WindowServer: Support windows with alpha channels. And per-WSWindow opacity.

This patch also adds a Format concept to GraphicsBitmap. For now there are
only two formats: RGB32 and RGBA32. Windows with alpha channel have their
backing stores created in the RGBA32 format.

Use this to make Terminal windows semi-transparent for that comfy rice look.
There is one problem here, in that window compositing overdraw incurs
multiple passes of blending of the same pixels. This leads to a mismatch in
opacity which is obviously not good. I will work on this in a later patch.

The alpha blending is currently straight C++. It should be relatively easy
to optimize this using SSE instructions.

For now I'm just happy with the cute effect. :^)

1 files changed, 1 insertions, 1 deletions

diff --git a/LibGUI/GLabel.cpp b/LibGUI/GLabel.cpp
index ef9813a07a..140d1282f3 100644
--- a/LibGUI/GLabel.cpp
+++ b/LibGUI/GLabel.cpp
@@ -31,7 +31,7 @@ void GLabel::paint_event(GPaintEvent&)
         painter.fill_rect({ 0, 0, width(), height() }, background_color());
     if (m_icon) {
         auto icon_location = rect().center().translated(-(m_icon->width() / 2), -(m_icon->height() / 2));
-        painter.blit_with_alpha(icon_location, *m_icon, m_icon->rect());
+        painter.blit(icon_location, *m_icon, m_icon->rect());
     }
     if (!text().is_empty())
         painter.draw_text({ 0, 0, width(), height() }, text(), m_text_alignment, foreground_color());