LibGfx: Add a draw_scaled_bitmap() variant that takes a FloatRect as src_rect

Consider

    draw_scaled_bitmap({0, 0, 10, 10}, source, {0, 0, 5, 5}).

Imagine wanting to split that up into two calls, like e.g. the
compositor when redrawing the background with damage rects. You really
want to be able to say

    draw_scaled_bitmap({0, 0, 5, 10}, source, {0, 0, 2.5, 5})

but up to now you couldn't. Now you can.

This makes painting very low-res images (such as tile.png) in mode
"stretch" work much better.

1 files changed, 4 insertions, 3 deletions

diff --git a/Userland/Services/WindowServer/Compositor.cpp b/Userland/Services/WindowServer/Compositor.cpp
index e93d4fddbf..1be79338bb 100644
--- a/Userland/Services/WindowServer/Compositor.cpp
+++ b/Userland/Services/WindowServer/Compositor.cpp
@@ -262,11 +262,12 @@ void Compositor::compose()
             } else if (m_wallpaper_mode == WallpaperMode::Tile) {
                 painter.draw_tiled_bitmap(rect, *m_wallpaper);
             } else if (m_wallpaper_mode == WallpaperMode::Stretch) {
-                float hscale = (float)m_wallpaper->size().width() / (float)ws.size().width();
-                float vscale = (float)m_wallpaper->size().height() / (float)ws.size().height();
+                float hscale = (float)m_wallpaper->width() / (float)ws.width();
+                float vscale = (float)m_wallpaper->height() / (float)ws.height();
 
                 // TODO: this may look ugly, we should scale to a backing bitmap and then blit
-                painter.draw_scaled_bitmap(rect, *m_wallpaper, { rect.x() * hscale, rect.y() * vscale, rect.width() * hscale, rect.height() * vscale });
+                auto src_rect = Gfx::FloatRect { rect.x() * hscale, rect.y() * vscale, rect.width() * hscale, rect.height() * vscale };
+                painter.draw_scaled_bitmap(rect, *m_wallpaper, src_rect);
             } else {
                 ASSERT_NOT_REACHED();
             }