[Bf-taskforce25] brush and paint settings

[Brecht Van Lommel]

Hi,

Working on the painting code in 2.5 shows clearly again that each paint
mode works different. Curve falloff, textures, pressure sensitivity only
work in some mode. Vertex paint only supports a subset of the blend
modes for texture paint, and has blur as a blend mode instead of a tool.
Mirror editing works different for sculpt and weight paint, and does not
work for other modes.

How to improve the situation is pretty clear to me, with the exception
of some design decisions I'm not sure about.

* Where is the tool (draw/soften/.., comb/cut/.., etc) best stored? Is
that in the brush itself, or outside of the brush? In other words, if
you select a brush datablock, should that also set the tool?

* In case it is outside of the brush, do you want the brush to be shared
between all tools, or should each tool have its own brush?

* Should all paint modes share the same brush datablock? Vertex/texture
paint and sculpt datablocks I can imagine being useful to share by
default. For weight painting and particle mode it is perhaps less
useful, so should those two get a new brush datablock?

Also the toolbar is clearly too small for the buttons, partially that is
due to the scrollbar area, but it also could use some extra pixels I
think, though we do want to keep this as thin as possible I guess?

Brecht.