Puppy Linux Discussion Forum

MochiMoppel · Joined: 26 Jan 2011 Posts: 1925 Location: Japan

For small image corrections and format conversions I use mtPaint 3.40.
In some cases mtPaint would not allow me to save an image as JPEG. For example my avatar is in PNG format and mtPaint offers no JPEG options in the Save As dialog (see screenshot). For other PNGs I would be offered a much wider range:

What determines which Save As options I get and how can I force mtPaint to offer me a JPEG choice?

8Geee · Joined: 12 May 2008 Posts: 2088 Location: N.E. USA

The Save As option in FILE usually has the selection JPG or JPEG with a %Quality box. I see this is mtpaint3.40 you may need 3.44 if this is a bug.

One other thing occured to me... you might need to set the pallette as a 24bit RGB instead of an indexed pallette.

Regards
8Geee

nosystemdthanks · Joined: 03 May 2018 Posts: 699

palette.

https://bbs.archlinux.org/viewtopic.php?id=107250

don570 · Joined: 10 Mar 2010 Posts: 5374 Location: Ontario

The answer above is correct, however I would suggest GIF format
since it is a lossless format and is designed to work
with high quality grey scale images which you have.
Then you could still use an indexed palette.

I avoid using jpeg because it adds fuzz i.e. lossy format.

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tallboy · Joined: 21 Sep 2010 Posts: 1545 Location: Drøbak, Norway

Hi MochiMoppel.
I stumbled on a sentence in an answer to a problem related to Imagemagick, and thought I might have found the answer to you problem.

https://stackoverflow.com/questions/12424018/how-to-replace-white-background-color-with-transparent-of-an-image-in-imagemagic

MochiMoppel · Joined: 26 Jan 2011 Posts: 1925 Location: Japan

Thanks everybody. I finally got it:
Menu > Image > Convert to RGB
I would have wished that mtPaint does the conversion automatically but I somehow understand the reasoning behind this unintuitive interface.

nosystemdthanks · Joined: 03 May 2018 Posts: 699

tallboy · Joined: 21 Sep 2010 Posts: 1545 Location: Drøbak, Norway

Thank you, I learn something new every day! Very Happy

Look at my avatar, I finally managed to get rid of the white square background, I used Imagemagic.
I first scaled the .jpg image to max 80x80 pixels in mtpaint, and then:

don570 · Joined: 10 Mar 2010 Posts: 5374 Location: Ontario

Additional information:

The GIMP gmic plugins has a feature in its 'Color' section
where a color can be selected and converted into transparency in an image.
-----------------------------------------------------------------
Latest Gimp appimage works in fatdog64 and Easy 0.9.10

https://github.com/aferrero2707/gimp-appimage/releases/download/continuous/GIMP_AppImage-git-2.10.9-withplugins-20181206-x86_64.AppImage
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MochiMoppel · Joined: 26 Jan 2011 Posts: 1925 Location: Japan

If I wanted to set a transparent background for my avatar I would keep it as PNG and "Save As" in mtPaint with Transparency index changed from -1 to 0 (white happens to have an index number 0 in the displayed color palette).
Anyway, I mentioned my avatar only as an example (spares me to post another sample pic). Transparency is an interesting subject but not related to my question.

tallboy · Joined: 21 Sep 2010 Posts: 1545 Location: Drøbak, Norway

Looks spooky? I agree, especially on a darker background, but that is because I probably am a little spooky... Laughing

It's funny how the brain interprets a drawing, without the white frame the avatar suddenly looks a bit anonymous...
Sorry for bringing in a new subject to your thread.