LibGfx: Implement `Rect::to_rounded<U>()`

This replaces the usage of `rounded_int_rect`, whose name did not
accurately reflect the rounding operation happening. For example, the
position of the rect was not rounded but floored, and the size was
pulled through `roundf` before casting to `int` which could result in
inadvertent flooring if the resulting floating point could not exactly
represent the rounded value.

Userland/Libraries/LibGfx/Rect.h

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2022, Jelle Raaijmakers <jelle@gmta.nl>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -696,6 +697,17 @@ public:
         return Rect<U>(*this);
     }
 
+    template<typename U>
+    [[nodiscard]] ALWAYS_INLINE Rect<U> to_rounded() const
+    {
+        return {
+            static_cast<U>(llroundd(x())),
+            static_cast<U>(llroundd(y())),
+            static_cast<U>(llroundd(width())),
+            static_cast<U>(llroundd(height())),
+        };
+    }
+
     [[nodiscard]] String to_string() const;
 
 private:
@@ -715,11 +727,6 @@ using FloatRect = Rect<float>;
     return Gfx::IntRect::from_two_points({ x1, y1 }, { x2, y2 });
 }
 
-[[nodiscard]] ALWAYS_INLINE IntRect rounded_int_rect(FloatRect const& float_rect)
-{
-    return IntRect { floorf(float_rect.x()), floorf(float_rect.y()), roundf(float_rect.width()), roundf(float_rect.height()) };
-}
-
 }
 
 namespace AK {

Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.cpp

@@ -180,7 +180,7 @@ DOM::ExceptionOr<void> CanvasRenderingContext2D::draw_image(CanvasImageSource co
     if (!painter)
         return {};
     auto transformed_destination_rect = m_drawing_state.transform.map(destination_rect);
-    painter->draw_scaled_bitmap(rounded_int_rect(transformed_destination_rect), *bitmap, source_rect, 1.0f, Gfx::Painter::ScalingMode::BilinearBlend);
+    painter->draw_scaled_bitmap(transformed_destination_rect.to_rounded<int>(), *bitmap, source_rect, 1.0f, Gfx::Painter::ScalingMode::BilinearBlend);
 
     // 7. If image is not origin-clean, then set the CanvasRenderingContext2D's origin-clean flag to false.
     if (image_is_not_origin_clean(image))

Userland/Libraries/LibWeb/Painting/CanvasPaintable.cpp

@@ -36,7 +36,7 @@ void CanvasPaintable::paint(PaintContext& context, PaintPhase phase) const
             return;
 
         if (layout_box().dom_node().bitmap())
-            context.painter().draw_scaled_bitmap(rounded_int_rect(absolute_rect()), *layout_box().dom_node().bitmap(), layout_box().dom_node().bitmap()->rect(), 1.0f, to_gfx_scaling_mode(computed_values().image_rendering()));
+            context.painter().draw_scaled_bitmap(absolute_rect().to_rounded<int>(), *layout_box().dom_node().bitmap(), layout_box().dom_node().bitmap()->rect(), 1.0f, to_gfx_scaling_mode(computed_values().image_rendering()));
     }
 }
 

Userland/Libraries/LibWeb/Painting/ImagePaintable.cpp

@@ -47,7 +47,7 @@ void ImagePaintable::paint(PaintContext& context, PaintPhase phase) const
                 alt = image_element.src();
             context.painter().draw_text(enclosing_int_rect(absolute_rect()), alt, Gfx::TextAlignment::Center, computed_values().color(), Gfx::TextElision::Right);
         } else if (auto bitmap = layout_box().image_loader().bitmap(layout_box().image_loader().current_frame_index())) {
-            context.painter().draw_scaled_bitmap(rounded_int_rect(absolute_rect()), *bitmap, bitmap->rect(), 1.0f, to_gfx_scaling_mode(computed_values().image_rendering()));
+            context.painter().draw_scaled_bitmap(absolute_rect().to_rounded<int>(), *bitmap, bitmap->rect(), 1.0f, to_gfx_scaling_mode(computed_values().image_rendering()));
         }
     }
 }

Userland/Libraries/LibWeb/Painting/StackingContext.cpp

@@ -270,7 +270,7 @@ void StackingContext::paint(PaintContext& context) const
 
         auto transformed_destination_rect = affine_transform.map(source_rect).translated(transform_origin);
         source_rect.translate_by(transform_origin);
-        context.painter().draw_scaled_bitmap(Gfx::rounded_int_rect(transformed_destination_rect), *bitmap, source_rect, opacity, Gfx::Painter::ScalingMode::BilinearBlend);
+        context.painter().draw_scaled_bitmap(transformed_destination_rect.to_rounded<int>(), *bitmap, source_rect, opacity, Gfx::Painter::ScalingMode::BilinearBlend);
     } else {
         paint_internal(context);
     }