From: Keith Packard <keithp@keithp.com>
Date: Mon, 27 Feb 2023 02:46:40 +0000 (-0800)
Subject: altos/draw: Check for horiz/vert line when clipping
X-Git-Tag: 1.9.16~1^2~30
X-Git-Url: https://git.gag.com/?a=commitdiff_plain;ds=sidebyside;h=9a79e8d8903b63f3f630d7f6455ee09715f55615;p=fw%2Faltos

altos/draw: Check for horiz/vert line when clipping

Horizontal or vertical lines won't step along the minor axis while
clipping.

Signed-off-by: Keith Packard <keithp@keithp.com>
---

diff --git a/src/draw/ao_line.c b/src/draw/ao_line.c
index 832a916c..7aa3662d 100644
--- a/src/draw/ao_line.c
+++ b/src/draw/ao_line.c
@@ -211,16 +211,20 @@ ao_clip_line(struct ao_cc *c, struct ao_cbox *b)
 	 */
 	int32_t	adj_min;
 
-	if (!c->first)
-		adj_min = div_ceil(c->e + adjust_major * c->e1, -c->e3);
-	else
-		adj_min = div_floor_plus_one(c->e + adjust_major * c->e1, -c->e3);
+	if (c->e3) {
+		if (!c->first)
+			adj_min = div_ceil(c->e + adjust_major * c->e1, -c->e3);
+		else
+			adj_min = div_floor_plus_one(c->e + adjust_major * c->e1, -c->e3);
+	}
 
 	if (adj_min < adjust_minor) {
-		if (c->first)
-			adjust_major = div_ceil(c->e - adjust_minor * c->e3, c->e1);
-		else
-			adjust_major = div_floor_plus_one(c->e - adjust_minor * c->e3, c->e1);
+		if (c->e1) {
+			if (c->first)
+				adjust_major = div_ceil(c->e - adjust_minor * c->e3, c->e1);
+			else
+				adjust_major = div_floor_plus_one(c->e - adjust_minor * c->e3, c->e1);
+		}
 	} else {
 		adjust_minor = adj_min;
 	}