kanryu / quickviewer

A image/comic viewer application for Windows, Mac and Linux, it can show images very fast
https://kanryu.github.io/quickviewer/
GNU General Public License v3.0
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Add description to Lanczos4/Lanczos3 #98

Open gitoss opened 5 years ago

gitoss commented 5 years ago

Probably using a portable program is a bit nerdy anyway, but for simple-minded people like me it would be nice to have a short description in () about the difference Lanczos3 and Lanczos4 like with bicubic and nearest neighbor.

A quick googling results in "4 taps (Lanczos4) is sharper than 3 taps (Lanczos3), but introduces more ringing (halo effect)", so there seems to be no straight better/worse, but you never know :-o

kanryu commented 5 years ago

Thank you for your interest in QuickViewer. This software is developed for people who have many digital books, scrapbooks and photos of digital cameras.

Some filters (Shaders) that QuickViewer has can have a better image display than the usual algorithm.

For many people, what Shader to choose is just an option, and you may not be interested in what that option means. For example, do you imagine how the compressor works when you make the refrigerator stronger?

With filters (zimg) that QuickViewer adopts, it seems that Bicubic returns the best performance in many cases. The Lanczos 3/4 is a sharper filter, but it is good for reading scrapbooks.

gitoss commented 5 years ago

Thanks for the answer, and let me please clarify my suggestion.

It's just about the difference between Lanczos4 and Lanczos3 which is not specified in the Shader menu.

Exposing people to an option that is not clear imho is not ideal design - the menu should be like "bilinear (fast)" and "bicubic (quality)": "Lanczos4 (faster)" and "Lanczos3 (slower)" or something along these lines.

For many people, what Shader to choose is an option they'd like to try, and you may be interested in what that option means. For example, if your new refrigerator has a button labeled "HCX+", do you imagine wondering what that means and what it will do?

In any case: Thanks for the great app!!!

kanryu commented 5 years ago

I think your suggested expressions "Lanczos4 (faster)" and "Lanczos3 (slower)" are not very appropriate. Because Lanczos is anyway more computationally expensive and therefore slower than Bicubic.

When comparing Lanczos and Bicubic, the former resizing result is sharper and gives better results especially when the image is enlarged.

On the other hand, bicubic seems to be a natural gradation at the time of reduction. Shrinking with Lanczos has the effect of emphasizing the edges.

Generally Lanczos 3 is sharper Lanczos 4 should have a more natural gradation, but in fact it is very difficult to find the difference. Especially when using zimg engine.

I think it's difficult to give Lanczos's menu a reasonably short annotation based on the above considerations.