PDF scale incorrect when importing between OB 1.02 and 1.3 about openboard HOT 1 CLOSED

(Should be fixed, but commenting for future me or future whoever reads this in case any related issues pop up)

New problems were just discovered: exporting a document containing a PDF as PDF with v1.3.0-rc.2 -- or just saving and loading that document -- sometimes led to a change in the scale of the PDF items in that document.

As far as I can tell, the problem was with the pageDpi setting again. For some reason, it is a persistent setting, i.e it is saved to OpenBoardUser.config.
So normally, if we load a document created on another screen / OB version / whatever, we read that document's DPI value to be able to render the contents correctly (the dpi affects the size of PDF and text items; they are scaled depending on the (document dpi)/(current dpi) ratio).
However, this document's dpi value is then saved to OpenBoardUser.config. Which means that the next time we save a document with a PDF in it, that document's dpi matches the one of the first document.
Thus, the next time this new document is loaded, its contents are scaled (because its dpi value doesn't match the current screen's dpi).

For example:
We have a document, A, created on another OB version, or another computer. The dpi is indicated as 80.
We open document A in OB 1.3. The current screen dpi is calculated to be, say, 120. So the PDF item in the document is scaled by 80/120 = 0.75 to be displayed correctly on this machine.
And UBSettings::pageDpi is set to 80.
Everything is ok until we create a new document, B, and save it. At that point, the document's dpi is set to UBSettings::pageDpi which is 80 in this case.
Next time we open B, we read its dpi value, calculate the current one, and scale the PDF items in the document. So the scale is all wrong.

So it seems this new issue arose as a result of the previous fix. But changing the pageDpi setting so that it is not saved to the config file anymore solves both the problems: documents can be transferred from 1.02 to 1.3 and from 1.3 to 1.02, exported to PDF etc without any worries (so far).

from openboard.