ImagePaint Refactoring:

- ImagePaint now uses ImBuf directly, and the rect blending functions
  were moved into the imbuf module.
- The brush spacing, timing and sampling was abstracted into brush.c, for
  later reuse in other paint modes.

Float ImagePaint support.

Textured Brushes:
- Only the first texture channel is used now.
- Options for size and offset should be added, but need to find some space
  in the panel, or add a second one ..

source/blender/src/header_buttonswin.c

@@ -44,6 +44,7 @@
 
 #include "DNA_ID.h"
 #include "DNA_armature_types.h"
+#include "DNA_brush_types.h"
 #include "DNA_lamp_types.h"
 #include "DNA_material_types.h"
 #include "DNA_node_types.h"
@@ -321,6 +322,13 @@ void buttons_active_id(ID **id, ID **idfrom)
 					if(mtex) *id= (ID *)mtex->tex;
 				}
 			}
+			else if(G.buts->texfrom==3) {
+				Brush *brush= G.scene->toolsettings->imapaint.brush;
+				if (brush) {
+					mtex= brush->mtex[brush->texact];
+					if(mtex) *id= (ID*)mtex->tex;
+				}
+			}
 		}
 	}
 	else if(G.buts->mainb==CONTEXT_OBJECT || G.buts->mainb==CONTEXT_LOGIC) {