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pixi.js / src / core / display / DisplayObject.js
@Matt Karl Matt Karl on 13 Sep 2016 16 KB Disallow the use of `var`
let EventEmitter = require('eventemitter3'),
    CONST = require('../const'),
    TransformStatic = require('./TransformStatic'),
    Transform = require('./Transform'),
    Bounds = require('./Bounds'),
    math = require('../math');//,
    //_tempDisplayObjectParent = new DisplayObject();

/**
 * The base class for all objects that are rendered on the screen.
 * This is an abstract class and should not be used on its own rather it should be extended.
 *
 * @class
 * @extends EventEmitter
 * @mixes PIXI.interaction.interactiveTarget
 * @memberof PIXI
 */
class DisplayObject extends EventEmitter {
    constructor()
    {
        super();

        let TransformClass = CONST.TRANSFORM_MODE.DEFAULT === CONST.TRANSFORM_MODE.STATIC ? TransformStatic : Transform;

        this.tempDisplayObjectParent = null;
        
        //TODO: need to create Transform from factory
        /**
         * World transform and local transform of this object.
         * This will be reworked in v4.1, please do not use it yet unless you know what are you doing!
         *
         * @member {PIXI.TransformBase}
         */
        this.transform =  new TransformClass();

        /**
         * The opacity of the object.
         *
         * @member {number}
         */
        this.alpha = 1;

        /**
         * The visibility of the object. If false the object will not be drawn, and
         * the updateTransform function will not be called.
         *
         * @member {boolean}
         */
        this.visible = true;

        /**
         * Can this object be rendered, if false the object will not be drawn but the updateTransform
         * methods will still be called.
         *
         * @member {boolean}
         */
        this.renderable = true;

        /**
         * The display object container that contains this display object.
         *
         * @member {PIXI.Container}
         * @readonly
         */
        this.parent = null;

        /**
         * The multiplied alpha of the displayObject
         *
         * @member {number}
         * @readonly
         */
        this.worldAlpha = 1;

        /**
         * The area the filter is applied to. This is used as more of an optimisation
         * rather than figuring out the dimensions of the displayObject each frame you can set this rectangle
         *
         * Also works as an interaction mask
         *
         * @member {PIXI.Rectangle}
         */
        this.filterArea = null;

        this._filters = null;
        this._enabledFilters = null;

        /**
         * The bounds object, this is used to calculate and store the bounds of the displayObject
         *
         * @member {PIXI.Rectangle}
         * @private
         */
        this._bounds = new Bounds();
        this._boundsID = 0;
        this._lastBoundsID = -1;
        this._boundsRect = null;
        this._localBoundsRect = null;

        /**
         * The original, cached mask of the object
         *
         * @member {PIXI.Rectangle}
         * @private
         */
        this._mask = null;

    }

    get _tempDisplayObjectParent() {
        if (this.tempDisplayObjectParent === null) {
            this.tempDisplayObjectParent = new DisplayObject();
        }    
        return this.tempDisplayObjectParent;        
    }

    /*
     * Updates the object transform for rendering
     *
     * TODO - Optimization pass!
     */
    updateTransform()
    {
        this.transform.updateTransform(this.parent.transform);
        // multiply the alphas..
        this.worldAlpha = this.alpha * this.parent.worldAlpha;

        this._bounds.updateID++;
    }

    /**
     * recursively updates transform of all objects from the root to this one
     * internal function for toLocal()
     */
    _recursivePostUpdateTransform()
    {
        if (this.parent)
        {
            this.parent._recursivePostUpdateTransform();
            this.transform.updateTransform(this.parent.transform);
        }
        else
        {
            this.transform.updateTransform(this._tempDisplayObjectParent.transform);
        }
    }

    /**
     *
     *
     * Retrieves the bounds of the displayObject as a rectangle object.
     * @param skipUpdate {boolean} setting to true will stop the transforms of the scene graph from being updated. This means the calculation returned MAY be out of date BUT will give you a nice performance boost
     * @param rect {PIXI.Rectangle} Optional rectangle to store the result of the bounds calculation
     * @return {PIXI.Rectangle} the rectangular bounding area
     */
    getBounds(skipUpdate, rect)
    {
        if(!skipUpdate)
        {
            if(!this.parent)
            {
                this.parent = this._tempDisplayObjectParent;
                this.parent.transform._worldID++;
                this.updateTransform();
                this.parent = null;
            }
            else
            {
                this._recursivePostUpdateTransform();
                this.updateTransform();
            }
        }

        if(this._boundsID !== this._lastBoundsID)
        {
            this.calculateBounds();
        }

        if(!rect)
        {
            if(!this._boundsRect)
            {
                this._boundsRect = new math.Rectangle();
            }

            rect = this._boundsRect;
        }

        return this._bounds.getRectangle(rect);
    }

    /**
     * Retrieves the local bounds of the displayObject as a rectangle object
     * @param rect {PIXI.Rectangle} Optional rectangle to store the result of the bounds calculation
     * @return {PIXI.Rectangle} the rectangular bounding area
     */
    getLocalBounds(rect)
    {
        let transformRef = this.transform;
        let parentRef = this.parent;

        this.parent = null;
        this.transform = this._tempDisplayObjectParent.transform;

        if(!rect)
        {
            if(!this._localBoundsRect)
            {
                this._localBoundsRect = new math.Rectangle();
            }

            rect = this._localBoundsRect;
        }

        let bounds = this.getBounds(false, rect);

        this.parent = parentRef;
        this.transform = transformRef;

        return bounds;
    }

    /**
     * Calculates the global position of the display object
     *
     * @param position {PIXI.Point} The world origin to calculate from
     * @return {PIXI.Point} A point object representing the position of this object
     */
    toGlobal(position, point, skipUpdate)
    {
        if(!skipUpdate)
        {
            this._recursivePostUpdateTransform();

            // this parent check is for just in case the item is a root object.
            // If it is we need to give it a temporary parent so that displayObjectUpdateTransform works correctly
            // this is mainly to avoid a parent check in the main loop. Every little helps for performance :)
            if(!this.parent)
            {
                this.parent = this._tempDisplayObjectParent;
                this.displayObjectUpdateTransform();
                this.parent = null;
            }
            else
            {
                this.displayObjectUpdateTransform();
            }
        }

        // don't need to update the lot
        return this.worldTransform.apply(position, point);
    }

    /**
     * Calculates the local position of the display object relative to another point
     *
     * @param position {PIXI.Point} The world origin to calculate from
     * @param [from] {PIXI.DisplayObject} The DisplayObject to calculate the global position from
     * @param [point] {PIXI.Point} A Point object in which to store the value, optional (otherwise will create a new Point)
     * @return {PIXI.Point} A point object representing the position of this object
     */
    toLocal(position, from, point, skipUpdate)
    {
        if (from)
        {
            position = from.toGlobal(position, point, skipUpdate);
        }

        if(! skipUpdate)
        {
            this._recursivePostUpdateTransform();

            // this parent check is for just in case the item is a root object.
            // If it is we need to give it a temporary parent so that displayObjectUpdateTransform works correctly
            // this is mainly to avoid a parent check in the main loop. Every little helps for performance :)
            if(!this.parent)
            {
                this.parent = this._tempDisplayObjectParent;
                this.displayObjectUpdateTransform();
                this.parent = null;
            }
            else
            {
                this.displayObjectUpdateTransform();
            }
        }

        // simply apply the matrix..
        return this.worldTransform.applyInverse(position, point);
    }

    /**
     * Renders the object using the WebGL renderer
     *
     * @param renderer {PIXI.WebGLRenderer} The renderer
     */
    renderWebGL(renderer) // jshint unused:false
    {
        // OVERWRITE;
    }

    /**
     * Renders the object using the Canvas renderer
     *
     * @param renderer {PIXI.CanvasRenderer} The renderer
     */
    renderCanvas(renderer) // jshint unused:false
    {
        // OVERWRITE;
    }

    /**
     * Set the parent Container of this DisplayObject
     *
     * @param container {PIXI.Container} The Container to add this DisplayObject to
     * @return {PIXI.Container} The Container that this DisplayObject was added to
     */
    setParent(container)
    {
        if (!container || !container.addChild)
        {
            throw new Error('setParent: Argument must be a Container');
        }

        container.addChild(this);
        return container;
    }

    /**
     * Convenience function to set the postion, scale, skew and pivot at once.
     *
     * @param [x=0] {number} The X position
     * @param [y=0] {number} The Y position
     * @param [scaleX=1] {number} The X scale value
     * @param [scaleY=1] {number} The Y scale value
     * @param [rotation=0] {number} The rotation
     * @param [skewX=0] {number} The X skew value
     * @param [skewY=0] {number} The Y skew value
     * @param [pivotX=0] {number} The X pivot value
     * @param [pivotY=0] {number} The Y pivot value
     * @return {PIXI.DisplayObject} The DisplayObject instance
     */
    setTransform(x, y, scaleX, scaleY, rotation, skewX, skewY, pivotX, pivotY) //jshint ignore:line
    {
        this.position.x = x || 0;
        this.position.y = y || 0;
        this.scale.x = !scaleX ? 1 : scaleX;
        this.scale.y = !scaleY ? 1 : scaleY;
        this.rotation = rotation || 0;
        this.skew.x = skewX || 0;
        this.skew.y = skewY || 0;
        this.pivot.x = pivotX || 0;
        this.pivot.y = pivotY || 0;
        return this;
    }

    /**
     * Base destroy method for generic display objects. This will automatically
     * remove the display object from its parent Container as well as remove
     * all current event listeners and internal references. Do not use a DisplayObject 
     * after calling `destroy`.
     */
    destroy()
    {
        this.removeAllListeners();
        if (this.parent)
        {
            this.parent.removeChild(this);
        }
        this.transform = null;

        this.parent = null;

        this._bounds = null;
        this._currentBounds = null;
        this._mask = null;

        this.filterArea = null;

        this.interactive = false;
        this.interactiveChildren = false;
    }

}

module.exports = DisplayObject;


Object.defineProperties(DisplayObject.prototype, {
    /**
     * The position of the displayObject on the x axis relative to the local coordinates of the parent.
     * An alias to position.x
     *
     * @member {number}
     * @memberof PIXI.DisplayObject#
     */
    x: {
        get: function ()
        {
            return this.position.x;
        },
        set: function (value)
        {
            this.transform.position.x = value;
        }
    },

    /**
     * The position of the displayObject on the y axis relative to the local coordinates of the parent.
     * An alias to position.y
     *
     * @member {number}
     * @memberof PIXI.DisplayObject#
     */
    y: {
        get: function ()
        {
            return this.position.y;
        },
        set: function (value)
        {
            this.transform.position.y = value;
        }
    },

    /**
     * Current transform of the object based on world (parent) factors
     *
     * @member {PIXI.Matrix}
     * @memberof PIXI.DisplayObject#
     * @readonly
     */
    worldTransform: {
        get: function ()
        {
            return this.transform.worldTransform;
        }
    },

    /**
     * Current transform of the object based on local factors: position, scale, other stuff
     *
     * @member {PIXI.Matrix}
     * @memberof PIXI.DisplayObject#
     * @readonly
     */
    localTransform: {
        get: function ()
        {
            return this.transform.localTransform;
        }
    },

    /**
     * The coordinate of the object relative to the local coordinates of the parent.
     * Assignment by value since pixi-v4.
     *
     * @member {PIXI.Point|PIXI.ObservablePoint}
     * @memberof PIXI.DisplayObject#
     */
    position: {
        get: function()
        {
            return this.transform.position;
        },
        set: function(value) {
            this.transform.position.copy(value);
        }
    },

    /**
     * The scale factor of the object.
     * Assignment by value since pixi-v4.
     *
     * @member {PIXI.Point|PIXI.ObservablePoint}
     * @memberof PIXI.DisplayObject#
     */
    scale: {
        get: function() {
            return this.transform.scale;
        },
        set: function(value) {
            this.transform.scale.copy(value);
        }
    },

    /**
     * The pivot point of the displayObject that it rotates around
     * Assignment by value since pixi-v4.
     *
     * @member {PIXI.Point|PIXI.ObservablePoint}
     * @memberof PIXI.DisplayObject#
     */
    pivot: {
        get: function() {
            return this.transform.pivot;
        },
        set: function(value) {
            this.transform.pivot.copy(value);
        }
    },

    /**
     * The skew factor for the object in radians.
     * Assignment by value since pixi-v4.
     *
     * @member {PIXI.ObservablePoint}
     * @memberof PIXI.DisplayObject#
     */
    skew: {
        get: function() {
            return this.transform.skew;
        },
        set: function(value) {
            this.transform.skew.copy(value);
        }
    },

    /**
     * The rotation of the object in radians.
     *
     * @member {number}
     * @memberof PIXI.DisplayObject#
     */
    rotation: {
        get: function ()
        {
            return this.transform.rotation;
        },
        set: function (value)
        {
            this.transform.rotation = value;
        }
    },

    /**
     * Indicates if the sprite is globally visible.
     *
     * @member {boolean}
     * @memberof PIXI.DisplayObject#
     * @readonly
     */
    worldVisible: {
        get: function ()
        {
            let item = this;

            do {
                if (!item.visible)
                {
                    return false;
                }

                item = item.parent;
            } while (item);

            return true;
        }
    },

    /**
     * Sets a mask for the displayObject. A mask is an object that limits the visibility of an object to the shape of the mask applied to it.
     * In PIXI a regular mask must be a PIXI.Graphics or a PIXI.Sprite object. This allows for much faster masking in canvas as it utilises shape clipping.
     * To remove a mask, set this property to null.
     *
     * @todo For the moment, PIXI.CanvasRenderer doesn't support PIXI.Sprite as mask.
     *
     * @member {PIXI.Graphics|PIXI.Sprite}
     * @memberof PIXI.DisplayObject#
     */
    mask: {
        get: function ()
        {
            return this._mask;
        },
        set: function (value)
        {
            if (this._mask)
            {
                this._mask.renderable = true;
            }

            this._mask = value;

            if (this._mask)
            {
                this._mask.renderable = false;
            }
        }
    },

    /**
     * Sets the filters for the displayObject.
     * * IMPORTANT: This is a webGL only feature and will be ignored by the canvas renderer.
     * To remove filters simply set this property to 'null'
     *
     * @member {PIXI.AbstractFilter[]}
     * @memberof PIXI.DisplayObject#
     */
    filters: {
        get: function ()
        {
            return this._filters && this._filters.slice();
        },
        set: function (value)
        {
            this._filters = value && value.slice();
        }
    }

});

// performance increase to avoid using call.. (10x faster)
DisplayObject.prototype.displayObjectUpdateTransform = DisplayObject.prototype.updateTransform;