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Implement Matrix#rotate() without relying on Matrix#getRotateInstance().

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This commit is contained in:
Jürg Lehni 2013-02-09 11:40:49 -08:00
parent 53474aa5c0
commit 3930a40c7e
1 changed files with 20 additions and 2 deletions

22
src/basic/Matrix.js
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@ -195,8 +195,26 @@ var Matrix = this.Matrix = Base.extend(/** @lends Matrix# */{
* @return {Matrix} This affine transform
*/
rotate: function(angle, center) {
return this.concatenate(
Matrix.getRotateInstance.apply(Matrix, arguments));
center = Point.read(arguments, 1);
angle = angle * Math.PI / 180;
// Concatenate rotation matrix into this one
var x = center.x,
y = center.y,
cos = Math.cos(angle),
sin = Math.sin(angle),
tx = x - x * cos + y * sin,
ty = y - x * sin - y * cos,
a = this._a,
b = this._b,
c = this._c,
d = this._d;
this._a = cos * a + sin * b;
this._b = -sin * a + cos * b;
this._c = cos * c + sin * d;
this._d = -sin * c + cos * d;
this._tx += tx * a + ty * b;
this._ty += tx * c + ty * d;
return this;
},
/**