bluegen

Stochastic Screen Generator (for printing, stippling, etc)

Click here to try it out

This little web app generates stochastic (blue noise) screens for digital halftoning/stippling. It has four methods:

• Smoothmask: Makes a standard hiearchial blue noise mask, then computes offsets to nudge each mask level to be more smooth. These go into a table.
• Void-and-cluster: A classic, this one works best for generating stochastic screens for printers.
• Dart: Classic, progressive dart throwing. Generates the highest quality masks.
• SPH: SPH fluid method. Not quite as good as dart, and a bit harder to control. Is much slower at higher resolutions.
• Jitter: A very simple randomlized hexagonal grid method. Randomizes the hiearhcial levels, not the point positions. Mostly for reference purposes. Produces the worst results.

Usage

Load index.html in a web browser. Press "Start Generating".

Using with Blue Noise Stippler

To test the generated masks, you can use this stippling app of mine. Here's a direct link to the app itself.

Click on the "Save To Cache" button on the lower-right side of the screen. You should see a message like "saving blue noise mask to local storage." You should be able to use the new mask in the stippling app.

FFT

The FFT power spectrum feature is ported from PSA. I recommend using it with "dimensions" set to 50 or less (I usually use 32).