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mtPaint - How to save as JPEG? [SOLVED]

Posted: Mon 10 Dec 2018, 04:02
by MochiMoppel
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:
  • BMP
    J2K
    JPEG2000
    JPEG
    PAM
    PCX
    PNG
    PPM
    TGA
    TIFF
    XPM
What determines which Save As options I get and how can I force mtPaint to offer me a JPEG choice?

Posted: Mon 10 Dec 2018, 04:53
by 8Geee
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

Re: mtPaint - How to save as JPEG?

Posted: Mon 10 Dec 2018, 04:54
by nosystemdthanks
palette.

https://bbs.archlinux.org/viewtopic.php?id=107250
By default the mtpaint setting for new documents is set to 'indexed pallette'.
This format is not saveable in jpg-Format!
You have to change setting for new documents to 24bit RGB once and you can save as jpg/jpeg and much more formats.

Posted: Mon 10 Dec 2018, 23:03
by don570
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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Posted: Tue 11 Dec 2018, 13:05
by tallboy
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/124 ... imagemagic
You cannot have transparent background colors in your JPEGs. The JPEG file format doesn't support transparency.
But that was until I reopened the forum and saw your avatar, which I thought was transparent, which it is not. Sorry! :? But there may be other limitations with .jpg that makes a conversion problematic?

BTW: You may find the scripts in this collection quite interesting: http://www.fmwconcepts.com/imagemagick/magicwand/ The homepage takes a while to open, it contains all the examples...

Posted: Tue 11 Dec 2018, 15:23
by MochiMoppel
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.

Posted: Tue 11 Dec 2018, 17:44
by nosystemdthanks
tallboy wrote:
You cannot have transparent background colors in your JPEGs. The JPEG file format doesn't support transparency.
jpeg2000 does, and mtpaint even supports it. the browser doesnt though-- neither does geeqie, but you can save as jpeg2000 (after converting to rgb) and that can be converted to a png.

but a lot of good that does for transparent jpegs. note i never saved a jpeg2000 file until today.

Posted: Tue 11 Dec 2018, 20:58
by tallboy
Thank you, I learn something new every day! :D
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:

Code: Select all

convert alfred.e.jpeg -fuzz 20% -transparent white afred-5.gif
The fuzz option takes hight for a not 100% clean white color.
Voila! as the say in french bistros...
I obviously managed to imagine the french bistro visit so intense that I misspelled alfred. 8)
And as I was in the mood, a transparent mm.gif!

Posted: Tue 11 Dec 2018, 22:19
by don570
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-ap ... 4.AppImage
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Posted: Wed 12 Dec 2018, 01:03
by MochiMoppel
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.

Posted: Wed 12 Dec 2018, 15:26
by tallboy
Looks spooky? I agree, especially on a darker background, but that is because I probably am a little spooky... :lol:
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.