bugfix: prevent crash if the window is bigger than the screen

setup.py

@@ -41,7 +41,7 @@ setuptools.setup(
     # For a discussion on single-sourcing the version across setup.py and the
     # project code, see
     # https://packaging.python.org/en/latest/single_source_version.html
-    version='18.1.1',  # Required
+    version='18.1.2',  # Required
 
     # This is a one-line description or tagline of what your project does. This
     # corresponds to the "Summary" metadata field:

ueberzug/ui.py

@@ -189,7 +189,9 @@ class OverlayWindow:
 
         self._image.copy_to(
             self.window.id,
-            0, 0, self._width, self._height)
+            0, 0,
+            min(self._width, self._screen.width_in_pixels),
+            min(self._height, self._screen.height_in_pixels))
         self.window.shape_rectangles(
             Xshape.SO.Set, Xshape.SK.Bounding, 0,
             0, 0, rectangles)