Fix wonky gravity

Author: timkelty

src/imagetransforms/ImageTransform.php

@@ -70,7 +70,7 @@ class ImageTransform extends \craft\models\ImageTransform
     public ?float $gamma = null;
 
     /**
-     * @var 'auto'|'face'|'left'|'right'|'top'|'bottom'|array{x?: float, y?: float, mode?: 'remainder'|'box-center'}|null
+     * @var 'auto'|'face'|'left'|'right'|'top'|'bottom'|array{x?: float, y?: float}|null
      */
     public string|array|null $gravity = null;
 

src/imagetransforms/ImageTransformer.php

@@ -70,11 +70,48 @@ protected function applyAssetFocalPointGravity(Asset $asset, ImageTransform $ima
             return;
         }
 
+        $sourceWidth = $asset->getWidth();
+        $sourceHeight = $asset->getHeight();
+        $targetWidth = $imageTransform->width;
+        $targetHeight = $imageTransform->height;
+
+        if (!$sourceWidth || !$sourceHeight || !$targetWidth || !$targetHeight) {
+            $imageTransform->gravity = $asset->getFocalPoint();
+            return;
+        }
+
         $focalPoint = $asset->getFocalPoint();
+        $factor = min($sourceWidth / $targetWidth, $sourceHeight / $targetHeight);
+        $newWidth = round($sourceWidth / $factor);
+        $newHeight = round($sourceHeight / $factor);
+
+        $centerX = $newWidth * $focalPoint['x'];
+        $centerY = $newHeight * $focalPoint['y'];
+        $x1 = $centerX - $targetWidth / 2;
+        $y1 = $centerY - $targetHeight / 2;
+        $x2 = $x1 + $targetWidth;
+        $y2 = $y1 + $targetHeight;
+
+        if ($x1 < 0) {
+            $x2 -= $x1;
+            $x1 = 0;
+        }
+        if ($y1 < 0) {
+            $y2 -= $y1;
+            $y1 = 0;
+        }
+        if ($x2 > $newWidth) {
+            $x1 -= ($x2 - $newWidth);
+            $x2 = $newWidth;
+        }
+        if ($y2 > $newHeight) {
+            $y1 -= ($y2 - $newHeight);
+            $y2 = $newHeight;
+        }
+
         $imageTransform->gravity = [
-            'x' => $focalPoint['x'],
-            'y' => $focalPoint['y'],
-            'mode' => 'box-center',
+            'x' => $newWidth > $targetWidth ? $x1 / ($newWidth - $targetWidth) : $focalPoint['x'],
+            'y' => $newHeight > $targetHeight ? $y1 / ($newHeight - $targetHeight) : $focalPoint['y'],
         ];
     }
 

tests/unit/ImageTransformTest.php

@@ -14,7 +14,7 @@ class ImageTransformTest extends Unit
      */
     protected $tester;
 
-    public function testCropModeWithExplicitGravityModePreservesItInOptions(): void
+    public function testCropModeWithExplicitGravityPreservesItInOptions(): void
     {
         $transform = new ImageTransform([
             'mode' => 'crop',
@@ -23,7 +23,6 @@ public function testCropModeWithExplicitGravityModePreservesItInOptions(): void
             'gravity' => [
                 'x' => 0.57,
                 'y' => 0.7707,
-                'mode' => 'box-center',
             ],
         ]);
 
@@ -32,7 +31,6 @@ public function testCropModeWithExplicitGravityModePreservesItInOptions(): void
             'gravity' => [
                 'x' => 0.57,
                 'y' => 0.7707,
-                'mode' => 'box-center',
             ],
             'height' => 750,
             'width' => 1200,
@@ -59,53 +57,58 @@ public function testCropModeWithoutGravityUsesPositionMapping(): void
         ], $transform->toOptions());
     }
 
-    public function testFocalPointCropUsesBoxCenteredGravity(): void
+    public function testCropModeMapsFocalPointToClampedCropOriginGravity(): void
     {
-        $asset = $this->makeAssetStub(true, ['x' => 0.57, 'y' => 0.7707]);
+        $asset = $this->makeAssetStub(3402, 4253, ['x' => 0.474, 'y' => 0.3064]);
         $transform = new ImageTransform([
             'mode' => 'crop',
+            'position' => 'top-center',
             'width' => 1200,
             'height' => 750,
-            'position' => 'top-center',
         ]);
 
         (new TestImageTransformer())->applyFocalPointGravity($asset, $transform);
 
-        $this->assertSame([
-            'x' => 0.57,
-            'y' => 0.7707,
-            'mode' => 'box-center',
-        ], $transform->gravity);
+        $this->assertEqualsWithDelta([
+            'x' => 0.474,
+            'y' => 0.1128,
+        ], $transform->gravity, 0.0001);
     }
 
-    private function makeAssetStub(bool $hasFocalPoint, array $focalPoint): Asset
+    private function makeAssetStub(int $width, int $height, array $focalPoint): Asset
     {
-        return new class($hasFocalPoint, $focalPoint) extends Asset {
-            public function __construct(private bool $hasFocalPoint, private array $focalPoint)
+        return new class($width, $height, $focalPoint) extends Asset {
+            public function __construct(private int $widthValue, private int $heightValue, private array $focalPointValue)
             {
                 parent::__construct();
             }
 
             public function getHasFocalPoint(): bool
             {
-                return $this->hasFocalPoint;
+                return true;
             }
 
             public function getFocalPoint(bool $asCss = false): array|string|null
             {
                 if ($asCss) {
-                    return ($this->focalPoint['x'] * 100) . '% ' . ($this->focalPoint['y'] * 100) . '%';
+                    return ($this->focalPointValue['x'] * 100) . '% ' . ($this->focalPointValue['y'] * 100) . '%';
                 }
 
-                return $this->focalPoint;
+                return $this->focalPointValue;
             }
 
-            public function getMimeType(mixed $transform = null): ?string
+            public function getWidth(array|string|\craft\models\ImageTransform $transform = null): ?int
             {
-                return 'image/jpeg';
+                return $this->widthValue;
+            }
+
+            public function getHeight(mixed $transform = null): ?int
+            {
+                return $this->heightValue;
             }
         };
     }
+
 }
 
 class TestImageTransformer extends ImageTransformer