Egret 贝塞尔曲线

/**
 * @copyright www.egret.com
 * @author yjtx
 * @desc 贝塞尔曲线示例。
 *      拖动舞台上圆点，可以查看贝塞尔曲线不同的显示。
 */
module game {
    export class bezierCurve extends egret.DisplayObjectContainer {

        private _shape: egret.Shape;

        constructor() {
            super();

            this.addEventListener(egret.Event.ADDED_TO_STAGE, this.onAddToStage, this);
        }

        private onAddToStage(event: egret.Event) {
            this._shape = new egret.Shape();
            this.addChild(this._shape);

            this.init();

            this.initGraphics();
        }

        //初始化赋值
        private initGraphics(): void {
            var shape: egret.Shape = this._shape;

            /*** 本示例关键代码段开始 ***/
            shape.graphics.lineStyle(3, 0xff0ff0);
            shape.graphics.moveTo(140, 400);
            shape.graphics.curveTo(340, 200, 480, 500);
            /*** 本示例关键代码段结束 ***/
        }

        private resetCure(): void {
            var shape: egret.Shape = this._shape;
            /*** 本示例关键代码段开始 ***/
            shape.graphics.clear();
            shape.graphics.lineStyle(3, 0xff0ff0);
            shape.graphics.moveTo(this._startShape.x, this._startShape.y);
            shape.graphics.curveTo(this._control.x, this._control.y, this._anchor.x, this._anchor.y);
            /*** 本示例关键代码段结束 ***/
        }

        private _startShape: egret.Shape;
        private _control: egret.Shape;
        private _anchor: egret.Shape;

        private init(): void {
            this._startShape = this.initShape(140, 400, 0xffff00);
            this._control = this.initShape(340, 200, 0xff0000);
            this._anchor = this.initShape(480, 500, 0x000ff0);
        }

        private initShape(x: number, y: number, color: number): egret.Shape {
            var shape: egret.Shape = new egret.Shape();
            shape.graphics.beginFill(color);
            shape.graphics.drawCircle(0, 0, 20);
            shape.graphics.endFill();
            this.addChild(shape);
            shape.x = x;
            shape.y = y;
            shape.touchEnabled = true;
            shape.addEventListener(egret.TouchEvent.TOUCH_BEGIN, this.onBeginHandler, this);
            return shape;
        }

        private drapShape: egret.Shape;
        private onBeginHandler(e: egret.TouchEvent): void {
            e.stopImmediatePropagation();

            this.drapShape = <egret.Shape>e.currentTarget;
            this.drapShape.removeEventListener(egret.TouchEvent.TOUCH_BEGIN, this.onBeginHandler, this);

            this.drapShape.touchEnabled = false;

            this.stage.addEventListener(egret.TouchEvent.TOUCH_MOVE, this.onMoveHandler, this);
            this.stage.addEventListener(egret.TouchEvent.TOUCH_END, this.onEndHandler, this);
        }

        private onMoveHandler(e: egret.TouchEvent): void {
            this.drapShape.x = e.stageX;
            this.drapShape.y = e.stageY;

            this.resetCure();
        }

        private onEndHandler(e: egret.TouchEvent): void {
            this.stage.removeEventListener(egret.TouchEvent.TOUCH_MOVE, this.onMoveHandler, this);
            this.stage.removeEventListener(egret.TouchEvent.TOUCH_END, this.onEndHandler, this);

            this.drapShape.touchEnabled = true;;

            this.drapShape.addEventListener(egret.TouchEvent.TOUCH_BEGIN, this.onBeginHandler, this);
        }
    }
}

参考地址：https://developer.egret.com/cn/example/egret2d/index.html#030-graph-bezier；

来源：https://blog.csdn.net/Fanstasic/article/details/102731590