jsbmp - JavaScript Bitmap Generator

Create Windows bitmap (.BMP) files with JavaScript.

Please note that this is not a high-level image composition library: included functions do little more than pack raw pixel data.

It supports 24-bit uncompressed (BI_RGB):

// 5x1 pixel progression from black to light grey
var greys = bmp_rgb(5, 1, ['000000','333333', '666666', '999999', 'cccccc']);

And 8-bit run-length encoded (BI_RLE8):

// 2000x2 pixel line, blue on top and red below
var bluelineredline = bmp_rle8(2000, 2, [['0000FF', 2000], ['FF0000', 2000]]);

Cool Examples

Compatibility

Tested with Firefox 3.0.11, Internet Explorer 8 and Safari version something.

Please note that, although version 8 finally adds data URI support to Internet Explorer, it is limited to URIs 32,000-odd characters long. (Consider that one pixel in an uncompressed bitmap takes up 4+ bytes, for a maximum base64-encoded size of ~80x80.)

Sources

Bitmap generation:

jsbmp.js

Supporting files:

datauri.js - generate data URIs
xpm2.js - parse XPM v2 text

Extra:

jsbmpblock.js - has one function, block(width, height, colour), which is more or less a minified/optimized bmp_rle8(). Firefox only; demo.