Add background opacity

src/Image.php

@@ -12,6 +12,7 @@ class Image
     protected string $accentColor;
     protected ?Background $background = null;
     protected string $backgroundColor = '#ffffff';
+    protected float $backgroundOpacity = 1.0;
     protected ?Border $border = null;
     protected string $callToAction;
     protected string $description;
@@ -64,13 +65,14 @@ public function accentColor(string $hexCode): self
         $this->accentColor = $hexCode;
         return $this;
     }
-    
-    public function background(Background $background): self
+
+    public function background(Background $background, float $opacity = 1.0): self
     {
+        $this->backgroundOpacity = $opacity < 0 ? 0 : ($opacity > 1 ? 1 : $opacity);
         $this->background = $background;
         return $this;
     }
-    
+
     public function callToAction(string $content): self
     {
         $this->callToAction = $content;

src/Traits/RendersImages.php

@@ -2,6 +2,7 @@
 
 namespace SimonHamp\TheOg\Traits;
 
+use Imagick;
 use Intervention\Image\Image;
 use Intervention\Image\ImageManager;
 use Intervention\Image\Typography\FontFactory;
@@ -144,9 +145,15 @@ protected function renderHorizontalAccentedRectangle(): callable
 
     protected function renderBackground(): void
     {
-        // How many iterations are needed to fill the width?
         $panel = $this->manager->read($this->background->path());
 
+        $imagick = $panel->core()->native();
+
+        $imagick->setImageVirtualPixelMethod(1);
+        $imagick->setImageAlphaChannel(Imagick::ALPHACHANNEL_ACTIVATE);
+
+        $imagick->evaluateImage(Imagick::EVALUATE_MULTIPLY, $this->backgroundOpacity, Imagick::CHANNEL_ALPHA);
+
         $width = $panel->width();
         $height = $panel->height();
 

tests/test.php

@@ -11,5 +11,5 @@
     ->url('https://example.com/blog/some-blog-post-url')
     ->title('Some blog post title that is quite big and quite long')
     ->description('Some slightly smaller but potentially much longer subtext. It could be really long so we might need to trim it completely after many words')
-    ->background(Background::JustWaves)
+    ->background(Background::JustWaves, 0.2)
     ->save(__DIR__.'/test.png');