From: Melissa LeBlanc-Williams <melissa@adafruit.com>
Date: Wed, 8 Jul 2020 16:31:27 +0000 (-0700)
Subject: Avoid drawing offscreen stuff
X-Git-Tag: 0.5.2^2~1
X-Git-Url: https://git.ayoreis.com/hackapet/Adafruit_Blinka_Displayio.git/commitdiff_plain/0ab5cf2fae7d14a4125d911d5323f080485e25ac?hp=-c

Avoid drawing offscreen stuff
---

0ab5cf2fae7d14a4125d911d5323f080485e25ac
diff --git a/displayio/tilegrid.py b/displayio/tilegrid.py
index 2b2f8c7..2c815a4 100644
--- a/displayio/tilegrid.py
+++ b/displayio/tilegrid.py
@@ -279,15 +279,22 @@ class TileGrid:
 
         source_x = source_y = 0
         if x < 0:
-            source_x = 0 - x
+            source_x = round(0 - x)
             x = 0
         if y < 0:
-            source_y = 0 - y
+            source_y = round(0 - y)
             y = 0
 
-        buffer.alpha_composite(
-            image, (round(x), round(y)), source=(round(source_x), round(source_y))
-        )
+        x = round(x)
+        y = round(y)
+
+        if (
+            x <= buffer.width
+            and y <= buffer.height
+            and source_x <= image.width
+            and source_y <= image.height
+        ):
+            buffer.alpha_composite(image, (x, y), source=(source_x, source_y))
 
     # pylint: enable=too-many-locals,too-many-branches