From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 23 Apr 2016 22:19:21 +0000 (+0100)
Subject: Offsets: In button zone code, cope with negative "pos" values
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=xf86-input-mtrack.git;a=commitdiff_plain;h=5f452ab77f51f34395be0280c8a87233a26d8cce

Offsets: In button zone code, cope with negative "pos" values

Coordinates might be negative, so we need a separate boolean rather
than using -1 as a sentinel.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/src/gestures.c b/src/gestures.c
index 22a94ac..b49ca6e 100644
--- a/src/gestures.c
+++ b/src/gestures.c
@@ -210,10 +210,12 @@ static void buttons_update(struct Gestures* gs,
 		}
 
 		if (emulate) {
-			int pos = -1;
+			int try_zone;
+			int pos;
 
 			if (cfg->button_zones && earliest >= 0) {
 				pos = ms->touch[earliest].x;
+				try_zone = 1;
 			}
 			if (cfg->bottom_edge_zones) {
 				int latest_bottom = -1;
@@ -227,11 +229,13 @@ static void buttons_update(struct Gestures* gs,
 					if (latest_bottom == -1 || timercmp(&ms->touch[i].down, &ms->touch[latest_bottom].down, >))
 						latest_bottom = i;
 				}
-				if (latest_bottom >= 0)
+				if (latest_bottom >= 0) {
 					pos = ms->touch[latest_bottom].x;
+					try_zone = 1;
+				}
 			}
 
-			if (pos >= 0) {
+			if (try_zone) {
 				int zones, left, right;
 				double width;