We were jumping through some pretty wasteful hoops in the resize event
handler of OOPWV by first creating a bitmap and then immediately
creating a new (shareable) clone of that bitmap. Now we go straight
to the shareable bitmap instead.
We were painting unfinished pixels while waiting for the WebContent
process to render the page. This caused OOPWV to flicker black
sometimes, which looked pretty bad.
This way we still flicker, but at least we flicker with the correct
palette color. :^)
This isn't entirely symmetrical with on_load_start as it will also fire
on reloads and back/forward navigations. However, it's good enough for
some basic use cases, and we can do more sophisticated notifications
later on when we need them.
It's not possible to construct a Gfx::Bitmap with empty size. Let the
client know the new viewport rect and return before even attempting to
create new front and back bitmaps.
Also consider that we might have to paint the widget but not have a
front/back bitmap available (e.g. when only part of a scrollbar is
visible, and the inner rect is empty).
Every widget now has a GUI::FocusPolicy that determines how it can
receive focus:
- NoFocus: The widget is not focusable (default)
- TabFocus: The widget can be focused using the tab key.
- ClickFocus: The widget can be focused by clicking on it.
- StrongFocus: Both of the above.
For widgets that have a focus proxy, getting/setting the focus policy
will affect the proxy instead.
This fixes an assertion in TextEditor when changing the system theme,
since that would trigger a repaint request for the HTML preview widget
which may not have backing unless it's actually been used to perform
HTML (or Markdown) preview yet.
