var MvCvsSprite = function(ui, asset, sourceX, sourceY, sourceWidth, sourceHeight, x, y, width, height) {

    DisplayObject.bind(this)(ui, x, y, width, height);

    this.asset = asset;

    this.sourceX = sourceX

    this.sourceY = sourceY

    this.sourceWidth = sourceWidth;

    this.sourceHeight = sourceHeight;

    this.startY = undefined;

    this.moveY = 0;

    this.onMoveThis = this.onMove.bind(this);

    this.onUpThis = this.onUp.bind(this);   

    this.onClick(() => {

        console.info('You got me!');

        window.addEventListener('mousemove', this.onMoveThis);

        window.addEventListener('mouseup',this.onUpThis);

    });

};

MvCvsSprite.prototype = Object.create(DisplayObject.prototype);

MvCvsSprite.prototype.draw = function(context, x, y, width, height) {

    context.drawImage(this.asset, this.sourceX, this.sourceY, this.sourceWidth, this.sourceHeight, x, y, width, height);

};

// wx.onTouchMove(

MvCvsSprite.prototype.onMove = function (e) {

    var canvasPos = {x:0, y:0};

    canvasPos = ui.windowToUISpace(e.clientX, e.clientY)

    if (this.startY === undefined) {

        this.startY = canvasPos.y + this.moveY;

    }

    this.moveY = this.startY - canvasPos.y;

    console.log(this.moveY);

    this.sourceY = this.moveY;

    ui.shouldReDraw = true;

}

// wx.onTouchEnd(

MvCvsSprite.prototype.onUp = function (e) {

    this.startY = undefined;

    if (this.moveY < 0) { // 到顶

        this.moveY = 0;

    } else if (this.moveY > this.asset.height - this.height) { // 到底

        this.moveY = this.asset.height - this.height;

    }

    console.log(this.moveY);

    this.sourceY = this.moveY;

    ui.shouldReDraw = true;

    window.removeEventListener('mousemove', this.onMoveThis);

    window.removeEventListener('mouseup', this.onUpThis);

};