Source: gfx/core/text/BitmapText.js

const Vector = require('engine/Vector');
const { removeItems } = require('engine/utils/array');
const Node = require('../Node');
const Sprite = require('../sprites/Sprite');

/**
 * A BitmapText object will create a line or multiple lines of text using bitmap font. To
 * split a line you can use '\n', '\r' or '\r\n' in your string. You can generate the fnt files using:
 *
 * A BitmapText can only be created when the font is loaded
 *
 * ```js
 * // in this case the font is in a file called 'desyrel.fnt'
 * var bitmapText = new BitmapText({
 *   text: "text using a fancy font!",
 *   font: "35px Desyrel",
 *   align: "right",
 * });
 * ```
 *
 * http://www.angelcode.com/products/bmfont/ for windows or
 * http://www.bmglyph.com/ for mac.
 *
 * @class
 * @extends Node
 * @param text {string} The copy that you would like the text to display
 * @param style {object} The style parameters
 * @param style.font {string|object} The font descriptor for the object, can be passed as a string of form
 *      "24px FontName" or "FontName" or as an object with explicit name/size properties.
 * @param [style.font.name] {string} The bitmap font id
 * @param [style.font.size] {number} The size of the font in pixels, e.g. 24
 * @param [style.align='left'] {string} Alignment for multiline text ('left', 'center' or 'right'), does not affect
 *      single line text
 * @param [style.tint=0xFFFFFF] {number} The tint color
 */
class BitmapText extends Node {
  constructor(text, style = {}) {
    super();

    /**
     * The width of the overall text, different from fontSize,
     * which is defined in the style object
     *
     * @member {number}
     * @readOnly
     */
    this.textWidth = 0;

    /**
     * The height of the overall text, different from fontSize,
     * which is defined in the style object
     *
     * @member {number}
     * @readOnly
     */
    this.textHeight = 0;

    /**
     * Private tracker for the letter sprite pool.
     *
     * @member {Sprite[]}
     * @private
     */
    this._glyphs = [];

    /**
     * Private tracker for the current style.
     *
     * @member {object}
     * @private
     */
    this._font = {
      tint: style.tint !== undefined ? style.tint : 0xFFFFFF,
      align: style.align || 'left',
      name: null,
      size: 0,
    };

    /**
     * Private tracker for the current font.
     *
     * @member {object}
     * @private
     */
    this.font = style.font; // run font setter

    /**
     * Private tracker for the current text.
     *
     * @member {string}
     * @private
     */
    this._text = text;

    /**
     * The max width of this bitmap text in pixels. If the text provided is longer than the value provided, line breaks will be automatically inserted in the last whitespace.
     * Disable by setting value to 0
     *
     * @member {number}
     */
    this.maxWidth = 0;

    /**
     * The max line height. This is useful when trying to use the total height of the Text, ie: when trying to vertically align.
     *
     * @member {number}
     */
    this.maxLineHeight = 0;

    /**
     * The dirty state of this object.
     *
     * @member {boolean}
     */
    this.dirty = false;

    this.updateText();
  }

  /**
   * Renders text and updates it when needed
   *
   * @private
   */
  updateText() {
    var data = BitmapText.fonts[this._font.name];
    var pos = Vector.create();
    var prevCharCode = null;
    var chars = [];
    var lastLineWidth = 0;
    var maxLineWidth = 0;
    var lineWidths = [];
    var line = 0;
    var scale = this._font.size / data.size;
    var lastSpace = -1;
    var maxLineHeight = 0;

    for (var i = 0; i < this.text.length; i++) {
      var charCode = this.text.charCodeAt(i);
      lastSpace = /(\s)/.test(this.text.charAt(i)) ? i : lastSpace;

      if (/(?:\r\n|\r|\n)/.test(this.text.charAt(i))) {
        lineWidths.push(lastLineWidth);
        maxLineWidth = Math.max(maxLineWidth, lastLineWidth);
        line++;

        pos.x = 0;
        pos.y += data.lineHeight;
        prevCharCode = null;
        continue;
      }

      if (lastSpace !== -1 && this.maxWidth > 0 && pos.x * scale > this.maxWidth) {
        removeItems(chars, lastSpace, i - lastSpace);
        i = lastSpace;
        lastSpace = -1;

        lineWidths.push(lastLineWidth);
        maxLineWidth = Math.max(maxLineWidth, lastLineWidth);
        line++;

        pos.x = 0;
        pos.y += data.lineHeight;
        prevCharCode = null;
        continue;
      }

      var charData = data.chars[charCode];

      if (!charData) {
        continue;
      }

      if (prevCharCode && charData.kerning[prevCharCode]) {
        pos.x += charData.kerning[prevCharCode];
      }

      chars.push({ texture:charData.texture, line: line, charCode: charCode, position: Vector.create(pos.x + charData.xOffset, pos.y + charData.yOffset) });
      lastLineWidth = pos.x + (charData.texture.width + charData.xOffset);
      pos.x += charData.xAdvance;
      maxLineHeight = Math.max(maxLineHeight, (charData.yOffset + charData.texture.height));
      prevCharCode = charCode;
    }

    lineWidths.push(lastLineWidth);
    maxLineWidth = Math.max(maxLineWidth, lastLineWidth);

    var lineAlignOffsets = [];

    for (i = 0; i <= line; i++) {
      var alignOffset = 0;

      if (this._font.align === 'right') {
        alignOffset = maxLineWidth - lineWidths[i];
      }
      else if (this._font.align === 'center') {
        alignOffset = (maxLineWidth - lineWidths[i]) / 2;
      }

      lineAlignOffsets.push(alignOffset);
    }

    var lenChars = chars.length;
    var tint = this.tint;

    for (i = 0; i < lenChars; i++) {
      var c = this._glyphs[i]; // get the next glyph sprite

      if (c) {
        c.texture = chars[i].texture;
      }
      else {
        c = new Sprite(chars[i].texture);
        this._glyphs.push(c);
      }

      c.position.x = (chars[i].position.x + lineAlignOffsets[chars[i].line]) * scale;
      c.position.y = chars[i].position.y * scale;
      c.scale.x = c.scale.y = scale;
      c.tint = tint;

      if (!c.parent) {
        this.addChild(c);
      }
    }

      // remove unnecessary children.
    for (i = lenChars; i < this._glyphs.length; ++i) {
      this.removeChild(this._glyphs[i]);
    }

    this.textWidth = maxLineWidth * scale;
    this.textHeight = (pos.y + data.lineHeight) * scale;
    this.maxLineHeight = maxLineHeight * scale;
  }

  /**
   * Updates the transform of this object
   *
   * @private
   */
  updateTransform() {
    this.validate();
    this.containerUpdateTransform();
  }

  /**
   * Validates text before calling parent's getLocalBounds
   *
   * @return {Rectangle} The rectangular bounding area
   */

  getLocalBounds() {
    this.validate();
    return super.getLocalBounds();
  }

  /**
   * Updates text when needed
   *
   * @private
   */
  validate() {
    if (this.dirty) {
      this.updateText();
      this.dirty = false;
    }
  }
}

Object.defineProperties(BitmapText.prototype, {
  /**
   * The tint of the BitmapText object
   *
   * @member {number}
   * @memberof extras.BitmapText#
   */
  tint: {
    get: function() {
      return this._font.tint;
    },
    set: function(value) {
      this._font.tint = (typeof value === 'number' && value >= 0) ? value : 0xFFFFFF;

      this.dirty = true;
    },
  },

  /**
   * The alignment of the BitmapText object
   *
   * @member {string}
   * @default 'left'
   * @memberof extras.BitmapText#
   */
  align: {
    get: function() {
      return this._font.align;
    },
    set: function(value) {
      this._font.align = value || 'left';

      this.dirty = true;
    },
  },

  /**
   * The font descriptor of the BitmapText object
   *
   * @member {Font}
   * @memberof extras.BitmapText#
   */
  font: {
    get: function() {
      return this._font;
    },
    set: function(value) {
      if (!value) {
        return;
      }

      if (typeof value === 'string') {
        value = value.split(' ');

        this._font.name = value.length === 1 ? value[0] : value.slice(1).join(' ');
        this._font.size = value.length >= 2 ? parseInt(value[0], 10) : BitmapText.fonts[this._font.name].size;
      }
      else {
        this._font.name = value.name;
        this._font.size = typeof value.size === 'number' ? value.size : parseInt(value.size, 10);
      }

      this.dirty = true;
    },
  },

  /**
   * The text of the BitmapText object
   *
   * @member {string}
   * @memberof extras.BitmapText#
   */
  text: {
    get: function() {
      return this._text;
    },
    set: function(value) {
      value = value.toString() || ' ';
      if (this._text === value) {
        return;
      }
      this._text = value;
      this.dirty = true;
    },
  },
});

BitmapText.fonts = {};

module.exports = BitmapText;