LibGfx: Fix crash when calling draw_triangle_wave() offscreen

I think this regressed in SerenityOS#5018. It easily triggered when scrolling a page that uses `text-decoration-style: wavy`.
nico · Nov 16, 2024 · 44bfee2 · 44bfee2
1 parent 4678fc1
commit 44bfee2
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diff --git a/Tests/LibGfx/TestPainter.cpp b/Tests/LibGfx/TestPainter.cpp
@@ -53,3 +53,11 @@ TEST_CASE(draw_rect_rough_bounds)
     painter.draw_rect(Gfx::IntRect(0, 0, 1, 1), Color::Black, true);
     painter.draw_rect(Gfx::IntRect(9, 9, 1, 1), Color::Black, true);
 }
+
+TEST_CASE(draw_triangle_wave)
+{
+    auto bitmap = MUST(Gfx::Bitmap::create(Gfx::BitmapFormat::BGRx8888, { 10, 10 }));
+    Gfx::Painter painter(*bitmap);
+    for (int y = -3; y < bitmap->height() + 3; ++y)
+        painter.draw_triangle_wave({0, y}, {bitmap->width(), y}, Gfx::Color::Red, 3, 2);
+}
diff --git a/Userland/Libraries/LibGfx/Painter.cpp b/Userland/Libraries/LibGfx/Painter.cpp
@@ -1912,6 +1912,8 @@ void Painter::draw_physical_pixel(IntPoint physical_position, Color color, int t
 
     IntRect rect { physical_position, { thickness, thickness } };
     rect.intersect(clip_rect() * scale());
+    if (rect.is_empty())
+        return;
     fill_physical_rect(rect, color);
 }