Prawn Shadings

This is a Prawn extension that implements advanced PDF shadings.

Specifically, it a bit refactors already implemented linear and radial gradients and adds a few more advanced ones.

Currently implemented shadings:

• Axial Shadings (or linear gradients) (PDF Type 2 Shading)
• Radial Shading (PDF Type 3 Shading)
• Free-Form Gouraud-Shaded Triangle Meshes (PDF Type 4 Shading)
• Lattice-Form Gouraud-Shaded Triangle Meshes (PDF Type 5 Shading)
• Coons Patch Meshes (PDF Type 6 Shading)
• Tensor-Product Patch Meshes (PDF Type 7 Shading)

API is simple but you need to know what data to supply. Please get familiar with Section 4.6.3 of PDF Reference.

Please note that this gem gives you ability use all these shadings in your generated PDF but gives no guarantee that PDF will be rendered correctly.

Just a few examples:

• OS X Preview has problems with flags other than 0 in Type 4, 6 and 7 type shadings.
• OS X Previews renders Type 7 shadings exactly the same as Type 6 shadings ignoring all 4 extra control points.
• PDF.js can not render pretty much any of these.

gem install prawn-shadings

require 'prawn/shadings'

To run the tests:

$ rake

1. Fork it.
2. Create a branch (git checkout -b my_shading)
3. Commit your changes (git commit -am "Added Shading")
4. Push to the branch (git push origin my_shading)
5. Open a Pull Request