[Bf-blender-cvs] [d00a331] master: Fix assert in UI align code in some specific situations.

[Bastien Montagne]

Commit: d00a3316e7f6bbcb52793efe28271da77b81ce4c
Author: Bastien Montagne
Date:   Thu Nov 26 14:28:47 2015 +0100
Branches: master
https://developer.blender.org/rBd00a3316e7f6bbcb52793efe28271da77b81ce4c

Fix assert in UI align code in some specific situations.

Situations like [top_button over [label, button]] need some subtle handling, since
we only store one neighbor per side of a button...

===================================================================

M	source/blender/editors/interface/interface_align.c

===================================================================

diff --git a/source/blender/editors/interface/interface_align.c b/source/blender/editors/interface/interface_align.c
index 89a44db..e9d6014 100644
--- a/source/blender/editors/interface/interface_align.c
+++ b/source/blender/editors/interface/interface_align.c
@@ -164,11 +164,16 @@ static void block_align_proximity_compute(ButAlign *butal, ButAlign *butal_other
 			if (delta < max_delta) {
 				/* We are only interested in neighbors that are at least as close as already found ones. */
 				if (delta <= butal->dists[side]) {
-					if (delta < butal->dists[side]) {
-						/* We found a closer neighbor.
+					{
+						/* We found an as close or closer neighbor.
 						 * If both buttons are alignable, we set them as each other neighbors.
 						 * Else, we have an unalignable one, we need to reset the others matching neighbor to NULL
-						 * if its 'proximity distance' is really lower with current one. */
+						 * if its 'proximity distance' is really lower with current one.
+						 *
+						 * NOTE: We cannot only execute that piece of code in case we found a **closer** neighbor,
+						 *       due to the limited way we represent neighbors (buttons only know **one** neighbor
+						 *       on each side, when they can actually have several ones), it would prevent
+						 *       some buttons to be properly 'neighborly-initialized'. */
 						if (butal_can_align && butal_other_can_align) {
 							butal->neighbors[side] = butal_other;
 							butal_other->neighbors[side_opp] = butal;
@@ -181,6 +186,7 @@ static void block_align_proximity_compute(ButAlign *butal, ButAlign *butal_other
 						}
 						butal->dists[side] = butal_other->dists[side_opp] = delta;
 					}
+
 					if (butal_can_align && butal_other_can_align) {
 						const int side_s1 = SIDE1(side);
 						const int side_s2 = SIDE2(side);