If I have anti-aliasing on and I enter a custom page size for a drawing document with no margins when I don't export using transparency, then white / anti-aliased to white lines appear right and bottom of any PNG export.
If I export using transparency, it's okay.
THE PROBLEM with exporting with transparency is that nothing on a master page in Windows LO Draw shows up. It's an unfortunate either-or situation:
a. Don't export with transparency and have items on master pages export
b. Export with transparency and no items on master pages export
SO there's two different problems.
The first problem with transparency / no master was reported here https://bugs.documentfoundation.org/show_bug.cgi?id=123973
The second problem is what I'm reporting today with the lines right and bottom of the export based on non-standard page dimensions (the destination program I'm using that consumes what I'm exporting from LO Draw wants 2048x2048 pixels EXACTLY which LO draw produces if the dimensions are 21.33″x21.33″).
Even the slightest deviation from standard page dimensions causes the bug which I've included in the steps to reproduce.
I am not convinced that the bug I'm reporting today is the same as this bug https://bugs.documentfoundation.org/show_bug.cgi?id=117160 because that bug had more to do with SKIA / hardware acceleration only rather than anti-aliasing+weird page dimensions.
Steps to Reproduce:
1. Launch LO Draw in Microsoft Windows
2. Assure that anti-aliasing in on in Options (Options / General / View)
3. Set the page margins to None
4. Set the page dimensions to something other than default (11x8.5 to 11x8.6)
5. Set the background color of the page to black
6. Export to PNG (no transparency option selected, interlacing irrelevant)
7. Observe the exported PNG right and bottom edges
A white line (or a line anti-aliased to alpha which appears white) shows up right and bottom of the exported PNG.
There should never be any artifacts on the PNG export.
User Profile Reset: No
Version: 188.8.131.52 (x64) / LibreOffice Community
Build ID: 0e408af0b27894d652a87aa5f21fe17bf058124c
CPU threads: 8; OS: Windows 10.0 Build 19043; UI render: Skia/Vulkan; VCL: win
Locale: en-US (en_US); UI: en-US
Created attachment 175332 [details]
png output with transparency
Result when PNG exported using transparency
Created attachment 175333 [details]
png export with no transparency
result when PNG is exported with no transparency
Workaround: Add even the slimmest margin all the way around the the problem goes away.
The rendering process should still extend all the way to the edge of the document, not just the margin, but the bug is still a bug. People who create posters or signs with a bleed of color to the edge of the document would still have a problem with this bug.
Created attachment 184737 [details]
The images you attached are identical - there is no white line in them.
I do not reproduce the white lines. However, if I open my own "no transparency" exported PNG and zoom into the bottom, I can see it has a 1 pixel wide dark gray colour, unlike the export with transparency.
Same dark gray pixel in 6.3, 5.0, 4.3.