From 9a6e61e5101bb3214562395af393119b7f0a8929 Mon Sep 17 00:00:00 2001
From: Benjamin Otte <otte@redhat.com>
Date: Wed, 10 Jul 2024 00:26:57 +0200
Subject: [PATCH] rect: There's no coverage witout overlap

The rectangles need to touch/overlap in both directions, otherwise
there's no coverage that covers both rectangles.

Test included.

Fixes rendering glitches in various apps when redrawing.

Fixes: #6849
---
 gsk/gskrectprivate.h                         | 7 ++-----
 testsuite/gsk/opaque/not-near-0-0-50-50.node | 6 ++++++
 2 files changed, 8 insertions(+), 5 deletions(-)
 create mode 100644 testsuite/gsk/opaque/not-near-0-0-50-50.node

diff --git a/gsk/gskrectprivate.h b/gsk/gskrectprivate.h
index 413b202143..daae5516a8 100644
--- a/gsk/gskrectprivate.h
+++ b/gsk/gskrectprivate.h
@@ -131,9 +131,10 @@ gsk_rect_coverage (const graphene_rect_t *r1,
   x2max = MAX (r1->origin.x + r1->size.width, r2->origin.x + r2->size.width);
   y2max = MAX (r1->origin.y + r1->size.height, r2->origin.y + r2->size.height);
 
-  if (x2min >= x1max)
+  if (x2min >= x1max && y2min >= y1max)
     {
       float w, h;
+
       w = x2min - x1max;
       h = y2max - y1min;
       size2 = w * h;
@@ -142,11 +143,7 @@ gsk_rect_coverage (const graphene_rect_t *r1,
           r = GRAPHENE_RECT_INIT (x1max, y1min, w, h);
           size = size2;
         }
-    }
 
-  if (y2min >= y1max)
-    {
-      float w, h;
       w = x2max - x1min;
       h = y2min - y1max;
       size2 = w * h;
diff --git a/testsuite/gsk/opaque/not-near-0-0-50-50.node b/testsuite/gsk/opaque/not-near-0-0-50-50.node
new file mode 100644
index 0000000000..1d0deefc23
--- /dev/null
+++ b/testsuite/gsk/opaque/not-near-0-0-50-50.node
@@ -0,0 +1,6 @@
+color {
+  bounds: 0 0 50 50;
+}
+color {
+  bounds: 1000 0 10 10;
+}