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, 1 insertions, 2 deletions

diff --git a/source/blender/editors/space_file/file_draw.c b/source/blender/editors/space_file/file_draw.c
index fb438ae45fb..08f01b47b52 100644
--- a/source/blender/editors/space_file/file_draw.c
+++ b/source/blender/editors/space_file/file_draw.c
@@ -321,8 +321,7 @@ void file_calc_previews(const bContext *C, ARegion *ar)
 	View2D *v2d = &ar->v2d;
 	
 	ED_fileselect_init_layout(sfile, ar);
-	/* +SCROLL_HEIGHT is bad hack to work around issue in UI_view2d_totRect_set */
-	UI_view2d_totRect_set(v2d, sfile->layout->width, sfile->layout->height + V2D_SCROLL_HEIGHT);
+	UI_view2d_totRect_set(v2d, sfile->layout->width, sfile->layout->height);
 }
 
 static void file_draw_preview(uiBlock *block, struct direntry *file, int sx, int sy, ImBuf *imb, FileLayout *layout, short dropshadow)