LibWeb/HTML: Fix crash calling setTransform on canvas without context

This isn't a full fix, as the paint function does not handle this
either. But instead of getting the bitmap from the image source
immediately, follow the spec a bit more closely by creating the
CanvasPatern object with the ImageSource directly.

Fixes a crash for the 5 included WPT tests.

Libraries/LibWeb/HTML/CanvasPattern.cpp

@@ -46,8 +46,17 @@ void CanvasPatternPaintStyle::paint(Gfx::IntRect physical_bounding_box, PaintFun
 
     // 6. The resulting bitmap is what is to be rendered, with the same origin and same scale.
 
-    auto const bitmap_width = m_immutable_bitmap->width();
-    auto const bitmap_height = m_immutable_bitmap->height();
+    // FIXME: This doesn't handle a 'none' canvas context mode.
+    auto bitmap = m_image.visit(
+        [](GC::Root<HTMLImageElement> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return source->immutable_bitmap(); },
+        [](GC::Root<SVG::SVGImageElement> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return source->current_image_bitmap(); },
+        [](GC::Root<HTMLCanvasElement> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return Gfx::ImmutableBitmap::create_snapshot_from_painting_surface(*source->surface()); },
+        [](GC::Root<HTMLVideoElement> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return Gfx::ImmutableBitmap::create(*source->bitmap()); },
+        [](GC::Root<ImageBitmap> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return Gfx::ImmutableBitmap::create(*source->bitmap()); });
+    VERIFY(bitmap);
+
+    auto const bitmap_width = bitmap->width();
+    auto const bitmap_height = bitmap->height();
 
     paint([=, this](auto point) {
         point.translate_by(physical_bounding_box.location());
@@ -78,8 +87,8 @@ void CanvasPatternPaintStyle::paint(Gfx::IntRect physical_bounding_box, PaintFun
                 VERIFY_NOT_REACHED();
             }
         }();
-        if (m_immutable_bitmap->rect().contains(point))
-            return m_immutable_bitmap->get_pixel(point.x(), point.y());
+        if (bitmap->rect().contains(point))
+            return bitmap->get_pixel(point.x(), point.y());
         return Gfx::Color();
     });
 }
@@ -127,16 +136,8 @@ WebIDL::ExceptionOr<GC::Ptr<CanvasPattern>> CanvasPattern::create(JS::Realm& rea
     if (!repetition_value.has_value())
         return WebIDL::SyntaxError::create(realm, "Repetition value is not valid"_string);
 
-    // Note: Bitmap won't be null here, as if it were it would have "bad" usability.
-    auto bitmap = image.visit(
-        [](GC::Root<HTMLImageElement> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return source->immutable_bitmap(); },
-        [](GC::Root<SVG::SVGImageElement> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return source->current_image_bitmap(); },
-        [](GC::Root<HTMLCanvasElement> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return Gfx::ImmutableBitmap::create_snapshot_from_painting_surface(*source->surface()); },
-        [](GC::Root<HTMLVideoElement> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return Gfx::ImmutableBitmap::create(*source->bitmap()); },
-        [](GC::Root<ImageBitmap> const& source) -> RefPtr<Gfx::ImmutableBitmap> { return Gfx::ImmutableBitmap::create(*source->bitmap()); });
-
     // 6. Let pattern be a new CanvasPattern object with the image image and the repetition behavior given by repetition.
-    auto pattern = TRY_OR_THROW_OOM(realm.vm(), CanvasPatternPaintStyle::create(*bitmap, *repetition_value));
+    auto pattern = TRY_OR_THROW_OOM(realm.vm(), CanvasPatternPaintStyle::create(image, *repetition_value));
 
     // FIXME: 7. If image is not origin-clean, then mark pattern as not origin-clean.
 

Libraries/LibWeb/HTML/CanvasPattern.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2023, MacDue <macdue@dueutil.tech>
+ * Copyright (c) 2025, Shannon Booth <shannon@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -21,21 +22,21 @@ class CanvasPatternPaintStyle final : public Gfx::PaintStyle {
         NoRepeat
     };
 
-    static ErrorOr<NonnullRefPtr<CanvasPatternPaintStyle>> create(Gfx::ImmutableBitmap const& bitmap, Repetition repetition)
+    static ErrorOr<NonnullRefPtr<CanvasPatternPaintStyle>> create(CanvasImageSource image, Repetition repetition)
     {
-        return adopt_nonnull_ref_or_enomem(new (nothrow) CanvasPatternPaintStyle(bitmap, repetition));
+        return adopt_nonnull_ref_or_enomem(new (nothrow) CanvasPatternPaintStyle(move(image), repetition));
     }
 
     virtual void paint(Gfx::IntRect physical_bounding_box, PaintFunction paint) const override;
 
 private:
-    CanvasPatternPaintStyle(Gfx::ImmutableBitmap const& immutable_bitmap, Repetition repetition)
-        : m_immutable_bitmap(immutable_bitmap)
+    CanvasPatternPaintStyle(CanvasImageSource image, Repetition repetition)
+        : m_image(move(image))
         , m_repetition(repetition)
     {
     }
 
-    NonnullRefPtr<Gfx::ImmutableBitmap> m_immutable_bitmap;
+    CanvasImageSource m_image;
     Repetition m_repetition { Repetition::Repeat };
 };
 

Tests/LibWeb/Text/expected/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.basic.nocontext.txt

@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Fail
+Fail	Canvas test: 2d.pattern.basic.nocontext

Tests/LibWeb/Text/expected/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.repeat.null.txt

@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Pass
+Pass	Canvas test: 2d.pattern.repeat.null

Tests/LibWeb/Text/expected/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.transform.identity.txt

@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Fail
+Fail	Canvas test: 2d.pattern.transform.identity

Tests/LibWeb/Text/expected/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.transform.infinity.txt

@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Fail
+Fail	Canvas test: 2d.pattern.transform.infinity

Tests/LibWeb/Text/expected/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.transform.invalid.txt

@@ -0,0 +1,6 @@
+Harness status: OK
+
+Found 1 tests
+
+1 Pass
+Pass	Canvas test: 2d.pattern.transform.invalid

Tests/LibWeb/Text/input/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.basic.nocontext.html

@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<title>Canvas test: 2d.pattern.basic.nocontext</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<script src="../../../../html/canvas/resources/canvas-tests.js"></script>
+<link rel="stylesheet" href="../../../../html/canvas/resources/canvas-tests.css">
+<body class="show_output">
+
+<h1>2d.pattern.basic.nocontext</h1>
+<p class="desc"></p>
+
+
+<p class="output">Actual output:</p>
+<canvas id="c" class="output" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>
+<p class="output expectedtext">Expected output:<p><img src="../../../../images/green-100x50.png" class="output expected" id="expected" alt="">
+<ul id="d"></ul>
+<script>
+var t = async_test("");
+_addTest(function(canvas, ctx) {
+
+  var canvas2 = document.createElement('canvas');
+  canvas2.width = 100;
+  canvas2.height = 50;
+  var pattern = ctx.createPattern(canvas2, 'no-repeat');
+
+  ctx.fillStyle = '#0f0';
+  ctx.fillRect(0, 0, 100, 50);
+  ctx.fillStyle = '#f00';
+  ctx.fillStyle = pattern;
+  ctx.fillRect(0, 0, 100, 50);
+
+  _assertPixel(canvas, 1,1, 0,255,0,255);
+  _assertPixel(canvas, 98,1, 0,255,0,255);
+  _assertPixel(canvas, 1,48, 0,255,0,255);
+  _assertPixel(canvas, 98,48, 0,255,0,255);
+
+});
+</script>
+

Tests/LibWeb/Text/input/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.repeat.null.html

@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<title>Canvas test: 2d.pattern.repeat.null</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<script src="../../../../html/canvas/resources/canvas-tests.js"></script>
+<link rel="stylesheet" href="../../../../html/canvas/resources/canvas-tests.css">
+<body class="show_output">
+
+<h1>2d.pattern.repeat.null</h1>
+<p class="desc"></p>
+
+
+<p class="output">Actual output:</p>
+<canvas id="c" class="output" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>
+
+<ul id="d"></ul>
+<script>
+var t = async_test("");
+_addTest(function(canvas, ctx) {
+
+  _assert(ctx.createPattern(canvas, null) != null, "ctx.createPattern(canvas, null) != null");
+
+});
+</script>
+

Tests/LibWeb/Text/input/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.transform.identity.html

@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<title>Canvas test: 2d.pattern.transform.identity</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<script src="../../../../html/canvas/resources/canvas-tests.js"></script>
+<link rel="stylesheet" href="../../../../html/canvas/resources/canvas-tests.css">
+<body class="show_output">
+
+<h1>2d.pattern.transform.identity</h1>
+<p class="desc"></p>
+
+
+<p class="output">Actual output:</p>
+<canvas id="c" class="output" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>
+<p class="output expectedtext">Expected output:<p><img src="../../../../images/green-100x50.png" class="output expected" id="expected" alt="">
+<ul id="d"></ul>
+<script>
+var t = async_test("");
+_addTest(function(canvas, ctx) {
+
+  var canvas2 = document.createElement('canvas');
+  canvas2.width = 100;
+  canvas2.height = 50;
+  var pattern = ctx.createPattern(canvas2, 'no-repeat');
+  pattern.setTransform(new DOMMatrix());
+
+  ctx.fillStyle = '#0f0';
+  ctx.fillRect(0, 0, 100, 50);
+  ctx.fillStyle = '#f00';
+  ctx.fillStyle = pattern;
+  ctx.fillRect(0, 0, 100, 50);
+
+  _assertPixel(canvas, 1,1, 0,255,0,255);
+  _assertPixel(canvas, 98,1, 0,255,0,255);
+  _assertPixel(canvas, 1,48, 0,255,0,255);
+  _assertPixel(canvas, 98,48, 0,255,0,255);
+
+});
+</script>
+

Tests/LibWeb/Text/input/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.transform.infinity.html

@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<title>Canvas test: 2d.pattern.transform.infinity</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<script src="../../../../html/canvas/resources/canvas-tests.js"></script>
+<link rel="stylesheet" href="../../../../html/canvas/resources/canvas-tests.css">
+<body class="show_output">
+
+<h1>2d.pattern.transform.infinity</h1>
+<p class="desc"></p>
+
+
+<p class="output">Actual output:</p>
+<canvas id="c" class="output" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>
+<p class="output expectedtext">Expected output:<p><img src="../../../../images/green-100x50.png" class="output expected" id="expected" alt="">
+<ul id="d"></ul>
+<script>
+var t = async_test("");
+_addTest(function(canvas, ctx) {
+
+  var canvas2 = document.createElement('canvas');
+  canvas2.width = 100;
+  canvas2.height = 50;
+  var pattern = ctx.createPattern(canvas2, 'no-repeat');
+  pattern.setTransform({a: Infinity});
+
+  ctx.fillStyle = '#0f0';
+  ctx.fillRect(0, 0, 100, 50);
+  ctx.fillStyle = '#f00';
+  ctx.fillStyle = pattern;
+  ctx.fillRect(0, 0, 100, 50);
+
+  _assertPixel(canvas, 1,1, 0,255,0,255);
+  _assertPixel(canvas, 98,1, 0,255,0,255);
+  _assertPixel(canvas, 1,48, 0,255,0,255);
+  _assertPixel(canvas, 98,48, 0,255,0,255);
+
+});
+</script>
+

Tests/LibWeb/Text/input/wpt-import/html/canvas/element/fill-and-stroke-styles/2d.pattern.transform.invalid.html

@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<title>Canvas test: 2d.pattern.transform.invalid</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<script src="../../../../html/canvas/resources/canvas-tests.js"></script>
+<link rel="stylesheet" href="../../../../html/canvas/resources/canvas-tests.css">
+<body class="show_output">
+
+<h1>2d.pattern.transform.invalid</h1>
+<p class="desc"></p>
+
+
+<p class="output">Actual output:</p>
+<canvas id="c" class="output" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>
+
+<ul id="d"></ul>
+<script>
+var t = async_test("");
+_addTest(function(canvas, ctx) {
+
+  var canvas2 = document.createElement('canvas');
+  canvas2.width = 100;
+  canvas2.height = 50;
+  var pattern = ctx.createPattern(canvas2, 'no-repeat');
+  assert_throws_js(TypeError, function() { pattern.setTransform({a: 1, m11: 2}); });
+
+});
+</script>
+