Add canvas draw cacheHEADmaster

1 files changed, 12 insertions, 0 deletions

diff --git a/index.html b/index.html
index 405e6f8..a2223dc 100644
--- a/index.html
+++ b/index.html
@@ -120,6 +120,9 @@ function boardY(idx){
 	return (~~(idx/currentGame.size)+0.5)*CELL_WID;
 }
 
+var _redrawBoard_cache_board=null;
+var _redrawBoard_cache_canvas=null;
+
 function redrawBoard(){
 	if(currentGame==null){
 		interfaceSwitch("connect");
@@ -127,6 +130,12 @@ function redrawBoard(){
 	}
 
 	var G=currentGame;
+	var GboardJSON=JSON.stringify(G.board);
+
+	if(_redrawBoard_cache_board&&GboardJSON==_redrawBoard_cache_board){
+		ctx.putImageData(_redrawBoard_cache_canvas,0,0);
+		return;
+	}
 	var bsz=G.size*CELL_WID;
 
 	if(cvs.width!=bsz||cvs.height!=bsz){cvs.width=bsz; cvs.height=bsz;}
@@ -164,6 +173,9 @@ function redrawBoard(){
 		ctx.arc(boardX(i),boardY(i),STONE_SIZE,0,2*Math.PI,true);
 		ctx.fill();
 	}
+
+	_redrawBoard_cache_board=GboardJSON;
+	_redrawBoard_cache_canvas=ctx.getImageData(0,0,cvs.width,cvs.height);
 }
 
 function interfaceGameState(state){