Type2-charstring NPM

A human-readable Type2 Charstring to bytecode converter

A simple converter for Type2 charstrings in human readable and byte form

In Node.js source code

Install with npm install type2-charstring, then use it in your code as:

var convert = require('type2-charstring');
var charstring = convert.toBytes([
]);

In the browser

Use the convert.js from the repo:

<script src="convert.js"></script>
<script>
  var charstring = Type2Convert.toBytes([
  ]);
</script>

API

The following functions are exposed:

bindSubroutine: function(functor, bytes), binds a global subroutine (to do this from human readable form, run the code through .toBytes and then bind that to a name). The functor can be used in subsequent charstrings to autoresolve to the right subr, so:

bindSubroutine("sin()", [.....]);
// we can now use sin() as charstring code:
var ncs = "3.1415 sin() endchar";
var ncsBytes = Type2Convert.toBytes(ncs);

getSubroutines: function(), returns the list of global subroutines known until now, with bias correction applied. Generally useful if you need to actually build a font based on the charstrings you've been creating.
toBytes: function(string, subroutines), converts a human readable charstring to byte form. White space and commas are treated as non-semantic, and line comments are stripped, so you can write properly readable code:

...

// When we start the stack contains: [angle, ox, oy, x, y],
// so we put them onto the transient stack in argument order:
4 put, 3 put, 2 put, 1 put, 0 put

// compute the sin(x) and cos(x) of the provided angle
0 get, sin(x), 5 put
0 get, cos(x), 6 put
...