<head>
<script src='jquery-1.9.1.js'></script>
<script src='jcanvas.min.js'></script>
<!--<script src='js/jquery.mobile-1.2.0.min.js'></script> -->
<script>
var maxX=-1;
var maxY=-1;
var minX=99999;
var minY=99999;
function checkData(event){
var x=event.pageX-$('canvas').offset().left;
var y=event.pageY-$('canvas').offset().top;
if(x>maxX){
maxX=x;
}else if(x<minX){
minX=x;
}
if(y>maxY){
maxY=y;
}else if(y<minY){
minY=y;
}
}
$(function(){
var obj=$('canvas');
var temp_e;
var temp_draw=false;
obj.on({
mousedown:function(e){
temp_e=e;
temp_draw=true;
checkData(e);
},
mousemove:function(e){
if(temp_draw){
obj.drawLine({
strokeStyle: '#000',
strokeWidth: 3,
x1: temp_e.pageX-$('canvas').offset().left, y1: temp_e.pageY-$('canvas').offset().top,
x2: e.pageX-$('canvas').offset().left, y2: e.pageY-$('canvas').offset().top,
});
}
temp_e=e;
checkData(e);
},
mouseup:function(e){
temp_e=null;
temp_draw=false;
checkData(e);
},
mouseout:function(){
temp_e=null;
temp_draw=false;
}
});
$("#clean").on("click",function(){
maxX=-1;
maxY=-1;
minX=99999;
minY=99999;
obj.clearCanvas();
});
$("#save").on("click",function(){
var image=obj.getCanvasImage("png");
alert(image);
});
});
</script>
</head>
<body>
<input type="button" id="save" value="保存" />
<input type="button" id="clean" value="清除" />
<br/>
<canvas width='320' height='480' style="background:#f00"></canvas>
<p id="points"></p>
</body>