[Libreoffice-bugs] [Bug 136012] New: Regression: embedded png files look extremely bad in Impress 7.0.x, OK in 6.4.6

[bugzilla-daemon at bugs.documentfoundation.org]

https://bugs.documentfoundation.org/show_bug.cgi?id=136012

            Bug ID: 136012
           Summary: Regression: embedded png files look extremely bad in
                    Impress 7.0.x, OK in 6.4.6
           Product: LibreOffice
           Version: 7.0.0.3 release
          Hardware: All
                OS: Linux (All)
            Status: UNCONFIRMED
          Severity: normal
          Priority: medium
         Component: Impress
          Assignee: libreoffice-bugs at lists.freedesktop.org
          Reporter: sergio.callegari at gmail.com

Description:
I am producing some slides with a university logo, which unfortunately I cannot
share.

The logo is available both in SVG and PNG format (the latter at 2.5 x 2.5 cm,
300 dpi).

If I insert in the slides the SVG, this looks OK in edit mode, but bad-ish in
presentation, both in LibO 6.4.6 and 7.0.1.1, because in presentation some thin
lines disappear. So I decided to resort to the PNG.

If I insert the PNG "as is" (no scaling) it looks perfect in 6.4.6 and
extremely bad (as if it was rescaled and an extremely bad resolution) in 7.0,
either in edit and presentation mode. Interestingly:

- if I save the odp file and reopen it, then the file keeps opening with the
png looking OK in 6.4.6 and bad in 7.0.

- if in 7.0 I play with the image compress dialog, at times I can make LibO 7.0
draw the PNG correctly, but typically it does not survive a save reload
roundtrip.

I guess that impress caches images and uses the cached images for display. In
LibO 7, my impression is that PNGs are rendered at the wrong resolution before
caching.

I'll try to see if I can reproduce with another image that I can share to
provide an example.

In the meantime, note that the quality of the PNGs in 7.0 is unfortunately so
bad that if you run in a case where you have one image that is problematic with
LibO 7.0, then impress 7.0 cannot be an option to deliver presentations at all.

Steps to Reproduce:
1. Open impress, create a new presentation
2. Insert a PNG image with small size, high resolution a lot of detail
See that it does not display acceptably in LibO 7 while it is OK in LibO 6.4.x

Actual Results:
Image does not display acceptably in LibO 7 while it is OK in LibO 6.4.x

Expected Results:
Image should always display well.


Reproducible: Always


User Profile Reset: No



Additional Info:
[Information automatically included from LibreOffice]
Locale: en-US
Module: PresentationDocument
[Information guessed from browser]
OS: Linux (All)
OS is 64bit: yes

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