Bug 91768 - FILESAVE : png export changes object size
Summary: FILESAVE : png export changes object size
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Draw (show other bugs)
Version:
(earliest affected)
4.3.6.2 release
Hardware: Other Windows (All)
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: Graphics-Export Image-DPI
  Show dependency treegraph
 
Reported: 2015-05-31 07:43 UTC by Topi
Modified: 2020-07-13 11:04 UTC (History)
4 users (show)

See Also:
Crash report or crash signature:


Attachments
screenshot (434.63 KB, image/png)
2015-05-31 07:43 UTC, Topi
Details

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Description Topi 2015-05-31 07:43:56 UTC
Created attachment 116189 [details]
screenshot

Steps to Reproduce:
 1. Draw a rectangle and select it
 2. Export to PNG ("selection" disabled)
 3. Change DPI to eg 600 and restore original page size
 4. Press ok
 5. Open exported file with favourite editor (like gimp)  
 6. Measure the size of the rectangle (I use the crop dialog in gimp for that)

Expected: Rectangle-size in both programs are measured to be equal
Actual: Rectangle-size differs

Additional Information: The size-difference might relate to the transparent area created by the export within the png image (see attachment)

Version: 4.3.6.2
Build-ID: d50a87b2e514536ed401c18000dad4660b6a169e
Comment 1 Buovjaga 2015-06-09 12:44:21 UTC
Reproduced.

Win 7 Pro 64-bit Version: 5.1.0.0.alpha1+
Build ID: d28102b1ed0c31500bbc68453a7b7613bd2bfa06
TinderBox: Win-x86@39, Branch:master, Time: 2015-06-09_01:06:39
Locale: fi-FI (fi_FI)
Comment 2 QA Administrators 2016-09-20 10:00:56 UTC Comment hidden (obsolete)
Comment 3 Julien Nabet 2020-07-10 10:29:38 UTC
in step 3, I'm not sure to understand "restore original page size" means.
Indeed, if I put back 21/29.7, LO calculates a huge size file.

Anyway, any better with a recent LO version? (last one is 6.4.5)
Comment 4 Buovjaga 2020-07-11 15:42:38 UTC
(In reply to Julien Nabet from comment #3)
> in step 3, I'm not sure to understand "restore original page size" means.
> Indeed, if I put back 21/29.7, LO calculates a huge size file.

Yep, I assume this is what was meant. Doesn't seem to be any better.

Arch Linux 64-bit
Version: 7.1.0.0.alpha0+
Build ID: 57fedb272cfcad3436142dbe9eac2870e3c3e3d2
CPU threads: 8; OS: Linux 5.7; UI render: default; VCL: kf5
Locale: fi-FI (fi_FI.UTF-8); UI: en-US
Calc: threaded
Built on 9 July 2020
Comment 5 Julien Nabet 2020-07-11 18:23:33 UTC
Buovjaga: a bit lost between initial dimensions, resolutions, the fact I can't put initial dimensions after having changed resolution because it seems to keep a ratio instead of just applying what I chose...
Anyway, since you reproduced this, let's let this one opened.
Comment 6 Buovjaga 2020-07-11 19:14:07 UTC
(In reply to Julien Nabet from comment #5)
> Buovjaga: a bit lost between initial dimensions, resolutions, the fact I
> can't put initial dimensions after having changed resolution because it
> seems to keep a ratio instead of just applying what I chose...
> Anyway, since you reproduced this, let's let this one opened.

I'm lost too. Maybe Topi should give a more detailed theoretical explanation of his expected vs. actual and we should ask some graphics wizard for opinions.
Comment 7 Buovjaga 2020-07-13 11:04:33 UTC
Comment from Noel on IRC:

most likely the PNG metadata is wrong
(the metadata says what physical dimension a pixel has)