0.80: Pan Tool show corruption

[c-herr-g]

A corruption is seen on the Pan Tool when using the option "Change Color Depth". It happens when you select the 8 bit option and any of the filters on the option box. I have checked against several type of images and it happens on all of them (png, gif, jpeg). This however, doesn't seem to corrupt any file when I save them.

This issue was not seen on v0.78, I uninstalled this version and installed 0.79, the issue is also seen there, didn't noticed before because I skipped that version.

Here is how it looks :
Step 1

file opened

Step 2

changed options

And the corruption :

the corruption

pan_tool_corruption4.png (94.75 KiB) Viewed 1420 times

My system is Opensuse Leap, with the kernel ver 4.1.26, with plasma desktop 5.5.5 and Qt version 5.5.1

[helmut]

Thank you for your problem report and sorry for the very late reply.

I could reproduce your problem using the following steps:
1. Open a JPG photo
2. Select Image » Adjust » Enhance colors
3. Set "Saturation" to "-100" and apply with "OK" button.
(Your image is a greyscale image, now).
4. Zoom into the image. XnView displays the Pan tool in the bottom-right corner. The image in the Pan tool looks fine. (correct).
5. Select "Image » Change color depth..."
6. Choose "Color = 8 and Dithering = Floyd Steinberg.
7. Confirm with "OK".
(Your image is a dithered image with 8 colours, now)
Actual result: The image in the Pan tool looks very messy and full of pixels.
Expected result: The image in the Pan tool should show a miniature of the actual picture.

Until now (XnView MP 0.84), XnView MP doesn't use high quality zooming for the pan tool. For this reason dithered black&white images look very ugly in the pan tool.

Suggestion/Bug fix: High quality zooming should be applied for Pan tool.

[c-herr-g]

Thank you for checking this odd behavior, will try this on the current version to see if this fixes it.

[helmut]

Thank you for checking this odd behavior, will try this on the current version to see if this fixes it.

High quality miniature image in the pan tool isn't available, yet, so you will experience the same problem with v0.84 (see my description above).

[c-herr-g]

Oh, sorry, my bad. I thought you meant the current version. It's ok, this a low priority bug, I can wait until the next version. On a semi-related note, may I suggest you another thing for the bug report?, a "Attempts to reproduce" line. This can help to see if the bug happens all the time or just rarely, and set the developer to prioritize fixes. Just a suggestion. Keep up the good work

[helmut]

Oh, sorry, my bad. I thought you meant the current version. It's ok, this a low priority bug, I can wait until the next version.

Thank you for your reply, c-herr-g. A moderator will post here so you will be informed once a test version with the bug fix is available.

On a semi-related note, may I suggest you another thing for the bug report?, a "Attempts to reproduce" line. This can help to see if the bug happens all the time or just rarely, and set the developer to prioritize fixes. Just a suggestion. Keep up the good work

Such an additional info might be useful. Prioritizing bug fixes might be a good idea though as long as we use the forum for bug reporting and handling it's handle to add even more info. But I'll keep this in mind.

[xnview]

O.k., thank you, I can also reproduce the problem. Issue 890 is fixed in next version.

[xnview]

This problem is supposed to be fixed in XnView MP 0.85 beta 1. Please check and confirm the bug fix here.

[helmut]

Confirmed fixed in 0.85 beta 1.