Region scrollbar fix!

Now scrollbars correctly hide and show, making space for the actual contents
in a region. It solves several old hacks, and puts view2d code a bit more
back in control as well. 

Implementation notes:

- The view2d mask feature is working again
- The #define V2D_SCROLL_HORIZONTAL_HIDE means: "turn on hiding".
- Code for UI_view2d_region_reinit() is enforcing better standard view settings

But... two hack/patches needed to be added:

- Region panel drawing: if after generating the button panels it appears
  a scroller hides or reveils, it calls all the generating code again.
  (a simple scale doesn't work due to rounding differences in layout code)

- View2d code that maps 'tot' and 'cur' rects: if this code detects that
  the mask changes, it calcs the map code again.

Also a bugfix (issue in 2.65)

- The left/bottom area split widget was drawing 1 pixel too large sometimes, 
  leaving bad trails on moving area dividers.

1 files changed, 2 insertions, 2 deletions

diff --git a/source/blender/editors/interface/view2d_ops.c b/source/blender/editors/interface/view2d_ops.c
index 006644bf366..8bea308e90a 100644
--- a/source/blender/editors/interface/view2d_ops.c
+++ b/source/blender/editors/interface/view2d_ops.c
@@ -1744,8 +1744,8 @@ static int scroller_activate_invoke(bContext *C, wmOperator *op, wmEvent *event)
 		}
 		
 		/* zone is also inappropriate if scroller is not visible... */
-		if (((vsm->scroller == 'h') && (v2d->scroll & (V2D_SCROLL_HORIZONTAL_HIDE | V2D_SCROLL_HORIZONTAL_FULLR))) ||
-		    ((vsm->scroller == 'v') && (v2d->scroll & (V2D_SCROLL_VERTICAL_HIDE | V2D_SCROLL_VERTICAL_FULLR))) )
+		if (((vsm->scroller == 'h') && (v2d->scroll & (V2D_SCROLL_HORIZONTAL_FULLR))) ||
+		    ((vsm->scroller == 'v') && (v2d->scroll & (V2D_SCROLL_VERTICAL_FULLR))) )
 		{
 			/* free customdata initialized */
 			scroller_activate_exit(C, op);