diff --git a/src/Plugin/ImageEffect/SetCanvasImageEffect.php b/src/Plugin/ImageEffect/SetCanvasImageEffect.php
index dc1e42b..a6dc24e 100644
--- a/src/Plugin/ImageEffect/SetCanvasImageEffect.php
+++ b/src/Plugin/ImageEffect/SetCanvasImageEffect.php
@@ -65,7 +65,7 @@ class SetCanvasImageEffect extends ConfigurableImageEffectBase {
       '#data' => $data,
     ] + parent::getSummary();
   }
-  
+
   /**
    * {@inheritdoc}
    */
@@ -80,7 +80,7 @@ class SetCanvasImageEffect extends ConfigurableImageEffectBase {
       ],
       '#required' => TRUE,
     ];
-    
+
     // Exact size canvas.
     $form['exact'] = [
       '#type' => 'details',
@@ -251,7 +251,7 @@ class SetCanvasImageEffect extends ConfigurableImageEffectBase {
    */
   public function transformDimensions(array &$dimensions, $uri) {
     if ($dimensions['width'] && $dimensions['height']) {
-      $d = $this->getDimensions($image->getWidth(), $image->getHeight());
+      $d = $this->getDimensions($dimensions['width'], $dimensions['height']);
       $dimensions['width'] = $d['width'];
       $dimensions['height'] = $d['height'];
     }
diff --git a/src/Tests/ImageEffectsSetCanvasTest.php b/src/Tests/ImageEffectsSetCanvasTest.php
new file mode 100644
index 0000000..54c4e06
--- /dev/null
+++ b/src/Tests/ImageEffectsSetCanvasTest.php
@@ -0,0 +1,136 @@
+<?php
+
+/**
+ * @file
+ * Set canvas effect test case script.
+ */
+
+namespace Drupal\image_effects\Tests;
+
+use Drupal\image\Entity\ImageStyle;
+
+/**
+ * Set canvas effect test.
+ *
+ * @group Image Effects
+ */
+class ImageEffectsSetCanvasTest extends ImageEffectsTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+    $this->toolkits = ['gd', 'imagemagick'];
+  }
+
+  /**
+   * Set canvas effect test.
+   */
+  public function testColorShiftEffect() {
+    // Test operations on toolkits.
+    $this->executeTestOnToolkits([$this, 'doTestSetCanvasOperations']);
+  }
+
+  /**
+   * Set canvas operations test.
+   */
+  public function doTestSetCanvasOperations() {
+    $image_factory = $this->container->get('image.factory');
+
+    $test_file = drupal_get_path('module', 'simpletest') . '/files/image-test.png';
+    $original_uri = file_unmanaged_copy($test_file, 'public://', FILE_EXISTS_RENAME);
+    $generated_uri = 'public://styles/image_effects_test/public/' . \Drupal::service('file_system')->basename($original_uri);
+
+    // Test EXACT size canvas.
+    $effect = [
+      'id' => 'image_effects_set_canvas',
+      'data' => [
+        'canvas_mode' => 'exact',
+        'canvas_color][container][transparent' => FALSE,
+        'canvas_color][container][hex' => '#FF00FF',
+        'canvas_color][container][opacity' => 100,
+        'exact][width' => '200%',
+        'exact][height' => '200%',
+      ],
+    ];
+    $uuid = $this->addEffectToTestStyle($effect);
+
+    // Load Image Style.
+    $image_style = ImageStyle::load('image_effects_test');
+
+    // Check that ::transformDimensions returns expected dimensions.
+    $image = $image_factory->get($original_uri);
+    $this->assertEqual(40, $image->getWidth());
+    $this->assertEqual(20, $image->getHeight());
+    $url = file_url_transform_relative($image_style->buildUrl($original_uri));
+    $variables = array(
+      '#theme' => 'image_style',
+      '#style_name' => 'image_effects_test',
+      '#uri' => $original_uri,
+      '#width' => $image->getWidth(),
+      '#height' => $image->getHeight(),
+    );
+    $this->assertEqual('<img src="' . $url . '" width="80" height="40" alt="" class="image-style-image-effects-test" />', $this->getImageTag($variables));
+
+    // Check that ::applyEffect generates image with expected canvas.
+    $image_style->createDerivative($original_uri, $image_style->buildUri($original_uri));
+    $image = $image_factory->get($generated_uri, 'gd');
+    $this->assertEqual(80, $image->getWidth());
+    $this->assertEqual(40, $image->getHeight());
+    $this->assertTrue($this->colorsAreEqual($this->fuchsia, $this->getPixelColor($image, 0, 0)));
+    $this->assertTrue($this->colorsAreEqual($this->fuchsia, $this->getPixelColor($image, 79, 0)));
+    $this->assertTrue($this->colorsAreEqual($this->fuchsia, $this->getPixelColor($image, 0, 39)));
+    $this->assertTrue($this->colorsAreEqual($this->fuchsia, $this->getPixelColor($image, 79, 39)));
+
+    // Remove effect.
+    $this->removeEffectFromTestStyle($uuid);
+
+    // Test RELATIVE size canvas.
+    $effect = [
+      'id' => 'image_effects_set_canvas',
+      'data' => [
+        'canvas_mode' => 'relative',
+        'canvas_color][container][transparent' => FALSE,
+        'canvas_color][container][hex' => '#FFFF00',
+        'canvas_color][container][opacity' => 100,
+        'relative][right' => 10,
+        'relative][left' => 20,
+        'relative][top' => 30,
+        'relative][bottom' => 40,
+      ],
+    ];
+    $uuid = $this->addEffectToTestStyle($effect);
+
+    // Load Image Style.
+    $image_style = ImageStyle::load('image_effects_test');
+
+    // Check that ::transformDimensions returns expected dimensions.
+    $image = $image_factory->get($original_uri);
+    $this->assertEqual(40, $image->getWidth());
+    $this->assertEqual(20, $image->getHeight());
+    $url = file_url_transform_relative($image_style->buildUrl($original_uri));
+    $variables = array(
+      '#theme' => 'image_style',
+      '#style_name' => 'image_effects_test',
+      '#uri' => $original_uri,
+      '#width' => $image->getWidth(),
+      '#height' => $image->getHeight(),
+    );
+    $this->assertEqual('<img src="' . $url . '" width="70" height="90" alt="" class="image-style-image-effects-test" />', $this->getImageTag($variables));
+
+    // Check that ::applyEffect generates image with expected canvas.
+    $image_style->createDerivative($original_uri, $image_style->buildUri($original_uri));
+    $image = $image_factory->get($generated_uri, 'gd');
+    $this->assertEqual(70, $image->getWidth());
+    $this->assertEqual(90, $image->getHeight());
+    $this->assertTrue($this->colorsAreEqual($this->yellow, $this->getPixelColor($image, 0, 0)));
+    $this->assertTrue($this->colorsAreEqual($this->yellow, $this->getPixelColor($image, 69, 0)));
+    $this->assertTrue($this->colorsAreEqual($this->yellow, $this->getPixelColor($image, 0, 89)));
+    $this->assertTrue($this->colorsAreEqual($this->yellow, $this->getPixelColor($image, 69, 89)));
+
+    // Remove effect.
+    $this->removeEffectFromTestStyle($uuid);
+  }
+
+}