node-fonts.js

// bwip-js/node-fonts.js
//
// node-js font lib interface
//
// This is part of the bwip-js project available at:
//
// 		http://metafloor.github.io/bwip-js
//
// Copyright (c) 2011-2018 Mark Warren
//
// The MIT License
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
"use strict";

var fs = require('fs');
var monochr = false;

// Load the font description files
var fontmap = {
	names:{},
	fontsets:[],
};

(function() {
	try {
		for (var i = 0; i < 10; i++) {
			var font = require('./fonts/fnt' + i + '-desc');
			fontmap.names[font.name.toUpperCase()] = i;	// font-name to font-id
			fontmap.fontsets[i] = font;					// font-id to font-descriptor
		}
	} catch (e) {
		if (!e.code || e.code != 'MODULE_NOT_FOUND') {
			console.log(e);
		}
	}
})();

// bwipjs needs the following interfaces:
//  lookup(fontname)    returns fontid
//  monochrome(bool)    set the fonts to monochrome or anti-aliased
//  getglyph(fontid, charcode, width, height)
module.exports = {
	lookup:lookup,
	monochrome:monochrome,
	getglyph:getglyph,
}

function lookup(name) {
	var fontid = fontmap.names[name.toUpperCase()];
	return fontid === undefined ? 1 : fontid;		// OCR B default
}

function monochrome(mono) {
	monochr = mono;
}

// `width` and `height` are the same size, scaled respectively by the
// x,y factors.  Because bar code width is what we care about, font
// width is the only metric we use to match the font.
function getglyph(fontid, charcode, width, height) {
	if (fontid < 0 || fontid >= fontmap.fontsets.length) {
		fontid = 1;		// OCR B default
	}
	var fontset = fontmap.fontsets[fontid];
	if (width < fontset.minsize) {
		width = fontset.minsize;
	} else if (width > fontset.maxsize) {
		width = fontset.maxsize;
	}

	// Find the largest size not exceeding
	var size = width;
	while (size > 5 && !fontset.sizes[size]) {
		size--;
	}
	if (size == 5) {
		throw 'font-size too small (' + width + ')';
	}

	var fkey = (monochr ? 'm' : 'a') + size;
	var font = fontset.fonts[fkey];

	// demand-load the font file
	if (!font) {
		// We can avoid this Sync() interface (the browser version does), but
		// requires more work for the user.
		var fontdir = process.env.BWIPJS_FONTS || __dirname + '/fonts';
		if (fontdir[fontdir.length-1] == '/') {
			fontdir = fontdir.substr(0, fontdir.length-1);
		}
		var bytes = fs.readFileSync(fontdir + '/fnt' + fontid +
									(monochr ? 'm-' : 'a-') + size + '.bin');
		fontset.fonts[fkey] = font = { bytes:bytes, glyphs:[] };
	} 

	// Convert the charcode to a glyph index
	if (charcode < fontset.minchar || charcode > fontset.maxchar) {
		charcode = fontset.minchar;		// default, space
	}
	charcode -= fontset.minchar;

	var glyph = font.glyphs[charcode];
	if (!glyph) {
		var bytes  = font.bytes;
		var offset = bytes.readUInt32LE(charcode * 4);
		font.glyphs[charcode] = glyph = {
			advance: bytes.readUInt16LE(offset),
			top:	 bytes.readInt16LE(offset + 2),
			left:	 bytes.readInt16LE(offset + 4),
			width:	 bytes.readUInt16LE(offset + 6),
			height:	 bytes.readUInt16LE(offset + 8),
			offset:  offset + 10,
			bytes:	 bytes,
		};
	}

	return glyph;
}