Implement image resolution management

src/Drivers/Abstract/AbstractImage.php

@@ -385,6 +385,13 @@ abstract class AbstractImage implements ImageInterface
         return is_null($query) ? $this->exif : $this->exif->get($query);
     }
 
+    public function setResolution(float $x, float $y): ImageInterface
+    {
+        return $this->modify(
+            $this->resolveDriverClass('Modifiers\ResolutionModifier', $x, $y)
+        );
+    }
+
     public function destroy(): void
     {
         $this->modify(

src/Drivers/Gd/Image.php

@@ -13,6 +13,8 @@ use Intervention\Image\Interfaces\ColorspaceInterface;
 use Intervention\Image\Interfaces\FrameInterface;
 use Intervention\Image\Interfaces\ImageInterface;
 use Intervention\Image\Interfaces\ProfileInterface;
+use Intervention\Image\Interfaces\ResolutionInterface;
+use Intervention\Image\Resolution;
 use IteratorAggregate;
 use Traversable;
 
@@ -78,6 +80,16 @@ class Image extends AbstractImage implements ImageInterface, IteratorAggregate
         return imagesy($this->frame()->core());
     }
 
+    /**
+     * {@inheritdoc}
+     *
+     * @see ImageInterface::resolution()
+     */
+    public function resolution(): ResolutionInterface
+    {
+        return new Resolution(...imageresolution($this->frame()->core()));
+    }
+
     public function pickColor(int $x, int $y, int $frame_key = 0): ColorInterface
     {
         return $this->integerToColor(

src/Drivers/Gd/Modifiers/ResolutionModifier.php

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

src/Drivers/Gd/Modifiers/RotateModifier.php

@@ -14,6 +14,10 @@ class RotateModifier extends AbstractRotateModifier implements ModifierInterface
     public function apply(ImageInterface $image): ImageInterface
     {
         foreach ($image as $frame) {
+            // retain resolution because imagerotate() seems to reset density to 96dpi
+            $resolution = imageresolution($frame->core());
+
+            // rotate image
             $frame->setCore(
                 imagerotate(
                     $frame->core(),
@@ -21,6 +25,9 @@ class RotateModifier extends AbstractRotateModifier implements ModifierInterface
                     $this->colorToInteger($this->backgroundColor())
                 )
             );
+
+            // restore original image resolution
+            imageresolution($frame->core(), $resolution[0], $resolution[1]);
         }
 
         return $image;

src/Drivers/Imagick/Image.php

@@ -19,6 +19,8 @@ use Intervention\Image\Interfaces\ColorspaceInterface;
 use Intervention\Image\Interfaces\FrameInterface;
 use Intervention\Image\Interfaces\ImageInterface;
 use Intervention\Image\Interfaces\ProfileInterface;
+use Intervention\Image\Interfaces\ResolutionInterface;
+use Intervention\Image\Resolution;
 use Iterator;
 
 class Image extends AbstractImage implements ImageInterface, Iterator
@@ -134,6 +136,16 @@ class Image extends AbstractImage implements ImageInterface, Iterator
         return $this->frame()->core()->getImageHeight();
     }
 
+    /**
+     * {@inheritdoc}
+     *
+     * @see ImageInterface::resolution()
+     */
+    public function resolution(): ResolutionInterface
+    {
+        return new Resolution(...$this->frame()->core()->getImageResolution());
+    }
+
     /**
      * {@inheritdoc}
      *

src/Drivers/Imagick/Modifiers/ResolutionModifier.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Intervention\Image\Drivers\Imagick\Modifiers;
+
+use Intervention\Image\Interfaces\ImageInterface;
+use Intervention\Image\Interfaces\ModifierInterface;
+use Intervention\Image\Drivers\Imagick\Image;
+use Intervention\Image\Traits\CanCheckType;
+
+class ResolutionModifier implements ModifierInterface
+{
+    use CanCheckType;
+
+    public function __construct(protected float $x, protected float $y)
+    {
+        //
+    }
+
+    public function apply(ImageInterface $image): ImageInterface
+    {
+        $imagick = $this->failIfNotClass($image, Image::class)->getImagick();
+        $imagick->setImageResolution($this->x, $this->y);
+
+        return $image;
+    }
+}

src/Interfaces/ImageInterface.php

@@ -386,6 +386,22 @@ interface ImageInterface extends Traversable, Countable
      */
     public function height(): int;
 
+    /**
+     * Return image resolution/density
+     *
+     * @return ResolutionInterface
+     */
+    public function resolution(): ResolutionInterface;
+
+    /**
+     * Se the image resolution/density
+     *
+     * @param  float $x
+     * @param  float $y
+     * @return ImageInterface
+     */
+    public function setResolution(float $x, float $y): ImageInterface;
+
     /**
      * Destroy current image instance and free up memory
      *

src/Interfaces/ResolutionInterface.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace Intervention\Image\Interfaces;
+
+interface ResolutionInterface
+{
+    public function x(): float;
+    public function y(): float;
+}

src/Resolution.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Intervention\Image;
+
+use Intervention\Image\Interfaces\ResolutionInterface;
+
+class Resolution implements ResolutionInterface
+{
+    public function __construct(protected float $x, protected float $y)
+    {
+        //
+    }
+
+    public function x(): float
+    {
+        return $this->x;
+    }
+
+    public function y(): float
+    {
+        return $this->y;
+    }
+}

tests/Drivers/Abstract/AbstractImageTest.php

@@ -11,6 +11,7 @@ use Intervention\Image\Interfaces\EncoderInterface;
 use Intervention\Image\Interfaces\FrameInterface;
 use Intervention\Image\Interfaces\ImageInterface;
 use Intervention\Image\Interfaces\ModifierInterface;
+use Intervention\Image\Resolution;
 use Intervention\Image\Tests\TestCase;
 use Mockery;
 

tests/Drivers/Gd/ImageTest.php

@@ -12,6 +12,7 @@ use Intervention\Image\Colors\Rgb\Colorspace as RgbColorspace;
 use Intervention\Image\Colors\Cmyk\Colorspace as CmykColorspace;
 use Intervention\Image\Exceptions\NotSupportedException;
 use Intervention\Image\Exceptions\AnimationException;
+use Intervention\Image\Resolution;
 
 /**
  * @requires extension gd
@@ -152,4 +153,10 @@ class ImageTest extends TestCase
         $this->expectException(NotSupportedException::class);
         $this->image->setColorspace(new CmykColorspace());
     }
+
+    public function testResolution(): void
+    {
+        $result = $this->image->resolution();
+        $this->assertInstanceOf(Resolution::class, $result);
+    }
 }

tests/Drivers/Gd/Modifiers/ResolutionModifierTest.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Intervention\Image\Tests\Drivers\Gd\Modifiers;
+
+use Intervention\Image\Drivers\Gd\Modifiers\ResolutionModifier;
+use Intervention\Image\Tests\TestCase;
+use Intervention\Image\Tests\Traits\CanCreateGdTestImage;
+
+/**
+ * @requires extension gd
+ * @covers \Intervention\Image\Drivers\Gd\Modifiers\ResolutionModifier
+ */
+class ResolutionModifierTest extends TestCase
+{
+    use CanCreateGdTestImage;
+
+    public function testResolutionChange(): void
+    {
+        $image = $this->createTestImage('test.jpg');
+        $this->assertEquals(72.0, $image->resolution()->x());
+        $this->assertEquals(72.0, $image->resolution()->y());
+        $image->modify(new ResolutionModifier(1, 2));
+        $this->assertEquals(1.0, $image->resolution()->x());
+        $this->assertEquals(2.0, $image->resolution()->y());
+    }
+}

tests/Drivers/Imagick/ImageTest.php

@@ -12,6 +12,7 @@ use Intervention\Image\Drivers\Imagick\Image;
 use Intervention\Image\Exceptions\AnimationException;
 use Intervention\Image\Exceptions\ColorException;
 use Intervention\Image\Geometry\Rectangle;
+use Intervention\Image\Resolution;
 use Intervention\Image\Tests\TestCase;
 
 /**
@@ -155,4 +156,10 @@ class ImageTest extends TestCase
         $this->expectException(ColorException::class);
         $image->profile();
     }
+
+    public function testResolution(): void
+    {
+        $result = $this->image->resolution();
+        $this->assertInstanceOf(Resolution::class, $result);
+    }
 }

tests/Drivers/Imagick/Modifiers/ResolutionModifierTest.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Intervention\Image\Tests\Drivers\Imagick\Modifiers;
+
+use Intervention\Image\Drivers\Imagick\Modifiers\ResolutionModifier;
+use Intervention\Image\Tests\TestCase;
+use Intervention\Image\Tests\Traits\CanCreateImagickTestImage;
+
+/**
+ * @requires extension gd
+ * @covers \Intervention\Image\Drivers\Imagick\Modifiers\ResolutionModifier
+ */
+class ResolutionModifierTest extends TestCase
+{
+    use CanCreateImagickTestImage;
+
+    public function testResolutionChange(): void
+    {
+        $image = $this->createTestImage('test.jpg');
+        $this->assertEquals(72.0, $image->resolution()->x());
+        $this->assertEquals(72.0, $image->resolution()->y());
+        $image->modify(new ResolutionModifier(1, 2));
+        $this->assertEquals(1.0, $image->resolution()->x());
+        $this->assertEquals(2.0, $image->resolution()->y());
+    }
+}