GApplication now has a palette. This palette contains all the system
theme colors by default, and is inherited by a new top-level GWidget.
New child widgets inherit their parents palette.
It is possible to override the GApplication palette, and the palette
of any GWidget.
The Palette object contains a bunch of colors, each corresponding to
a ColorRole. Each role has a convenience getter as well.
Each GWidget now has a background_role() and foreground_role(), which
are then looked up in their current palette when painting. This means
that you no longer alter the background color of a widget by setting
it directly, rather you alter either its background role, or the
widget's palette.
You can now register a GWidget subclass with REGISTER_GWIDGET(class)
and it will be available for factory construction through the new
GWidgetClassRegistration interface.
To obtain a GWidgetClassRegistration for a given class name, you call
GWidgetClassRegistration::find(class_name). You can also iterate over
all the registered classes using GWCR::for_each(callback).
This will be very useful for implementing a proper GUI designer, and
also in the future for things like script bindings.
NOTE: All of the registrations are done in GWidget.cpp at the moment
since I ran into trouble with the fricken linker pruning the global
constructors this mechanism relies on. :^)
You now have to pass an Orientation to the GSlider constructor. It's not
possible to change the orientation after construction.
Added some vertical GSliders to the WidgetGallery demo for testing. :^)
Instead of LibGUI and WindowServer building their own copies of the drawing
and graphics code, let's it in a separate LibDraw library.
This avoids building the code twice, and will encourage better separation
of concerns. :^)
Regardless of mode, made the knob container clickable so the knob position
can be moved without dragging the knob itself.
Added a 3rd GSlider to the WidgetGallery showing the proportional mode in
action.
