fix smear at edge of canvas bug

1 files changed, 9 insertions, 0 deletions

diff --git a/js/blit.js b/js/blit.js
index b434742..2dce3e5 100644
--- a/js/blit.js
+++ b/js/blit.js
@@ -28,6 +28,15 @@ var blit = (function(){
       }
     })
   }
+  blit.copy_toroidal_from = function(A, B, x, y){
+    x = x || 0 ; y = y || 0
+    B.forEach(function(lex, u, v){
+      var cell = A.get(u+x, v+y)
+      if (cell) {
+        lex.assign(cell)
+      }
+    })
+  }
   blit.copy_to = function(A, B, x, y){
     x = x || 0 ; y = y || 0
     B.forEach(function(lex, u, v){