Merge pull request #1277 from Intervention/feature/1253-add-transparency-param-for-place

Add opacity parameter to PlaceModifier

src/Drivers/Gd/Modifiers/PlaceModifier.php

@@ -5,8 +5,10 @@ declare(strict_types=1);
 namespace Intervention\Image\Drivers\Gd\Modifiers;
 
 use Intervention\Image\Drivers\DriverSpecialized;
+use Intervention\Image\Interfaces\FrameInterface;
 use Intervention\Image\Interfaces\ImageInterface;
 use Intervention\Image\Interfaces\ModifierInterface;
+use Intervention\Image\Interfaces\PointInterface;
 
 /**
  * @method mixed getPosition(ImageInterface $image, ImageInterface $watermark)
@@ -14,6 +16,7 @@ use Intervention\Image\Interfaces\ModifierInterface;
  * @property string $position
  * @property int $offset_x
  * @property int $offset_y
+ * @property int $opacity
  */
 class PlaceModifier extends DriverSpecialized implements ModifierInterface
 {
@@ -24,18 +27,93 @@ class PlaceModifier extends DriverSpecialized implements ModifierInterface
 
         foreach ($image as $frame) {
             imagealphablending($frame->native(), true);
-            imagecopy(
-                $frame->native(),
-                $watermark->core()->native(),
-                $position->x(),
-                $position->y(),
-                0,
-                0,
-                $watermark->width(),
-                $watermark->height()
-            );
+
+            if ($this->opacity === 100) {
+                $this->placeOpaque($frame, $watermark, $position);
+            } else {
+                $this->placeTransparent($frame, $watermark, $position);
+            }
         }
 
         return $image;
     }
+
+    /**
+     * Insert watermark with 100% opacity
+     *
+     * @param FrameInterface $frame
+     * @param ImageInterface $watermark
+     * @param PointInterface $position
+     * @return void
+     */
+    private function placeOpaque(FrameInterface $frame, ImageInterface $watermark, PointInterface $position): void
+    {
+        imagecopy(
+            $frame->native(),
+            $watermark->core()->native(),
+            $position->x(),
+            $position->y(),
+            0,
+            0,
+            $watermark->width(),
+            $watermark->height()
+        );
+    }
+
+    /**
+     * Insert watermark transparent with current opacity
+     *
+     * Unfortunately, the original PHP function imagecopymerge does not work reliably.
+     * For example, any transparency of the image to be inserted is not applied correctly.
+     * For this reason, a new GDImage is created into which the original image is inserted
+     * in the first step and the watermark is inserted with 100% opacity in the second
+     * step. This combination is then transferred to the original image again with the
+     * respective opacity.
+     *
+     * Please note: Unfortunately, there is still an edge case, when a transparent image
+     * is placed on a transparent background, the "double" transparent areas appear opaque!
+     *
+     * @param FrameInterface $frame
+     * @param ImageInterface $watermark
+     * @param PointInterface $position
+     * @return void
+     */
+    private function placeTransparent(FrameInterface $frame, ImageInterface $watermark, PointInterface $position): void
+    {
+        $cut = imagecreatetruecolor($watermark->width(), $watermark->height());
+
+        imagecopy(
+            $cut,
+            $frame->native(),
+            0,
+            0,
+            $position->x(),
+            $position->y(),
+            imagesx($cut),
+            imagesy($cut)
+        );
+
+        imagecopy(
+            $cut,
+            $watermark->core()->native(),
+            0,
+            0,
+            0,
+            0,
+            imagesx($cut),
+            imagesy($cut)
+        );
+
+        imagecopymerge(
+            $frame->native(),
+            $cut,
+            $position->x(),
+            $position->y(),
+            0,
+            0,
+            $watermark->width(),
+            $watermark->height(),
+            $this->opacity
+        );
+    }
 }

src/Drivers/Imagick/Modifiers/PlaceModifier.php

@@ -15,6 +15,7 @@ use Intervention\Image\Interfaces\ModifierInterface;
  * @property string $position
  * @property int $offset_x
  * @property int $offset_y
+ * @property int $opacity
  */
 class PlaceModifier extends DriverSpecialized implements ModifierInterface
 {
@@ -23,6 +24,15 @@ class PlaceModifier extends DriverSpecialized implements ModifierInterface
         $watermark = $this->driver()->handleInput($this->element);
         $position = $this->getPosition($image, $watermark);
 
+        // set opacity of watermark
+        if ($this->opacity < 100) {
+            $watermark->core()->native()->evaluateImage(
+                Imagick::EVALUATE_DIVIDE,
+                $this->opacity > 0 ? (100 / $this->opacity) : 1000,
+                Imagick::CHANNEL_ALPHA,
+            );
+        }
+
         foreach ($image as $frame) {
             $frame->native()->compositeImage(
                 $watermark->core()->native(),

src/Image.php

@@ -744,9 +744,10 @@ final class Image implements ImageInterface
         mixed $element,
         string $position = 'top-left',
         int $offset_x = 0,
-        int $offset_y = 0
+        int $offset_y = 0,
+        int $opacity = 100
     ): ImageInterface {
-        return $this->modify(new PlaceModifier($element, $position, $offset_x, $offset_y));
+        return $this->modify(new PlaceModifier($element, $position, $offset_x, $offset_y, $opacity));
     }
 
     /**

src/Interfaces/ImageInterface.php

@@ -5,7 +5,6 @@ declare(strict_types=1);
 namespace Intervention\Image\Interfaces;
 
 use Countable;
-use Intervention\Image\EncodedImage;
 use Intervention\Image\Origin;
 use IteratorAggregate;
 
@@ -522,13 +521,15 @@ interface ImageInterface extends IteratorAggregate, Countable
      * @param string $position
      * @param int    $offset_x
      * @param int    $offset_y
+     * @param int    $opacity
      * @return ImageInterface
      */
     public function place(
         mixed $element,
         string $position = 'top-left',
         int $offset_x = 0,
-        int $offset_y = 0
+        int $offset_y = 0,
+        int $opacity = 100
     ): ImageInterface;
 
     /**

src/Modifiers/PlaceModifier.php

@@ -13,7 +13,8 @@ class PlaceModifier extends SpecializableModifier
         public mixed $element,
         public string $position,
         public int $offset_x,
-        public int $offset_y
+        public int $offset_y,
+        public int $opacity = 100
     ) {
     }
 

tests/Drivers/Gd/Modifiers/PlaceModifierTest.php

@@ -24,4 +24,12 @@ class PlaceModifierTest extends TestCase
         $image->modify(new PlaceModifier(__DIR__ . '/../../../images/circle.png', 'top-right', 0, 0));
         $this->assertEquals('32250d', $image->pickColor(300, 25)->toHex());
     }
+
+    public function testColorChangeOpacity(): void
+    {
+        $image = $this->readTestImage('test.jpg');
+        $this->assertEquals('febc44', $image->pickColor(300, 25)->toHex());
+        $image->modify(new PlaceModifier(__DIR__ . '/../../../images/circle.png', 'top-right', 0, 0, 50));
+        $this->assertEquals('987028', $image->pickColor(300, 25)->toHex());
+    }
 }

tests/Drivers/Imagick/Modifiers/PlaceModifierTest.php

@@ -24,4 +24,12 @@ class PlaceModifierTest extends TestCase
         $image->modify(new PlaceModifier(__DIR__ . '/../../../images/circle.png', 'top-right', 0, 0));
         $this->assertEquals('33260e', $image->pickColor(300, 25)->toHex());
     }
+
+    public function testColorChangeOpacity(): void
+    {
+        $image = $this->readTestImage('test.jpg');
+        $this->assertEquals('febc44', $image->pickColor(300, 25)->toHex());
+        $image->modify(new PlaceModifier(__DIR__ . '/../../../images/circle.png', 'top-right', 0, 0, 50));
+        $this->assertEquals('987129', $image->pickColor(300, 25)->toHex());
+    }
 }