Graph Editor: Allow "cursor x" to have fractional values when working with Drivers (T46004)

When working is the Graph Editor it can be very important to be able to work with fractions
(sub integers), especially when working with Drivers. Currently the "Cursor Y" is hooked up
to "cursor_position_y" which allows fractions  but "Cursor X" is directly hooked up to
"frame_current" which is an integer.

This commit adds initial support for this feature.
* When in Drivers mode, the x-part of the cursor is mapped to a new "cursor_position_x"
  value which can have fractional values. Animation mode however remains mapped to frame_current

* This commit only adds the UI/property/drawing tweaks needed to support this.
  Many operators still need to be modified to consider this value instead of the
  current frame, for this to be more useful.

1 files changed, 2 insertions, 0 deletions

diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index b8f2ce1b2ea..d9d3b5cc37d 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -327,8 +327,10 @@ typedef struct SpaceIpo {
 	short autosnap;         /* time-transform autosnapping settings for Graph editor (eAnimEdit_AutoSnap in DNA_action_types.h) */
 	int flag;               /* settings for Graph editor (eGraphEdit_Flag) */
 	
+	float cursorTime;       /* time value for cursor (when in drivers mode; animation uses current frame) */
 	float cursorVal;        /* cursor value (y-value, x-value is current frame) */
 	int around;             /* pivot point for transforms */
+	int pad;
 } SpaceIpo;