Created
September 15, 2016 05:36
-
-
Save deNULL/a14132a8a66fa8968551920efb7a9c8c to your computer and use it in GitHub Desktop.
Basic matrix transforms for canvas
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// Transform utils by Simon Sarris (www.simonsarris.com, sarris@acm.org) | |
// Minor additions by deNULL (me@denull.ru) | |
function Transform(copy) { | |
if (copy) { | |
this.m = [copy.m[0], copy.m[1], copy.m[2], copy.m[3], copy.m[4], copy.m[5]]; | |
} else { | |
this.reset(); | |
} | |
} | |
Transform.prototype.reset = function() { | |
this.m = [1, 0, 0, 1, 0, 0]; | |
}; | |
Transform.prototype.clone = function() { | |
return new Transform(this); | |
} | |
Transform.prototype.multiply = function(matrix) { | |
var m11 = this.m[0] * matrix.m[0] + this.m[2] * matrix.m[1]; | |
var m12 = this.m[1] * matrix.m[0] + this.m[3] * matrix.m[1]; | |
var m21 = this.m[0] * matrix.m[2] + this.m[2] * matrix.m[3]; | |
var m22 = this.m[1] * matrix.m[2] + this.m[3] * matrix.m[3]; | |
var dx = this.m[0] * matrix.m[4] + this.m[2] * matrix.m[5] + this.m[4]; | |
var dy = this.m[1] * matrix.m[4] + this.m[3] * matrix.m[5] + this.m[5]; | |
this.m[0] = m11; | |
this.m[1] = m12; | |
this.m[2] = m21; | |
this.m[3] = m22; | |
this.m[4] = dx; | |
this.m[5] = dy; | |
}; | |
Transform.prototype.invert = function() { | |
var d = 1 / (this.m[0] * this.m[3] - this.m[1] * this.m[2]); | |
var m0 = this.m[3] * d; | |
var m1 = -this.m[1] * d; | |
var m2 = -this.m[2] * d; | |
var m3 = this.m[0] * d; | |
var m4 = d * (this.m[2] * this.m[5] - this.m[3] * this.m[4]); | |
var m5 = d * (this.m[1] * this.m[4] - this.m[0] * this.m[5]); | |
this.m[0] = m0; | |
this.m[1] = m1; | |
this.m[2] = m2; | |
this.m[3] = m3; | |
this.m[4] = m4; | |
this.m[5] = m5; | |
}; | |
Transform.prototype.rotate = function(rad) { | |
var c = Math.cos(rad); | |
var s = Math.sin(rad); | |
var m11 = this.m[0] * c + this.m[2] * s; | |
var m12 = this.m[1] * c + this.m[3] * s; | |
var m21 = this.m[0] * -s + this.m[2] * c; | |
var m22 = this.m[1] * -s + this.m[3] * c; | |
this.m[0] = m11; | |
this.m[1] = m12; | |
this.m[2] = m21; | |
this.m[3] = m22; | |
}; | |
Transform.prototype.translate = function(x, y) { | |
this.m[4] += this.m[0] * x + this.m[2] * y; | |
this.m[5] += this.m[1] * x + this.m[3] * y; | |
}; | |
Transform.prototype.scale = function(sx, sy) { | |
this.m[0] *= sx; | |
this.m[1] *= sx; | |
this.m[2] *= sy; | |
this.m[3] *= sy; | |
}; | |
Transform.prototype.transformPoint = function(px, py) { | |
var x = px; | |
var y = py; | |
px = x * this.m[0] + y * this.m[2] + this.m[4]; | |
py = x * this.m[1] + y * this.m[3] + this.m[5]; | |
return [px, py]; | |
}; | |
Transform.prototype.apply = function(context) { | |
context.setTransform(this.m[0], this.m[1], this.m[2], this.m[3], this.m[4], this.m[5]); | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment