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/WindowServer/WSMessageLoop.cpp b/WindowServer/WSMessageLoop.cpp
index 6cf92b8374..199222a4dd 100644
--- a/WindowServer/WSMessageLoop.cpp
+++ b/WindowServer/WSMessageLoop.cpp
@@ -302,7 +302,7 @@ void WSMessageLoop::on_receive_from_client(int client_id, const WSAPI_ClientMess
         break;
     case WSAPI_ClientMessage::Type::CreateWindow:
         ASSERT(message.text_length < sizeof(message.text));
-        post_message(client, make<WSAPICreateWindowRequest>(client_id, message.window.rect, String(message.text, message.text_length)));
+        post_message(client, make<WSAPICreateWindowRequest>(client_id, message.window.rect, String(message.text, message.text_length), message.window.has_alpha_channel, message.window.opacity));
         break;
     case WSAPI_ClientMessage::Type::DestroyWindow:
         post_message(client, make<WSAPIDestroyWindowRequest>(client_id, message.window_id));