Previous visual changes in the library were quite limited with some
colors and some global properties. This commit changes all that and
provides way more control over every widgets visual appearance.
Changes include extended color selection, per widget properties and
the possibility to use skinning.
While the new API allows for a lot more control it is currently quite
low level and needs a lot more testing and probably another higher
level style API to make changes in code easier. I also had to remove
the style modification code inside the demo and will probably first
try to write another higher level API before adding it back in.
This commit also include some breaking changes to existing code like
the missing style stack API and some widget names changes due to
added granularity granted by the rewritten style.
The default draw command buffering API now supports filled and
outlined shapes as well as two additional commands: polygon and
polyline. While zahnrad only requires a small number of basic
filled draw command shapes to actual function the underlying canvas
to convert from draw commands to vertex buffer commands allows
for lot more. So the gap should now be filled and drawing more
complex custom is now a little bit easier. I thought about adding a
path drawing API to the draw command API but decided it is not
worth the hassle, at least for now.
The conversion function from rgb color to hsv color was bugged and
provided wrong values. It is now fixed and hopefully is now correct.
In addition a number of utility functions have been added to make
conversion between user provided color format and zahnrads own
format easier.
While dividing previously spared me from a lot of work and problems
it is probably best to have everything working for every or as many
platforms as possible. Some platforms fail to provide good ways
to support everything (e.g.:X11 does not have pixmap clipping with
different width/height or alpha-blending) but all OpenGL demos
outside allegro (needs some additional work) should be able to run.
