Source: scene/text-bitmap/BitmapFont.ts

import { Rectangle } from '../../maths/shapes/Rectangle';
import { Texture } from '../../rendering/renderers/shared/texture/Texture';
import { AbstractBitmapFont } from './AbstractBitmapFont';
import { BitmapFontManager } from './BitmapFontManager';

import type { FontMetrics } from '../text/canvas/CanvasTextMetrics';
import type { BitmapFontData } from './AbstractBitmapFont';
import type { BitmapFontInstallOptions } from './BitmapFontManager';

/**
 * Options for creating a BitmapFont.
 * @memberof text
 */
export interface BitmapFontOptions
{
    data: BitmapFontData
    textures: Texture[]
}

/**
 * A BitmapFont object represents a particular font face, size, and style.
 * @memberof text
 */
export class BitmapFont extends AbstractBitmapFont<BitmapFont>
{
    /** the url of the font */
    public url?: string;

    constructor(options: BitmapFontOptions, url?: string)
    {
        super();

        const { textures, data } = options;

        Object.keys(data.pages).forEach((key: string) =>
        {
            const pageData = data.pages[parseInt(key, 10)];

            const texture = textures[pageData.id];

            this.pages.push({ texture });
        });

        Object.keys(data.chars).forEach((key: string) =>
        {
            const charData = data.chars[key];
            const {
                frame: textureFrame,
                source: textureSource,
            } = textures[charData.page];

            const frameReal = new Rectangle(
                charData.x + textureFrame.x,
                charData.y + textureFrame.y,
                charData.width,
                charData.height,
            );

            const texture = new Texture({
                source: textureSource,
                frame: frameReal
            });

            this.chars[key] = {
                id: key.codePointAt(0),
                xOffset: charData.xOffset,
                yOffset: charData.yOffset,
                xAdvance: charData.xAdvance,
                kerning: charData.kerning ?? {},
                texture,
            };
        });

        this.baseRenderedFontSize = data.fontSize;

        (this.baseMeasurementFontSize as number) = data.fontSize;
        (this.fontMetrics as FontMetrics) = {
            ascent: 0,
            descent: 0,
            fontSize: data.fontSize,
        };
        (this.baseLineOffset as number) = data.baseLineOffset;
        (this.lineHeight as number) = data.lineHeight;
        (this.fontFamily as string) = data.fontFamily;
        (this.distanceField as { type: string, range: number }) = data.distanceField ?? {
            type: 'none',
            range: 0,
        };

        this.url = url;
    }

    /** Destroys the BitmapFont object. */
    public override destroy(): void
    {
        super.destroy();

        for (let i = 0; i < this.pages.length; i++)
        {
            const { texture } = this.pages[i];

            texture.destroy(true);
        }

        (this.pages as null) = null;
    }

    /**
     * Generates a bitmap-font for the given style and character set
     * @param options - Setup options for font generation.
     * @returns Font generated by style options.
     * @example
     * import { BitmapFont, BitmapText } from 'pixi.js';
     *
     * BitmapFont.install('TitleFont', {
     *     fontFamily: 'Arial',
     *     fontSize: 12,
     *     strokeThickness: 2,
     *     fill: 'purple',
     * });
     *
     * const title = new BitmapText({ text: 'This is the title', fontFamily: 'TitleFont' });
     */
    public static install(options: BitmapFontInstallOptions)
    {
        BitmapFontManager.install(options);
    }
    /**
     * Uninstalls a bitmap font from the cache.
     * @param {string} name - The name of the bitmap font to uninstall.
     */
    public static uninstall(name: string)
    {
        BitmapFontManager.uninstall(name);
    }
}