added helper methods for color transformations

php-imagine · Feb 27, 2011 · f28268b · henrikbjorn · Feb 27, 2011 · avalanche123
1 parent f80c68a
commit f28268b
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diff --git a/lib/Imagine/Color.php b/lib/Imagine/Color.php
@@ -90,6 +90,59 @@ public function getAlpha()
         return $this->alpha;
     }
 
+    /**
+     * Returns a copy of current color, incrementing the alpha channel by the
+     * given amount
+     *
+     * @param integer $alpha
+     *
+     * @return Imagine\Color
+     */
+    public function dissolve($alpha)
+    {
+        return new Color((string) $this, $this->alpha + $alpha);
+    }
+
+    /**
+     * Returns a copy of the current color, darkened by the specified number of
+     * shades
+     *
+     * @param integer $shade
+     *
+     * @retun Imagine\Color
+     */
+    public function lighten($shade)
+    {
+        return new Color(
+            array(
+                min(255, $this->r + $shade),
+                min(255, $this->g + $shade),
+                min(255, $this->b + $shade),
+            ),
+            $this->alpha
+        );
+    }
+
+    /**
+     * Returns a copy of the current color, darkened by the specified number of
+     * shades
+     *
+     * @param integer $shade
+     *
+     * @retun Imagine\Color
+     */
+    public function darken($shade)
+    {
+        return new Color(
+            array(
+                max(0, $this->r - $shade),
+                max(0, $this->g - $shade),
+                max(0, $this->b - $shade),
+            ),
+            $this->alpha
+        );
+    }
+
     /**
      * Internal
      *

diff --git a/tests/Imagine/ColorTest.php b/tests/Imagine/ColorTest.php
@@ -104,4 +104,28 @@ public function testShortColorNotationAndLongNotationProducesTheSameColor()
         $this->assertEquals(new Color('#fff'), new Color('ffffff'));
         $this->assertEquals(new Color('fff'), new Color('#ffffff'));
     }
+
+    public function testShouldLigtenColor()
+    {
+        $color = new Color('000');
+
+        $this->assertEquals(new Color('222'), $color->lighten(34));
+        $this->assertEquals(new Color('fff'), $color->lighten(300));
+    }
+
+    public function testShouldDarnenColor()
+    {
+        $color = new Color('fff');
+
+        $this->assertEquals(new Color('ddd'), $color->darken(34));
+        $this->assertEquals(new Color('000'), $color->darken(300));
+    }
+
+    public function testShouldDissolveColor()
+    {
+        $color = new Color('fff');
+
+        $this->assertEquals(new Color('fff', 50), $color->dissolve(50));
+        $this->assertEquals(new Color('fff'), $color->dissolve(100)->dissolve(-100));
+    }
 }