Chromatic Aberration Filters Proposal

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Chromatic Aberration Filters Proposal

Fabien Fellay
Hi all,

I released some filters that allow emulating a very basic chromatic aberration effect. They are available here with some explanations:
<https://inkscape.org/da/~fabien.fellay/%E2%98%85chromatic-aberration-filters>

I later noticed that Inkscape already has similar filters available in the menu Filters > Color > Nudge RGB/CMY...
However, the proposed filters here differ slightly regarding the alpha channel management and they do not flood the background with any color. If one just want to apply quickly a basic chromatic aberration effect, I think those filters may come in handy.

In the hope that someone will like them or find them useful.

Best regards,
Fabien

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Re: Chromatic Aberration Filters Proposal

_ makiimai
Those are great, thank you very much! makiimai

2018-01-28 10:50 GMT+10:30 Fabien Fellay <[hidden email]>:
Hi all,

I released some filters that allow emulating a very basic chromatic aberration effect. They are available here with some explanations:
<https://inkscape.org/da/~fabien.fellay/%E2%98%85chromatic-aberration-filters>

I later noticed that Inkscape already has similar filters available in the menu Filters > Color > Nudge RGB/CMY...
However, the proposed filters here differ slightly regarding the alpha channel management and they do not flood the background with any color. If one just want to apply quickly a basic chromatic aberration effect, I think those filters may come in handy.

In the hope that someone will like them or find them useful.

Best regards,
Fabien

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Re: Chromatic Aberration Filters Proposal

Inkscape - User mailing list
Works fine for me too !

On the other hand you can remove the background of the existing filters afterwards : select the first primitive (Fill) in the Filters Editor and put the Fill opacity to zero.

ivan


Le dimanche 28 janvier 2018 à 02:55:13 UTC+1, makiimai # <[hidden email]> a écrit :


Those are great, thank you very much! makiimai

2018-01-28 10:50 GMT+10:30 Fabien Fellay <[hidden email]>:
Hi all,

I released some filters that allow emulating a very basic chromatic aberration effect. They are available here with some explanations:
<https://inkscape.org/da/~ fabien.fellay/%E2%98% 85chromatic-aberration-filters >

I later noticed that Inkscape already has similar filters available in the menu Filters > Color > Nudge RGB/CMY...
However, the proposed filters here differ slightly regarding the alpha channel management and they do not flood the background with any color. If one just want to apply quickly a basic chromatic aberration effect, I think those filters may come in handy.

In the hope that someone will like them or find them useful.

Best regards,
Fabien

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Re: Chromatic Aberration Filters Proposal

Fabien Fellay
Thank you very much for your feedback.

As long as the background can be easily removed when using the existing filters, I am now figuring out that my proposed chromatic aberration filters do not bring something fundamentally new (except from the behavior with the alpha channel, which is different).

However, I see 2 issues with the existing filters that can be improved:

1) Aliazing issue with the 'nudge RGB' filter:
The 'nudge CMY' and the 'nudge RGB' filters do not have a totally symmetrical behavior. While the 'nudge CMY' filter is perfectly fine, by careful examination, one will notice that the 'nudge RGB' filter suffers from a subtle aliasing effect at the border of the 3 decomposed layers (present in all browsers rendering and Inkscape itself). However, I found a nice (not so easy to figure out) solution to this. Replace the 3 color matrices:
 red:
  0 0 0 0 1
  0 0 0 0 0
  0 0 0 0 0
  1 0 0 0 0
 green:
  0 0 0 0 0
  0 0 0 0 1
  0 0 0 0 0
  0 1 0 0 0
 blue:
  0 0 0 0 0
  0 0 0 0 0
  0 0 0 0 1
  0 0 1 0 0
by the following new ones (in short: add the 1 -1 at the end of the last lines):
 red:
  0 0 0 0 1
  0 0 0 0 0
  0 0 0 0 0
  1 0 0 1 -1
 green:
  0 0 0 0 0
  0 0 0 0 1
  0 0 0 0 0
  0 1 0 1 -1
 blue:
  0 0 0 0 0
  0 0 0 0 0
  0 0 0 0 1
  0 0 1 1 -1
and you will see that the weird aliasing effect just vanishes. Moreover, that way, the 'nudge RGB' filter recovers a totally symmetrical behavior compared to the 'nudge CMY' filter and everything is fine.

2) Offset issue with the 'nudge RGB' and 'nudge CMY' filters:
The 2 first offsets are (logically) applied to the source graphic while the third offset is (surprisingly) applied to the blended results of the first 2 layers. This is rather counter-intuitive. It seems more logical that the third offset also applies to the source graphic (my filters just do that).

And, voilà: if those 2 issues are corrected, one will not really need my filters anymore. As long as the existing filters are actually built-in filters, I'm going to open a bug report (with solution) to <https://bugs.launchpad.net/inkscape/>.

Warm regards,
Fabien

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