# src/pixi/text/Text.js - Pixi.JS

#

API Docs for: 1.0.0
Show: Inherited Protected Private Deprecated

# File: src/pixi/text/Text.js

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

    /**
     * A Text Object will create a line(s) of text to split a line you can use "\n"
     * @class Text
     * @extends Sprite
     * @constructor
     * @param {String} text The copy that you would like the text to display
     * @param {Object} [style] The style parameters
     * @param {String} [style.font] default "bold 20pt Arial" The style and size of the font
     * @param {Object} [style.fill="black"] A canvas fillstyle that will be used on the text eg "red", "#00FF00"
     * @param {String} [style.align="left"] An alignment of the multiline text ("left", "center" or "right")
     * @param {String} [style.stroke] A canvas fillstyle that will be used on the text stroke eg "blue", "#FCFF00"
     * @param {Number} [style.strokeThickness=0] A number that represents the thickness of the stroke. Default is 0 (no stroke)
     */
    PIXI.Text = function(text, style)
    {
        this.canvas = document.createElement("canvas");
        this.context = this.canvas.getContext("2d");
        PIXI.Sprite.call(this, PIXI.Texture.fromCanvas(this.canvas));

        this.setText(text);
        this.setStyle(style);

         this.updateText();
        this.dirty = false;
    };

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

    /**
     * Set the style of the text
     * @method setStyle
     * @param {Object} [style] The style parameters
     * @param {String} [style.font="bold 20pt Arial"] The style and size of the font
     * @param {Object} [style.fill="black"] A canvas fillstyle that will be used on the text eg "red", "#00FF00"
     * @param {String} [style.align="left"] An alignment of the multiline text ("left", "center" or "right")
     * @param {String} [style.stroke] A canvas fillstyle that will be used on the text stroke eg "blue", "#FCFF00"
     * @param {Number} [style.strokeThickness=0] A number that represents the thickness of the stroke. Default is 0 (no stroke)
     */
    PIXI.Text.prototype.setStyle = function(style)
    {
        style = style || {};
        style.font = style.font || "bold 20pt Arial";
        style.fill = style.fill || "black";
        style.align = style.align || "left";
        style.strokeThickness = style.strokeThickness || 0;
        this.style = style;
        this.dirty = true;
    };

    /**
     * Set the copy for the text object. To split a line you can use "\n"
     * @methos setText
     * @param {String} text The copy that you would like the text to display
     */
    PIXI.Sprite.prototype.setText = function(text)
    {
        this.text = text || " ";
        this.dirty = true;
    };

    /**
     * Renders text
     * @private
     */
    PIXI.Text.prototype.updateText = function()
    {
    	this.context.font = this.style.font;

    	//split text into lines
    	var lines = this.text.split(/(?:\r\n|\r|\n)/);

    	//calculate text width
    	var lineWidths = [];
    	var maxLineWidth = 0;
    	for (var i = 0; i < lines.length; i++)
    	{
    		var lineWidth = this.context.measureText(lines[i]).width;
    		lineWidths[i] = lineWidth;
    		maxLineWidth = Math.max(maxLineWidth, lineWidth);
    	}
    	this.canvas.width = maxLineWidth + this.style.strokeThickness;

    	//calculate text height
    	var lineHeight = this.determineFontHeight("font: " + this.style.font  + ";") + this.style.strokeThickness;
    	this.canvas.height = lineHeight * lines.length;

    	//set canvas text styles
    	this.context.fillStyle = this.style.fill;
    	this.context.font = this.style.font;

    	this.context.strokeStyle = this.style.stroke;
    	this.context.lineWidth = this.style.strokeThickness;

    	this.context.textBaseline = "top";

    	//draw lines line by line
    	for (i = 0; i < lines.length; i++)
    	{
    		var linePosition = new PIXI.Point(this.style.strokeThickness / 2, this.style.strokeThickness / 2 + i * lineHeight);

    		if(this.style.align == "right")
    		{
    			linePosition.x += maxLineWidth - lineWidths[i];
    		}
    		else if(this.style.align == "center")
    		{
    			linePosition.x += (maxLineWidth - lineWidths[i]) / 2;
    		}

    		if(this.style.stroke && this.style.strokeThickness)
    		{
    			this.context.strokeText(lines[i], linePosition.x, linePosition.y);
    		}

    		if(this.style.fill)
    		{
    			this.context.fillText(lines[i], linePosition.x, linePosition.y);
    		}
    	}

        this.updateTexture();
    };

    /**
     * Updates texture size based on canvas size
     * @private
     */
    PIXI.Text.prototype.updateTexture = function()
    {

        this.texture.baseTexture.width = this.canvas.width;
        this.texture.baseTexture.height = this.canvas.height;
        this.texture.frame.width = this.canvas.width;
        this.texture.frame.height = this.canvas.height;

      	this._width = this.canvas.width;
        this._height = this.canvas.height;

        PIXI.texturesToUpdate.push(this.texture.baseTexture);
    };

    /**
     * @private
     */
    PIXI.Text.prototype.updateTransform = function()
    {
    	if(this.dirty)
    	{
    		this.updateText();
    		this.dirty = false;
    	}

    	PIXI.Sprite.prototype.updateTransform.call(this);
    };

    /*
     * http://stackoverflow.com/users/34441/ellisbben
     * great solution to the problem!
     */
    PIXI.Text.prototype.determineFontHeight = function(fontStyle)
    {
    	// build a little reference dictionary so if the font style has been used return a
    	// cached version...
    	var result = PIXI.Text.heightCache[fontStyle];

    	if(!result)
    	{
    		var body = document.getElementsByTagName("body")[0];
    		var dummy = document.createElement("div");
    		var dummyText = document.createTextNode("M");
    		dummy.appendChild(dummyText);
    		dummy.setAttribute("style", fontStyle);
    		body.appendChild(dummy);

    		result = dummy.offsetHeight;
    		PIXI.Text.heightCache[fontStyle] = result;

    		body.removeChild(dummy);
    	}

    	return result;
    };

    PIXI.Text.prototype.destroy = function(destroyTexture)
    {
    	if(destroyTexture)
    	{
    		this.texture.destroy();
    	}

    };

    PIXI.Text.heightCache = {};