sqmk#130 Fix color higher than 255

- fixed coding standards in color conversion tool.
- added unit test for the 0..255 range fix.

library/Phue/Helper/ColorConversion.php

@@ -29,7 +29,7 @@ public static function convertRGBToXY($red, $green, $blue)
         $normalizedToOne['red'] = $red / 255;
         $normalizedToOne['green'] = $green / 255;
         $normalizedToOne['blue'] = $blue / 255;
-
+        
         // Make colors more vivid
         foreach ($normalizedToOne as $key => $normalized) {
             if ($normalized > 0.04045) {
@@ -38,12 +38,12 @@ public static function convertRGBToXY($red, $green, $blue)
                 $color[$key] = $normalized / 12.92;
             }
         }
-
+        
         // Convert to XYZ using the Wide RGB D65 formula
         $xyz['x'] = $color['red'] * 0.664511 + $color['green'] * 0.154324 + $color['blue'] * 0.162028;
         $xyz['y'] = $color['red'] * 0.283881 + $color['green'] * 0.668433 + $color['blue'] * 0.047685;
         $xyz['z'] = $color['red'] * 0.000000 + $color['green'] * 0.072310 + $color['blue'] * 0.986039;
-
+        
         // Calculate the x/y values
         if (array_sum($xyz) == 0) {
             $x = 0;
@@ -52,14 +52,14 @@ public static function convertRGBToXY($red, $green, $blue)
             $x = $xyz['x'] / array_sum($xyz);
             $y = $xyz['y'] / array_sum($xyz);
         }
-
+        
         return array(
             'x'   => $x,
             'y'   => $y,
             'bri' => round($xyz['y'] * 255)
         );
     }
-
+    
     /**
      * Converts XY (and brightness) values to RGB
      *
@@ -76,24 +76,33 @@ public static function convertXYToRGB($x, $y, $bri = 255)
         $xyz['y'] = $bri / 255;
         $xyz['x'] = ($xyz['y'] / $y) * $x;
         $xyz['z'] = ($xyz['y'] / $y) * $z;
-
+        
         // Convert to RGB using Wide RGB D65 conversion
         $color['red'] = $xyz['x'] * 1.656492 - $xyz['y'] * 0.354851 - $xyz['z'] * 0.255038;
         $color['green'] = -$xyz['x'] * 0.707196 + $xyz['y'] * 1.655397 + $xyz['z'] * 0.036152;
         $color['blue'] = $xyz['x'] * 0.051713 - $xyz['y'] * 0.121364 + $xyz['z'] * 1.011530;
-
+
+        $maxValue = 0;
         foreach ($color as $key => $normalized) {
             // Apply reverse gamma correction
             if ($normalized <= 0.0031308) {
                 $color[$key] = 12.92 * $normalized;
             } else {
                 $color[$key] = (1.0 + 0.055) * pow($normalized, 1.0 / 2.4) - 0.055;
             }
-
+            $color[$key] = max(0, $color[$key]);
+            if ($maxValue < $color[$key]) {
+                $maxValue = $color[$key];
+            }
+        }
+        foreach ($color as $key => $normalized) {
+            if ($maxValue > 1) {
+                $color[$key] /= $maxValue;
+            }
             // Scale back from a maximum of 1 to a maximum of 255
             $color[$key] = round($color[$key] * 255);
         }
-
+        
         return $color;
     }
-}
+}

tests/Phue/Test/Helper/ColorConversionTest.php

@@ -16,32 +16,32 @@ class ColorConversionTest extends \PHPUnit_Framework_TestCase
 {
     /**
      * Test: convert RGB to XY and brightness
-     * 
+     *
      * @covers \Phue\Helper\ColorConversion::convertRGBToXY
      */
     public function testConvertRGBToXY()
     {
         // Values from: http://www.developers.meethue.com/documentation/hue-xy-values
-
+        
         // Alice Blue
         $xy = ColorConversion::convertRGBToXY(239, 247, 255);
         $this->assertEquals(0.3088, $xy['x'], '', 0.0001);
         $this->assertEquals(0.3212, $xy['y'], '', 0.0001);
         $this->assertEquals(233, $xy['bri']);
-
+        
         // Firebrick
         $xy = ColorConversion::convertRGBToXY(178, 33, 33);
         $this->assertEquals(0.6622, $xy['x'], '', 0.0001);
         $this->assertEquals(0.3024, $xy['y'], '', 0.0001);
         $this->assertEquals(35, $xy['bri']);
-
+        
         // Medium Sea Green
         $xy = ColorConversion::convertRGBToXY(61, 178, 112);
         $this->assertEquals(0.1979, $xy['x'], '', 0.0001);
         $this->assertEquals(0.5005, $xy['y'], '', 0.0001);
         $this->assertEquals(81, $xy['bri']);
     }
-
+    
     /**
      * Test: convert XY and brightness to RGB
      *
@@ -50,23 +50,30 @@ public function testConvertRGBToXY()
     public function testConvertXYToRGB()
     {
         // Conversion back from the test above
-
+        
         // Alice Blue
         $rgb = ColorConversion::convertXYToRGB(0.3088, 0.3212, 233);
         $this->assertEquals($rgb['red'], 239);
         $this->assertEquals($rgb['green'], 247);
         $this->assertEquals($rgb['blue'], 255);
-
+        
         // Firebrick
         $rgb = ColorConversion::convertXYToRGB(0.6622, 0.3024, 35);
         $this->assertEquals($rgb['red'], 178);
         $this->assertEquals($rgb['green'], 33);
         $this->assertEquals($rgb['blue'], 33);
-
+        
         // Medium Sea Green
         $rgb = ColorConversion::convertXYToRGB(0.1979, 0.5005, 81);
         $this->assertEquals($rgb['red'], 61);
         $this->assertEquals($rgb['green'], 178);
         $this->assertEquals($rgb['blue'], 112);
+
+        // Test to make sure single RGB values falls within 0..255 range.
+        // old situation this was r -18, g 186, b -613.
+        $rgb = ColorConversion::convertXYToRGB(0.1979, 1.5005, 81);
+        $this->assertEquals($rgb['red'], 0);
+        $this->assertEquals($rgb['green'], 186);
+        $this->assertEquals($rgb['blue'], 0);
     }
-}
+}