fix for hanging while drawing fcurves, the function made some attempt to avoid the problem but when the view is zero pixels wide it still hung for some time.

3 files changed, 19 insertions, 5 deletions

diff --git a/source/blender/editors/include/UI_view2d.h b/source/blender/editors/include/UI_view2d.h
index 38c2780608f..bf4a3de9cc6 100644
--- a/source/blender/editors/include/UI_view2d.h
+++ b/source/blender/editors/include/UI_view2d.h
@@ -164,6 +164,7 @@ void UI_view2d_view_restore(const struct bContext *C);
 View2DGrid *UI_view2d_grid_calc(const struct bContext *C, struct View2D *v2d, short xunits, short xclamp, short yunits, short yclamp, int winx, int winy);
 void UI_view2d_grid_draw(const struct bContext *C, struct View2D *v2d, View2DGrid *grid, int flag);
 void UI_view2d_constant_grid_draw(const struct bContext *C, struct View2D *v2d);
+void UI_view2d_grid_size(View2DGrid *grid, float *r_dx, float *r_dy);
 void UI_view2d_grid_free(View2DGrid *grid);
 
 /* scrollbar drawing */
diff --git a/source/blender/editors/interface/view2d.c b/source/blender/editors/interface/view2d.c
index d482f20b077..9a88a52d4b4 100644
--- a/source/blender/editors/interface/view2d.c
+++ b/source/blender/editors/interface/view2d.c
@@ -1314,6 +1314,13 @@ void UI_view2d_constant_grid_draw(const bContext *C, View2D *v2d)
 	glEnd();
 }
 
+/* the price we pay for not exposting structs :( */
+void UI_view2d_grid_size(View2DGrid *grid, float *r_dx, float *r_dy)
+{
+	*r_dx= grid->dx;
+	*r_dy= grid->dy;
+}
+
 /* free temporary memory used for drawing grid */
 void UI_view2d_grid_free(View2DGrid *grid)
 {
diff --git a/source/blender/editors/space_graph/graph_draw.c b/source/blender/editors/space_graph/graph_draw.c
index b297178c498..543bd8b9964 100644
--- a/source/blender/editors/space_graph/graph_draw.c
+++ b/source/blender/editors/space_graph/graph_draw.c
@@ -502,7 +502,15 @@ static void draw_fcurve_curve (bAnimContext *ac, ID *id, FCurve *fcu, SpaceIpo *
 	float samplefreq, ctime;
 	float stime, etime;
 	float unitFac;
-	
+	float dx, dy;
+
+	/* when opening a blend file on a different sized screen or while dragging the toolbar this can happen
+	 * best just bail out in this case */
+	UI_view2d_grid_size(grid, &dx, &dy);
+	if(dx <= 0.0f)
+		return;
+
+
 	/* disable any drivers temporarily */
 	driver= fcu->driver;
 	fcu->driver= NULL;
@@ -522,11 +530,9 @@ static void draw_fcurve_curve (bAnimContext *ac, ID *id, FCurve *fcu, SpaceIpo *
 	 *	loop (i.e. too close to 0), then clamp it to a determined "safe" value. The value
 	 * 	chosen here is just the coarsest value which still looks reasonable...
 	 */
-		/* grid->dx is the first float in View2DGrid struct, so just cast to float pointer, and use it
-		 * It represents the number of 'frames' between gridlines, but we divide by U.v2d_min_gridsize to get pixels-steps
-		 */
+		/* grid->dx represents the number of 'frames' between gridlines, but we divide by U.v2d_min_gridsize to get pixels-steps */
 		// TODO: perhaps we should have 1.0 frames as upper limit so that curves don't get too distorted?
-	samplefreq= *((float *)grid) / U.v2d_min_gridsize;
+	samplefreq= dx / U.v2d_min_gridsize;
 	if (samplefreq < 0.00001f) samplefreq= 0.00001f;