I can't comment on the KineticJS aspect of it, but couldn't you do something like: determine the click coordinates relative to the canvas, divide that by the size of your blocks (and round down) for each axis, and then you'd know which block was clicked. Edit that value in your map
and redraw that block on the canvas?
This is what I mean:
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Maker</title>
<style>
#can{display:block; background-color:#666;}
</style>
</head>
<body onload="init();">
<canvas id="can"></canvas>
</body>
<script>
var blocksize=30;
var map=[[1,1,1,1,1,1,1,1,1,1],[1,3,0,0,0,0,2,4,0,1],[1,1,1,1,1,1,1,1,1,1]];
var can=document.getElementById('can')
if(can){ctx=can.getContext('2d');}
function init(){
can.width=map[0].length*blocksize; //adjusts canvas size to fit map
can.height=map.length*blocksize;
for(y=0;y<map.length;y++){
for(x=0;x<map[y].length;x++){
draw(y,x);
}
}
can.addEventListener('click',builder);
}
function builder(e){
if (e == null) {e = window.event;}
x = e.clientX; //where the click was
y = e.clientY;
offsetX = ExtractNumber(can.offsetLeft)-window.scrollX;//where the canvas is
offsetY = ExtractNumber(can.offsetTop)-window.scrollY;
x_grid=Math.floor((x-offsetX)/blocksize); //which block in the canvas was clicked
y_grid=Math.floor((y-offsetY)/blocksize);
map[y_grid][x_grid]++;
if(map[y_grid][x_grid]>4){map[y_grid][x_grid]=0;}
draw(y_grid,x_grid);
}
function draw(y,x){
kind=map[y][x];
switch(kind){
case 0:
ctx.drawImage(floorimg,x*blocksize,y*blocksize);
break;
case 1:
ctx.drawImage(wallimg,x*blocksize,y*blocksize);
break;
case 2:
ctx.drawImage(blockimg,x*blocksize,y*blocksize);
break;
case 3:
ctx.drawImage(playerimg,x*blocksize,y*blocksize);
break;
case 4:
ctx.drawImage(goalimg,x*blocksize,y*blocksize);
break;
}
}
function ExtractNumber(value){
var n = parseInt(value);
return n == null || isNaN(n) ? 0 : n;
}
var floorimg=new Image();
floorimg.src='data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB4AAAAeCAIAAAC0Ujn1AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAE5JREFUeNpiNDU1ZaANYAHiadOmEaM0KysLSOaCSYJg8rRpTAw0A6NGjxo9avQIMJqRdiUfDV3NQlI5SVIJPJpCRo0eNXrU6EFaqAIEGABIow4bXRyDLQAAAABJRU5ErkJggg==';
var wallimg=new Image();
wallimg.src='data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB4AAAAeCAIAAAC0Ujn1AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAEFJREFUeNpirK+vZ8AGGhsbcUkRqYaJgWZg1Gj6AUZIFFOeHjDVjEbjcEoho2XIaAoZLUNGU8hoGTKaQmgAAAIMAJeMK58/yjg2AAAAAElFTkSuQmCC';
var blockimg=new Image();
blockimg.src='data:image/png;base64,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';
var playerimg=new Image();
playerimg.src='data:image/png;base64,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';
var goalimg=new Image();
goalimg.src='data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB4AAAAeCAIAAAC0Ujn1AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAFtJREFUeNpilJSUZKANYAFiGRkZqpv75MkTJgaagWFv9BMwGA2QUaNHttEsmPmCYMbBJYVWzNHR1XgKWIh7iS+BR1PIqNEjIaPjAaQ2V0bDGktYk9S6IB4ABBgADi4U6URvDncAAAAASUVORK5CYII=';
</script>
</html>