Здесь представлено несколько примеров создания градиентов, в том числе и анимированных (подробнее об анимации).
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg" width="200" height="400"
xmlns:xlink="http://www.w3.org/1999/xlink"
>
<title>Градиенты</title>
<defs>
<radialGradient id="MyGradient1"
fx="20%" fy="25%" >
<stop offset="0" stop-color="#f0ffff"/>
<stop offset="100%" stop-color="#00a0a0">
<animate attributeName="offset"
from="0%" to="100%" dur="10s"
repeatCount="indefinite"/>
</stop>
</radialGradient>
<radialGradient id="MyGradient2"
fx="25%" fy="50%" >
<stop offset="0" stop-color="#ffffff"/>
<stop offset="100%" stop-color="#ff00ff">
<animate attributeName="offset"
from="0%" to="100%" dur="5s"
repeatCount="indefinite"/>
</stop>
</radialGradient>
<linearGradient id="MyGradient3"
x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0" style="stop-color:#ffffff"/>
<stop offset="100%" style="stop-color:#008000">
<animate attributeName="offset"
from="0%" to="100%" dur="3s"
repeatCount="indefinite"/>
</stop>
</linearGradient>
</defs>
<circle cx="60" cy="60" r="50" fill="url(#MyGradient1)" fill-opacity="0.5"/>
<circle cx="100" cy="100" r="35" fill="url(#MyGradient2)" fill-opacity="0.5"/>
<rect x="10" y="150" width="200" height="60" fill="url(#MyGradient3)" />
</svg>
Еще пример >...