Custom shapes for Newsprint Filter

[rospo]

Hi all,

I am wondering how I can add custom shapes (not round, line, diamond, or square) to the newsprint filter.

I would like to rasterize an old grayscale photo using five-pointed-stars.

• Can it be done in gimp using the newsprint filter?
  
• How can we add custom dot-shapes to this filter?
  
• Suggestions for work-arounds?
  

[Ofnuts]

1) No because 2),
2) No as far as I can see you can't without changing the code and rrecompiling
3) maybe my luminosity-tiler script (there is an equivalent function in GMIC). See examples here (but discuss here on Gimp-Forum if needed)

[rich2005]

(11-07-2017, 12:26 AM)rospo Wrote: [*]Suggestions for work-arounds?

You can get a sort of pseudo-halftone effect, all depends on your greyscale image size. The larger the better.

First problem is the star, needs to be small which results in less-than-star-like shape.

This one 16x16 pix on transparent background, then copied to the clipboard and used as the clipboard pattern

   

Open the greyscale image then transparent layer on top. Filled with the star pattern, Layer mode set to Overlay

   

The next bit you will have to take my word for:

Still on that star layer Layer -> Transparency -> Alpha-to-Selection then invert the selection Select -> Invert

With the selection still active create a new from visible Layer -> New from Visible 

On that new from visible layer, with the selection still active fill with white.

Kill the selection, Select -> None Put the layer into Hard Light mode.
Turn visibility of the middle layer off.

   

Why pseudo half tone?  Strictly the stars should be sized according to luminosity.

[Espermaschine]

There are a few halftone filters in G'MIC. I think one of them also has a star.
EDIT: yes, its the Op-Art filter. Thats under 'Patterns'.

You can also use Inkscape to make a halftone with tiled clones tracing an underlying image.