New proposal color chooser

[stpere]

I propose a new behaviour for the color chooser.

Currently, the color bands in the color chooser goes from black to max {red,green,blue}. In the apparence preflet, it's ok, since we see the resulting color at the left.

But in other places, the preview isn't shown (as in terminal)

The new behaviour I propose (I think we have that behaviour in some graphical utilities - gnome or photoshop, I don't remember which) is to change the color of the color bands to show the possible values you can get.

For example, if you have 0 at red, 0 at green and 0 blue, the bands will continue to show as currently. Then if you move the red up a bit, the starting color of green and blue will be a red (as much of the currently selected value in the red band).

Ok, enough words, look at the screenies (or apply the patch and see) !

PS : As a side effect, it fixes the drawing artifacts mentioned in other tickets..

[leavengood]

I think this patch is pretty interesting in the behavior it introduces, but it seems to have a bug: it uses a lot of CPU from what I assume is a lot of calls to Invalidate(). Whenever a color control is showing the CPU is pegged, whenever it is hidden the CPU slows down.

So there is some flaw in the logic somewhere, I believe in _DrawSelector. Unfortunately I do not have time now to figure it out, but please take a look as I think this may be a worthwhile patch!

[pulkomandy]

Done in hrev48477. Had to rewrite the patch, not sure about that "drawing artifacts" thing.