Fix T44685 - In grease pencil stroke editing, selecting points is offset by a few pixels

The problem was that it was aborting too early after stumbling across a point which
might fit within the bounds required. This commit improves the logic here to solve
this and a few other little bugs like that.

Disclaimer: There are still a few cases where it randomly ends up picking something
way off. However, this only seems to occur very sporadically, so it's hard to say
how bad the problem may be.

1 files changed, 11 insertions, 10 deletions

diff --git a/source/blender/editors/gpencil/gpencil_select.c b/source/blender/editors/gpencil/gpencil_select.c
index 9d0cb6d711a..1b66f366b70 100644
--- a/source/blender/editors/gpencil/gpencil_select.c
+++ b/source/blender/editors/gpencil/gpencil_select.c
@@ -775,6 +775,7 @@ static int gpencil_select_exec(bContext *C, wmOperator *op)
 	
 	bGPDstroke *hit_stroke = NULL;
 	bGPDspoint *hit_point = NULL;
+	int hit_distance = radius_squared;
 	
 	/* sanity checks */
 	if (sa == NULL) {
@@ -797,7 +798,6 @@ static int gpencil_select_exec(bContext *C, wmOperator *op)
 	{
 		bGPDspoint *pt;
 		int i;
-		int hit_index = -1;
 		
 		/* firstly, check for hit-point */
 		for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
@@ -807,18 +807,19 @@ static int gpencil_select_exec(bContext *C, wmOperator *op)
 		
 			/* do boundbox check first */
 			if (!ELEM(V2D_IS_CLIPPED, x0, x0)) {
-				/* only check if point is inside */
-				if (((x0 - mx) * (x0 - mx) + (y0 - my) * (y0 - my)) <= radius_squared) {				
-					hit_stroke = gps;
-					hit_point  = pt;
-					break;
+				const int pt_distance = ((x0 - mx) * (x0 - mx) + (y0 - my) * (y0 - my));
+				
+				/* check if point is inside */
+				if (pt_distance <= radius_squared) {
+					/* only use this point if it is a better match than the current hit - T44685 */
+					if (pt_distance < hit_distance) {
+						hit_stroke = gps;
+						hit_point  = pt;
+						hit_distance = pt_distance;
+					}
 				}
 			}
 		}
-		
-		/* skip to next stroke if nothing found */
-		if (hit_index == -1) 
-			continue;
 	}
 	CTX_DATA_END;