Labelling: Rotation computation improved and commented on

[leo.git] / lab-lines.c

diff --git a/lab-lines.c b/lab-lines.c
index 35f9f457c53c3b9d7a9e53fe6a80ed20c0b23a2f..a0fc3c79a48141d09ded41e608db0dd0c9832c0b 100644 (file)
--- a/lab-lines.c
+++ b/lab-lines.c
@@ -505,8 +505,18 @@ static void make_segments(void)
       rs->x2 = e->n2->o->x;
       rs->y2 = e->n2->o->y;
 
-      rs->slope = (rs->y2 - rs->y1) / (rs->x2 - rs->x1);
-      ((struct sym_text *) rs->label)->rotate = convert_to_deg(atan(rs->slope));
+      if (fabs(rs->x2 - rs->x1) > 0.01)
+      {
+        rs->slope = (rs->y2 - rs->y1) / (rs->x2 - rs->x1);
+        // This works a little bit magically :)
+        // It's possible not to care about quadrants as it "just works" as expected
+        ((struct sym_text *) rs->label)->rotate = convert_to_deg(atan(rs->slope));
+      }
+      else
+      {
+        rs->slope = 142; // Magic!
+        ((struct sym_text *) rs->label)->rotate = 1;
+      }
       struct variant *v = GARY_PUSH(rs->request.variants);
       make_bitmap(v, rs->label);