Does this work well enough?: function luminanceRatio c1,c2 -- pass two RGB triplets put calcLuminance(c1) into tL1 put calcLuminance(c2) into tL2 return max(tL1,tL2) / min(tL1,tL2) end luminanceRatio
function calcLuminance pRGB -- wikipedia: Y = 0.2126 R + 0.7152 G + 0.0722 B put item 1 of pRGB * 0.2126 into tR put item 2 of pRGB * 0.7152 into tG put item 3 of pRGB * 0.0722 into tB return sum(tR,tG,tB) # if sum(tR,tG,tB) > 125 then return "black" # else return "white" end calcLuminance On 10/6/16 12:58 PM, Sannyasin Brahmanathaswami wrote:
For the RGB wizards… what is the algorithm to determine the luminance ratio between two colors? See w3C recommendations posted in today's Adobe's XD newsletter (useful feed) below. I'm thinking the total value of all three will serve. The WC3 sets minimum standards for contrast ratios, which represent how different a color is from another color (commonly written as 1:1 or 21:1, the higher the difference between the two numbers in the ratio, the greater the difference in relative luminance between the colors). The W3C recommends the following contrast ratios for body text and image text: * Small text should have a contrast ratio of at least 4.5:1 against its background. A ratio of 7:1 is preferred. * Large text (at 14 pt bold/18 pt regular and up) should have a contrast ratio of at least 3:1 against its background. _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
-- Jacqueline Landman Gay | jac...@hyperactivesw.com HyperActive Software | http://www.hyperactivesw.com _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
