PDFs blurry in presentation view on scaled displays

Distribution

EndeavourOS

Package version

xreader 4.0.2

Frequency

Always

Bug description

Presentation view on a scaled display is blurry. This does not happen in any other view.

Steps to reproduce

1. Set the 'Monitor scale' setting (under 'Display' in System Settings) to 200% for a monitor which has a resolution of 2560 × 1440.
2. Open any PDF file, preferably one with 16:9 pages containing a lot of text. You can use this file.
3. [optional] Switch to page view using Ctrl2. Close the side pane (if it is open) using F9. Enter fullscreen mode using F11. The text is sharp. Crystal-clear.
4. Switch to presentation view using F5. The text is blurry.

Expected behavior

Presentation view should be sharp.

Additional information

I assume this is an Xreader bug and not a Cinnamon (Cinnamon 6.0.4) bug because Xreader shows sharp text in fullscreen page view. Here are the screenshots of the PDF file after executing steps 3 and 4 above.

Fullscreen Page View

Presentation View

The same effect is observed at 150% scale. It's less blurry, but nonetheless noticeable.

Start by reproducing the issue in Xreader's presentation view using F5 on a 150% or 200% scaled display, then compare it with fullscreen page view using F11. Trace the presentation-view rendering entry point and verify that text is sharp at the same scale without changing the sharp page-view behavior.