modules/util/color_test.go | 65 |
3 files changed, 158 insertions, 29 deletions
diff --git a/modules/templates/util_render.go b/modules/templates/util_render.go index a59ddd3f17..a26c0531f8 100644 --- a/modules/templates/util_render.go +++ b/modules/templates/util_render.go @@ -20,6 +20,7 @@ import ( "code.gitea.io/gitea/modules/markup" "code.gitea.io/gitea/modules/markup/markdown" "code.gitea.io/gitea/modules/setting" + "code.gitea.io/gitea/modules/util" ) // RenderCommitMessage renders commit message with XSS-safe and special links. @@ -133,7 +134,9 @@ func RenderLabel(ctx context.Context, label *issues_model.Label) template.HTML { labelScope := label.ExclusiveScope() textColor := "#111" - if label.UseLightTextColor() { + r, g, b := util.HexToRBGColor(label.Color) + // Determine if label text should be light or dark to be readable on background color + if util.UseLightTextOnBackground(r, g, b) { textColor = "#eee" } @@ -150,34 +153,30 @@ func RenderLabel(ctx context.Context, label *issues_model.Label) template.HTML { scopeText := RenderEmoji(ctx, labelScope) itemText := RenderEmoji(ctx, label.Name[len(labelScope)+1:]) - itemColor := label.Color - scopeColor := label.Color - if r, g, b, err := label.ColorRGB(); err == nil { - // Make scope and item background colors slightly darker and lighter respectively. - // More contrast needed with higher luminance, empirically tweaked. - luminance := (0.299*r + 0.587*g + 0.114*b) / 255 - contrast := 0.01 + luminance*0.03 - // Ensure we add the same amount of contrast also near 0 and 1. - darken := contrast + math.Max(luminance+contrast-1.0, 0.0) - lighten := contrast + math.Max(contrast-luminance, 0.0) - // Compute factor to keep RGB values proportional. - darkenFactor := math.Max(luminance-darken, 0.0) / math.Max(luminance, 1.0/255.0) - lightenFactor := math.Min(luminance+lighten, 1.0) / math.Max(luminance, 1.0/255.0) - - scopeBytes := []byte{ - uint8(math.Min(math.Round(r*darkenFactor), 255)), - uint8(math.Min(math.Round(g*darkenFactor), 255)), - uint8(math.Min(math.Round(b*darkenFactor), 255)), - } - itemBytes := []byte{ - uint8(math.Min(math.Round(r*lightenFactor), 255)), - uint8(math.Min(math.Round(g*lightenFactor), 255)), - uint8(math.Min(math.Round(b*lightenFactor), 255)), - } - - itemColor = "#" + hex.EncodeToString(itemBytes) - scopeColor = "#" + hex.EncodeToString(scopeBytes) - } + // Make scope and item background colors slightly darker and lighter respectively. + // More contrast needed with higher luminance, empirically tweaked. + luminance := util.GetLuminance(r, g, b) + contrast := 0.01 + luminance*0.03 + // Ensure we add the same amount of contrast also near 0 and 1. + darken := contrast + math.Max(luminance+contrast-1.0, 0.0) + lighten := contrast + math.Max(contrast-luminance, 0.0) + // Compute factor to keep RGB values proportional. + darkenFactor := math.Max(luminance-darken, 0.0) / math.Max(luminance, 1.0/255.0) + lightenFactor := math.Min(luminance+lighten, 1.0) / math.Max(luminance, 1.0/255.0) + + scopeBytes := []byte{ + uint8(math.Min(math.Round(r*darkenFactor), 255)), + uint8(math.Min(math.Round(g*darkenFactor), 255)), + uint8(math.Min(math.Round(b*darkenFactor), 255)), + } + itemBytes := []byte{ + uint8(math.Min(math.Round(r*lightenFactor), 255)), + uint8(math.Min(math.Round(g*lightenFactor), 255)), + uint8(math.Min(math.Round(b*lightenFactor), 255)), + } + + itemColor := "#" + hex.EncodeToString(itemBytes) + scopeColor := "#" + hex.EncodeToString(scopeBytes) s := fmt.Sprintf("<span class='ui label scope-parent' title='%s'>"+ "<div class='ui label scope-left' style='color: %s !important; background-color: %s !important'>%s</div>"+ diff --git a/modules/util/color.go b/modules/util/color.go new file mode 100644 index 0000000000..240b045c28 --- /dev/null +++ b/modules/util/color.go @@ -0,0 +1,65 @@ +// Copyright 2023 The Gitea Authors. All rights reserved. +// SPDX-License-Identifier: MIT +package util + +import ( + "fmt" + "math" + "strconv" + "strings" +) + +// Check similar implementation in web_src/js/utils/color.js and keep synchronization + +// Return R, G, B values defined in reletive luminance +func getLuminanceRGB(channel float64) float64 { + sRGB := channel / 255 + if sRGB <= 0.03928 { + return sRGB / 12.92 + } + return math.Pow((sRGB+0.055)/1.055, 2.4) +} + +// Get color as RGB values in 0..255 range from the hex color string (with or without #) +func HexToRBGColor(colorString string) (float64, float64, float64) { + hexString := colorString + if strings.HasPrefix(colorString, "#") { + hexString = colorString[1:] + } + // only support transfer of rgb, rgba, rrggbb and rrggbbaa + // if not in these formats, use default values 0, 0, 0 + if len(hexString) != 3 && len(hexString) != 4 && len(hexString) != 6 && len(hexString) != 8 { + return 0, 0, 0 + } + if len(hexString) == 3 || len(hexString) == 4 { + hexString = fmt.Sprintf("%c%c%c%c%c%c", hexString[0], hexString[0], hexString[1], hexString[1], hexString[2], hexString[2]) + } + if len(hexString) == 8 { + hexString = hexString[0:6] + } + color, err := strconv.ParseUint(hexString, 16, 64) + if err != nil { + return 0, 0, 0 + } + r := float64(uint8(0xFF & (uint32(color) >> 16))) + g := float64(uint8(0xFF & (uint32(color) >> 8))) + b := float64(uint8(0xFF & uint32(color))) + return r, g, b +} + +// return luminance given RGB channels +// Reference from: https://www.w3.org/WAI/GL/wiki/Relative_luminance +func GetLuminance(r, g, b float64) float64 { + R := getLuminanceRGB(r) + G := getLuminanceRGB(g) + B := getLuminanceRGB(b) + luminance := 0.2126*R + 0.7152*G + 0.0722*B + return luminance +} + +// Reference from: https://firsching.ch/github_labels.html +// In the future WCAG 3 APCA may be a better solution. +// Check if text should use light color based on RGB of background +func UseLightTextOnBackground(r, g, b float64) bool { + return GetLuminance(r, g, b) < 0.453 +} diff --git a/modules/util/color_test.go b/modules/util/color_test.go new file mode 100644 index 0000000000..d96ac36730 --- /dev/null +++ b/modules/util/color_test.go @@ -0,0 +1,65 @@ +// Copyright 2023 The Gitea Authors. All rights reserved. +// SPDX-License-Identifier: MIT +package util + +import ( + "testing" + + "github.com/stretchr/testify/assert" +) + +func Test_HexToRBGColor(t *testing.T) { + cases := []struct { + colorString string + expectedR float64 + expectedG float64 + expectedB float64 + }{ + {"2b8685", 43, 134, 133}, + {"1e1", 17, 238, 17}, + {"#1e1", 17, 238, 17}, + {"1e16", 17, 238, 17}, + {"3bb6b3", 59, 182, 179}, + {"#3bb6b399", 59, 182, 179}, + {"#0", 0, 0, 0}, + {"#00000", 0, 0, 0}, + {"#1234567", 0, 0, 0}, + } + for n, c := range cases { + r, g, b := HexToRBGColor(c.colorString) + assert.Equal(t, c.expectedR, r, "case %d: error R should match: expected %f, but get %f", n, c.expectedR, r) + assert.Equal(t, c.expectedG, g, "case %d: error G should match: expected %f, but get %f", n, c.expectedG, g) + assert.Equal(t, c.expectedB, b, "case %d: error B should match: expected %f, but get %f", n, c.expectedB, b) + } +} + +func Test_UseLightTextOnBackground(t *testing.T) { + cases := []struct { + r float64 + g float64 + b float64 + expected bool + }{ + {215, 58, 74, true}, + {0, 117, 202, true}, + {207, 211, 215, false}, + {162, 238, 239, false}, + {112, 87, 255, true}, + {0, 134, 114, true}, + {228, 230, 105, false}, + {216, 118, 227, true}, + {255, 255, 255, false}, + {43, 134, 133, true}, + {43, 135, 134, true}, + {44, 135, 134, true}, + {59, 182, 179, true}, + {124, 114, 104, true}, + {126, 113, 108, true}, + {129, 112, 109, true}, + {128, 112, 112, true}, + } + for n, c := range cases { + result := UseLightTextOnBackground(c.r, c.g, c.b) + assert.Equal(t, c.expected, result, "case %d: error should match", n) + } +} |