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, 3 insertions, 3 deletions

diff --git a/source/blender/editors/space_userpref/space_userpref.c b/source/blender/editors/space_userpref/space_userpref.c
index 1ea3876f5cc..6560f218002 100644
--- a/source/blender/editors/space_userpref/space_userpref.c
+++ b/source/blender/editors/space_userpref/space_userpref.c
@@ -105,14 +105,14 @@ static SpaceLink *userpref_duplicate(SpaceLink *sl)
 /* add handlers, stuff you only do once or on area/region changes */
 static void userpref_main_area_init(wmWindowManager *wm, ARegion *ar)
 {
+	ar->v2d.flag &= ~V2D_IS_INITIALISED;
+	ar->v2d.scroll = V2D_SCROLL_RIGHT | V2D_SCROLL_VERTICAL_HIDE;
+
 	ED_region_panels_init(wm, ar);
 }
 
 static void userpref_main_area_draw(const bContext *C, ARegion *ar)
 {
-	/* this solves "vibrating UI" bug #25422 */
-	UI_view2d_region_reinit(&ar->v2d, V2D_COMMONVIEW_PANELS_UI, ar->winx, ar->winy);
-	
 	ED_region_panels(C, ar, 1, NULL, -1);
 }