HORNEKS ANS

ACF Library

isLightColor

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Description: Calculate if color is light or dark

FileMaker Prototype: 

Set Variable [$res; ACF_Run("isLightColor"; string_hex)]

Category: UTILITY

Dependencies

  • Hex2Dec: Convert hex value to decimal

Function source:

function isLightColor ( string hex )
   int r,g,b;
   hex = regex_replace ( "[^0-9A-F]", upper(hex), "");
   // calc r, g, and b decimal values.  
   r = Hex2Dec(substring(hex,0,2)); 
   g = Hex2Dec(substring(hex,2,2)); 
   b = Hex2Dec(substring(hex,4,2)); 
   // Calculate colour luminance
   float lum =  0.299 * r + 0.587 * g +  0.114 * b ;
   return (lum > 128.0); // 
end

The isLightColor Function calculates if a color is light according to its RGB input. Use Hex values, 6 digits.

Example

Set Variable [$res; ACF_Run("isLightColor"; "#7962a8")]

Result: False because it calculates to luminance = 112, means is less than 128 that is the threshold.

The function is rewritten from colorContrast ( color ) found on Brian Dunnings Custom Functions site. It says on the web page that it returns "1", but I have tested it with the given parameter, and this also returns "0" with this given value.

We have made a general Hex to Decimal function that also can be of general use. 

Set Variable [$res; ACF_Run("Hex2Dec"; string_hex)]
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