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52 lines
1.4 KiB
52 lines
1.4 KiB
5 years ago
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export function point(that, x, y) {
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that._context.bezierCurveTo(
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(2 * that._x0 + that._x1) / 3,
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(2 * that._y0 + that._y1) / 3,
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(that._x0 + 2 * that._x1) / 3,
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(that._y0 + 2 * that._y1) / 3,
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(that._x0 + 4 * that._x1 + x) / 6,
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(that._y0 + 4 * that._y1 + y) / 6
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);
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}
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export function Basis(context) {
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this._context = context;
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}
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Basis.prototype = {
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areaStart: function() {
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this._line = 0;
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},
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areaEnd: function() {
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this._line = NaN;
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},
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lineStart: function() {
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this._x0 = this._x1 =
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this._y0 = this._y1 = NaN;
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this._point = 0;
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},
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lineEnd: function() {
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switch (this._point) {
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case 3: point(this, this._x1, this._y1); // proceed
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case 2: this._context.lineTo(this._x1, this._y1); break;
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}
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if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
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this._line = 1 - this._line;
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},
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point: function(x, y) {
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x = +x, y = +y;
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switch (this._point) {
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case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
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case 1: this._point = 2; break;
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case 2: this._point = 3; this._context.lineTo((5 * this._x0 + this._x1) / 6, (5 * this._y0 + this._y1) / 6); // proceed
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default: point(this, x, y); break;
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}
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this._x0 = this._x1, this._x1 = x;
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this._y0 = this._y1, this._y1 = y;
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}
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};
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export default function(context) {
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return new Basis(context);
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}
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