apply shader to selection canvas if it exists

1 files changed, 4 insertions, 2 deletions

diff --git a/js/shader.js b/js/shader.js
index 8d13546..1418805 100644
--- a/js/shader.js
+++ b/js/shader.js
@@ -19,8 +19,10 @@ var shader = (function(){
     return fn
   }
   exports.run = function(canvas){
-    var t = +new Date, w = canvas.w, h = canvas.h
-    canvas.forEach(function(lex, x, y){
+    var t = +new Date
+    var shader_canvas = selection.hidden ? canvas : selection.canvas;
+    var w = shader_canvas.w, h = shader_canvas.h
+    shader_canvas.forEach(function(lex, x, y){
       fn(lex, x, y, w, h, t)
       lex.build()
     })