matrix.js

js基本操作

		return dojo.gfx.matrix._multiplyPoint(m, a.x, a.y); // dojo.gfx.Point
	},
	multiply: function(matrix){
		// summary: combines matrices by multiplying them sequentially in the given order
		// matrix: dojo.gfx.matrix.Matrix2D...: a 2D matrix-like object, 
		//		all subsequent arguments are matrix-like objects too
		var m = dojo.gfx.matrix.normalize(matrix);
		// combine matrices
		for(var i = 1; i < arguments.length; ++i){
			var l = m;
			var r = dojo.gfx.matrix.normalize(arguments[i]);
			m = new dojo.gfx.matrix.Matrix2D();
			m.xx = l.xx * r.xx + l.xy * r.yx;
			m.xy = l.xx * r.xy + l.xy * r.yy;
			m.yx = l.yx * r.xx + l.yy * r.yx;
			m.yy = l.yx * r.xy + l.yy * r.yy;
			m.dx = l.xx * r.dx + l.xy * r.dy + l.dx;
			m.dy = l.yx * r.dx + l.yy * r.dy + l.dy;
		}
		return m; // dojo.gfx.matrix.Matrix2D
	},
	
	// high level operations
	
	_sandwich: function(m, x, y){
		// summary: applies a matrix at a centrtal point
		// m: dojo.gfx.matrix.Matrix2D: a 2D matrix-like object, which is applied at a central point
		// x: Number: an x component of the central point
		// y: Number: a y component of the central point
		return dojo.gfx.matrix.multiply(dojo.gfx.matrix.translate(x, y), m, dojo.gfx.matrix.translate(-x, -y)); // dojo.gfx.matrix.Matrix2D
	},
	scaleAt: function(a, b, c, d){
		// summary: scales a picture using a specified point as a center of scaling
		// description: Compare with dojo.gfx.matrix.scale().
		// a: Number: a scaling factor used for the x coordinate
		// b: Number: a scaling factor used for the y coordinate
		// c: Number: an x component of a central point
		// d: Number: a y component of a central point
		
		// accepts several signatures:
		//	1) uniform scale factor, Point
		//	2) uniform scale factor, x, y
		//	3) x scale, y scale, Point
		//	4) x scale, y scale, x, y
		
		switch(arguments.length){
			case 4:
				// a and b are scale factor components, c and d are components of a point
				return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.scale(a, b), c, d); // dojo.gfx.matrix.Matrix2D
			case 3:
				if(typeof c == "number"){
					// branch
					// a: Number: a uniform scaling factor used for both coordinates
					// b: Number: an x component of a central point
					// c: Number: a y component of a central point
					// d: null
					return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.scale(a), b, c); // dojo.gfx.matrix.Matrix2D
				}
				// branch
				// a: Number: a scaling factor used for the x coordinate
				// b: Number: a scaling factor used for the y coordinate
				// c: dojo.gfx.Point: a central point
				// d: null
				return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.scale(a, b), c.x, c.y); // dojo.gfx.matrix.Matrix2D
		}
		// branch
		// a: Number: a uniform scaling factor used for both coordinates
		// b: dojo.gfx.Point: a central point
		// c: null
		// d: null
		return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.scale(a), b.x, b.y); // dojo.gfx.matrix.Matrix2D
	},
	rotateAt: function(angle, a, b){
		// summary: rotates a picture using a specified point as a center of rotation
		// description: Compare with dojo.gfx.matrix.rotate().
		// angle: Number: an angle of rotation in radians (>0 for CCW)
		// a: Number: an x component of a central point
		// b: Number: a y component of a central point
		
		// accepts several signatures:
		//	1) rotation angle in radians, Point
		//	2) rotation angle in radians, x, y
		
		if(arguments.length > 2){
			return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.rotate(angle), a, b); // dojo.gfx.matrix.Matrix2D
		}
		
		// branch
		// angle: Number: an angle of rotation in radians (>0 for CCW)
		// a: dojo.gfx.Point: a central point
		// b: null
		return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.rotate(angle), a.x, a.y); // dojo.gfx.matrix.Matrix2D
	},
	rotategAt: function(degree, a, b){
		// summary: rotates a picture using a specified point as a center of rotation
		// description: Compare with dojo.gfx.matrix.rotateg().
		// degree: Number: an angle of rotation in degrees (>0 for CCW)
		// a: Number: an x component of a central point
		// b: Number: a y component of a central point
		
		// accepts several signatures:
		//	1) rotation angle in degrees, Point
		//	2) rotation angle in degrees, x, y
		
		if(arguments.length > 2){
			return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.rotateg(degree), a, b); // dojo.gfx.matrix.Matrix2D
		}

		// branch
		// degree: Number: an angle of rotation in degrees (>0 for CCW)
		// a: dojo.gfx.Point: a central point
		// b: null
		return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.rotateg(degree), a.x, a.y); // dojo.gfx.matrix.Matrix2D
	},
	skewXAt: function(angle, a, b){
		// summary: skews a picture along the x axis using a specified point as a center of skewing
		// description: Compare with dojo.gfx.matrix.skewX().
		// angle: Number: an skewing angle in radians
		// a: Number: an x component of a central point
		// b: Number: a y component of a central point
		
		// accepts several signatures:
		//	1) skew angle in radians, Point
		//	2) skew angle in radians, x, y
		
		if(arguments.length > 2){
			return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.skewX(angle), a, b); // dojo.gfx.matrix.Matrix2D
		}

		// branch
		// angle: Number: an skewing angle in radians
		// a: dojo.gfx.Point: a central point
		// b: null
		return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.skewX(angle), a.x, a.y); // dojo.gfx.matrix.Matrix2D
	},
	skewXgAt: function(degree, a, b){
		// summary: skews a picture along the x axis using a specified point as a center of skewing
		// description: Compare with dojo.gfx.matrix.skewXg().
		// degree: Number: an skewing angle in degrees
		// a: Number: an x component of a central point
		// b: Number: a y component of a central point
		
		// accepts several signatures:
		//	1) skew angle in degrees, Point
		//	2) skew angle in degrees, x, y

		if(arguments.length > 2){
			return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.skewXg(degree), a, b); // dojo.gfx.matrix.Matrix2D
		}

		// branch
		// degree: Number: an skewing angle in degrees
		// a: dojo.gfx.Point: a central point
		// b: null
		return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.skewXg(degree), a.x, a.y); // dojo.gfx.matrix.Matrix2D
	},
	skewYAt: function(angle, a, b){
		// summary: skews a picture along the y axis using a specified point as a center of skewing
		// description: Compare with dojo.gfx.matrix.skewY().
		// angle: Number: an skewing angle in radians
		// a: Number: an x component of a central point
		// b: Number: a y component of a central point
		
		// accepts several signatures:
		//	1) skew angle in radians, Point
		//	2) skew angle in radians, x, y
		
		if(arguments.length > 2){
			return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.skewY(angle), a, b); // dojo.gfx.matrix.Matrix2D
		}

		// branch
		// angle: Number: an skewing angle in radians
		// a: dojo.gfx.Point: a central point
		// b: null
		return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.skewY(angle), a.x, a.y); // dojo.gfx.matrix.Matrix2D
	},
	skewYgAt: function(/* Number */ degree, /* Number||Point */ a, /* Number, optional */ b){
		// summary: skews a picture along the y axis using a specified point as a center of skewing
		// description: Compare with dojo.gfx.matrix.skewYg().
		// degree: Number: an skewing angle in degrees
		// a: Number: an x component of a central point
		// b: Number: a y component of a central point
		
		// accepts several signatures:
		//	1) skew angle in degrees, Point
		//	2) skew angle in degrees, x, y

		if(arguments.length > 2){
			return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.skewYg(degree), a, b); // dojo.gfx.matrix.Matrix2D
		}

		// branch
		// degree: Number: an skewing angle in degrees
		// a: dojo.gfx.Point: a central point
		// b: null
		return dojo.gfx.matrix._sandwich(dojo.gfx.matrix.skewYg(degree), a.x, a.y); // dojo.gfx.matrix.Matrix2D
	}
	
	// TODO: rect-to-rect mapping, scale-to-fit (isotropic and anisotropic versions)
	
});