Source: src/pixi/display/Sprite.js

/**
 * @author Mat Groves http://matgroves.com/ @Doormat23
 */

/**
 * The Sprite object is the base for all textured objects that are rendered to the screen
 *
 * @class Sprite
 * @extends DisplayObjectContainer
 * @constructor
 * @param texture {Texture} The texture for this sprite
 */
PIXI.Sprite = function (texture) {

    PIXI.DisplayObjectContainer.call(this);

    /**
     * The anchor sets the origin point of the texture.
     * The default (0, 0) is the top left.
     * (0.5, 0.5) is the center.
     * (1, 1) is the bottom right.
     *
     * You can modify the default values in PIXI.Sprite.defaultAnchor.
     *
     * @property anchor
     * @type Point
     */
    this.anchor = new PIXI.Point(PIXI.Sprite.defaultAnchor.x, PIXI.Sprite.defaultAnchor.y);

    /**
     * The texture that the sprite is using
     *
     * @property texture
     * @type Texture
     */
    this.texture = texture || PIXI.Texture.emptyTexture;

    /**
     * The width of the sprite (this is initially set by the texture)
     *
     * @property _width
     * @type Number
     * @private
     */
    this._width = 0;

    /**
     * The height of the sprite (this is initially set by the texture)
     *
     * @property _height
     * @type Number
     * @private
     */
    this._height = 0;

    /**
     * The tint applied to the sprite. This is a hex value. A value of 0xFFFFFF will remove any tint effect.
     *
     * @property tint
     * @type Number
     * @default 0xFFFFFF
     */
    this.tint = 0xFFFFFF;

    /**
     * The tint applied to the sprite. This is a hex value. A value of 0xFFFFFF will remove any tint effect.
     *
     * @property cachedTint
     * @private
     * @type Number
     * @default -1
     */
    this.cachedTint = -1;

    /**
     * A canvas that contains the tinted version of the Sprite (in Canvas mode, WebGL doesn't populate this)
     *
     * @property tintedTexture
     * @type Canvas
     * @default null
     */
    this.tintedTexture = null;

    /**
     * The blend mode to be applied to the sprite. Set to PIXI.blendModes.NORMAL to remove any blend mode.
     *
     * Warning: You cannot have a blend mode and a filter active on the same Sprite. Doing so will render the sprite invisible.
     *
     * @property blendMode
     * @type Number
     * @default PIXI.blendModes.NORMAL;
     */
    this.blendMode = PIXI.blendModes.NORMAL;

    /**
     * The shader that will be used to render this Sprite.
     * Set to null to remove a current shader.
     *
     * @property shader
     * @type Phaser.Filter
     * @default null
     */
    this.shader = null;

    /**
    * Controls if this Sprite is processed by the core Phaser game loops and Group loops (except {@link Phaser.Group#update}).
    *
    * @property exists
    * @type Boolean
    * @default true
    */
    this.exists = true;

    if (this.texture.baseTexture.hasLoaded)
    {
        this.onTextureUpdate();
    }

    this.renderable = true;

};

/**
 * @property PIXI.Sprite.defaultAnchor - A Point-like object.
 * @type {{x: number, y: number}}
 * @default
 */
PIXI.Sprite.defaultAnchor = {x: 0, y: 0};

// constructor
PIXI.Sprite.prototype = Object.create(PIXI.DisplayObjectContainer.prototype);
PIXI.Sprite.prototype.constructor = PIXI.Sprite;

/**
 * The width of the sprite, setting this will actually modify the scale to achieve the value set
 *
 * @property width
 * @type Number
 */
Object.defineProperty(PIXI.Sprite.prototype, 'width', {
    get: function() {
        return this.scale.x * this.texture.frame.width;
    },

    set: function(value) {
        this.scale.x = value / this.texture.frame.width;
        this._width = value;
    }

});

/**
 * The height of the sprite, setting this will actually modify the scale to achieve the value set
 *
 * @property height
 * @type Number
 */
Object.defineProperty(PIXI.Sprite.prototype, 'height', {
    get: function() {
        return  this.scale.y * this.texture.frame.height;
    },

    set: function(value) {
        this.scale.y = value / this.texture.frame.height;
        this._height = value;
    }

});

/**
 * Sets the texture of the sprite. Be warned that this doesn't remove or destroy the previous
 * texture this Sprite was using.
 *
 * @method setTexture
 * @param texture {Texture} The PIXI texture that is displayed by the sprite
 * @param [destroy=false] {boolean} Call Texture.destroy on the current texture before replacing it with the new one?
 */
PIXI.Sprite.prototype.setTexture = function(texture, destroyBase)
{
    if (destroyBase !== undefined)
    {
        this.texture.baseTexture.destroy();
    }

    //  Over-ridden by loadTexture as needed
    this.texture.baseTexture.skipRender = false;
    this.texture = texture;
    this.texture.valid = true;
    this.cachedTint = -1;
};

/**
 * When the texture is updated, this event will fire to update the scale and frame
 *
 * @method onTextureUpdate
 * @param event
 * @private
 */
PIXI.Sprite.prototype.onTextureUpdate = function()
{
    // so if _width is 0 then width was not set..
    if (this._width) this.scale.x = this._width / this.texture.frame.width;
    if (this._height) this.scale.y = this._height / this.texture.frame.height;
};

/**
* Returns the bounds of the Sprite as a rectangle.
* The bounds calculation takes the worldTransform into account.
*
* It is important to note that the transform is not updated when you call this method.
* So if this Sprite is the child of a Display Object which has had its transform
* updated since the last render pass, those changes will not yet have been applied
* to this Sprites worldTransform. If you need to ensure that all parent transforms
* are factored into this getBounds operation then you should call `updateTransform`
* on the root most object in this Sprites display list first.
*
* @method getBounds
* @param matrix {Matrix} the transformation matrix of the sprite
* @return {Rectangle} the framing rectangle
*/
PIXI.Sprite.prototype.getBounds = function(matrix)
{
    var width = this.texture.frame.width;
    var height = this.texture.frame.height;

    var w0 = width * (1-this.anchor.x);
    var w1 = width * -this.anchor.x;

    var h0 = height * (1-this.anchor.y);
    var h1 = height * -this.anchor.y;

    var worldTransform = matrix || this.worldTransform;

    var a = worldTransform.a;
    var b = worldTransform.b;
    var c = worldTransform.c;
    var d = worldTransform.d;
    var tx = worldTransform.tx;
    var ty = worldTransform.ty;

    var maxX = -Infinity;
    var maxY = -Infinity;

    var minX = Infinity;
    var minY = Infinity;

    if (b === 0 && c === 0)
    {
        // scale may be negative!
        if (a < 0)        {
            a *= -1;
            var temp = w0;
            w0 = -w1;
            w1 = -temp;
        }

        if (d < 0)        {
            d *= -1;
            var temp = h0;
            h0 = -h1;
            h1 = -temp;
        }

        // this means there is no rotation going on right? RIGHT?
        // if thats the case then we can avoid checking the bound values! yay
        minX = a * w1 + tx;
        maxX = a * w0 + tx;
        minY = d * h1 + ty;
        maxY = d * h0 + ty;
    }
    else
    {
        var x1 = a * w1 + c * h1 + tx;
        var y1 = d * h1 + b * w1 + ty;

        var x2 = a * w0 + c * h1 + tx;
        var y2 = d * h1 + b * w0 + ty;

        var x3 = a * w0 + c * h0 + tx;
        var y3 = d * h0 + b * w0 + ty;

        var x4 =  a * w1 + c * h0 + tx;
        var y4 =  d * h0 + b * w1 + ty;

        minX = x1 < minX ? x1 : minX;        minX = x2 < minX ? x2 : minX;        minX = x3 < minX ? x3 : minX;        minX = x4 < minX ? x4 : minX;
        minY = y1 < minY ? y1 : minY;        minY = y2 < minY ? y2 : minY;        minY = y3 < minY ? y3 : minY;        minY = y4 < minY ? y4 : minY;
        maxX = x1 > maxX ? x1 : maxX;
        maxX = x2 > maxX ? x2 : maxX;
        maxX = x3 > maxX ? x3 : maxX;
        maxX = x4 > maxX ? x4 : maxX;

        maxY = y1 > maxY ? y1 : maxY;
        maxY = y2 > maxY ? y2 : maxY;
        maxY = y3 > maxY ? y3 : maxY;
        maxY = y4 > maxY ? y4 : maxY;
    }

    var bounds = this._bounds;

    bounds.x = minX;
    bounds.width = maxX - minX;

    bounds.y = minY;
    bounds.height = maxY - minY;

    // store a reference so that if this function gets called again in the render cycle we do not have to recalculate
    this._currentBounds = bounds;

    return bounds;
};

/**
 * Retrieves the non-global local bounds of the Sprite as a rectangle. The calculation takes all visible children into consideration.
 *
 * @method getLocalBounds
 * @return {Rectangle} The rectangular bounding area
 */
PIXI.Sprite.prototype.getLocalBounds = function () {

    var matrixCache = this.worldTransform;

    this.worldTransform = Phaser.identityMatrix;

    for (var i = 0; i < this.children.length; i++)    {
        this.children[i].updateTransform();
    }

    var bounds = this.getBounds();

    this.worldTransform = matrixCache;

    for (i = 0; i < this.children.length; i++)    {
        this.children[i].updateTransform();
    }

    return bounds;

};

/**
* Renders the object using the WebGL renderer
*
* @method _renderWebGL
* @param renderSession {RenderSession}
* @param {Matrix} [matrix] - Optional matrix. If provided the Display Object will be rendered using this matrix, otherwise it will use its worldTransform.
* @private
*/
PIXI.Sprite.prototype._renderWebGL = function(renderSession, matrix)
{
    // if the sprite is not visible or the alpha is 0 then no need to render this element
    if (!this.visible || this.alpha <= 0 || !this.renderable) return;
    //  They provided an alternative rendering matrix, so use it
    var wt = this.worldTransform;

    if (matrix)
    {
        wt = matrix;
    }

    //  A quick check to see if this element has a mask or a filter.
    if (this._mask || this._filters)
    {
        var spriteBatch = renderSession.spriteBatch;

        // push filter first as we need to ensure the stencil buffer is correct for any masking
        if (this._filters)
        {
            spriteBatch.flush();
            renderSession.filterManager.pushFilter(this._filterBlock);
        }

        if (this._mask)
        {
            spriteBatch.stop();
            renderSession.maskManager.pushMask(this.mask, renderSession);
            spriteBatch.start();
        }

        // add this sprite to the batch
        spriteBatch.render(this);

        // now loop through the children and make sure they get rendered
        for (var i = 0; i < this.children.length; i++)        {
            this.children[i]._renderWebGL(renderSession);
        }

        // time to stop the sprite batch as either a mask element or a filter draw will happen next
        spriteBatch.stop();

        if (this._mask) renderSession.maskManager.popMask(this._mask, renderSession);
        if (this._filters) renderSession.filterManager.popFilter();

        spriteBatch.start();
    }
    else
    {
        renderSession.spriteBatch.render(this);

        //  Render children!
        for (var i = 0; i < this.children.length; i++)        {
            this.children[i]._renderWebGL(renderSession, wt);
        }

    }
};

/**
* Renders the object using the Canvas renderer
*
* @method _renderCanvas
* @param renderSession {RenderSession}
* @param {Matrix} [matrix] - Optional matrix. If provided the Display Object will be rendered using this matrix, otherwise it will use its worldTransform.
* @private
*/
PIXI.Sprite.prototype._renderCanvas = function(renderSession, matrix)
{
    // If the sprite is not visible or the alpha is 0 then no need to render this element
    if (!this.visible || this.alpha === 0 || !this.renderable || this.texture.crop.width <= 0 || this.texture.crop.height <= 0)    {
        return;
    }

    var wt = this.worldTransform;

    //  If they provided an alternative rendering matrix then use it
    if (matrix)
    {
        wt = matrix;
    }

    if (this.blendMode !== renderSession.currentBlendMode)
    {
        renderSession.currentBlendMode = this.blendMode;
        renderSession.context.globalCompositeOperation = PIXI.blendModesCanvas[renderSession.currentBlendMode];
    }

    if (this._mask)
    {
        renderSession.maskManager.pushMask(this._mask, renderSession);
    }

    //  Ignore null sources
    if (!this.texture.valid)
    {
        //  Update the children and leave
        for (var i = 0; i < this.children.length; i++)        {
            this.children[i]._renderCanvas(renderSession);
        }

        if (this._mask)
        {
            renderSession.maskManager.popMask(renderSession);
        }

        return;
    }

    var resolution = this.texture.baseTexture.resolution / renderSession.resolution;

    renderSession.context.globalAlpha = this.worldAlpha;

    //  If smoothingEnabled is supported and we need to change the smoothing property for this texture
    if (renderSession.smoothProperty && renderSession.scaleMode !== this.texture.baseTexture.scaleMode)
    {
        renderSession.scaleMode = this.texture.baseTexture.scaleMode;
        renderSession.context[renderSession.smoothProperty] = (renderSession.scaleMode === PIXI.scaleModes.LINEAR);
    }

    //  If the texture is trimmed we offset by the trim x/y, otherwise we use the frame dimensions
    var dx = (this.texture.trim) ? this.texture.trim.x - this.anchor.x * this.texture.trim.width : this.anchor.x * -this.texture.frame.width;
    var dy = (this.texture.trim) ? this.texture.trim.y - this.anchor.y * this.texture.trim.height : this.anchor.y * -this.texture.frame.height;

    var tx = (wt.tx * renderSession.resolution) + renderSession.shakeX;
    var ty = (wt.ty * renderSession.resolution) + renderSession.shakeY;

    var cw = this.texture.crop.width;
    var ch = this.texture.crop.height;

    if (this.texture.rotated)
    {
        var a = wt.a;
        var b = wt.b;
        var c = wt.c;
        var d = wt.d;
        var e = cw;

        // Offset before rotating
        tx = wt.c * ch + tx;
        ty = wt.d * ch + ty;

        // Rotate matrix by 90 degrees
        // We use precalculated values for sine and cosine of rad(90)
        wt.a = a * 6.123233995736766e-17 + -c;
        wt.b = b * 6.123233995736766e-17 + -d;
        wt.c = a + c * 6.123233995736766e-17;
        wt.d = b + d * 6.123233995736766e-17;

        // Update cropping dimensions.
        cw = ch;
        ch = e;
    }

    //  Allow for pixel rounding
    if (renderSession.roundPixels)
    {
        renderSession.context.setTransform(wt.a, wt.b, wt.c, wt.d, tx | 0, ty | 0);
        dx |= 0;
        dy |= 0;
    }
    else
    {
        renderSession.context.setTransform(wt.a, wt.b, wt.c, wt.d, tx, ty);
    }

    dx /= resolution;
    dy /= resolution;

    if (this.tint !== 0xFFFFFF)
    {
        if (this.texture.requiresReTint || this.cachedTint !== this.tint)
        {
            this.tintedTexture = PIXI.CanvasTinter.getTintedTexture(this, this.tint);

            this.cachedTint = this.tint;
            this.texture.requiresReTint = false;
        }

        renderSession.context.drawImage(this.tintedTexture, 0, 0, cw, ch, dx, dy, cw / resolution, ch / resolution);
    }
    else
    {
        var cx = this.texture.crop.x;
        var cy = this.texture.crop.y;

        cw = Math.floor(cw)
        ch = Math.floor(ch)

        renderSession.context.drawImage(this.texture.baseTexture.source, cx, cy, cw, ch, dx, dy, cw / resolution, ch / resolution);
    }

    for (var i = 0; i < this.children.length; i++)    {
        this.children[i]._renderCanvas(renderSession);
    }

    if (this._mask)
    {
        renderSession.maskManager.popMask(renderSession);
    }

};