scrawl-canvas/source/factory/star.js

Version 8.9.4 - 19 Nov 2022

// # Star factory
// A factory for generating star shape-based entitys
//
// Path-defined entitys represent a diverse range of shapes rendered onto a DOM <canvas> element using the Canvas API's [Path2D interface](https://developer.mozilla.org/en-US/docs/Web/API/Path2D). They use the [shapeBasic](../mixin/shapeBasic.html) and [shapePathCalculation](../mixin/shapePathCalculation.html) (some also use [shapeCurve](../mixin/shapeCurve.html)) mixins to define much of their functionality.
// 
// All path-defined entitys can be positioned, cloned, filtered etc:
// + Positioning functionality for the entity is supplied by the __position__ mixin, while rendering functionality comes from the __entity__ mixin. 
// + Dimensions, however, have little meaning for path-defined entitys - their width and height are determined by their SVG path data Strings; use `scale` instead.
// + Path-defined entitys can use CSS color Strings for their fillStyle and strokeStyle values, alongside __Gradient__, __RadialGradient__, __Color__ and __Pattern__ objects. 
// + They will also accept __Filter__ objects.
// + They can use __Anchor__ objects for user navigation. 
// + They can be rendered to the canvas by including them in a __Cell__ object's __Group__. 
// + They can be __animated__ directly, or using delta animation, or act as the target for __Tween__ animations.
// + Path-defined entitys can be cloned, and killed.


// #### Using path-defined entitys as Scrawl-canvas paths
// A path is a track - straight, or curved, or as complex as required - placed across a container which artefacts can use as a source of their positioning data. We can animate an artifact to move along the path:
// + To enable a path-defined entity to be used as a path by other artefacts, set its `useAsPath` flag to `true`.
// + The artefact can then set its `path` attribute to the path-defined entity's name-String (or the entity itself), and set its `lockTo` Array values to `"path"`.
// + We position the artefact by setting its `pathPosition` attribute to a float Number value between `0.0 - 1.0`, with `0` being the start of the path, and `1` being its end.
// + Path-defined entitys can use other path-defined entitys as a path.
// + Phrase entitys can use a path to position their text block; they can also use a path to position each letter individually along the path.
// + Artefacts (and letters) can be rotated so that they match the rotation at that point along the path - ___tangential rotation___ by setting their `addPathRotation` flag to `true`.
// + Animate an artefact along the path by either using the artefact's `delta` object, or triggering a Tween to perform the movement.


// #### Demos:
// + [Canvas-011](../../demo/canvas-011.html) - Shape entity (make, clone, method); drag and drop shape entitys
// + [Canvas-012](../../demo/canvas-012.html) - Shape entity position; shape entity as a path for other artefacts to follow
// + [Canvas-013](../../demo/canvas-013.html) - Path-defined entitys: oval, rectangle, line, quadratic, bezier, tetragon, polygon, star, spiral
// + [Canvas-014](../../demo/canvas-014.html) - Line, quadratic and bezier entitys - control lock alternatives
// + [Canvas-018](../../demo/canvas-018.html) - Phrase entity - text along a path
// + [Canvas-024](../../demo/canvas-024.html) - Loom entity functionality
// + [Canvas-030](../../demo/canvas-030.html) - Polyline entity functionality
// + [Canvas-038](../../demo/canvas-038.html) - Responsive Shape-based entitys
// + [DOM-015](../../demo/dom-015.html) - Use stacked DOM artefact corners as pivot points
// + [Packets-002](../../demo/packets-002.html) - Scrawl-canvas packets - save and load a range of different entitys


// #### Imports
import { constructors } from '../core/library.js';
import { mergeOver, Ωempty } from '../core/utilities.js';

import { requestVector, releaseVector } from './vector.js';

import baseMix from '../mixin/base.js';
import shapeMix from '../mixin/shapeBasic.js';


// #### Star constructor
const Star = function (items = Ωempty) {

    this.shapeInit(items);
    return this;
};


// #### Star prototype
let P = Star.prototype = Object.create(Object.prototype);
P.type = 'Star';
P.lib = 'entity';
P.isArtefact = true;
P.isAsset = false;


// #### Mixins
// + [base](../mixin/base.html)
// + [shapeBasic](../mixin/shapeBasic.html)
P = baseMix(P);
P = shapeMix(P);


// #### Star attributes
// + Attributes defined in the [base mixin](../mixin/base.html): __name__.
// + Attributes defined in the [position mixin](../mixin/position.html): __group, visibility, order, calculateOrder, stampOrder, start, _startX_, _startY_, handle, _handleX_, _handleY_, offset, _offsetX_, _offsetY_, dimensions, _width_, _height_, pivoted, mimicked, lockTo, _lockXTo_, _lockYTo_, scale, roll, noUserInteraction, noPositionDependencies, noCanvasEngineUpdates, noFilters, noPathUpdates, purge, bringToFrontOnDrag__.
// + Attributes defined in the [delta mixin](../mixin/delta.html): __delta, noDeltaUpdates__.
// + Attributes defined in the [pivot mixin](../mixin/pivot.html): __pivot, pivotCorner, addPivotHandle, addPivotOffset, addPivotRotation__.
// + Attributes defined in the [mimic mixin](../mixin/mimic.html): __mimic, useMimicDimensions, useMimicScale, useMimicStart, useMimicHandle, useMimicOffset, useMimicRotation, useMimicFlip, addOwnDimensionsToMimic, addOwnScaleToMimic, addOwnStartToMimic, addOwnHandleToMimic, addOwnOffsetToMimic, addOwnRotationToMimic__.
// + Attributes defined in the [path mixin](../mixin/path.html): __path, pathPosition, addPathHandle, addPathOffset, addPathRotation, constantPathSpeed__.
// + Attributes defined in the [entity mixin](../mixin/entity.html): __method, pathObject, winding, flipReverse, flipUpend, scaleOutline, lockFillStyleToEntity, lockStrokeStyleToEntity, onEnter, onLeave, onDown, onUp, _fillStyle, strokeStyle, globalAlpha, globalCompositeOperation, lineWidth, lineCap, lineJoin, lineDash, lineDashOffset, miterLimit, shadowOffsetX, shadowOffsetY, shadowBlur, shadowColor, filter___.
// + Attributes defined in the [anchor mixin](../mixin/anchor.html): __anchor__.
// + Attributes defined in the [filter mixin](../mixin/filter.html): __filters, isStencil__.
// + Attributes defined in the [shapeBasic mixin](../mixin/shapeBasic.html): __species, useAsPath, precision, pathDefinition, showBoundingBox, boundingBoxColor, minimumBoundingBoxDimensions, constantPathSpeed__.
let defaultAttributes = {

    radius1: 0,
    radius2: 0,
    points: 0,
    twist: 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
let S = P.setters,
    D = P.deltaSetters;

// __radius1__, __radius2__
S.radius1 = function (item) {

    this.radius1 = item;
    this.updateDirty();
};
D.radius1 = function (item) {

    this.radius1 += item;
    this.updateDirty();
};
S.radius2 = function (item) {

    this.radius2 = item;
    this.updateDirty();
};
D.radius2 = function (item) {

    this.radius2 += item;
    this.updateDirty();
};

// __points__
S.points = function (item) {

    this.points = item;
    this.updateDirty();
};
D.points = function (item) {

    this.points += item;
    this.updateDirty();
};

// __twist__
S.twist = function (item) {

    this.twist = item;
    this.updateDirty();
};
D.twist = function (item) {

    this.twist += item;
    this.updateDirty();
};


// #### Prototype functions

// `cleanSpecies` - internal helper function - called by `prepareStamp`
P.cleanSpecies = function () {

    this.dirtySpecies = false;

    let p = 'M0,0';
    p = this.makeStarPath();

    this.pathDefinition = p;
};


// `makeStarPath` - internal helper function - called by `cleanSpecies`
P.makeStarPath = function () {

    let points = this.points,
        twist = this.twist,
        radius1 = this.radius1,
        radius2 = this.radius2,
        turn = 360 / points,
        xPts = [],
        currentX, currentY, x, y,
        myMin, myXoffset, myYoffset, i,
        myPath = '';

    if (radius1.substring || radius2.substring) {

        // let here = this.getHere();

        // radius1 = (radius1.substring) ? (parseFloat(radius1) / 100) * here.w : radius1;
        // radius2 = (radius2.substring) ? (parseFloat(radius2) / 100) * here.w : radius2;

        let host = this.getHost();

        if (host) {

            let [hW, hH] = host.currentDimensions;

            radius1 = (radius1.substring) ? (parseFloat(radius1) / 100) * hW : radius1;
            radius2 = (radius2.substring) ? (parseFloat(radius2) / 100) * hW : radius2;
        } 
    }

    let v1 = requestVector({x: 0, y: -radius1}),
        v2 = requestVector({x: 0, y: -radius2});

    currentX = v1.x;
    currentY = v1.y;

    xPts.push(currentX);

    v2.rotate(-turn/2);
    v2.rotate(twist);

    for (i = 0; i < points; i++) {

        v2.rotate(turn);

        x = parseFloat((v2.x - currentX).toFixed(1));
        currentX += x;
        xPts.push(currentX);

        y = parseFloat((v2.y - currentY).toFixed(1));
        currentY += y;

        myPath += `${x},${y} `;

        v1.rotate(turn);

        x = parseFloat((v1.x - currentX).toFixed(1));
        currentX += x;
        xPts.push(currentX);

        y = parseFloat((v1.y - currentY).toFixed(1));
        currentY += y;

        myPath += `${x},${y} `;

    }

    releaseVector(v1);
    releaseVector(v2);

    myMin = Math.min(...xPts);
    myXoffset = Math.abs(myMin).toFixed(1);

    myPath = `m${myXoffset},0l${myPath}z`;

    return myPath;
};


// #### Factories

// ##### makeStar
// Accepts argument with attributes:
// + __radius1__ (required) - the _outer_ radius representing the distance between the center of the Shape and the tips of its (acute angle) points.
// + __radius2__ (required) - the _inner_ radius representing the distance between the center of the Shape and the obtuse angle at the valley between the tips of its (acute angle) points.
// + ... where these radius values are supplied as %Strings, they are calculated as relative to the canvas/cell ___width___ value.
// + __points__ (required) - a positive integer Number representing the number of points the star will have.
// + __twist__ - a float Number representing the degrees by which the star's second radius will be rotated out of line from its first radius; the default value `0` will produce a star with all of its sides of equal length and the star's valleys falling midway between its connecting points.
// + Note that the use of _inner_ and _outer_ above is purely descriptive: `radius2` can be larger than `radius1`
//
// ```
// scrawl.makeStar({
//
//     name: '5star',
//
//     startX: 20,
//     startY: 100,
//
//     radius1: 80,
//     radius2: 50,
//
//     points: 5,
//
//     fillStyle: 'linen',
//     method: 'fillAndDraw',
// });
// ```
const makeStar = function (items) {

    if (!items) return false;
    items.species = 'star';
    return new Star(items);
};

constructors.Star = Star;


// #### Exports
export {
    makeStar,
};