//Flood fill
//(c) 2011 by Tomasz Lubinski
//www.algorytm.org

/* Data of the image */
var imageData;
var width, height;
var R, G, B;
var RtoFill, GtoFill, BtoFill;

/* Flood fill */
function floodFill(x, y, type)
{
	var canvas = document.getElementById("canvas");
	var ctx = canvas.getContext("2d");

	RtoFill = imageData.data[(y*width+x)*4+0];
	GtoFill = imageData.data[(y*width+x)*4+1];
	BtoFill = imageData.data[(y*width+x)*4+2];
	
	// do not fill if already filled with this color
	if (RtoFill == R && GtoFill == G && BtoFill == B)
		return;

	if (type == 4)
	{
		//call flood fill with four directions
		floodFill4(x, y);
	}
	else
	{
		//call flood fill with eight directions
		floodFill8(x, y);
	}
	
	// copy the image data back onto the canvas
	ctx.putImageData(imageData, 0, 0);
}

/* Flood fill algorithm with 4 directions */
function floodFill4(x, y)
{
   if (x<0 || x>=width || y<0 || y>=height)
   {
      //outside image
      return;
   }

   if (imageData.data[(y*width+x)*4+0] != RtoFill || 
       imageData.data[(y*width+x)*4+1] != GtoFill ||
       imageData.data[(y*width+x)*4+2] != BtoFill)
   {
      //not color to fill
      return;
   }
   
   //fill with color
   imageData.data[(y*width+x)*4+0] = R;
   imageData.data[(y*width+x)*4+1] = G;
   imageData.data[(y*width+x)*4+2] = B;
   
   //call in four new directions
   floodFill4(x-1, y  );
   floodFill4(x+1, y  );
   floodFill4(x  , y-1);   
   floodFill4(x  , y+1);
}

/* Flood fill algorithm with 8 directions */
function floodFill8(x, y)
{
   if (x<0 || x>=width || y<0 || y>=height)
   {
      //outside image
      return;
   }

   if (imageData.data[(y*width+x)*4+0] != RtoFill || 
       imageData.data[(y*width+x)*4+1] != GtoFill ||
       imageData.data[(y*width+x)*4+2] != BtoFill)
   {
      //not color to fill
      return;
   }
   
   //fill with color
   imageData.data[(y*width+x)*4+0] = R;
   imageData.data[(y*width+x)*4+1] = G;
   imageData.data[(y*width+x)*4+2] = B;
   
   //call in eight new directions
   floodFill8(x-1, y  );
   floodFill8(x-1, y+1);
   floodFill8(x  , y+1);
   floodFill8(x+1, y+1);
   floodFill8(x+1, y  );
   floodFill8(x+1, y-1);
   floodFill8(x  , y-1);
   floodFill8(x-1, y-1);
}

/* load image pointed by param_file to canvas */
function loadImage(imgSrc) 
{
	var canvas = document.getElementById("canvas");
	var ctx = canvas.getContext("2d");
	
	// add file:// if user specified local path
	if (imgSrc.indexOf("//") == -1 && imgSrc.indexOf(".") != 0) 
	{
		imgSrc = "file:///" + imgSrc;
	}
	
	// load file into canvas
	var img = new Image();
  	img.onload = function(){
		width = img.width;
		height = img.height;
 		canvas.width = width;
  		canvas.height = height;
    		ctx.drawImage(img,0,0);
		// get image data
		try 
		{
    			imageData = ctx.getImageData(0, 0, width, height);
  		} catch(e) 
  		{
  			netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");
  			imageData = ctx.getImageData(0, 0, width, height);
  		}
  	}
  	img.src = imgSrc;
}