From 5ae7076d65e8064d8ae828307a7ad305cf1bade4 Mon Sep 17 00:00:00 2001
From: David Capello <david@igarastudio.com>
Date: Wed, 16 Jun 2021 09:39:42 -0300
Subject: [PATCH] Add extra check/asserts to detect/avoid a reported crash in
 draw_image_into_new_tilemap_cel (fix #2770)

---
 src/app/util/cel_ops.cpp | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/app/util/cel_ops.cpp b/src/app/util/cel_ops.cpp
index 486f83f0d..28200838e 100644
--- a/src/app/util/cel_ops.cpp
+++ b/src/app/util/cel_ops.cpp
@@ -425,9 +425,15 @@ void draw_image_into_new_tilemap_cel(
         delete addTile;
     }
 
-    newTilemap->putPixel(
-      tilePt.x-tilemapBounds.x,
-      tilePt.y-tilemapBounds.y, tileIndex);
+    // We were using newTilemap->putPixel() directly but received a
+    // crash report about an "access violation". So now we've added
+    // some checks to the operation.
+    {
+      const int u = tilePt.x-tilemapBounds.x;
+      const int v = tilePt.y-tilemapBounds.y;
+      ASSERT((u >= 0) && (v >= 0) && (u < newTilemap->width()) && (v < newTilemap->height()));
+      doc::put_pixel(newTilemap.get(), u, v, tileIndex);
+    }
   }
 
   static_cast<Doc*>(dstLayer->sprite()->document())