SVG使用Javascript将形状平滑地变形为其他预定义的形状

Question

• 我想要形状之间的平滑过渡（下面的例子显示了一个突然的过渡，这样你就知道我需要平滑过渡的地方）
• 形状的顺序由Javascript决定（例如，我修复了一个任意序列，但在实际问题中，用户输入决定了选择哪个形状，因此事先并不知道）

example.svg:

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<svg xmlns="http://www.w3.org/2000/svg"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    width="100%" height="100%" viewBox="0 0 400 400">
<script>
window.animate = function( fromId, toId, next )
{
    return function()
    {
        var elem = document.getElementById( 'elem' );
        /* Here a smooth animation is supposed to happen. */
        elem.setAttribute( 'xlink:href', '#' + toId );
        if( next )
        {
            window.setTimeout( next, 1000 );
        }
    };
};
window.onload = function()
{
    /* The animation order is determined by javascript. */
    var step3 = window.animate( 'path-2', 'path-1', null );
    var step2 = window.animate( 'path-1', 'path-2', step3 );
    var step1 = window.animate( 'path-0', 'path-1', step2 );
    var step0 = window.animate( 'path-0', 'path-0', step1 );
    step0();
};
</script>
<style>path{stroke:#000;}</style>
<defs>
<path id="path-0" style="fill:#fcc" d="M0,0 h100 v100 h-100 v-100" />
<path id="path-1" style="fill:#ccf" d="M0,0 h50 l50 50 l-100 50 v-100" />
<path id="path-2" style="fill:#cfc" d="M0,0 h150 l-50 50 l-100 50 v-100" />
</defs>
<use id="elem" xlink:href="#path-0" x="150" y="150" />
</svg>

据推测，<animate>在某种程度上是可行的，但我无法让它发挥作用。

animate.svg:

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<svg xmlns="http://www.w3.org/2000/svg"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    width="100%" height="100%" viewBox="0 0 400 400">
<script>
window.set_animation = function( animId, fromId, toId )
{
    var anim = document.getElementById( animId );
    var from = document.getElementById( fromId );
    var to = document.getElementById( toId );
    anim.setAttribute( 'from', from.getAttribute( 'd' ) );
    anim.setAttribute( 'to', to.getAttribute( 'd' ) );
};
window.onload = function()
{
    /* The animation order is determined by javascript. */
    window.set_animation( 'anim-0', 'path-0', 'path-1' );
    window.set_animation( 'anim-1', 'path-1', 'path-2' );
    window.set_animation( 'anim-2', 'path-2', 'path-1' );
    /* Can start animation only once animation steps are defined. */
    var anim = document.getElementById( 'anim-0' );
    anim.beginElement();
};
</script>
<style>path{stroke:#000;}</style>
<defs>
    <path id="path-0" style="fill:#fcc" d="M0,0 l100,0 l0,100 l-100,0 l0,-100" />
    <path id="path-1" style="fill:#ccf" d="M0,0 l50,0 l50,50 l-100,50 l0,-100" />
    <path id="path-2" style="fill:#cfc" d="M0,0 l150,0 l-50,50 l-100,50 l0,-100" />
</defs>
<path id="elem" x="150" y="150" d="">
    <animate id="anim-0" begin="indefinite" attributeType="XML" attributeName="d" dur="2s" from="[set by javascript]" to="[set by javascript]" />
    <animate id="anim-1" begin="anim-1.end" attributeType="XML" attributeName="d" dur="2s" from="[set by javascript]" to="[set by javascript]" />
    <animate id="anim-2" begin="anim-2.end" attributeType="XML" attributeName="d" dur="2s" from="[set by javascript]" to="[set by javascript]" />
</path>
</svg>

Answer 1

像我在这里所做的那样，将所有值放入一个动画中更容易。如果不这样做，则必须在前一个动画完成时开始每个后续动画，这是可行的，但更复杂。

你需要fakeSmile或用于IE/Chrome的Chrome SMIL填充程序，但这在Firefox上没有插件。

<svg xmlns="http://www.w3.org/2000/svg"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    width="100%" height="100%" viewBox="0 0 400 400">
<script>
function create_animation(animId, paths, attribute)
{
    var anim = document.getElementById( animId );
    var values = paths.map(function(item) { return document.getElementById(item).getAttribute(attribute) }).join(';'); 
        
    anim.setAttribute( 'values', values );
}
window.set_animation = function( animId, paths )
{
    create_animation(animId, paths, 'd');
    create_animation(animId + '-colour', paths, 'fill');
};
window.onload = function()
{
    /* The animation order is determined by javascript. */
    window.set_animation( 'anim-0', ['path-0', 'path-1', 'path-2'] );
};
</script>
<style>path{stroke:#000;}</style>
<defs>
    <path id="path-0" fill="#fcc" d="M0,0 l100,0 l0,100 l-100,0 l0,-100" />
    <path id="path-1" fill="#ccf" d="M0,0 l50,0 l50,50 l-100,50 l0,-100" />
    <path id="path-2" fill="#cfc" d="M0,0 l150,0 l-50,50 l-100,50 l0,-100" />
</defs>
  
<path>
  <animate id='anim-0' dur="3s" attributeName='d' fill="freeze"/>
  <animate id='anim-0-colour' dur="3s" attributeName='fill' fill="freeze"/>
</path>

Answer 2

对于<animate>，规则是两条路径必须：

1. 具有相同数量的路径元素
2. 具有匹配的路径命令

你的动画无法工作，因为路径不兼容：

path-0: M h v h v
path-1: M h l l v