scrawl-canvas
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Responsive, interactive and more accessible HTML5 canvas elements. Scrawl-canvas is a JavaScript library designed to make using the HTML5 canvas element easier, and more fun
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JavaScript
// # Spiral factory
// A factory for generating spiral shape-based entitys
// #### Imports
import { constructors } from '../core/library.js';
import { doCreate, mergeOver, Ωempty } from '../helper/utilities.js';
import { releaseArray, requestArray } from '../helper/array-pool.js';
import baseMix from '../mixin/base.js';
import shapeMix from '../mixin/shape-basic.js';
// Shared constants
import { _floor, ENTITY, ZERO_PATH } from '../helper/shared-vars.js';
// Local constants
const SPIRAL = 'spiral',
T_SPIRAL = 'Spiral';
const FIRST_TURN = [
[0.043, 0, 0.082, -0.035, 0.088, -0.088],
[0.007, -0.057, -0.024, -0.121, -0.088, -0.162],
[-0.07, -0.045, -0.169, -0.054, -0.265, -0.015],
[-0.106, 0.043, -0.194, 0.138, -0.235, 0.265],
[-0.044, 0.139, -0.026, 0.3, 0.058, 0.442],
[0.091, 0.153, 0.25, 0.267, 0.442, 0.308],
[0.206, 0.044, 0.431, -0.001, 0.619, -0.131],
[0.2, -0.139, 0.34, -0.361, 0.381, -0.619]
];
const SUBSEQUENT_TURNS = [
[0, -0.27, -0.11, -0.52, -0.29, -0.71],
[-0.19, -0.19, -0.44, -0.29, -0.71, -0.29],
[-0.27, 0, -0.52, 0.11, -0.71, 0.29],
[-0.19, 0.19, -0.29, 0.44, -0.29, 0.71],
[0, 0.27, 0.11, 0.52, 0.29, 0.71],
[0.19, 0.19, 0.44, 0.29, 0.71, 0.29],
[0.27, 0, 0.52, -0.11, 0.71, -0.29],
[0.19, -0.19, 0.29, -0.44, 0.29, -0.71]
];
// #### Spiral constructor
const Spiral = function (items = Ωempty) {
this.shapeInit(items);
return this;
};
// #### Spiral prototype
const P = Spiral.prototype = doCreate();
P.type = T_SPIRAL;
P.lib = ENTITY;
P.isArtefact = true;
P.isAsset = false;
// #### Mixins
baseMix(P);
shapeMix(P);
// #### Spiral attributes
const defaultAttributes = {
loops: 1,
loopIncrement: 1,
drawFromLoop: 0,
};
P.defs = mergeOver(P.defs, defaultAttributes);
// #### Packet management
// No additional packet functionality required
// #### Clone management
// No additional clone functionality required
// #### Kill management
// No additional kill functionality required
// #### Get, Set, deltaSet
const S = P.setters,
D = P.deltaSetters;
// __loops__
S.loops = function (item) {
this.loops = item;
this.updateDirty();
};
D.loops = function (item) {
this.loops += item;
this.updateDirty();
};
// __loopIncrement__
S.loopIncrement = function (item) {
this.loopIncrement = item;
this.updateDirty();
};
D.loopIncrement = function (item) {
this.loopIncrement += item;
this.updateDirty();
};
// __drawFromLoop__
S.drawFromLoop = function (item) {
this.drawFromLoop = _floor(item);
this.updateDirty();
};
D.drawFromLoop = function (item) {
this.drawFromLoop = _floor(this.drawFromLoop + item);
this.updateDirty();
};
// #### Prototype functions
// `cleanSpecies` - internal helper function - called by `prepareStamp`
P.cleanSpecies = function () {
this.dirtySpecies = false;
this.pathDefinition = this.makeSpiralPath();
};
// `makeSpiralPath` - internal helper function - called by `cleanSpecies`
P.makeSpiralPath = function () {
const loops = _floor(this.loops),
loopIncrement = this.loopIncrement,
drawFromLoop = _floor(this.drawFromLoop),
currentTurn = requestArray();
let x1, y1, x2, y2, x3, y3,
sx1, sy1, sx2, sy2, sx3, sy3;
for (let i = 0, iz = FIRST_TURN.length; i < iz; i++) {
[x1, y1, x2, y2, x3, y3] = FIRST_TURN[i];
currentTurn.push([x1 * loopIncrement, y1 * loopIncrement, x2 * loopIncrement, y2 * loopIncrement, x3 * loopIncrement, y3 * loopIncrement]);
}
let path = ZERO_PATH;
for (let j = 0; j < loops; j++) {
for (let i = 0, iz = currentTurn.length; i < iz; i++) {
[x1, y1, x2, y2, x3, y3] = currentTurn[i];
if (j >= drawFromLoop) path += `c${x1},${y1} ${x2},${y2} ${x3},${y3}`;
[sx1, sy1, sx2, sy2, sx3, sy3] = SUBSEQUENT_TURNS[i];
currentTurn[i] = [x1 + (sx1 * loopIncrement), y1 + (sy1 * loopIncrement), x2 + (sx2 * loopIncrement), y2 + (sy2 * loopIncrement), x3 + (sx3 * loopIncrement), y3 + (sy3 * loopIncrement)];
}
}
releaseArray(currentTurn);
return path;
};
P.calculateLocalPathAdditionalActions = function () {
const [x, y] = this.localBox,
scale = this.scale;
this.pathDefinition = this.pathDefinition.replace(ZERO_PATH, `m${-x / scale},${-y / scale}`);
this.pathCalculatedOnce = false;
// ALWAYS, when invoking `calculateLocalPath` from `calculateLocalPathAdditionalActions`, include the second argument, set to `true`! Failure to do this leads to an infinite loop which will make your machine weep.
// + We need to recalculate the local path to take into account the offset required to put the Spiral entity's start coordinates at the top-left of the local box, and to recalculate the data used by other artefacts to place themselves on, or move along, its path.
this.calculateLocalPath(this.pathDefinition, true);
};
// #### Factories
// ##### makeSpiral
// A spiral drawn from an inner-radius outwards by a given number of loops, with the distance between each loop determined by a given increment. Accepts argument with attributes:
// + __loops__ (required) - positive float Number representing the number of times the Shape line will wind arount the Shape's center point
// + __loopIncrement__ - float Number representative of the distance between successive loops; negative values have the effect of rotating the spiral 180 degrees
// + __drawFromLoop__ - positive integer Number representing the loop on which the spiral starts to be drawn
//
// ```
// scrawl.makeSpiral({
//
// name: 'mySpiral',
//
// strokeStyle: 'darkgreen',
// method: 'draw',
//
// startX: 50,
// startY: 100,
//
// loops: 5,
// loopIncrement: 0.8,
// drawFromLoop: 1,
// });
// ```
export const makeSpiral = function (items) {
if (!items) return false;
items.species = SPIRAL;
return new Spiral(items);
};
constructors.Spiral = Spiral;