Replace (semi-)transparent alpha values in BlendTransparencyModifier::class

src/Drivers/Gd/Modifiers/BlendTransparencyModifier.php

@@ -18,16 +18,13 @@ class BlendTransparencyModifier extends GenericBlendTransparencyModifier impleme
      */
     public function apply(ImageInterface $image): ImageInterface
     {
-        // decode blending color
+        $blendingColor = $this->blendingColor($this->driver());
-        $color = $this->driver()->handleInput(
-            $this->color ? $this->color : $this->driver()->config()->blendingColor
-        );
 
         foreach ($image as $frame) {
             // create new canvas with blending color as background
             $modified = Cloner::cloneBlended(
                 $frame->native(),
-                background: $color
+                background: $blendingColor
             );
 
             // set new gd image

src/Drivers/Imagick/Modifiers/BlendTransparencyModifier.php

@@ -13,15 +13,12 @@ class BlendTransparencyModifier extends GenericBlendTransparencyModifier impleme
 {
     public function apply(ImageInterface $image): ImageInterface
     {
-        // decode blending color
+        $blendingColor = $this->blendingColor($this->driver());
-        $color = $this->driver()->handleInput(
-            $this->color ? $this->color : $this->driver()->config()->blendingColor
-        );
 
-        // get imagickpixel from color
+        // get imagickpixel from blending color
         $pixel = $this->driver()
             ->colorProcessor($image->colorspace())
-            ->colorToNative($color);
+            ->colorToNative($blendingColor);
 
         // merge transparent areas with the background color
         foreach ($image as $frame) {

src/Modifiers/BlendTransparencyModifier.php

@@ -4,7 +4,15 @@ declare(strict_types=1);
 
 namespace Intervention\Image\Modifiers;
 
+use Intervention\Image\Colors\Rgb\Channels\Blue;
+use Intervention\Image\Colors\Rgb\Channels\Green;
+use Intervention\Image\Colors\Rgb\Channels\Red;
+use Intervention\Image\Colors\Rgb\Color;
 use Intervention\Image\Drivers\SpecializableModifier;
+use Intervention\Image\Exceptions\ColorException;
+use Intervention\Image\Exceptions\RuntimeException;
+use Intervention\Image\Interfaces\ColorInterface;
+use Intervention\Image\Interfaces\DriverInterface;
 
 class BlendTransparencyModifier extends SpecializableModifier
 {
@@ -16,5 +24,33 @@ class BlendTransparencyModifier extends SpecializableModifier
      */
     public function __construct(public mixed $color = null)
     {
+        //
+    }
+
+    /**
+     * Decode blending color of current modifier with given driver. Possible
+     * (semi-)transparent alpha channel values are made opaque.
+     *
+     * @throws RuntimeException
+     * @throws ColorException
+     * @return ColorInterface
+     */
+    protected function blendingColor(DriverInterface $driver): ColorInterface
+    {
+        // decode blending color
+        $color = $driver->handleInput(
+            $this->color ?: $driver->config()->blendingColor
+        );
+
+        // replace alpha channel value with opaque value
+        if ($color->isTransparent()) {
+            return new Color(
+                $color->channel(Red::class)->value(),
+                $color->channel(Green::class)->value(),
+                $color->channel(Blue::class)->value(),
+            );
+        }
+
+        return $color;
     }
 }

tests/Unit/Drivers/Gd/ImageTest.php

@@ -301,6 +301,15 @@ final class ImageTest extends GdTestCase
         $this->assertColor(255, 85, 0, 255, $result->pickColor(1, 0));
     }
 
+    public function testBlendTransparencyIgnoreTransparencyInBlendingColor(): void
+    {
+        $image = $this->readTestImage('gradient.gif');
+        $this->assertColor(0, 0, 0, 0, $image->pickColor(1, 0));
+        $result = $image->blendTransparency('ff550055');
+        $this->assertColor(255, 85, 0, 255, $image->pickColor(1, 0));
+        $this->assertColor(255, 85, 0, 255, $result->pickColor(1, 0));
+    }
+
     public function testToJpeg(): void
     {
         $this->assertMediaType('image/jpeg', $this->image->toJpeg());

tests/Unit/Drivers/Imagick/ImageTest.php

@@ -295,6 +295,15 @@ final class ImageTest extends ImagickTestCase
         $this->assertColor(255, 85, 0, 255, $result->pickColor(1, 0));
     }
 
+    public function testBlendTransparencyIgnoreTransparencyInBlendingColor(): void
+    {
+        $image = $this->readTestImage('gradient.gif');
+        $this->assertColor(0, 0, 0, 0, $image->pickColor(1, 0));
+        $result = $image->blendTransparency('ff550055');
+        $this->assertColor(255, 85, 0, 255, $image->pickColor(1, 0));
+        $this->assertColor(255, 85, 0, 255, $result->pickColor(1, 0));
+    }
+
     public function testToJpeg(): void
     {
         $this->assertMediaType('image/jpeg', $this->image->toJpeg());