jQuery旋转光标角度 [英] Jquery-rotate cursor angle
本文介绍了jQuery旋转光标角度的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我需要用Jquery-rotate旋转箭头,但是我不知道光标的角度:( 我尝试进行计算,但是脚本不起作用.
I need rotate arrow with Jquery-rotate, but i dont know cursor's angle :( I try calculate it, but script not work.
我想要这样的结果 http://www.lonhosford.com/content /html5/canvas/rotate_to_mouse.html
<script type="text/javascript">
//<![CDATA[
$(document).ready(function(){
function diff(x, y) {
var a = (x * Math.PI / 180) - Math.PI;
var b = (y * Math.PI / 180) - Math.PI;
return Math.atan2(Math.sin(b - a), Math.cos(b - a)) * (180 / Math.PI);
}
$('body').mousemove(function(e){
var x = e.pageX;
var y = e.pageY;
var myAngle = diff(x, y);
$("#image").rotate(myAngle);
});
});
//]]>
</script>
推荐答案
如果查看发布的示例的源代码,您会发现
If you look at the source code of the example you posted you will find
update: function()
{
// Distance from mouse x and center of canvas.
this._dx = mouse.x - this.centerX;
// Distance from mouse y and center of canvas.
this._dy = mouse.y - this.centerY;
// Radians for the canvas rotate method.
this._radians = Math.atan2(this._dy,this._dx);
}
要使此代码适合您自己的需求,请尝试
To adapt this code for your own needs try
function diff(x, y) {
var centerItem = $('imageid'),
centerLoc = centeItem.offset();
var dx = x - centerLoc.left + (centerItem.width() / 2);
dy = y - centerLoc.top + (centerItem.height() / 2);
return Math.atan2(dy, dx) * (180 / Math.PI);
}
示例,位于 http://jsfiddle.net/gaby/xWtKc/1/
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