Bug 157427 - vspace inconsistency when opening same ODP presentation on same version on different machines
Summary: vspace inconsistency when opening same ODP presentation on same version on di...
Status: UNCONFIRMED
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Impress (show other bugs)
Version:
(earliest affected)
7.6.0.3 release
Hardware: All All
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: Paragraph-Line-Spacing
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Reported: 2023-09-25 10:19 UTC by Eyal Rozenberg
Modified: 2024-02-18 07:35 UTC (History)
4 users (show)

See Also:
Crash report or crash signature:


Attachments
Presentation with which the discrepancy manifests (1.04 MB, application/vnd.oasis.opendocument.presentation)
2023-09-25 10:19 UTC, Eyal Rozenberg
Details
attachment 189805, Slide 14 - on my laptop, 1280x800 display (253.17 KB, image/png)
2023-10-12 20:12 UTC, Eyal Rozenberg
Details
attachment 189805, Slide 14 - on my desktop, 1920x1080 display (455.56 KB, image/png)
2023-10-12 20:12 UTC, Eyal Rozenberg
Details
attachment 189805, slide 14 - on my laptop, 1920x1080 display (381.55 KB, image/png)
2023-10-12 20:21 UTC, Eyal Rozenberg
Details

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Description Eyal Rozenberg 2023-09-25 10:19:24 UTC
Created attachment 189805 [details]
Presentation with which the discrepancy manifests

The attached file is (more-or-less) the presentation I gave at LOCon 2023 a few days ago.

I was working on it on my laptop, which runs Ubuntu GNU/Linux 22.04 LTS, using the 7.6.0.3 release version. Now, I'm opening it on my desktop, Devuan GNU/Linux Daedalus, with the same LO version (and same VCL) - but I'm seeing different vertical positioning and/or spacing (line spacing, pre/post paragraph vspace) than I was seeing on my laptop, which messes up the slide layouts, causing overlaps I didn't intend etc.

I should mention my laptop's monitor resolution is 1280x800, while my desktop is 1920x1080, and that may have something to do with it.

Note that not all slides seem that different. Slides 14, 28 had particularly striking vertical positioning/spacing differences.
Comment 1 V Stuart Foote 2023-09-25 12:09:06 UTC
Hi Eyal, looked at the presentation on Win10 with a 1920x1080 display. All the slides seemed OK (no comment on the subject ;-)

Looking at the sd 'Paragraph...' value for the text box list on slide 14--you've set its line spacing metrics to Proportional at 105%, while for the text box list on slide 28 you've set its line spacing metrics to Proportional at 80%

I kind of would expect *some* differences scaling those "proportional" metrics between a display at 1200 x 800 (1.6 ratio) compared to a 1920 x 1024 (1.875 ratio).

I will take a look on a desktop with a 4K 3840 x 2048 (1.875 ratio) display, but the pixel scaling between HD and 4K may not manifest the vertical repositioning you're seeing between the 1.5 (WXGA) and 1.875 (HD) displays.

Question would be if you get a similar shift when the font/line space metric is set to 100%/single so the scaling of the font metric is removed from the mix?

=-testing-=

Version: 7.6.0.3 (X86_64) / LibreOffice Community
Build ID: 69edd8b8ebc41d00b4de3915dc82f8f0fc3b6265
CPU threads: 8; OS: Windows 10.0 Build 19045; UI render: Skia/Raster; VCL: win
Locale: en-US (en_US); UI: en-US
Calc: threaded
Comment 2 V Stuart Foote 2023-09-25 13:17:16 UTC
sorry fat fingers...

s/1200 x 800 (1.6 ratio)/1280 x 800 (1.6 ratio)

s/between the 1.5 (WXGA) and/between the 1.6 (WXGA) and/
Comment 3 Eyal Rozenberg 2023-09-30 16:51:13 UTC
(In reply to V Stuart Foote from comment #1)
> I kind of would expect *some* differences scaling those "proportional"
> metrics between a display at 1280 x 800 (1.6 ratio) compared to a 1920 x
> 1024 (1.875 ratio).

That should not be the case for two reasons:

1. The slides' dimensions are defined in the presentation. The monitor they're viewed on should not matter. That is, of course the zoom level and resolution may affect how much of the slide we see on screen, or whether there are "slack" bars, vertical or horizontal, with no content. But that should not affect any of the font sizes, the number of lines required for each paragraph, and the relative vertical or horizontal positioning of slide elements.

2. In principle, the relative positioning of document elements (e.g. slide objects and paragraphs within them) must not depend on the machine on which one opens the presentation. If there's anything which causes this to happen (assuming all fonts are available etc.) - whatever the mechanism is, it's buggy.

> Question would be if you get a similar shift when the font/line space metric
> is set to 100%/single so the scaling of the font metric is removed from the
> mix?

I'll check the effect of dropping the proportional line spacing.
Comment 4 Stéphane Guillou (stragu) 2023-10-09 11:50:25 UTC
@Stuart, any luck with testing the different display?
@Eyal, what's the result without the proportional settings?
Comment 5 V Stuart Foote 2023-10-10 15:15:36 UTC
(In reply to Stéphane Guillou (stragu) from comment #4)
> @Stuart, any luck with testing the different display?
> @Eyal, what's the result without the proportional settings?

Sorry, thanks for the nudge.

As Eyal thought, minimal difference in the slide canvas when scaled on larger 4K display compared to Full HD. Just blank area of the surrounding app frame differs, and on the 4K the 'Slides' Slide Pane defaults to smaller thumbnails so more blank app frame.

However, for slide #14 and #28 changing the 'Paragraph' dialog line spacing to the font's metric height, i.e. 'Single' <==> 'Proportional 100%' does result in consistent spacings and seems to honor the font metric set (as point size) from the 'Character' dialog for each bullet line in the sd text box. 

While the spacing above/below for each bullet in the sd text box takes a value [mm|"|pt] (as converted to locale). If they're all set the same, the v-spacing of the bullets follows the Single/100% metric of the font used for the bullet(s).

In other words, I can't reproduce differing v-heights spacing of bullets between these two system displays--FullHD compared to 4K.  Could be different with asymmetrical displays Eyal was using.

=-testing-=
Version: 7.6.2.1 (X86_64) / LibreOffice Community
Build ID: 56f7684011345957bbf33a7ee678afaf4d2ba333
CPU threads: 8; OS: Windows 10.0 Build 19045; UI render: Skia/Vulkan; VCL: win
Locale: en-US (en_US); UI: en-US
Calc: CL threaded
Comment 6 Eyal Rozenberg 2023-10-12 20:12:18 UTC
Created attachment 190173 [details]
attachment 189805 [details], Slide 14 - on my laptop, 1280x800 display
Comment 7 Eyal Rozenberg 2023-10-12 20:12:39 UTC
Created attachment 190174 [details]
attachment 189805 [details],  Slide 14 - on my desktop, 1920x1080 display
Comment 8 Eyal Rozenberg 2023-10-12 20:20:27 UTC
> Question would be if you get a similar shift when the font/line space metric
> is set to 100%/single so the scaling of the font metric is removed from the
> mix?

The answer is YES. Switching to single line spacing just reduces vspacing slightly, not changing the overall effect (which you can now see in the screenshots).

However - something weird is happening. I hooked up my laptop to a 1920x1080 monitor - and the vspace inconsistencies persist! So - the difference between the two systems must lie elsewhere. Not sure what it is...


As for slide 28 - I can't reproduce the problem there for some reason, so let's focus on slide 14.
Comment 9 Eyal Rozenberg 2023-10-12 20:21:15 UTC
Created attachment 190175 [details]
attachment 189805 [details], slide 14 - on my laptop, 1920x1080 display