diff --git a/rgb.py b/rgb.py
index 3b95cb7..f4da902 100644
--- a/rgb.py
+++ b/rgb.py
@@ -196,7 +196,7 @@ def blit_buffer(self, buffer, x, y, width, height):
         onerow = 2 * width
         for row in range(height):
             offset = row * onerow
-            self._block(x, y + row, x + width - 1, 1,
+            self._block(x, y + row, x + width - 1, y + row,
                         view[offset:offset + onerow])