Geometries not selectionable when using global variables in symbology

[roedvingetrast]

Hi there and first: much appreciation for the great project!

Example: The circles in the symbology in a point-Layer predefined in QGIS are shown to big in QField map canvas so I have to choose between making them smaller for QField, but then I can't see them properly anymore in QGIS – or leave them, as they are in QGIS and have too big symbols in QField.

To solve that, I used a rule based symbology with a filter like "variable" = 'value' AND @qgis_os_name = 'android' for QField and the value 'linux' for QGIS on my laptop. The symbology is displayed correctly and differs between the two operating systems. But doing so I can' select the points in the map canvas of QField anymore.

In this special case maybe I can use a workaround changeing the symbols size unit from mm to pixel, but because of printing purposes I would prefer to stay with mm in the whole project. And sometimes I want to use different symbols in QGIS/QField staying in the same project and without duplicate layers with changed symbology.

Reproduction Steps:

1. Take a point layer, choose rule based symbology and enter something like

"variable" = 'value' AND @qgis_os_name = 'android'

as one rule and

"variable" = 'value' AND @qgis_os_name = 'linux'

as second rule (maybe you have to adjust the values android/linux to your own OS) and change the size/shape/color etc. of the symbols like you want it and you can see the difference between them clearly.

2. Load the project onto your smartphone/tablet etc. and open it with QField, the symbols should be displayed correctly and different between QGIS/QField.

3. Try to select a point of the point layer – it doesn't work.

Expected behavior:

Geometries still clickable/selectionable, even when using variables like "@qgis_os_name" in symbology.

Observed behavior:

Geometries not clickable/selectionable anymore when using variables mentioned above.

QField version: QField version 1.9.6 (d5dd01 v1.9.6)

Additional information:

• Problem started happening recently, didn't happen in an older version of QField: I don't know, I'm relatively new to QField
• Problem can be reliably reproduced, doesn't happen randomly: Yes
• Problem happens with all files and projects, not only some files or projects: Yes
• Problem happens with other variables: Not tested

[m-kuhn]

Thank you for reporting this, a fix for the identify problem with @qgis_os_name is underway in #2036

Regarding the scaling issue, could you check the units that are used for the size of the symbols?
Set the units to mm and use a (physical) ruler to check the size of the symbols on screen.

Here's a local result for QField and QGIS:

This was done on a hidpi screen: QGIS shows symbols too small. QField shows them correctly.
I don't have a low dip screen at hand to test, but last time I checked, both showed it correctly there.
I.e. QGIS does not properly scale symbols on hidpi screen (so that's very likely an upstream / QGIS issue we are dealing with here)

[roedvingetrast]

Hi m-kuhn,

thanks a lot for fixing, it seems to work now! I also appreciate the new function "Dim screen when idling"! Only issue in property menu now: when scrolling down, the menu always jumps to top again, so I can't change settings like "Use stylus pen". Maybe only in beta, because on 1.9.6 it works like expected.

On my old 86ppi screen and in QField on my smartphone with a 483ppi screen the size of symbols are shown correctly, on my laptop screen with a 96ppi screen the symbols are shown too small. I think, that refers to qgis/QGIS#41248

Still, the ruler doesn't work properly (shows too small length), but that's an issue already mentioned elsewhere.

Regards