232 lines
6.9 KiB
JavaScript
232 lines
6.9 KiB
JavaScript
/**
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* Package: svedit.math
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*
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* Licensed under the Apache License, Version 2
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*
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* Copyright(c) 2010 Alexis Deveria
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* Copyright(c) 2010 Jeff Schiller
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*/
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// Dependencies:
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// None.
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var svgedit = svgedit || {};
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(function() {
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if (!svgedit.math) {
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svgedit.math = {};
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}
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// Constants
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var NEAR_ZERO = 1e-14;
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// Throw away SVGSVGElement used for creating matrices/transforms.
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var svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
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// Function: svgedit.math.transformPoint
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// A (hopefully) quicker function to transform a point by a matrix
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// (this function avoids any DOM calls and just does the math)
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//
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// Parameters:
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// x - Float representing the x coordinate
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// y - Float representing the y coordinate
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// m - Matrix object to transform the point with
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// Returns a x,y object representing the transformed point
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svgedit.math.transformPoint = function(x, y, m) {
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return { x: m.a * x + m.c * y + m.e, y: m.b * x + m.d * y + m.f};
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};
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// Function: svgedit.math.isIdentity
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// Helper function to check if the matrix performs no actual transform
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// (i.e. exists for identity purposes)
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//
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// Parameters:
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// m - The matrix object to check
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//
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// Returns:
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// Boolean indicating whether or not the matrix is 1,0,0,1,0,0
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svgedit.math.isIdentity = function(m) {
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return (m.a === 1 && m.b === 0 && m.c === 0 && m.d === 1 && m.e === 0 && m.f === 0);
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};
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// Function: svgedit.math.matrixMultiply
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// This function tries to return a SVGMatrix that is the multiplication m1*m2.
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// We also round to zero when it's near zero
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//
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// Parameters:
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// >= 2 Matrix objects to multiply
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//
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// Returns:
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// The matrix object resulting from the calculation
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svgedit.math.matrixMultiply = function() {
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var args = arguments, i = args.length, m = args[i-1];
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while(i-- > 1) {
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var m1 = args[i-1];
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m = m1.multiply(m);
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}
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if (Math.abs(m.a) < NEAR_ZERO) m.a = 0;
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if (Math.abs(m.b) < NEAR_ZERO) m.b = 0;
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if (Math.abs(m.c) < NEAR_ZERO) m.c = 0;
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if (Math.abs(m.d) < NEAR_ZERO) m.d = 0;
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if (Math.abs(m.e) < NEAR_ZERO) m.e = 0;
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if (Math.abs(m.f) < NEAR_ZERO) m.f = 0;
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return m;
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};
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// Function: svgedit.math.hasMatrixTransform
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// See if the given transformlist includes a non-indentity matrix transform
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//
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// Parameters:
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// tlist - The transformlist to check
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//
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// Returns:
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// Boolean on whether or not a matrix transform was found
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svgedit.math.hasMatrixTransform = function(tlist) {
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if(!tlist) return false;
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var num = tlist.numberOfItems;
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while (num--) {
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var xform = tlist.getItem(num);
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if (xform.type == 1 && !svgedit.math.isIdentity(xform.matrix)) return true;
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}
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return false;
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};
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// Function: svgedit.math.transformBox
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// Transforms a rectangle based on the given matrix
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//
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// Parameters:
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// l - Float with the box's left coordinate
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// t - Float with the box's top coordinate
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// w - Float with the box width
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// h - Float with the box height
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// m - Matrix object to transform the box by
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//
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// Returns:
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// An object with the following values:
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// * tl - The top left coordinate (x,y object)
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// * tr - The top right coordinate (x,y object)
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// * bl - The bottom left coordinate (x,y object)
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// * br - The bottom right coordinate (x,y object)
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// * aabox - Object with the following values:
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// * Float with the axis-aligned x coordinate
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// * Float with the axis-aligned y coordinate
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// * Float with the axis-aligned width coordinate
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// * Float with the axis-aligned height coordinate
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svgedit.math.transformBox = function(l, t, w, h, m) {
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var topleft = {x:l,y:t},
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topright = {x:(l+w),y:t},
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botright = {x:(l+w),y:(t+h)},
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botleft = {x:l,y:(t+h)};
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var transformPoint = svgedit.math.transformPoint;
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topleft = transformPoint( topleft.x, topleft.y, m );
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var minx = topleft.x,
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maxx = topleft.x,
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miny = topleft.y,
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maxy = topleft.y;
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topright = transformPoint( topright.x, topright.y, m );
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minx = Math.min(minx, topright.x);
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maxx = Math.max(maxx, topright.x);
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miny = Math.min(miny, topright.y);
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maxy = Math.max(maxy, topright.y);
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botleft = transformPoint( botleft.x, botleft.y, m);
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minx = Math.min(minx, botleft.x);
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maxx = Math.max(maxx, botleft.x);
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miny = Math.min(miny, botleft.y);
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maxy = Math.max(maxy, botleft.y);
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botright = transformPoint( botright.x, botright.y, m );
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minx = Math.min(minx, botright.x);
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maxx = Math.max(maxx, botright.x);
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miny = Math.min(miny, botright.y);
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maxy = Math.max(maxy, botright.y);
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return {tl:topleft, tr:topright, bl:botleft, br:botright,
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aabox: {x:minx, y:miny, width:(maxx-minx), height:(maxy-miny)} };
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};
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// Function: svgedit.math.transformListToTransform
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// This returns a single matrix Transform for a given Transform List
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// (this is the equivalent of SVGTransformList.consolidate() but unlike
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// that method, this one does not modify the actual SVGTransformList)
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// This function is very liberal with its min,max arguments
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//
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// Parameters:
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// tlist - The transformlist object
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// min - Optional integer indicating start transform position
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// max - Optional integer indicating end transform position
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//
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// Returns:
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// A single matrix transform object
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svgedit.math.transformListToTransform = function(tlist, min, max) {
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if(tlist == null) {
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// Or should tlist = null have been prevented before this?
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return svg.createSVGTransformFromMatrix(svg.createSVGMatrix());
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}
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var min = min == undefined ? 0 : min;
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var max = max == undefined ? (tlist.numberOfItems-1) : max;
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min = parseInt(min);
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max = parseInt(max);
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if (min > max) { var temp = max; max = min; min = temp; }
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var m = svg.createSVGMatrix();
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for (var i = min; i <= max; ++i) {
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// if our indices are out of range, just use a harmless identity matrix
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var mtom = (i >= 0 && i < tlist.numberOfItems ?
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tlist.getItem(i).matrix :
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svg.createSVGMatrix());
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m = svgedit.math.matrixMultiply(m, mtom);
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}
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return svg.createSVGTransformFromMatrix(m);
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};
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// Function: svgedit.math.snapToAngle
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// Returns a 45 degree angle coordinate associated with the two given
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// coordinates
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//
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// Parameters:
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// x1 - First coordinate's x value
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// x2 - Second coordinate's x value
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// y1 - First coordinate's y value
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// y2 - Second coordinate's y value
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//
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// Returns:
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// Object with the following values:
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// x - The angle-snapped x value
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// y - The angle-snapped y value
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// snapangle - The angle at which to snap
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svgedit.math.snapToAngle = function(x1,y1,x2,y2) {
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var snap = Math.PI/4; // 45 degrees
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var dx = x2 - x1;
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var dy = y2 - y1;
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var angle = Math.atan2(dy,dx);
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var dist = Math.sqrt(dx * dx + dy * dy);
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var snapangle= Math.round(angle/snap)*snap;
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var x = x1 + dist*Math.cos(snapangle);
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var y = y1 + dist*Math.sin(snapangle);
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//console.log(x1,y1,x2,y2,x,y,angle)
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return {x:x, y:y, a:snapangle};
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};
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// Function: rectsIntersect
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// Check if two rectangles (BBoxes objects) intersect each other
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//
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// Paramaters:
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// r1 - The first BBox-like object
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// r2 - The second BBox-like object
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//
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// Returns:
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// Boolean that's true if rectangles intersect
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svgedit.math.rectsIntersect = function(r1, r2) {
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return r2.x < (r1.x+r1.width) &&
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(r2.x+r2.width) > r1.x &&
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r2.y < (r1.y+r1.height) &&
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(r2.y+r2.height) > r1.y;
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};
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})(); |