From 55299b2840acfbbb9dfe0d5a47f48bc9d1fd5a8b Mon Sep 17 00:00:00 2001
From: Oliver Vogel <oliver@olivervogel.com>
Date: Sat, 6 Jan 2024 17:25:15 +0100
Subject: [PATCH] Add BlendTransparencyModifier

---
 .../Modifiers/BlendTransparencyModifier.php   | 31 ++++++++++++++++++
 .../Modifiers/BlendTransparencyModifier.php   | 32 +++++++++++++++++++
 src/Image.php                                 | 11 +++++++
 src/Interfaces/ImageInterface.php             |  8 +++++
 src/Modifiers/BlendTransparencyModifier.php   | 10 ++++++
 5 files changed, 92 insertions(+)
 create mode 100644 src/Drivers/Gd/Modifiers/BlendTransparencyModifier.php
 create mode 100644 src/Drivers/Imagick/Modifiers/BlendTransparencyModifier.php
 create mode 100644 src/Modifiers/BlendTransparencyModifier.php

diff --git a/src/Drivers/Gd/Modifiers/BlendTransparencyModifier.php b/src/Drivers/Gd/Modifiers/BlendTransparencyModifier.php
new file mode 100644
index 00000000..0beed8af
--- /dev/null
+++ b/src/Drivers/Gd/Modifiers/BlendTransparencyModifier.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace Intervention\Image\Drivers\Gd\Modifiers;
+
+use Intervention\Image\Drivers\DriverSpecializedModifier;
+use Intervention\Image\Drivers\Gd\Cloner;
+use Intervention\Image\Interfaces\ImageInterface;
+
+class BlendTransparencyModifier extends DriverSpecializedModifier
+{
+    public function apply(ImageInterface $image): ImageInterface
+    {
+        // decode blending color
+        $color =  $this->driver()->handleInput(
+            $this->color ? $this->color : $image->blendingColor()
+        );
+
+        foreach ($image as $frame) {
+            // create new canvas with blending color as background
+            $modified = Cloner::cloneBlended(
+                $frame->native(),
+                background: $color
+            );
+
+            // set new gd image
+            $frame->setNative($modified);
+        }
+
+        return $image;
+    }
+}
diff --git a/src/Drivers/Imagick/Modifiers/BlendTransparencyModifier.php b/src/Drivers/Imagick/Modifiers/BlendTransparencyModifier.php
new file mode 100644
index 00000000..373635e4
--- /dev/null
+++ b/src/Drivers/Imagick/Modifiers/BlendTransparencyModifier.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Intervention\Image\Drivers\Imagick\Modifiers;
+
+use Imagick;
+use Intervention\Image\Drivers\DriverSpecializedModifier;
+use Intervention\Image\Interfaces\ImageInterface;
+
+class BlendTransparencyModifier extends DriverSpecializedModifier
+{
+    public function apply(ImageInterface $image): ImageInterface
+    {
+        // decode blending color
+        $color =  $this->driver()->handleInput(
+            $this->color ? $this->color : $image->blendingColor()
+        );
+
+        // get imagickpixel from color
+        $pixel = $this->driver()
+            ->colorProcessor($image->colorspace())
+            ->colorToNative($color);
+
+        // merge transparent areas with the background color
+        foreach ($image as $frame) {
+            $frame->native()->setImageBackgroundColor($pixel);
+            $frame->native()->setImageAlphaChannel(Imagick::ALPHACHANNEL_REMOVE);
+            $frame->native()->mergeImageLayers(Imagick::LAYERMETHOD_FLATTEN);
+        }
+
+        return $image;
+    }
+}
diff --git a/src/Image.php b/src/Image.php
index d44491aa..4577d700 100644
--- a/src/Image.php
+++ b/src/Image.php
@@ -45,6 +45,7 @@ use Intervention\Image\Interfaces\ModifierInterface;
 use Intervention\Image\Interfaces\ProfileInterface;
 use Intervention\Image\Interfaces\ResolutionInterface;
 use Intervention\Image\Interfaces\SizeInterface;
+use Intervention\Image\Modifiers\BlendTransparencyModifier;
 use Intervention\Image\Modifiers\BlurModifier;
 use Intervention\Image\Modifiers\BrightnessModifier;
 use Intervention\Image\Modifiers\ColorizeModifier;
@@ -402,6 +403,16 @@ final class Image implements ImageInterface
         return $this;
     }
 
+    /**
+     * {@inheritdoc}
+     *
+     * @see ImageInterface::blendTransparency()
+     */
+    public function blendTransparency(mixed $color = null): ImageInterface
+    {
+        return $this->modify(new BlendTransparencyModifier($color));
+    }
+
     /**
      * {@inheritdoc}
      *
diff --git a/src/Interfaces/ImageInterface.php b/src/Interfaces/ImageInterface.php
index 84dc34d1..95c9e3ef 100644
--- a/src/Interfaces/ImageInterface.php
+++ b/src/Interfaces/ImageInterface.php
@@ -202,6 +202,14 @@ interface ImageInterface extends IteratorAggregate, Countable
      */
     public function setBlendingColor(mixed $color): ImageInterface;
 
+    /**
+     * Replace transparent areas of the image with given color
+     *
+     * @param mixed $color
+     * @return ImageInterface
+     */
+    public function blendTransparency(mixed $color = null): ImageInterface;
+
     /**
      * Retrieve ICC color profile of image
      *
diff --git a/src/Modifiers/BlendTransparencyModifier.php b/src/Modifiers/BlendTransparencyModifier.php
new file mode 100644
index 00000000..5f7a782e
--- /dev/null
+++ b/src/Modifiers/BlendTransparencyModifier.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Intervention\Image\Modifiers;
+
+class BlendTransparencyModifier extends AbstractModifier
+{
+    public function __construct(public mixed $color = null)
+    {
+    }
+}