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Code Issues Releases Wiki Activity

Fix problem with "foreground"/"background" palette colours using <<colour>> macro

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See discussion here:

https://groups.google.com/d/topic/tiddlywiki/XDlO0EydXtY/discussion
This commit is contained in:
Jermolene 2015-04-21 22:07:16 +01:00
parent a3ed82b703
commit 75a33f5dff
1 changed files with 13 additions and 3 deletions
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16
core/modules/macros/contrastcolour.js
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@ -33,10 +33,20 @@ exports.run = function(target,fallbackTarget,colourA,colourB) {
if(!rgbTarget) {
return colourA;
}
// Colour brightness formula derived from http://www.w3.org/WAI/ER/WD-AERT/#color-contrast
var rgbColourA = $tw.utils.parseCSSColor(colourA),
rgbColourB = $tw.utils.parseCSSColor(colourB),
brightnessTarget = rgbTarget[0] * 0.299 + rgbTarget[1] * 0.587 + rgbTarget[2] * 0.114,
rgbColourB = $tw.utils.parseCSSColor(colourB);
if(rgbColourA && !rgbColourB) {
return rgbColourA;
}
if(rgbColourA && !rgbColourB) {
return rgbColourA;
}
if(!rgbColourA && !rgbColourB) {
// If neither colour is readable, return a crude inverse of the target
return [255 - rgbTarget[0],255 - rgbTarget[1],255 - rgbTarget[2],rgbTarget[3]];
}
// Colour brightness formula derived from http://www.w3.org/WAI/ER/WD-AERT/#color-contrast
var brightnessTarget = rgbTarget[0] * 0.299 + rgbTarget[1] * 0.587 + rgbTarget[2] * 0.114,
brightnessA = rgbColourA[0] * 0.299 + rgbColourA[1] * 0.587 + rgbColourA[2] * 0.114,
brightnessB = rgbColourB[0] * 0.299 + rgbColourB[1] * 0.587 + rgbColourB[2] * 0.114;
return Math.abs(brightnessTarget - brightnessA) > Math.abs(brightnessTarget - brightnessB) ? colourA : colourB;