javascript 如何沿具有贝塞尔曲线的路径为图像设置动画
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How to animate an image along a path with Bezier curves
提问by Bruno
My goal:
我的目标：
- Move/animate an image along a path like the drawing below (Could be connecting bezier curves).
- Must work in IE7+, don't what to build multiple solutions.
- I can pause/resume the moving image.
- The image will keep moving along the path (repeat).
- 沿着如下图所示的路径移动/动画图像（可能是连接贝塞尔曲线）。
- 必须在IE7+下工作，不要什么构建多个解决方案。
- 我可以暂停/恢复运动图像。
- 图像将继续沿路径移动（重复）。
What I have considered
我所考虑的
- CANVAS: not supported in IE7+8, haven't tested explorercanvas yet! Foresee some z-index issues.
- SVG, not supported in IE7+8.
- jQuery.path, a plugin that extends the jQuery animate function. Can't figure out the resume part and I want to use CSS transforms when supported.
- CANVAS：IE7+8不支持，还没有测试过explorercanvas！预见一些 z-index 问题。
- SVG，IE7+8 不支持。
- jQuery.path，一个扩展jQuery animate 功能的插件。无法弄清楚简历部分，我想在支持时使用 CSS 转换。
My plan
我的计划
- Animate the image with CSS 3D transform, CSS 2d transform or jQuery.animate (what supported) and requestAnimationFrame.
- Calculate all the coordinates and simple move the image pixel by pixel.
- 使用 CSS 3D 变换、CSS 2d 变换或 jQuery.animate（支持的内容）和 requestAnimationFrame 为图像设置动画。
- 计算所有坐标并简单地逐像素移动图像。
My question
我的问题
- Does my plan sound like madness? Better suggestions?
- Do you foresee some performance issues? I might end up with 5K or 10K coordinates.
- Do you know a smart way, a program, a function or anything similar to calculate all the coordinates?
- 我的计划听起来很疯狂吗？更好的建议？
- 您是否预见到一些性能问题？我最终可能会得到 5K 或 10K 坐标。
- 你知道计算所有坐标的聪明方法、程序、函数或类似的东西吗？
采纳答案by xavier.seignard
I would recommend you to use GSAP : http://www.greensock.com/get-started-js/
我建议您使用 GSAP：http: //www.greensock.com/get-started-js/
With that you can handle timelines, and here is a bezier plugin : http://api.greensock.com/js/com/greensock/plugins/BezierPlugin.html
有了它你可以处理时间线，这里有一个贝塞尔插件：http: //api.greensock.com/js/com/greensock/plugins/BezierPlugin.html
regards
问候
回答by vsync
There's a tiny script (SVG based), just for animation which isn't in straight lines,
called pathAnimator(2kb), It's very very small and very efficient.
No jQuery required.
有一个很小的脚本（基于 SVG），仅用于非直线的动画，
称为pathAnimator(2kb)，它非常非常小且非常高效。
不需要jQuery。
For example:
例如：
var path = "M150 0 L75 200 L225 200 Z"; // an SVG path
pathAnimator = new PathAnimator( path ), // initiate a new pathAnimator object
speed = 6, // seconds that will take going through the whole path
reverse = false, // go back or forward along the path
startOffset = 0, // between 0% to 100%
easing = function(t){ t*(2-t) }; // optional easing function
pathAnimator.start( speed, step, reverse, startOffset, finish, easing);
function step( point, angle ){
// do something every "frame" with: point.x, point.y & angle
}
function finish(){
// do something when animation is done
}
(can even get more efficient using fastdom)
（甚至可以使用fastdom提高效率）
