added opacity method

README.md

@@ -54,6 +54,7 @@ Add the facade of this package to the `$aliases` array.
 * Image::crop - Crop the current image
 * Image::grab - Cut out a detail of the image in given ratio and resize to output size
 * Image::resizeCanvas - Resize image boundaries
+* Image::opacity - Set opacity of current image
 * Image::mask - Apply given image as alpha mask on current image
 * Image::insert - Insert another image on top of the current image
 * Image::brightness - Changes brightness of current image (-100 = min brightness, 0 = no change, +100 = max brightness)
@@ -224,6 +225,9 @@ $img->mask('public/mask.png', true);
 // rotate image 90° clockwise
 $img->rotate(90);
 
+// set 75% opacity
+$img->opacity(75);
+
 // flip image horizontally
 $img->flip('h');
 

src/Intervention/Image/Image.php

@@ -678,6 +678,30 @@ class Image
         return $this;
     }
 
+    /**
+     * Set opacity of current image
+     * 
+     * @param  integer $value
+     * @return Image
+     */
+    public function opacity($value)
+    {
+        if ($value >= 0 && $value <= 100) {
+            $value = intval($value) / 100;
+        } else {
+            throw new Exception('Opacity must be between 0 and 100');
+        }
+
+        // create alpha mask
+        $alpha = new self(null, $this->width, $this->height);
+        $alpha->fill(sprintf('rgba(0, 0, 0, %.1f)', $value));
+
+        // apply alpha mask
+        $this->mask($alpha, true);
+
+        return $this;
+    }
+
     /**
      * Apply given image as alpha mask on current image
      *
@@ -1128,7 +1152,8 @@ class Image
     /**
      * Save image in filesystem
      *
-     * @param  string $path
+     * @param  string  $path
+     * @param  integer $quality
      * @return Image
      */
     public function save($path = null, $quality = 90)

tests/ImageTest.php

@@ -435,6 +435,28 @@ class ImageTest extends PHPUnit_Framework_Testcase
         $this->assertInstanceOf('Intervention\Image\Image', $img);
     }
 
+    public function testOpacity()
+    {
+        // simple image mask
+        $img = Image::make('public/test.jpg');
+        $img->resize(32, 32)->opacity(50);
+        $this->assertInstanceOf('Intervention\Image\Image', $img);
+        $this->assertInternalType('int', $img->width);
+        $this->assertInternalType('int', $img->height);
+        $this->assertEquals($img->width, 32);
+        $this->assertEquals($img->height, 32);
+        $checkColor = $img->pickColor(15, 15, 'array');
+        $this->assertEquals($checkColor['red'], 254);
+        $this->assertEquals($checkColor['green'], 204);
+        $this->assertEquals($checkColor['blue'], 112);
+        $this->assertEquals($checkColor['alpha'], 64);
+        $checkColor = $img->pickColor(31, 31, 'array');
+        $this->assertEquals($checkColor['red'], 255);
+        $this->assertEquals($checkColor['green'], 166);
+        $this->assertEquals($checkColor['blue'], 0);
+        $this->assertEquals($checkColor['alpha'], 64);
+    }
+
     public function testMaskImage()
     {
         // simple image mask