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
// # Tetragon factory
// A factory for generating various straight-line tetragonal shape-based entitys
// #### Imports
import { constructors } from '../core/library.js';
import { addStrings, doCreate, mergeOver, Ωempty } from '../helper/utilities.js';
import baseMix from '../mixin/base.js';
import shapeMix from '../mixin/shape-basic.js';
// Shared constants
import { ENTITY, RADIUS_X, RADIUS_XY, RADIUS_Y, ZERO_PATH } from '../helper/shared-vars.js';
// Local constants
const T_TETRAGON = 'Tetragon',
TETRAGON = 'tetragon';
// #### Tetragon constructor
const Tetragon = function (items = Ωempty) {
this.shapeInit(items);
return this;
};
// #### Tetragon prototype
const P = Tetragon.prototype = doCreate();
P.type = T_TETRAGON;
P.lib = ENTITY;
P.isArtefact = true;
P.isAsset = false;
// #### Mixins
baseMix(P);
shapeMix(P);
// #### Tetragon attributes
const defaultAttributes = {
radiusX: 5,
radiusY: 5,
intersectX: 0.5,
intersectY: 0.5,
};
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;
S.radius = function (item) {
this.setRectHelper(item, RADIUS_XY);
};
S.radiusX = function (item) {
this.setRectHelper(item, RADIUS_X);
};
S.radiusY = function (item) {
this.setRectHelper(item, RADIUS_Y);
};
D.radius = function (item) {
this.deltaRectHelper(item, RADIUS_XY);
};
D.radiusX = function (item) {
this.deltaRectHelper(item, RADIUS_X);
};
D.radiusY = function (item) {
this.deltaRectHelper(item, RADIUS_Y);
};
S.intersectX = function (item) {
if (item.toFixed) {
this.intersectX = item;
this.updateDirty();
}
};
S.intersectY = function (item) {
if (item.toFixed) {
this.intersectY = item;
this.updateDirty();
}
};
D.intersectX = function (item) {
if (item.toFixed) {
this.intersectX += item;
this.updateDirty();
}
};
D.intersectY = function (item) {
if (item.toFixed) {
this.intersectY += item;
this.updateDirty();
}
};
// #### Prototype functions
// `setRectHelper` - internal setter helper function
P.setRectHelper = function (item, corners) {
this.updateDirty();
corners.forEach(corner => {
this[corner] = item;
}, this);
};
// `deltaRectHelper` - internal setter helper function
P.deltaRectHelper = function (item, corners) {
this.updateDirty();
corners.forEach(corner => {
this[corner] = addStrings(this[corner], item);
}, this);
};
// `cleanSpecies` - internal helper function - called by `prepareStamp`
P.cleanSpecies = function () {
this.dirtySpecies = false;
this.pathDefinition = this.makeTetragonPath();
};
// `makeTetragonPath` - internal helper function - called by `cleanSpecies`
P.makeTetragonPath = function () {
const radiusX = this.radiusX,
radiusY = this.radiusY;
let width, height;
if (radiusX.substring || radiusY.substring) {
const host = this.getHost();
if (host) {
const [hW, hH] = host.currentDimensions;
const rx = (radiusX.substring) ? (parseFloat(radiusX) / 100) * hW : radiusX,
ry = (radiusY.substring) ? (parseFloat(radiusY) / 100) * hH : radiusY;
width = rx * 2;
height = ry * 2;
}
}
else {
width = radiusX * 2;
height = radiusY * 2;
}
const port = parseFloat((width * this.intersectX).toFixed(2)),
starboard = parseFloat((width - port).toFixed(2)),
fore = parseFloat((height * this.intersectY).toFixed(2)),
aft = parseFloat((height - fore).toFixed(2));
let myData = ZERO_PATH;
myData += `l${starboard},${fore} ${-starboard},${aft} ${-port},${-aft} ${port},${-fore}z`;
return myData;
};
P.calculateLocalPathAdditionalActions = function () {
let scale = this.scale;
if (scale < 0.001) scale = 0.001;
const [x, y] = this.localBox;
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 Tetragon 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
// ##### makeTetragon
// Scrawl-canvas uses lines internally to create the Shape path.
// + The main shape of the tetragon is determined by differing radius lengths in the `x` and `y` directions, as set by the attributes __radiusX__ and __radiusY__; to set both radiuses to the same value, use ___radius___ instead.
// + The radius values can be: _absolute_ (using Number values); or _relative_ using %-String values - with the y radius representing a portion of the Cell container's height and the x radius the Cell's width.
// + The radiuses (as diameter lines) cross in the middle of the tetragon shape. We can move the position of where the intersection happens by setting a float Number value between `0.0 - 1.0` (or beyond those limits) for the __intersectX__ and __intersectY__ attributes.
// + `intersectX` (default: `0.5`) represents the point at which the `y` diameter crosses the `x` diameter, with `0` being the left end and `1` being the right end.
// + `intersectY` (default: `0.5`) represents the point at which the `x` diameter crosses the `y` diameter, with `0` being the top end and `1` being the bottom end.
//
// ```
// scrawl.makeTetragon({
//
// name: 'diamond',
//
// fillStyle: 'lightGreen',
// method: 'fillAndDraw',
//
// startX: 20,
// startY: 750,
//
// radiusX: 40,
// radiusY: 60,
// });
// ```
export const makeTetragon = function (items) {
if (!items) return false;
items.species = TETRAGON;
return new Tetragon(items);
};
constructors.Tetragon = Tetragon;