Bug 449383

Created attachment 146080 [details]
where the zoom desktop effect and its settings are located

SUMMARY
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Currently is not possible to configure via KDE Settings the desktop zoom dynamizally using custom key + mouse scroll.

STEPS TO REPRODUCE
1.  Open System Settings. From CLI with US English locale: LC_ALL=C systemsettings5
2.  Workspace behaviour
3.  Desktop effects
4.  Zoom
5.  Configure...

OBSERVED RESULT
There is no option to define key to hold down, while scrolling mouse wheel in order to dynamically zoom desktop in and out, depending on which direction to scroll the mouse wheel.

Currently only via CLI configuration possible to achieve dynamical zoom with mouse as described in Additional information below.

EXPECTED RESULT
There is an option in KDE System Settings to define custom key graphically on keyboard to hold down, while scrolling mouse wheel.

SOFTWARE/OS VERSIONS
GNU/Linux: EndeavourOS
KDE Plasma Version: 5.23.5
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
Currently possible via CLI configuration:
1. install xbindkeys
2. create default configuration:
xbindkeys --defaults > $HOME/.xbindkeysrc
3. open the $HOME/.xbindkeysrc and comment unnecessary key bindings to avoid interfere with other shortcut keys in system.
4. add following lines into file $HOME/.xbindkeysrc in order to get Meta+mouse wheel to zoom dynamically:
# Zoom in
"qdbus org.kde.kglobalaccel /component/kwin invokeShortcut "view_zoom_in""
  m:0x50 + c:133 + b:4
# Zoom out
"qdbus org.kde.kglobalaccel /component/kwin invokeShortcut "view_zoom_out""
  m:0x50 + c:133 + b:5
Defining other key than meta needs further investigation, how to achieve.
5. start or restart xbindkeys
killall xbindkeys && xbindkeys&
6. add xbindkeys to autostart to ensure it will start when logging in