Bug 130300 - compress png files
Summary: compress png files
Status: RESOLVED NOTABUG
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: LibreOffice (show other bugs)
Version:
(earliest affected)
6.4.0.3 release
Hardware: All macOS (All)
: medium enhancement
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-01-30 18:48 UTC by G Seifert
Modified: 2020-05-02 16:30 UTC (History)
1 user (show)

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Description G Seifert 2020-01-30 18:48:39 UTC 
Running all .png files in the app package through a png optimiser saves around 72% of the space. That would make the uncompressed app package about 45 MB smaller (from 765 MB).
Comment 1 ian 2020-01-30 22:37:14 UTC 
Thank you for reporting this tip. 

I am reducing the bug report's severity to "Enhancement," as reducing LibreOffice's file size is not vital to its operation.
Comment 2 G Seifert 2020-01-30 23:58:04 UTC 
Sorry if I picked the wrong setting. It’s a bit overwhelming.
Comment 3 Alex Thurgood 2020-02-05 07:44:54 UTC 
@G Seifert : which open source png optimizer did you use ?
Comment 4 Alex Thurgood 2020-02-05 08:01:41 UTC 
Curerntly testing ImageOptim on LO6342 app bundle. Will report back on results.
Comment 5 Alex Thurgood 2020-02-05 08:45:55 UTC 
Well testing with ImagOptim on the LO6342 bundle only gained less than 1Mb in space saving, using the default compression options :

- non-lossless
- Zopfli
- OxiPNG
- AdvPNG
- JPEGOptim
- Jpegtran
- GIFsicle

Unless of course, you are talking about lossless compression...
Comment 6 Alex Thurgood 2020-02-05 08:46:34 UTC 
(In reply to Alex Thurgood from comment #5)
> Unless of course, you are talking about lossless compression...

Sorry, I meant, lossy compression...
Comment 7 Alex Thurgood 2020-02-05 08:47:45 UTC 
(In reply to Alex Thurgood from comment #5)
> Well testing with ImagOptim on the LO6342 bundle only gained less than 1Mb
> in space saving, using the default compression options :
> 

 - non-lossy
Comment 8 Alex Thurgood 2020-02-12 09:37:41 UTC 
G Seifert : it might help us if you specified which options you used, and which optimiser, to save so much space.
Comment 9 G Seifert 2020-02-12 10:39:39 UTC 
I’m traveling at the moment. I’ll check that ASAP.
Comment 10 G Seifert 2020-02-13 11:26:47 UTC 
I indeed had activated lossy magnification with PNG quality set to 80%. 

I checked some files and for some the difference was very little (only a few pixels changed a tiny bit), but for others, it would introduce dithering that was clearly visible in magnification (Inkscape.app/Contents/Resources/share/icons/Adwaita/256x256/legacy/face-angel.png). Those were also the ones with the biggest savings. 

I don't know where those icons will be used but a 125kB for Inkscape.app/Contents/Resources/share/icons/Adwaita/512x512/legacy/accessories-dictionary.png?? (this one compressed very nicely to 55 kB).

So just running it through ImagOptim will not work but seeing that icons can be better compressed and checking what icons are actually useful at what resolutions could save quite a bit.
Comment 11 QA Administrators 2020-02-15 06:51:38 UTC Comment hidden (obsolete)
Comment 12 eisa01 2020-05-02 16:30:22 UTC 
Judging by the savings in comment #5 this doesn't seem like a priority?

The examples in comment #10 also refer to Inkscape

It would probably not just apply to the macOS package either