[atk: 1/2] Make atk_text_rectangle_union ignore undefined rectangles

[Samuel Thibault <sthibaul src gnome org>]

commit c997214620d80adc0b1794b42a9e79ce856d9df2
Author: Samuel Thibault <samuel thibault ens-lyon org>
Date:   Mon Aug 19 15:53:18 2019 +0200

    Make atk_text_rectangle_union ignore undefined rectangles
    
    atk_text_get_character_extents might return "-1" rectangles for character
    positions without support for getting an extent. In that case we have to
    ignore them instead of using -1 values in computations.

 atk/atktext.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
---
diff --git a/atk/atktext.c b/atk/atktext.c
index 8f2e498..fbe05ab 100644
--- a/atk/atktext.c
+++ b/atk/atktext.c
@@ -1328,6 +1328,23 @@ atk_text_rectangle_union (AtkTextRectangle *src1,
 {
   gint dest_x, dest_y;
 
+  /*
+   * Some invocations of e.g. atk_text_get_character_extents
+   * may return "-1" rectangles for character positions without support for
+   * getting an extent. In that case we have to ignore them instead of using -1
+   * values in computations.
+   */
+  if (src1->width == -1)
+    {
+      *dest = *src2;
+      return;
+    }
+  if (src2->width == -1)
+    {
+      *dest = *src1;
+      return;
+    }
+
   dest_x = MIN (src1->x, src2->x);
   dest_y = MIN (src1->y, src2->y);
   dest->width = MAX (src1->x + src1->width, src2->x + src2->width) - dest_x;