Saving of big pictures (PNG) can be buggy (loading too)

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Guest

Saving of big pictures (PNG) can be buggy (loading too)

Post by Guest »

If I load a big PNG picture (like 100MB), the loading progress bar is sometimes not visible, sometimes it jumps very rapidly between different values (loading almost finished then it just starts again, jumps to the middle, back to the beginning and so on). But I did not try to repeat this behaviour on purpose, I just think it depends on the filesize (and maybe the compression level used in PNG -> '2').

What I can reproduce is:
If I select a part of the picture (about a third), remove the surrounding parts (Strg-Y) and save the new picture (again as PNG), some things can happen.

The progress bar does not appear at all, I can only see that the saving is finished by the disappearing of the * symbol in front of the filename in the titlebar. This seems to be a minor problem but in case of big pictures and therefore a noticeable time span of some seconds it can lead to these two severe problems:

1. If I try to reopen (Strg-R) the original picture during the saving (because I want to cut out a different part for example), than XNView saves bullshit only: A mixture between the selected part and the original picture. But no error messages occurs.

2. If I try to load the next picture during the saving, then XNView just crashes.

I don't know if this depends on PNGs only at all, but it is very annoying.

XNView 1.80.3 Windows XP SP2

Thanx
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xnview
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Re: Saving of big pictures (PNG) can be buggy (loading too)

Post by xnview »

Guest wrote:If I load a big PNG picture (like 100MB), the loading progress bar is sometimes not visible, sometimes it jumps very rapidly between different values (loading almost finished then it just starts again, jumps to the middle, back to the beginning and so on). But I did not try to repeat this behaviour on purpose, I just think it depends on the filesize (and maybe the compression level used in PNG -> '2').

What I can reproduce is:
If I select a part of the picture (about a third), remove the surrounding parts (Strg-Y) and save the new picture (again as PNG), some things can happen.

The progress bar does not appear at all, I can only see that the saving is finished by the disappearing of the * symbol in front of the filename in the titlebar. This seems to be a minor problem but in case of big pictures and therefore a noticeable time span of some seconds it can lead to these two severe problems:

1. If I try to reopen (Strg-R) the original picture during the saving (because I want to cut out a different part for example), than XNView saves bullshit only: A mixture between the selected part and the original picture. But no error messages occurs.

2. If I try to load the next picture during the saving, then XNView just crashes.

I don't know if this depends on PNGs only at all, but it is very annoying.

XNView 1.80.3 Windows XP SP2

Thanx
Could you tell me which size (pixels) do you use?
Pierre.
Guest

Post by Guest »

I had some hundreds pictures in different sizes, but as average value I would say 5k x 6k pixel.
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xnview
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Post by xnview »

Anonymous wrote:I had some hundreds pictures in different sizes, but as average value I would say 5k x 6k pixel.
And when you save such picture, you can reopen or load next file???
These features are disable between saving...
Pierre.
Guest

Post by Guest »

And when you save such picture, you can reopen or load next file???
These features are disable between saving...
Yes, I load this picture, do some little edits (contrast adjustment for example), and save it (Strg-S). For a very short period of time the progress bar shows the saving (<1sec). Then I press Strg-R (reload) or the 'next picture' icon in the toolbar. The selected action does not occur, at least not immediately, but the saved picture file is corrupted or XnView crashes after some seconds (happens not all the time).

It seems to me that XnView THINKS that the saving is complete, but it is not. Maybe this has to do with the compression algorithm used for PNG?

If you want I can set up a reproducable scenario (at least it is reproduceable at my computer) and send the picture to you. But I don't think that this behaviour depends on my pictures alone :-). Perhaps I can make some screenshots ... I will try.
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xnview
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Post by xnview »

Anonymous wrote:
And when you save such picture, you can reopen or load next file???
These features are disable between saving...
Yes, I load this picture, do some little edits (contrast adjustment for example), and save it (Strg-S). For a very short period of time the progress bar shows the saving (<1sec). Then I press Strg-R (reload) or the 'next picture' icon in the toolbar. The selected action does not occur, at least not immediately, but the saved picture file is corrupted or XnView crashes after some seconds (happens not all the time).

It seems to me that XnView THINKS that the saving is complete, but it is not. Maybe this has to do with the compression algorithm used for PNG?

If you want I can set up a reproducable scenario (at least it is reproduceable at my computer) and send the picture to you. But I don't think that this behaviour depends on my pictures alone :-). Perhaps I can make some screenshots ... I will try.
Yes please, i can't reproduce it
Pierre.
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JohnFredC
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Location: Sarasota Florida

Post by JohnFredC »

I too find that XNView (all recent versions) occasionally crashes when saving very large PNGs. I find it happens most often (which isn't "very" often.. more like rarely) if I attempt to close XNView before saving is complete AND the PNG is very large (~100Mb or more)...
John
guest

Post by guest »

Hi!

Sorry, I could not reproduce the effect with a single file. :( It's seems then clear to me that it depends on the work flow and/or environment (too). So I will describe what I did:

I got (paper) photos, and scanned them (three or four at once) with high resolution, saved each scan result als PNG with an average size of 90 MB. In a second step I opened every picture (one after one of course) and cutted the single photos (using STRG-Y) and saved these again (as PNG) in a different folder on my disk. Used STRG-R to restore the big picture and repeat this procedure with the next photo in it.

This way XnView switched many times between two directories, the first one containing for example 20 picture á 90MB, and the second one growing to e.g. 60 pictures á 30MB.

XnView needs a lot of time to create the thumbnail view of these directories of course. The browser view is active, because I use it sometimes to compare certain pictures. And there the thumbnails are displayed and - I assume - updated in the background too even if the browser view is in the background. I assume this because when I tried to create a single buggy picture as I suggested, I noticed that the saving and loading times were much, much smaller: The directory just contained one big and one small picture. And certainly I won't mail you my whole picture directories :D

So my guess is: The combination of big picture files and a certain amount of them can lead to a confusion (in XnView) when saving oder loading the actual picture and updating their thumbnails at once. Does this make sense to you :?: If not I will keep my eyes open for the next occurence of this effect. But I'm not scanning pictures on a regular base, so that can take some time.

Thanx for your patience!