Graph Editor: Added 2D Cursor

I've finally given in, and implemented a '2d-cursor' for the Graph Editor. This is simply represented as an additional horizontal line that meets with the current frame indicator, forming a cross-hair. It can be disabled from the View menu.

Currently, the only tool which takes this into account is the Snapping tools (Shift-S), where I've hooked up a tool I added some time ago. 

TODO:
- expose this cursor to the transform tools for scaling/rotation options...

1 files changed, 21 insertions, 0 deletions

diff --git a/source/blender/editors/space_graph/space_graph.c b/source/blender/editors/space_graph/space_graph.c
index 1f65a8cd7ea..b4b06844d13 100644
--- a/source/blender/editors/space_graph/space_graph.c
+++ b/source/blender/editors/space_graph/space_graph.c
@@ -261,6 +261,27 @@ static void graph_main_area_draw(const bContext *C, ARegion *ar)
 	/* only free grid after drawing data, as we need to use it to determine sampling rate */
 	UI_view2d_grid_free(grid);
 	
+	/* horizontal component of value-cursor (value line before the current frame line) */
+	if ((sipo->flag & SIPO_NODRAWCURSOR)==0) {
+		float vec[2];
+		
+		/* Draw a green line to indicate the cursor value */
+		vec[1]= sipo->cursorVal;
+		
+		UI_ThemeColorShadeAlpha(TH_CFRAME, -10, -50);
+		glLineWidth(2.0);
+		
+		glEnable(GL_BLEND);
+		glBegin(GL_LINE_STRIP);
+			vec[0]= v2d->cur.xmin;
+			glVertex2fv(vec);
+			
+			vec[0]= v2d->cur.xmax;
+			glVertex2fv(vec);
+		glEnd(); // GL_LINE_STRIP
+		glDisable(GL_BLEND);
+	}
+	
 	/* current frame */
 	if (sipo->flag & SIPO_DRAWTIME) 	flag |= DRAWCFRA_UNIT_SECONDS;
 	if ((sipo->flag & SIPO_NODRAWCFRANUM)==0)  flag |= DRAWCFRA_SHOW_NUMBOX;