Added gamma modifier

src/Drivers/Abstract/AbstractImage.php

@@ -139,6 +139,13 @@ abstract class AbstractImage
         );
     }
 
+    public function gamma(float $gamma): ImageInterface
+    {
+        return $this->modify(
+            $this->resolveDriverClass('Modifiers\GammaModifier', $gamma)
+        );
+    }
+
     public function blur(int $amount = 5): ImageInterface
     {
         return $this->modify(

src/Drivers/Gd/Modifiers/GammaModifier.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Intervention\Image\Drivers\Gd\Modifiers;
+
+use Intervention\Image\Interfaces\ImageInterface;
+use Intervention\Image\Interfaces\ModifierInterface;
+
+class GammaModifier implements ModifierInterface
+{
+    public function __construct(protected float $gamma)
+    {
+        //
+    }
+
+    public function apply(ImageInterface $image): ImageInterface
+    {
+        foreach ($image as $frame) {
+            imagegammacorrect($frame->getCore(), 1, $this->gamma);
+        }
+
+        return $image;
+    }
+}

src/Drivers/Imagick/Modifiers/GammaModifier.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Intervention\Image\Drivers\Imagick\Modifiers;
+
+use Intervention\Image\Interfaces\ImageInterface;
+use Intervention\Image\Interfaces\ModifierInterface;
+
+class GammaModifier implements ModifierInterface
+{
+    public function __construct(protected float $gamma)
+    {
+        //
+    }
+
+    public function apply(ImageInterface $image): ImageInterface
+    {
+        foreach ($image as $frame) {
+            $frame->getCore()->gammaImage($this->gamma);
+        }
+
+        return $image;
+    }
+}

tests/Drivers/Gd/Modifiers/GammaModifierTest.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Intervention\Image\Tests\Drivers\Gd\Modifiers;
+
+use Intervention\Image\Drivers\Gd\Modifiers\GammaModifier;
+use Intervention\Image\Tests\TestCase;
+use Intervention\Image\Tests\Traits\CanCreateGdTestImage;
+
+/**
+ * @requires extension gd
+ * @covers \Intervention\Image\Drivers\Gd\Modifiers\GammaModifier
+ */
+class GammaModifierTest extends TestCase
+{
+    use CanCreateGdTestImage;
+
+    public function testModifier(): void
+    {
+        $image = $this->createTestImage('trim.png');
+        $this->assertEquals('00aef0', $image->pickColor(0, 0)->toHex());
+        $image->modify(new GammaModifier(2.1));
+        $this->assertEquals('00d5f8', $image->pickColor(0, 0)->toHex());
+    }
+}

tests/Drivers/Imagick/Modifiers/GammaModifierTest.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Intervention\Image\Tests\Drivers\Imagick\Modifiers;
+
+use Intervention\Image\Drivers\Imagick\Modifiers\GammaModifier;
+use Intervention\Image\Tests\TestCase;
+use Intervention\Image\Tests\Traits\CanCreateImagickTestImage;
+
+/**
+ * @requires extension imagick
+ * @covers \Intervention\Image\Drivers\Imagick\Modifiers\GammaModifier
+ */
+class GammaModifierTest extends TestCase
+{
+    use CanCreateImagickTestImage;
+
+    public function testModifier(): void
+    {
+        $image = $this->createTestImage('trim.png');
+        $this->assertEquals('00aef0', $image->pickColor(0, 0)->toHex());
+        $image->modify(new GammaModifier(2.1));
+        $this->assertEquals('00d5f8', $image->pickColor(0, 0)->toHex());
+    }
+}