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<!DOCTYPE html> <html> <head> <title>Shape path calculation</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <meta name="viewport" content="width=device-width, target-densitydpi=160dpi, initial-scale=1.0; maximum-scale=1.0; user-scalable=0;"> <link rel="stylesheet" media="all" href="../../docco.css" /> </head> <body> <div id="container"> <div id="background"></div> <ul id="jump_to"> <li> <a class="large" href="javascript:void(0);">Jump To …</a> <a class="small" href="javascript:void(0);">+</a> <div id="jump_wrapper"> <div id="jump_page_wrapper"> <div id="jump_page"> <a class="source" href="../core/animationloop.html"> ./source/core/animationloop.js </a> <a class="source" href="../core/document.html"> ./source/core/document.js </a> <a class="source" href="../core/events.html"> ./source/core/events.js </a> <a class="source" href="../core/init.html"> ./source/core/init.js </a> <a class="source" href="../core/library.html"> ./source/core/library.js </a> <a 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class="source" href="styles.html"> ./source/mixin/styles.js </a> <a class="source" href="tween.html"> ./source/mixin/tween.js </a> </div> </div> </li> </ul> <ul class="sections"> <li id="section-1"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-1">§</a> </div> <h1 id="shape-path-calculation">Shape path calculation</h1> The function, and its helper functions, translates SVG path data string - example: <code>M0,0H100V100H-100V-100z</code> - into data which can be used to construct the a Path2D object which can be consumed by the canvasRenderingContext2D engine’s <code>fill</code>, <code>stroke</code> and <code>isPointInPath</code> functions <ul> <li>TODO: this file is in the wrong place: it’s not a mixin; it exports a single function currently imported only by ./factory.shape.js; and it duplicates Vector code</li> <li>Code has been separated out into its own file because it is a potential candidate for hiving off to a web worker</li> </ul> </div> </li> <li id="section-2"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-2">§</a> </div> <h4 id="imports">Imports</h4> No imports required </div> </li> <li id="section-3"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-3">§</a> </div> <h4 id="export-function">Export function</h4> </div> <div class="content"><div class='highlight'><pre>export default function (d, scale, start, useAsPath, precision) {</pre></div></div> </li> <li id="section-4"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-4">§</a> </div> Setup local variables </div> <div class="content"><div class='highlight'><pre> let points = [], myData = [], command = '', localPath = '', units = [], unitLengths = [], unitPartials = [], mySet = d.match(/([A-Za-z][0-9. ,\-]*)/g), myLen = 0, i, iz, j, jz; let returnObject = {}; let curX = 0, curY = 0, oldX = 0, oldY = 0; let xPoints = [], yPoints = [], progression = [], positions = []; let reflectX = 0, reflectY = 0;</pre></div></div> </li> <li id="section-5"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-5">§</a> </div> Local function to populate the temporary myData array with data for every path partial </div> <div class="content"><div class='highlight'><pre> let buildArrays = (thesePoints) => { myData.push({ c: command.toLowerCase(), p: thesePoints || null, x: oldX, y: oldY, cx: curX, cy: curY, rx: reflectX, ry: reflectY }); if (!useAsPath) { xPoints.push(curX); yPoints.push(curY); } oldX = curX; oldY = curY; };</pre></div></div> </li> <li id="section-6"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-6">§</a> </div> The purpose of this loop is to <ol> <li>convert all point values from strings to floats</li> <li>scale every value</li> <li>relativize every value to the last stated cursor position</li> <li>populate the temporary myData array with data which can be used for all subsequent calculations</li> </ol> </div> <div class="content"><div class='highlight'><pre> for (i = 0, iz = mySet.length; i < iz; i++) { command = mySet[i][0]; points = mySet[i].match(/(-?[0-9.]+\b)/g) || []; if (points.length) { for (j = 0, jz = points.length; j < jz; j++) { points[j] = parseFloat(points[j]); } if (i === 0) { if (command === 'M') { oldX = (points[0] * scale) - start.x; oldY = (points[1] * scale) - start.y; command = 'm'; } } else { oldX = curX; oldY = curY; } switch (command) { case 'H': for (j = 0, jz = points.length; j < jz; j++) { points[j] = (points[j] * scale) - oldX; curX += points[j]; reflectX = reflectY = 0; buildArrays(points.slice(j, j + 1)); } break; case 'V': for (j = 0, jz = points.length; j < jz; j++) { points[j] = (points[j] * scale) - oldY; curY += points[j]; reflectX = reflectY = 0; buildArrays(points.slice(j, j + 1)); } break; case 'M': for (j = 0, jz = points.length; j < jz; j += 2) { points[j] = (points[j] * scale) - oldX; points[j + 1] = (points[j + 1] * scale) - oldY; curX += points[j]; curY += points[j + 1]; reflectX = reflectY = 0; buildArrays(points.slice(j, j + 2)); } break; case 'L': case 'T': for (j = 0, jz = points.length; j < jz; j += 2) { points[j] = (points[j] * scale) - oldX; points[j + 1] = (points[j + 1] * scale) - oldY; curX += points[j]; curY += points[j + 1]; if (command === 'T') { reflectX = points[j] + oldX; reflectY = points[j + 1] + oldY; } else { reflectX = reflectY = 0; } buildArrays(points.slice(j, j + 2)); } break; case 'Q': case 'S': for (j = 0, jz = points.length; j < jz; j += 4) { points[j] = (points[j] * scale) - oldX; points[j + 1] = (points[j + 1] * scale) - oldY; points[j + 2] = (points[j + 2] * scale) - oldX; points[j + 3] = (points[j + 3] * scale) - oldY; curX += points[j + 2]; curY += points[j + 3]; reflectX = points[j] + oldX; reflectY = points[j + 1] + oldY; buildArrays(points.slice(j, j + 4)); } break; case 'C': for (j = 0, jz = points.length; j < jz; j += 6) { points[j] = (points[j] * scale) - oldX; points[j + 1] = (points[j + 1] * scale) - oldY; points[j + 2] = (points[j + 2] * scale) - oldX; points[j + 3] = (points[j + 3] * scale) - oldY; points[j + 4] = (points[j + 4] * scale) - oldX; points[j + 5] = (points[j + 5] * scale) - oldY; curX += points[j + 4]; curY += points[j + 5]; reflectX = points[j + 2] + oldX; reflectY = points[j + 3] + oldY; buildArrays(points.slice(j, j + 6)); } break; case 'A': for (j = 0, jz = points.length; j < jz; j += 7) { points[j + 5] = (points[j + 5] * scale) - oldX; points[j + 6] = (points[j + 6] * scale) - oldY; curX += points[j + 5]; curY += points[j + 6]; reflectX = reflectY = 0; buildArrays(points.slice(j, j + 7)); } break; case 'h': for (j = 0, jz = points.length; j < jz; j++) { points[j] *= scale; curX += points[j]; reflectX = reflectY = 0; buildArrays(points.slice(j, j + 1)); } break; case 'v': for (j = 0, jz = points.length; j < jz; j++) { points[j] *= scale; curY += points[j]; reflectX = reflectY = 0; buildArrays(points.slice(j, j + 1)); } break; case 'm': case 'l': case 't': for (j = 0, jz = points.length; j < jz; j += 2) { points[j] *= scale; points[j + 1] *= scale; curX += points[j]; curY += points[j + 1]; if (command === 't') { reflectX = points[j] + oldX; reflectY = points[j + 1] + oldY; } else { reflectX = reflectY = 0; } buildArrays(points.slice(j, j + 2)); } break; case 'q': case 's': for (j = 0, jz = points.length; j < jz; j += 4) { points[j] *= scale; points[j + 1] *= scale; points[j + 2] *= scale; points[j + 3] *= scale; curX += points[j + 2]; curY += points[j + 3]; reflectX = points[j] + oldX; reflectY = points[j + 1] + oldY; buildArrays(points.slice(j, j + 4)); } break; case 'c': for (j = 0, jz = points.length; j < jz; j += 6) { points[j] *= scale; points[j + 1] *= scale; points[j + 2] *= scale; points[j + 3] *= scale; points[j + 4] *= scale; points[j + 5] *= scale; curX += points[j + 4]; curY += points[j + 5]; reflectX = points[j + 2] + oldX; reflectY = points[j + 3] + oldY; buildArrays(points.slice(j, j + 6)); } break; case 'a': for (j = 0, jz = points.length; j < jz; j += 7) { points[j] *= scale; points[j + 1] *= scale; points[j + 5] *= scale; points[j + 6] *= scale; curX += points[j + 5]; curY += points[j + 6]; reflectX = reflectY = 0; buildArrays(points.slice(j, j + 7)); } break; } } else { reflectX = reflectY = 0; buildArrays(); } }</pre></div></div> </li> <li id="section-7"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-7">§</a> </div> This loop builds the local path string </div> <div class="content"><div class='highlight'><pre> for (i = 0, iz = myData.length; i < iz; i++) { let curData = myData[i], points = curData.p; if (points) { for (j = 0, jz = points.length; j < jz; j++) { points[j] = points[j].toFixed(1); } localPath += `${curData.c}${curData.p.join()}`; for (j = 0, jz = points.length; j < jz; j++) { points[j] = parseFloat(points[j]); } } else localPath += `${curData.c}`; } returnObject.localPath = localPath;</pre></div></div> </li> <li id="section-8"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-8">§</a> </div> Calculates unit lengths and sum of lengths, alongside obtaining data to build a more accurate bounding box </div> <div class="content"><div class='highlight'><pre> if (useAsPath) {</pre></div></div> </li> <li id="section-9"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-9">§</a> </div> Request a vector - used for reflection points </div> <div class="content"><div class='highlight'><pre> let v = vector;</pre></div></div> </li> <li id="section-10"> <div class="annotation"> <div class="sswrap "> <a class="ss" href="#section-10">§</a> </div> This loop calculates this.units array data <ul> <li>because the lengths calculations requires absolute coordinates</li> <li>and TtSs path units use reflective coordinates</li> </ul> </div> <div class="content"><div class='highlight'><pre> for (i = 0, iz = myData.length; i < iz; i++) { let curData = myData[i], prevData = (i > 0) ? myData[i - 1] : false; let {c, p, x, y, cx, cy, rx, ry} = curData; if (p) { switch (c) { case 'h' : units[i] = ['linear', x, y, p[0] + x, y]; break; case 'v' : units[i] = ['linear', x, y, x, p[0] + y]; break; case 'm' : units[i] = ['move', x, y]; break; case 'l' : units[i] = ['linear', x, y, p[0] + x, p[1] + y]; break; case 't' : if (prevData && (prevData.rx || prevData.ry)) { setVector(v, prevData.rx - cx, prevData.ry - cy); rotateVector(v, 180); units[i] = ['quadratic', x, y, v.x + cx, v.y + cy, p[0] + x, p[1] + y]; } else units[i] = ['quadratic', x, y, x, y, p[0] + x, p[1] + y]; break; case 'q' : units[i] = ['quadratic', x, y, p[0] + x, p[1] + y, p[2] + x, p[3] + y]; break; case 's' : if (prevData && (prevData.rx || prevData.ry)) { setVector(v, prevData.rx - cx, prevData.ry - cy); rotateVector(v, 180); units[i] = ['bezier', x, y, v.x + cx, v.y + cy, p[0] + x, p[1] + y, p[2] + x, p[3] + y]; } else units[i] = ['bezier', x, y, x, y, p[0] + x, p[1] + y, p[2] + x, p[3] + y]; break; case 'c' : units[i] = ['bezier', x, y, p[0] + x, p[1] + y, p[2] + x, p[3] + y, p[4] + x, p[5] + y]; break; case 'a' : units[i] = ['linear', x, y, p[5] + x, p[6] + y]; break; case 'z' : if (isNaN(x)) x = 0; if (isNaN(y)) y = 0; units[i] = ['close', x, y]; break; default : if (isNaN(x)) x = 0; if (isNaN(y)) y = 0; units[i] = ['unknown', x, y]; } } else units[i] = [`no-points-${c}`, x, y]; } returnObject.units = units; for (i = 0, iz = units.length; i < iz; i++) { let [spec, ...data] = units[i], results; switch (spec) { case 'linear' : case 'quadratic' : case 'bezier' : results = getShapeUnitMetaData(spec, precision, data); unitLengths[i] = results.length; xPoints = xPoints.concat(results.xPoints); yPoints = yPoints.concat(results.yPoints); progression.push(results.progression); positions.push(results.positions); break; default : unitLengths[i] = 0; } } myLen = unitLengths.<span c