Proposal: Add thumbnails of different sizes to .kra files?

Alvin Wong alvinhochun+krita at gmail.com
Mon Jun 6 18:11:10 UTC 2016


About the mergedimage.png, I see that the png itself isn't compressed
at all, only compressed by DEFLATE inside the zip container. For a
completely-transparent image of 3600x2400, the mergedimage.png is 33MB
uncompressed, which is ridiculous. It's 55KB compressed, much smaller,
but still a bit larger than expected.

Would compressing the png itself and STORE it inside the zip container
instead be better? Might want to benchmark and compare.

2016-06-07 0:59 GMT+08:00 Boudewijn Rempt <boud at valdyas.org>:
> On Mon, 6 Jun 2016, Dmitry Kazakov wrote:
>
>> The only trouble I see with thumbnail generation is the speed. It would be
>> great to see the speen benchmarks of saving a PNG of each size.
>
>
> Well that needs checking indeed.
>
>> People are complaining
>> about Krita saving too slow :( I even heard a wish (during the KomMissia)
>> to disable any preview and mergedimage.png saving into .kra to make the
>> saving quicker.
>
>
> That's just flat-out not going to happen.
>
>
>>
>>
>>
>>
>> On Mon, Jun 6, 2016 at 3:44 PM, Boudewijn Rempt <boud at valdyas.org> wrote:
>>       On Mon, 6 Jun 2016, Alvin Wong wrote:
>>
>>             Is that needed? I would imagine whatever plugins or programs
>> would
>>             already have known the absolute size they want in pixels,
>> independent
>>             of the dpi, and could just automatically take the closest
>> thumbnail or
>>             the mergedimage and scale it down accordingly.
>>
>>
>>       I don't know... Hidpi and Retina is still really confusing me across
>> the board.
>>
>>             Perhaps you can also add a thumbnail of size 2048x2048 but I
>> wonder
>>             how much it would add to the file size...
>>
>>             By the way I remember seeing in the Krita git repo some
>> scripts which
>>             look like plugins for certain programs to extract the
>> thumbnail, but I
>>             can't seem to find them now. Does anyone know, other than the
>> Windows
>>             shell extension, what other file managers or programs
>> currently
>>             supports extracting thumbnails from Krita files/
>>
>>
>>       Code for Qt applications is in the kimageformats repo now, I moved
>>       that some time ago. There are also scripts for nautilus and gnome.
>>
>>
>>             Best Regards,
>>
>>             Alvin
>>
>>
>>             2016-06-06 14:54 GMT+08:00 Boudewijn Rempt <boud at valdyas.org>:
>>                   I think we can easily do this: but maybe we should at
>> the same time
>>                   add thumbnails with a @2 extension to prepare for hidpi
>> and retina
>>                   displays?
>>
>>
>>                   On Mon, 6 Jun 2016, Alvin Wong wrote:
>>
>>                         Hi,
>>
>>                         I would like to suggest Krita add (uncropped)
>> thumbnail images of
>>                         different sizes to the file to allow faster
>> extraction of thumbnails
>>                         by external applications.
>>
>>                         There is currently one preview.png which is at
>> maximum 256x256, so
>>                         generating thumbnails larger than that would
>> require scaling down from
>>                         the mergedimage.png which could be very large and
>> may take a
>>                         comparatively long time to process. Even though
>> the actual time per
>>                         file might not be much, it could add up for a lot
>> of files.. Also, the
>>                         preview.png is cropped to the non-transparent
>> region
>>                         (https://bugs.kde.org/show_bug.cgi?id=363968)
>> which makes things a bit
>>                         weird and inconsistent.
>>
>>                         I think having thumbnails for the sizes
>> (maintaining aspect ratio) of
>>                         256x256 and 1024x1024 would suffice, but boud
>> suggested having 512x512
>>                         might be nice too. Adding in these sizes means
>> that, for thumbnails
>>                         equal to or below the available sizes, they can be
>> extracted and
>>                         optionally scaled down from those instead of
>> scaling down from the
>>                         mergedimage.png. Obviously, sizes larger than that
>> would still require
>>                         using the mergedimage.png, but hopefully it would
>> be quite rare for an
>>                         application to request for thumbnails larger than
>> 1024x1024... (4K
>>                         displays aren't popular yet... right?)
>>
>>                         For the record, according to this MSDN page
>>
>>
>> (https://msdn.microsoft.com/en-us/library/windows/desktop/cc144118(v=vs.85).aspx)
>>                         Windows asks for the sizes 32/96/256/1024.
>>
>>                         I am asking for this as the developer of the
>> Windows Shell Extension.
>>
>>                         Any suggestions?
>>
>>                         Best Regards,
>>
>>                         Alvin
>>                         _______________________________________________
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>>                         kimageshop at kde.org
>>                         https://mail.kde.org/mailman/listinfo/kimageshop
>>
>>
>>
>>                   --
>>                   Boudewijn Rempt | http://www.krita.org,
>> http://www.valdyas.org
>>                   _______________________________________________
>>                   Krita mailing list
>>                   kimageshop at kde.org
>>                   https://mail.kde.org/mailman/listinfo/kimageshop
>>
>>             _______________________________________________
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>>             https://mail.kde.org/mailman/listinfo/kimageshop
>>
>>
>>       --
>>       Boudewijn Rempt | http://www.krita.org, http://www.valdyas.org
>>       _______________________________________________
>>       Krita mailing list
>>       kimageshop at kde.org
>>       https://mail.kde.org/mailman/listinfo/kimageshop
>>
>>
>>
>>
>> --
>> Dmitry Kazakov
>>
>>
>
> --
> Boudewijn Rempt | http://www.krita.org, http://www.valdyas.org
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