From 575f5b691ffc22feffd6e22cbe82c97b0eb67d76 Mon Sep 17 00:00:00 2001
From: Nicolas Lemoine <nico.lemoine@gmail.com>
Date: Mon, 6 Jul 2026 18:44:50 +0200
Subject: [PATCH] Reset page geometry after Imagick rotation

Imagick's rotateImage() grows the virtual canvas for non-right angles and
leaves each frame with a negative page offset (a 480x480 frame rotated 45
degrees ends up 680x680-100-100). ImageMagick's animated-AVIF writer
(libheif sequences) honours that offset when compositing the sequence,
shifting every frame up and left and leaving the bottom/right region
transparent.

Reset each frame's page to +0+0 after rotating, mirroring TrimModifier
and CoverModifier which already normalize page geometry. This keeps the
Imagick driver consistent with the GD and vips drivers, which leave no
offset, and fixes the transparent-corner artifact in animated AVIF.
---
 src/Drivers/Imagick/Modifiers/RotateModifier.php  |  6 ++++++
 .../Imagick/Modifiers/RotateModifierTest.php      | 15 +++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/Drivers/Imagick/Modifiers/RotateModifier.php b/src/Drivers/Imagick/Modifiers/RotateModifier.php
index eff3fc232..22f126270 100644
--- a/src/Drivers/Imagick/Modifiers/RotateModifier.php
+++ b/src/Drivers/Imagick/Modifiers/RotateModifier.php
@@ -32,6 +32,12 @@ public function apply(ImageInterface $image): ImageInterface
                         'Failed to apply ' . self::class . ', unable to rotate image',
                     );
                 }
+
+                // Reset the virtual canvas page that rotateImage() leaves behind. A
+                // non-right angle produces a negative page offset which otherwise
+                // corrupts the animated-AVIF (libheif sequences) writer, leaving the
+                // bottom/right region transparent. Mirrors TrimModifier/CoverModifier.
+                $frame->native()->setImagePage(0, 0, 0, 0);
             } catch (ImagickException $e) {
                 throw new ModifierException(
                     'Failed to apply ' . self::class . ', unable to rotate image',
diff --git a/tests/Unit/Drivers/Imagick/Modifiers/RotateModifierTest.php b/tests/Unit/Drivers/Imagick/Modifiers/RotateModifierTest.php
index a280009cb..43188ddf6 100644
--- a/tests/Unit/Drivers/Imagick/Modifiers/RotateModifierTest.php
+++ b/tests/Unit/Drivers/Imagick/Modifiers/RotateModifierTest.php
@@ -23,4 +23,19 @@ public function testRotate(): void
         $this->assertEquals(240, $image->width());
         $this->assertEquals(320, $image->height());
     }
+
+    public function testRotateResetsFramePageOffset(): void
+    {
+        // A non-right-angle rotation grows the virtual canvas; ImageMagick leaves
+        // each frame with a negative page offset. That offset mis-composes the
+        // animated-AVIF (libheif sequences) writer, leaving the bottom/right
+        // transparent, so rotate must reset every frame's page to +0+0.
+        $image = $this->readTestImage('animation.gif');
+        $image->modify(new RotateModifier(45, 'fff'));
+
+        foreach ($image as $frame) {
+            $this->assertSame(0, $frame->offsetLeft());
+            $this->assertSame(0, $frame->offsetTop());
+        }
+    }
 }