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Description:

This plugin allows you to reduce the number of colors in an image with the help of eleven error diffusion dithering algorithms. You are able to choose one of the four software palettes or to use automatically generated palette with specified size. You can also enable "Serpentine scanning" to alternate scanning direction between lines. Unfortunately, these algorithms do not work quickly due to single-threadedness. The advantage of this plugin is that it correctly works with any selection.

 

Plugin: Effects > Stylize > Error diffusion dithering

B9xAJuj.png8qm3dZQ.pngkhNkqxp.png

 

Examples:

0C3y80m.pngUahXmvS.pngcgGpDVM.png

 

Github:

https://github.com/PavielKraskouski/PaintDotNetPlugins/tree/master/ErrorDiffusionDithering

 

Download:

 

ErrorDiffusionDithering.dll

 

Edited by pavlik1307
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@Joshua Lamusga, I can't parallelize dithering algorithm, because processing of following pixels depends on processing of previous pixels. But after your message, I realized that I could make neighbouring pixels be processed in parallel. I tried to use Parallel class with Partitioner class (to make processing more chunky). It works, but much longer than without parallelism. And I don't know why (I have experience using Parallel class, so it can't be my misunderstanding of its work).

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@Eli, I added "Black and white 2-color palette" to the plugin, because it is used on your sample image. Also, before applying dithering, I changed image contrast to 70. I achieved almost the same result as on Github, but it is slightly different. I think that github author made some preprocessing and other actions in his algorithms.

Preprocessed_Sierra_Light.jpg

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Thanks for the "Black and white 2-color palette" addition. The result is very close. I think that you should integrate in the effect contrast and brightnes sliders that way you should have better control over the results.

 

If you find out what other actions were applied in the Github example and add them to the effect would be nice too. The "wavy dithering" is very interesting.  It looks like the ones used on the presidents' portraits on the dollar bills.

Spoiler

Obverse_of_the_series_2009_$100_Federal_

 

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On 5/4/2018 at 5:32 PM, toe_head2001 said:

Why would someone want to apply dithering to their images these days?

^ This is not a rhetorical question.

Artistic effect or compatibility with very old games/softwares. Some older games have limited palette, and to reduce banding, dithering is used. If you are modding say Ultimate Ride Disney Coaster, you'd note that dithering is the only way to reduce banding in menu images. Some games are reduced to 256 colors, and dithering helps the issue of banding. For artistic effect, amiga images achieves have some very nice images of how low color and dithering can give a oil feel that is somewhat rough. But, I do agree that for modern softwares purpose, for all intents and purposes, dithering isn't very useful, and there's no point to it unless you have a taste for it or you specialize in pixel art.

 

Indexing still have use in separating colors for generating effects though. Threshold filter has some very useful niche usage for example.

Edited by Reptillian
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  • 6 months later...

Just checking in to let you know that this plugin is fantastic. The previous one in paint.net was getting frustrating because it would show horizontal banding artifacts. (I don't know if it was the included or one I added to Effects.) This one does not show those problems at all!

As to the modern uses - although not my day job (or paid job :-( ) I sometimes have to prep items for commercial printing. This plugin is ideal for reducing grey scale images to dithered black and white, which give much more predictable results at the print shop. On a similar note, it is ideal for building index separations from full colour images before sending them as shirt silk screen masters.

For that last use, the one feature that could make this even more useful is a way to specify a custom palette - which could be made to match up to a selection of available silk screen inks. Currently you have a selection of palettes, but no custom option. There is already an accepted paint.net palette format, so just allowing one of those as an input would be a nice feature!

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27 minutes ago, ChrisJS said:

The previous one in paint.net was getting frustrating because it would show horizontal banding artifacts.

 

You're talking about the one in my plugin pack. Just to let you know, I fixed that problem a long time ago. Update to my latest pack and see if you like it better.

Click to play:
j.pngs.pngd.pnga.pngp.png
Download: BoltBait's Plugin Pack | CodeLab | and how about a Computer Dominos Game

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1 minute ago, BoltBait said:

 

You're talking about the one in my plugin pack. Just to let you know, I fixed that problem a long time ago. Update to my latest pack and see if you like it better.

Yeah - I'm not great about keeping those up to date. My phone has me spoiled.

 

Has anyone created a Paint.net plugin subscription service??  🙂

 

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@ChrisJS, thanks for your feedback! Yes, it would be great to be able to choose a custom palette. But first, I need to learn how to work with paint.net palettes because, I never came across this. I also plan to add another color quantization algorithm. Currently, automatic colors are generated by dividing image RGB space into equal volumes. The new algorithm will use octree for color quantization.

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  • 5 months later...
On 5/1/2020 at 10:50 PM, pavlik1307 said:

@ChrisJS, thanks for your feedback! Yes, it would be great to be able to choose a custom palette. But first, I need to learn how to work with paint.net palettes because, I never came across this. I also plan to add another color quantization algorithm. Currently, automatic colors are generated by dividing image RGB space into equal volumes. The new algorithm will use octree for color quantization.

Hi Pavlik, thanks for your plug-in. It was very useful for comparing various algorithms for converting different types of images to monochrome bitmaps. Any chance you'd release a new version soon as you mentioned? I think it would also be good to see other methods:

Gradient-based error-diffusion dithering mentioned in https://en.wikipedia.org/wiki/Dither 

- A Simple and Efficient Error-Diffusion Algorithm (https://perso.liris.cnrs.fr/victor.ostromoukhov/publications/pdf/SIGGRAPH01_varcoeffED.pdf )

- Structure-Aware Error Diffusion (https://perso.liris.cnrs.fr/victor.ostromoukhov/publications/pdf/SIGGRAPH-ASIA09_saed.pdf) 

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  • 2 weeks later...

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