(Experimental) Scales a Raw ZPL file from 203 DPI (dots per inch) to 300 DPI

scale-zpl.js

/*
 * author:  Tres Finocchiaro
 * date:    2015-05-22
 * license: Public Domain; Use as you wish.
 * source:  http://qz.io
 */

/*
 * Scales text from a raw ZPL label from 203 DPI to 300 DPI
 */
function scaleZPL(rawCommands, scaleFactor) {
	if (!scaleFactor) {
		scaleFactor = 300/203;
	}
	var sections = rawCommands.split('^');
	
	// ZPL commands to perform conversion on
	var cmds = ['FO', 'A0', 'A@', 'LL', 'LH', 'GB', 'FB', 'BY', 'B3', 'FT'];

	var output = '';
	for (var i in cmds) {
		for (var j in sections) {
			if (sections[j].indexOf(cmds[i]) === 0) {
				sections[j] = scaleSection(cmds[i], sections[j], scaleFactor);
			}
		}
	}
	
	return sections.join('^');
}

/*
 * Scales all integers found in a designated section
 */
function scaleSection(cmd, section, scaleFactor) {
	section = section.slice(cmd.length, section.length);
	parts = section.split(',');
	for (var p in parts) {
		if (isInt(parts[p])) {
			parts[p] = Math.round(scaleFactor * parts[p]);
		}
	}
	
	return cmd + parts.join();
}

/*
 * Checks if a string is an integer
 */
function isInt(value) {
  return !isNaN(value) && 
         parseInt(Number(value)) == value && 
         !isNaN(parseInt(value, 10));
}

Hi,

I used this as the basis for a powershell version - see https://gist.github.com/timdw/391ecb62efd1dde9f6af017ead208ec9

Thanks!

Tim

I added some additional scaling functionality for barcodes: https://gist.github.com/alethea/3e409b0b1206099bee88eefac7fa7cbd

C# .NET version at isatufan/ZPLHandler.cs

I added a PHP version at: gist.

I added the 'FT' tag to the cmds array.

I added a Python version of the Zebra ZPL Rescaler at https://github.com/deexno/Zebra-ZPL-rescaler.

I've made the input more user-friendly, allowing the user to convert their ZPL file from any resolution to any other resolution without touching the code.

@deexno thanks for sharing!