LibWeb: Move painting of background images to common location

For now, painting of background color is kept separate. The ICB needs to
perform a "translate" call between painting the color and background,
whereas other divs must not make that call.

Userland/Libraries/LibWeb/Layout/Box.cpp

@@ -48,25 +48,9 @@ void Box::paint(PaintContext& context, PaintPhase phase)
     if (phase == PaintPhase::Background && !is_body()) {
         auto background_rect = enclosing_int_rect(padded_rect);
         context.painter().fill_rect(background_rect, computed_values().background_color());
+
         if (background_image() && background_image()->bitmap()) {
-            switch (computed_values().background_repeat()) {
-            case CSS::Repeat::Repeat:
-                // The background rect is already sized to align with 'repeat'.
-                break;
-            case CSS::Repeat::RepeatX:
-                background_rect.set_height(background_image()->bitmap()->height());
-                break;
-            case CSS::Repeat::RepeatY:
-                background_rect.set_width(background_image()->bitmap()->width());
-                break;
-            case CSS::Repeat::NoRepeat:
-            default: // FIXME: Support 'round' and 'square'
-                background_rect.set_width(background_image()->bitmap()->width());
-                background_rect.set_height(background_image()->bitmap()->height());
-                break;
-            }
-
-            context.painter().blit_tiled(background_rect, *background_image()->bitmap(), background_image()->bitmap()->rect());
+            paint_background_image(context, *background_image()->bitmap(), computed_values().background_repeat(), move(background_rect));
         }
     }
 
@@ -100,6 +84,32 @@ void Box::paint(PaintContext& context, PaintPhase phase)
     }
 }
 
+void Box::paint_background_image(
+    PaintContext& context,
+    const Gfx::Bitmap& background_image,
+    CSS::Repeat background_repeat,
+    Gfx::IntRect background_rect)
+{
+    switch (background_repeat) {
+    case CSS::Repeat::Repeat:
+        // The background rect is already sized to align with 'repeat'.
+        break;
+    case CSS::Repeat::RepeatX:
+        background_rect.set_height(background_image.height());
+        break;
+    case CSS::Repeat::RepeatY:
+        background_rect.set_width(background_image.width());
+        break;
+    case CSS::Repeat::NoRepeat:
+    default: // FIXME: Support 'round' and 'square'
+        background_rect.set_width(background_image.width());
+        background_rect.set_height(background_image.height());
+        break;
+    }
+
+    context.painter().blit_tiled(background_rect, background_image, background_image.rect());
+}
+
 HitTestResult Box::hit_test(const Gfx::IntPoint& position, HitTestType type) const
 {
     // FIXME: It would be nice if we could confidently skip over hit testing

Userland/Libraries/LibWeb/Layout/Box.h

@@ -153,6 +153,8 @@ protected:
 
     virtual void did_set_rect() { }
 
+    void paint_background_image(PaintContext&, const Gfx::Bitmap&, CSS::Repeat, Gfx::IntRect);
+
     Vector<LineBox> m_line_boxes;
 
 private:

Userland/Libraries/LibWeb/Layout/InitialContainingBlockBox.cpp

@@ -68,31 +68,8 @@ void InitialContainingBlockBox::paint_document_background(PaintContext& context)
     context.painter().translate(-context.viewport_rect().location());
 
     if (auto background_bitmap = document().background_image()) {
-        int painted_image_width = 0;
-        int painted_image_height = 0;
-
-        switch (document().background_repeat()) {
-        case CSS::Repeat::Repeat:
-            painted_image_width = context.viewport_rect().x() + context.viewport_rect().width();
-            painted_image_height = context.viewport_rect().y() + context.viewport_rect().height();
-            break;
-        case CSS::Repeat::RepeatX:
-            painted_image_width = context.viewport_rect().x() + context.viewport_rect().width();
-            painted_image_height = background_bitmap->rect().height();
-            break;
-        case CSS::Repeat::RepeatY:
-            painted_image_width = background_bitmap->rect().width();
-            painted_image_height = context.viewport_rect().y() + context.viewport_rect().height();
-            break;
-        case CSS::Repeat::NoRepeat:
-        default: // FIXME: Support 'round' and 'square'
-            painted_image_width = background_bitmap->rect().width();
-            painted_image_height = background_bitmap->rect().height();
-            break;
-        }
-
-        Gfx::IntRect background_rect { 0, 0, painted_image_width, painted_image_height };
-        context.painter().blit_tiled(background_rect, *background_bitmap, background_bitmap->rect());
+        Gfx::IntRect background_rect = { 0, 0, context.viewport_rect().x() + context.viewport_rect().width(), context.viewport_rect().y() + context.viewport_rect().height() };
+        paint_background_image(context, *background_bitmap, document().background_repeat(), move(background_rect));
     }
 }