GPencil Onion Skinning: Setting before/after to -1 will turn off onionskinning in that direction

This is an experimental option that I found would have been useful to have,
when making my earlier anim test. The only contentious point is whether it's
better to use a separate boolean flag (perhaps bound to the labels) instead
of overloading this setting (and describing the usage in the tooltip).

1 files changed, 10 insertions, 4 deletions

diff --git a/source/blender/editors/gpencil/drawgpencil.c b/source/blender/editors/gpencil/drawgpencil.c
index 6ccbd2777b4..7715169cafb 100644
--- a/source/blender/editors/gpencil/drawgpencil.c
+++ b/source/blender/editors/gpencil/drawgpencil.c
@@ -1067,7 +1067,7 @@ static void gp_draw_onionskins(bGPDlayer *gpl, bGPDframe *gpf, int offsx, int of
 		copy_v3_v3(color, gpl->color);
 	}
 	
-	if (gpl->gstep) {
+	if (gpl->gstep > 0) {
 		bGPDframe *gf;
 		float fac;
 		
@@ -1084,13 +1084,16 @@ static void gp_draw_onionskins(bGPDlayer *gpl, bGPDframe *gpf, int offsx, int of
 				break;
 		}
 	}
-	else {
+	else if (gpl->gstep == 0) {
 		/* draw the strokes for the ghost frames (at half of the alpha set by user) */
 		if (gpf->prev) {
 			color[3] = (alpha / 7);
 			gp_draw_strokes(gpf->prev, offsx, offsy, winx, winy, dflag, debug, lthick, color, color);
 		}
 	}
+	else {
+		/* don't draw - disabled */
+	}
 	
 	
 	/* 2) Now draw next frames */
@@ -1101,7 +1104,7 @@ static void gp_draw_onionskins(bGPDlayer *gpl, bGPDframe *gpf, int offsx, int of
 		copy_v3_v3(color, gpl->color);
 	}
 	
-	if (gpl->gstep_next) {
+	if (gpl->gstep_next > 0) {
 		bGPDframe *gf;
 		float fac;
 		
@@ -1118,13 +1121,16 @@ static void gp_draw_onionskins(bGPDlayer *gpl, bGPDframe *gpf, int offsx, int of
 				break;
 		}
 	}
-	else {
+	else if (gpl->gstep_next == 0) {
 		/* draw the strokes for the ghost frames (at half of the alpha set by user) */
 		if (gpf->next) {
 			color[3] = (alpha / 4);
 			gp_draw_strokes(gpf->next, offsx, offsy, winx, winy, dflag, debug, lthick, color, color);
 		}
 	}
+	else {
+		/* don't draw - disabled */
+	}
 	
 	/* 3) restore alpha */
 	glColor4fv(gpl->color);