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mirror of https://github.com/go-gitea/gitea synced 2025-07-22 18:28:37 +00:00

Fix and rewrite contrast color calculation, fix project-related bugs (#30326)

Backport https://github.com/go-gitea/gitea/pull/30237 to 1.22. Also
includes https://github.com/go-gitea/gitea/pull/30183. Both were clean
cherry-picks.

Co-authored-by: Giteabot <teabot@gitea.io>
This commit is contained in:
silverwind
2024-04-09 11:45:29 +02:00
committed by GitHub
parent 82992cf32d
commit b8e9d3c553
14 changed files with 148 additions and 203 deletions

View File

@@ -4,22 +4,10 @@ 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
@@ -47,19 +35,23 @@ func HexToRBGColor(colorString string) (float64, float64, float64) {
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
// Returns relative luminance for a SRGB color - https://en.wikipedia.org/wiki/Relative_luminance
// Keep this in sync with web_src/js/utils/color.js
func GetRelativeLuminance(color string) float64 {
r, g, b := HexToRBGColor(color)
return (0.2126729*r + 0.7151522*g + 0.0721750*b) / 255
}
// 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
func UseLightText(backgroundColor string) bool {
return GetRelativeLuminance(backgroundColor) < 0.453
}
// Given a background color, returns a black or white foreground color that the highest
// contrast ratio. In the future, the APCA contrast function, or CSS `contrast-color` will be better.
// https://github.com/color-js/color.js/blob/eb7b53f7a13bb716ec8b28c7a56f052cd599acd9/src/contrast/APCA.js#L42
func ContrastColor(backgroundColor string) string {
if UseLightText(backgroundColor) {
return "#fff"
}
return "#000"
}