javascript根据像素点取位置示例_javascript技巧

复制代码 代码如下:

    
        

        <script><BR> function position (x,y){<BR> this.x = x;<BR> this.y = y;<BR> }<br><br> var canvas = document.getElementById('canvas'),<BR> ctx = canvas.getContext('2d');<BR> width = canvas.width,<BR> height = canvas.height;<BR> ctx.fillStyle = "#FF0000";<BR> ctx.font = "20px Arial";<BR> ctx.fillText("妈妈",10,50);<br><br> var pixs = ctx.getImageData(0,0,width,height).data;<BR> var Pixels = new Array();<br><br> for(var i=0;i<pixs.length;i+= 4)<BR> {<BR> var r = pixs[i],<BR> g = pixs[i+1],<BR> b = pixs[i+2],<BR> a = pixs[i+3];<br><br> if(r != 0 || g != 0 || b != 0 ){<BR> var x = i%400;<BR> var y = i/400;<BR> Pixels.push(new position(x,y));<BR> }<BR> }<br><br> </script>