在曲线路径中移动div(如Flash中的补间)? [英] Move a div in a curved path (like tweening in Flash old days)?
问题描述
我想要建立一个函数,例如
fromHeretoThere(x1,y1,x2,y2){
// ....
}
$ c>< div> 或从HTML页面上的某一点到曲线中的另一点的图片。
使用Canvas? HTML5?
:这里有一个工作正在进行,打包的任何插件/脚本yo建议?第二概念描述为可重用的JS对象。您可以编辑代码或直观地拖动曲线以查看生成的代码:
http://phrogz.net/SVG/animation_on_a_curve.html
我个人使用SVG ,这使得使用 这样的东西(使用任意Bézier曲线进行动画处理) < animateMotion>
元素。作为奖励,你甚至可以使它计算你的旋转。一些示例:
- http://www.w3.org/TR/SVG/images/animate/animMotion01.svg
- https://developer.mozilla.org/en/SVG/Element/animateMotion
- http://devfiles.myopera.com/articles/76/SolarSystem.svg
ul>
注意,你甚至不必实际使用SVG来显示结果;您可以简单地使用此动画创建一个离屏SVG,并对动画元素的变换进行采样,以获得所需的点/旋转。
或者,想要旋转,或者希望在控制遍历速率时自己计算),您可以创建一个SVG路径,并使用 getPointAtLength()
/ getTotalLength()
,以找到您应该沿着路径在给定百分比的总遍历距离的位置。这样,你甚至不需要一个SVG文档:
//沿着S曲线从0,0移动到250,450
var p = document.createElementNS('http://www.w3.org/2000/svg','path');
p.setAttribute('d','M0,0 C350,20 -200,400 250,450');
var len = p.getTotalLength();
for(var i = 0; i <= 100; i + = 10){
var pct = i / 100;
var pt = p.getPointAtLength(pct * len);
console.log(i,pt.x,pt.y);
}
// 0 0 0
// 10 65.54324340820312 10.656576156616211
// 20 117.17988586425781 49.639259338378906
// 30 120.2674789428711 114.92564392089844
/ / 40 100.49604034423828 178.4400177001953
// 50 78.06965637207031 241.1177520751953
// 60 63.526206970214844 305.9412841796875
// 70 74.59959411621094 370.6294860639844
// 80 122.1227798461914 415.8912658691406
// 90 184.41302490234375 438.8457336425781
// 100 250 450
现在所有你需要做的是设置<$ c $ < div>
中的 .style.left
或< img>
。唯一的硬部分是决定曲线的外观,并定义放置手柄的位置 。
I'd like to build a function like
fromHeretoThere(x1,y1,x2,y2){
//....
}
So that I can move a <div>
or an image from one point on the HTML page to another point in a curve.
Is this doable only using Canvas? HTML5? any plugin/scripts yo suggest?
Edit: Here's a work in progress that packages up the second concept described below as a re-usable JS object. You can edit the code or visually drag the curve to see the resulting code:
http://phrogz.net/SVG/animation_on_a_curve.html
I'd personally use SVG, which makes this sort of thing (animating along an arbitrary Bézier curve) trivial using the <animateMotion>
element. As a bonus, you can even cause it to calculate the rotation for you. Some examples:
- http://www.w3.org/TR/SVG/images/animate/animMotion01.svg
- https://developer.mozilla.org/en/SVG/Element/animateMotion
- http://devfiles.myopera.com/articles/76/SolarSystem.svg
Note that you don't even have to actually use SVG to display the result; you could simply create an off-screen SVG with this animation and sample the transform of the animated element to get your desired point/rotation.
Alternatively (if you don't want the rotation, or want to calculate it yourself while controlling the rate of traversal) you can create an SVG path and just use getPointAtLength()
/getTotalLength()
to find where you should be along the path at a given percentage of the total traversal distance. With this you don't even need an SVG document:
// Moving along an S curve from 0,0 to 250,450
var p = document.createElementNS('http://www.w3.org/2000/svg','path');
p.setAttribute('d','M0,0 C350,20 -200,400 250,450');
var len = p.getTotalLength();
for (var i=0;i<=100;i+=10){
var pct = i/100;
var pt = p.getPointAtLength(pct*len);
console.log( i, pt.x, pt.y );
}
// 0 0 0
// 10 65.54324340820312 10.656576156616211
// 20 117.17988586425781 49.639259338378906
// 30 120.2674789428711 114.92564392089844
// 40 100.49604034423828 178.4400177001953
// 50 78.06965637207031 241.1177520751953
// 60 63.526206970214844 305.9412841796875
// 70 74.59959411621094 370.6294860839844
// 80 122.1227798461914 415.8912658691406
// 90 184.41302490234375 438.8457336425781
// 100 250 450
Now all you have to do is set the .style.top
and .style.left
of your <div>
or <img>
appropriately. The only 'hard' part is deciding what you want to the curve to look like and defining where to put the handles.
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