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, 6 insertions, 0 deletions

diff --git a/source/blender/editors/space_graph/space_graph.c b/source/blender/editors/space_graph/space_graph.c
index fa7c6bd472a..734c0e6c479 100644
--- a/source/blender/editors/space_graph/space_graph.c
+++ b/source/blender/editors/space_graph/space_graph.c
@@ -309,6 +309,12 @@ static void graph_channel_area_init(wmWindowManager *wm, ARegion *ar)
 {
 	wmKeyMap *keymap;
 	
+	/* make sure we keep the hide flags */
+	ar->v2d.scroll |= (V2D_SCROLL_RIGHT | V2D_SCROLL_BOTTOM);
+	ar->v2d.scroll &= ~(V2D_SCROLL_LEFT | V2D_SCROLL_TOP);	/* prevent any noise of past */
+	ar->v2d.scroll |= V2D_SCROLL_HORIZONTAL_HIDE;
+	ar->v2d.scroll |= V2D_SCROLL_VERTICAL_HIDE;
+	
 	UI_view2d_region_reinit(&ar->v2d, V2D_COMMONVIEW_LIST, ar->winx, ar->winy);
 	
 	/* own keymap */