Bug 142801 - Support partial transparency in table cell backgrounds
Summary: Support partial transparency in table cell backgrounds
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Impress (show other bugs)
Version:
(earliest affected)
Inherited From OOo
Hardware: All All
: medium enhancement
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
: 156997 (view as bug list)
Depends on:
Blocks: Impress-Gradient ImpressDraw-Tables
  Show dependency treegraph
 
Reported: 2021-06-11 13:59 UTC by Eyal Rozenberg
Modified: 2024-10-04 21:42 UTC (History)
2 users (show)

See Also:
Crash report or crash signature:


Attachments
Image under transparent table screenshot (58.14 KB, image/png)
2021-06-11 15:40 UTC, Mike Kaganski
Details

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Description Eyal Rozenberg 2021-06-11 13:59:54 UTC
One should be able to make a table semi-transparent, i.e. make the background of its cells transparent. The table background dialog pane is where I'd except to see the transparency setting, but it's not there.
Comment 1 Mike Kaganski 2021-06-11 15:40:32 UTC
Created attachment 172824 [details]
Image under transparent table screenshot

Please be specific, what do you mean and what is the intended result. What do you expect to see under the table? The "none" background is the transparent one; e.g., putting an image to the background and placing it "under" the table with none background makes the image visible inside the cells.

You mentioned "semi"; do you mean you want the background set, but half-transparent?
Comment 2 Eyal Rozenberg 2021-06-11 17:41:45 UTC
I mean, I expect to have at least a transparency fraction, and at most as much transparency control as in Format | Obect | Area 's transparency pane.
Comment 3 Heiko Tietze 2023-01-04 08:45:55 UTC
You can achieve transparency with an extra shape layer between the background image and the foreground table. The table needs to have no filling in this case. However, this approach fails if the table should have a highlighted row, for example.

The question is whether tables (or rather any object) can have a transparency attribute likewise shapes. If so I'd agree with the requirement.
Comment 4 Regina Henschel 2023-01-04 15:52:13 UTC
The ODF TC has discussed to extend the kind of filling for non-graphical objects, see https://issues.oasis-open.org/browse/OFFICE-4125, which introduces a new element <style:background-fill>.
Comment 5 Eyal Rozenberg 2023-01-04 21:19:17 UTC
(In reply to Heiko Tietze from comment #3)
(In reply to Regina Henschel from comment #4)

So, we're all in agreement then... :-)
Comment 6 Eyal Rozenberg 2023-09-01 16:13:43 UTC
*** Bug 156997 has been marked as a duplicate of this bug. ***
Comment 7 Eyal Rozenberg 2023-09-01 16:15:19 UTC
Copying a link from the dupe (sorry about that!), we already have this:

https://docs.oasis-open.org/office/OpenDocument/v1.3/os/part3-schema/OpenDocument-v1.3-os-part3-schema.html#__RefHeading__1416332_253892949

is it not enough to allow LO to support table (cell) background transparency?
Comment 8 Regina Henschel 2023-09-01 16:43:30 UTC
(In reply to Eyal Rozenberg from comment #7)
> Copying a link from the dupe (sorry about that!), we already have this:
> 
> https://docs.oasis-open.org/office/OpenDocument/v1.3/os/part3-schema/
> OpenDocument-v1.3-os-part3-schema.html#__RefHeading__1416332_253892949
> 
> is it not enough to allow LO to support table (cell) background transparency?

No, not the <table:background> element directly. It is part of a table template and references a cell style.

The table, row or cell background is currently determined by the fo:background-color attribute or the <style:background-image> element in the <style:table-properties> element. And since background-color is defined as RGB without alpha channel or as full transparent, semi-transparent cannot be described with ODF 1.3.
Comment 9 Eyal Rozenberg 2023-09-01 17:45:14 UTC
(In reply to Regina Henschel from comment #8)
> The table, row or cell background is currently determined by the
> fo:background-color attribute or the <style:background-image> element in the
> <style:table-properties> element. And since background-color is defined as
> RGB without alpha channel or as full transparent, semi-transparent cannot be
> described with ODF 1.3.

I was under the false impression that if you could make choices such as gradients, patterns, hatchings, etc. you could also set the transparency. I guess these are distinct. Are there other contexts in which we want to have the former but not the latter?
Comment 10 Regina Henschel 2023-09-01 18:16:01 UTC
(In reply to Eyal Rozenberg from comment #9)
> I was under the false impression that if you could make choices such as
> gradients, patterns, hatchings, etc. you could also set the transparency. I
> guess these are distinct. Are there other contexts in which we want to have
> the former but not the latter?

Yes, transparency is a distinct property in ODF. That is different in OOXML, where transparency is a color transformation. In ODF you can have a rectangular transparency gradient together with a linear color gradient, for example. Such is not possible in OOXML.

As noted already, ODF 1.4 will allow all kind of fill properties in all places where currently a <style:background-image> is possible. And then we can have semi-transparent table, table-row and table-cell background. It needs only someone to implement it.
Comment 11 Eyal Rozenberg 2024-10-04 21:42:55 UTC
(In reply to Regina Henschel from comment #10)
> As noted already, ODF 1.4 will allow all kind of fill properties in all
> places where currently a <style:background-image> is possible. And then we
> can have semi-transparent table, table-row and table-cell background. It
> needs only someone to implement it.

So, was this not at all supported in ODF 1.3? Partially supported? What about now, with ODF 1.4?

... I again find myself missing this feature preparing my LibOCon presentation :-(