Created
March 19, 2013 22:55
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| <?php | |
| /* | |
| ** Converts HSV to RGB values | |
| ** ––––––––––––––––––––––––––––––––––––––––––––––––––––– | |
| ** Reference: http://en.wikipedia.org/wiki/HSL_and_HSV | |
| ** Purpose: Useful for generating colours with | |
| ** same hue-value for web designs. | |
| ** Input: Hue (H) Integer 0-360 | |
| ** Saturation (S) Integer 0-100 | |
| ** Lightness (V) Integer 0-100 | |
| ** Output: String "R,G,B" | |
| ** Suitable for CSS function RGB(). | |
| */ | |
| function fGetRGB($iH, $iS, $iV) { | |
| if($iH < 0) $iH = 0; // Hue: | |
| if($iH > 360) $iH = 360; // 0-360 | |
| if($iS < 0) $iS = 0; // Saturation: | |
| if($iS > 100) $iS = 100; // 0-100 | |
| if($iV < 0) $iV = 0; // Lightness: | |
| if($iV > 100) $iV = 100; // 0-100 | |
| $dS = $iS/100.0; // Saturation: 0.0-1.0 | |
| $dV = $iV/100.0; // Lightness: 0.0-1.0 | |
| $dC = $dV*$dS; // Chroma: 0.0-1.0 | |
| $dH = $iH/60.0; // H-Prime: 0.0-6.0 | |
| $dT = $dH; // Temp variable | |
| while($dT >= 2.0) $dT -= 2.0; // php modulus does not work with float | |
| $dX = $dC*(1-abs($dT-1)); // as used in the Wikipedia link | |
| switch($dH) { | |
| case($dH >= 0.0 && $dH < 1.0): | |
| $dR = $dC; $dG = $dX; $dB = 0.0; break; | |
| case($dH >= 1.0 && $dH < 2.0): | |
| $dR = $dX; $dG = $dC; $dB = 0.0; break; | |
| case($dH >= 2.0 && $dH < 3.0): | |
| $dR = 0.0; $dG = $dC; $dB = $dX; break; | |
| case($dH >= 3.0 && $dH < 4.0): | |
| $dR = 0.0; $dG = $dX; $dB = $dC; break; | |
| case($dH >= 4.0 && $dH < 5.0): | |
| $dR = $dX; $dG = 0.0; $dB = $dC; break; | |
| case($dH >= 5.0 && $dH < 6.0): | |
| $dR = $dC; $dG = 0.0; $dB = $dX; break; | |
| default: | |
| $dR = 0.0; $dG = 0.0; $dB = 0.0; break; | |
| } | |
| $dM = $dV - $dC; | |
| $dR += $dM; $dG += $dM; $dB += $dM; | |
| $dR *= 255; $dG *= 255; $dB *= 255; | |
| return round($dR).",".round($dG).",".round($dB); | |
| } | |
| ?> |
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