[MU4 Issue] Export to png of a large panoramic score fails

[geniot]

Describe the bug It's a long unusual score (panoramic). Export to SVG works nicely, but export to PNG fails. (causes hanging, high memory/CPU usage, unresponsive UI) score.zip

To Reproduce Steps to reproduce the behavior:

1. Create a score with <pageWidth>1000</pageWidth>
2. Try to export it to PNG either through the UI or command line.

Expected behavior We should see the result after milliseconds.

Platform information

• OS: Windows 10.

Additional context It seems to be related to the huge width of the page.

[sammik]

"Problem" of souch scores is not panoramatic ratio, or large dimensions, but huge result image. If you try same score to export with different resolution (60 DPI), it is fast enough.

EDIT: May be progress bar would be nice, so user knows, something happens.

[geniot]

"Problem" of souch scores is not panoramatic ratio, or large dimensions, but huge result image. If you try same score to export with different resolution (60 DPI), it is fast enough.

EDIT: May be progress bar would be nice, so user knows, something happens.

I've just tested with 3.6.2. Different DPI. Indeed if I change DPI to 60 I get a PNG. But the quality is very low. At some point as I increase the DPI I get an empty PNG (0 bytes). Another interesting observation: if I use a regular page width I get multiple pages and they are exported into PNG with 360 DPI just fine.

The result image of a panoramically layed out score is not huge. It's the same score. The image is trimmed. It's a long image, and the height is just 300px (width 10,000 px e.g.)