PNG Export In Inkscape Via Pixman Library

[DJ Paul]

Hello,

*Summary:*
I am using Inkscape as my main drawing program and have been since version
0.48 or so.  Somewhere along the way, I had been able to use the PNG export
feature to export large banners with large pixel counts, however, this is
no longer working well.

Best I can tell, it worked better with Inkscape 0.48 on Mac OS 10.11.6
which was El-Capitan *{Not sure as the computer has been updated since
then}*.  I have recently updated to Mac OS 10.14.6 and cannot get this to
work as I needed.  I had submitted a bug to Inkscape, they narrowed it down
the Pixman library and said to open a ticket with you.

*Details:*
I am trying to export a PNG from a drawing that is 10'x3' at 300dpi or
600dpi.  Highest it will reliably is hard to figure out, but it seems to be
somewhere between 150dpi.  If I try to go higher, I just get blank or
corrupted PNG files.

I have PNG files from similar 2017-2018 projects with pixel sizes of 30,000
x 9,000 which is ~250dpi at 10'x3'  Inkscape would also not do the 300dpi
requested by the printers then, but the latest version won't do this size.

Versions of Inkscape I have tried on Mac OS 10.14.6 are 0.48, 0.91, 0.92,
1.00, and 1.01 and they all currently have this issue.  I have also tried
Inkscape 0.92 on the latest version of Ubuntu Studio and windows 10 with
similar results.

This issue also seems to be independent of the drawing size. If I try to
export a 10"x3" drawing to the 36,000 x 10,800 pixels I get similar results
when exporting a 10'x3' banner at 36,000 x 10,800 pixels.

Is this a bug or beyond the Pixman library's function?  Either way, I would
like to be able to export high dpi, banner sized images from Inkscape.
Biggest I can see me using is 86400x86400 pixels which is a 12'x12' image @
600dpi.

Output image size should not depend on the actual size of the drawings.
Drawing sizes can greatly change the result of Inkscape's filters.  So if I
have an 10"x3" picture, I'd still like to be able to export that to a
36,000 x 10,800 pixel image to print a 10'x3' banner @ 300dpi.

*Attached Files:*
   *Inkscape Drawing:* Banner_Background_1_10ftx3ft.svg
   *PNG Export Settings:* PNG_Export_Dialog_1.png
*   Resulting PNG File:* Banner_Background_1_36000x10800.png

Thank You,

David Paul
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