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Showing very large pictures in gallery

asked 2015-03-28 09:51:58 +0200

derHorst gravatar image

updated 2015-03-28 15:02:29 +0200

chemist gravatar image

Hi sailors, It seems the native gallery is crashing if one tries to open a very large picture. I've tried to open a externally created jpeg of 9600x6144 pixels, a compilation of smaller pictures merged to a single one.

Did anyone else tried something similar?

M

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Just tested 18000x18000px image of Orion Nebula on my device. It is handled nice and seems to be downscaled on decoding (jolla-gallery uses a bit more 100 MiB to show this image and details are blurred on zooming in).

Can you provide an example image to reproduce crash? It might be unrelated to image size.

Self-Perfection ( 2015-03-29 23:16:36 +0200 )edit

Hi, (is there a way to upload pictures here?)

To reproduce this:

  • start Gimp (2.8.10)
  • create a new picture of 10000x10000, 72 dpi, RGB, filled with background color, defaults to white here
  • save the result as jpg with 90% compression (also default)
  • open the picture on (at least my) Jolla crashes the Gallery and all other running apps!

I can open the Orion btw., so you might be right and this is not a memory problem. So whats wrong with the Gimp pictures? And why does it kill ALL other Aps?

Any hints to trace this down?

M

derHorst ( 2015-03-30 08:57:45 +0200 )edit

@derHorst

is there a way to upload pictures here?!

There is, but upload button is available only in question or answer dialog. But you can use uploaded images in comment field as well wink face

Posting here several megabytes image does not look like good idea, however. Please, do find a way to link example image. Your way reproduce involves too many variables and steps. For instance, your default jpeg saving options might be saved options from previous jpg exports and not Gimp defaults.

As for tracking the issue,check logs ( devel-su journalctl -af ) while dealing with your image. Also make sure that image is not saved with progressive option, as progressive jpg require much more resources for decoding.

Self-Perfection ( 2015-03-31 13:55:11 +0200 )edit

Hi,

Have fun with the picture...

And thank you for the hint! Btw. the browser is able to show it.

M

derHorst ( 2015-03-31 21:41:04 +0200 )edit

Have fun with the picture...

Your picture is displayed perfectly well on my device.

Self-Perfection ( 2015-03-31 22:27:19 +0200 )edit

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answered 2015-03-28 10:30:01 +0200

simo gravatar image

Pics opened should fit into RAM so that they can be handled. In your example, the full resolution takes 121 screens, why the need to watch that on the phone?

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It was just to show the picture to others.

The point is I believe the app doesn't check the required memory in order to render the picture for the designated screen and therefore crashed without notice or error message.

derHorst ( 2015-03-28 13:22:30 +0200 )edit
1

Pics opened should fit into RAM so that they can be handled.

They don't. There are number of possible approaches to view huge images, the simplest one for JPEG is to downscale them on decoding. This approach does not impose extra burden on CPU but instead reduces required calculations to get decoded bitmap in memory.

But even assuming dumb approach to just decode image fully: 9600*6144*3(24 bits colour?)/1024/1024=168.75 MiB. Jolla have much more RAM than 169 MiB, why it should not be able to display such image?

Self-Perfection ( 2015-03-29 23:01:38 +0200 )edit
1

answered 2016-03-17 19:11:09 +0200

derHorst gravatar image

After all the problem was in the jpeg encoding. The gallery seems to have had a problem with progressive encoding.

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Asked: 2015-03-28 09:51:58 +0200

Seen: 307 times

Last updated: Mar 17 '16