我有一个简单的问题:我想提取平移(tx,ty),旋转(r)和比例(sx,sy)值形成应用于我的svg元素的变换矩阵。
让我们使用此示例:
<g
id="myElement"
transform="matrix(0.93893241,0.34410162,-0.34410162,0.93893241,363.88475,-76.125919)"
>... </g>
如果使用javascript,我愿意
document.getElementById("myElement").getCTM()
我可以访问a,b,c,d,e,f值。如何从那里获取tx,ty,sx,sy和r?谢谢
受此ActionScript版本的启发:https://gist.github.com/fwextensions/2052247,我写了一个JavaScript端口:
function deltaTransformPoint(matrix, point) {
var dx = point.x * matrix.a + point.y * matrix.c + 0;
var dy = point.x * matrix.b + point.y * matrix.d + 0;
return { x: dx, y: dy };
}
function decomposeMatrix(matrix) {
// @see https://gist.github.com/2052247
// calculate delta transform point
var px = deltaTransformPoint(matrix, { x: 0, y: 1 });
var py = deltaTransformPoint(matrix, { x: 1, y: 0 });
// calculate skew
var skewX = ((180 / Math.PI) * Math.atan2(px.y, px.x) - 90);
var skewY = ((180 / Math.PI) * Math.atan2(py.y, py.x));
return {
translateX: matrix.e,
translateY: matrix.f,
scaleX: Math.sqrt(matrix.a * matrix.a + matrix.b * matrix.b),
scaleY: Math.sqrt(matrix.c * matrix.c + matrix.d * matrix.d),
skewX: skewX,
skewY: skewY,
rotation: skewX // rotation is the same as skew x
};
}
用法:decomposeMatrix(document.getElementById('myElement').getCTM())