LibGUI: Add Widget::repaint() to force an immediate repaint

In most situations, Widget::update() is preferable, since that allows us
to coalesce repaints and avoid redundant work, reducing system load.

However, there are some cases where you really want a paint to happen
right away, to make sure that the user has a chance to see a short-lived
visual state.

1 files changed, 10 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGUI/Window.cpp b/Userland/Libraries/LibGUI/Window.cpp
index 5dd3eb1ea9..5dbd41b5ea 100644
--- a/Userland/Libraries/LibGUI/Window.cpp
+++ b/Userland/Libraries/LibGUI/Window.cpp
@@ -1204,4 +1204,14 @@ void Window::set_modified(bool modified)
     WindowServerConnection::the().async_set_window_modified(m_window_id, modified);
 }
 
+void Window::flush_pending_paints_immediately()
+{
+    if (!m_window_id)
+        return;
+    if (m_pending_paint_event_rects.is_empty())
+        return;
+    MultiPaintEvent paint_event(move(m_pending_paint_event_rects), size());
+    handle_multi_paint_event(paint_event);
+}
+
 }