Javascript:跟随光标,但保持在圆形内,而不是矩形div
我试图获得下面的jsfiddle示例,使黄色的圆圈div跟随鼠标,但约束为圆圈,而不是正方形(div) JS代码如下所示:Javascript:跟随光标,但保持在圆形内,而不是矩形div,javascript,jquery,html,css,Javascript,Jquery,Html,Css,我试图获得下面的jsfiddle示例,使黄色的圆圈div跟随鼠标,但约束为圆圈,而不是正方形(div) JS代码如下所示: var mouseX = 0, mouseY = 0, limitX = 150-15, limitY = 150-15; $(window).mousemove(function(e){ mouseX = Math.min(e.pageX, limitX); mouseY = Math.min(e.pageY, limitY); }); // cache
var mouseX = 0, mouseY = 0, limitX = 150-15, limitY = 150-15;
$(window).mousemove(function(e){
mouseX = Math.min(e.pageX, limitX);
mouseY = Math.min(e.pageY, limitY);
});
// cache the selector
var follower = $("#follower");
var xp = 0, yp = 0;
var loop = setInterval(function(){
// change 12 to alter damping higher is slower
xp += (mouseX - xp) / 12;
yp += (mouseY - yp) / 12;
follower.css({left:xp, top:yp});
}, 30);
我理解代码的结构和方法,只是不太熟悉语法
更新
limitX/Y
并加入额外的半径
,距离
变量的最佳位置在哪里?您可以通过计算远离圆心的距离来实现这一点(2D距离是用(x*x+Y*Y)
计算的)。然后检查距离是否大于要约束到的圆的半径。如果是,请缩小距离以匹配约束半径
以下是片段:
var mouseX = 0, mouseY = 0, limitX = 150-15, limitY = 150-15;
var centerX = limitX / 2, centerY = limitY / 2;
var radius = centerX;
$(window).mousemove(function(e) {
var diffX = e.pageX - centerX;
var diffY = e.pageY - centerY;
// Get the mouse distance from the center
var r = Math.sqrt(diffX * diffX + diffY * diffY);
if (r > radius) {
// Scale the distance down to length 1
diffX /= r;
diffY /= r;
// Scale back up to the radius
diffX *= radius;
diffY *= radius;
}
mouseX = centerX + diffX;
mouseY = centerY + diffY;
});
下面是完整的代码:类似