Hidpi icon scaling bug on Windows

[gitblit]

Details for the issue

What did you expect to see?

Toolbar icons that scale correctly on 4k monitor set to 200% magnification. This seems to be a common issue with Qt-based apps, it is not specific to DB4S.

What did you see instead?

Useful extra information

The info below often helps, please fill it out if you're able to. :)

What operating system are you using?

• Windows: ( version: 10.something )
• Linux: ( distro: ___ )
• macOS: ( version: ___ )
• Other: ___

What is your DB4S version?

• 3.12.0
• 3.11.x
• Other: ___

Did you also

• Try out the latest nightly version: https://github.com/sqlitebrowser/sqlitebrowser#nightly-builds
• Search for an existing similar issue: https://github.com/sqlitebrowser/sqlitebrowser/issues?utf8=%E2%9C%93&q=is%3Aissue%20

[chrisjlocke]

Issue #1836 mentions setting an environment variable. Can you try setting this:
set QT_AUTO_SCREEN_SCALE_FACTOR=1

Slap that in a command-prompt, then run DB4S from the same command-line. Here's a screencast...
The directory you go to to run DB4S will be different though, but the process is the same...
https://screencast-o-matic.com/watch/cYiV1y5r6j

Set the variable (copied from above), plop into the DB4S directory, then run the .exe.

[gitblit]

Perfect! I didn't find that before. It does indeed fix the issue. My main entry point for your app is file associations (double-clicking .db files). Is there anyway to make this a setting? Or maybe I can mod the launch definition for the association. 🤔

[chrisjlocke]

Yay! Thanks for reporting back! Glad it worked. We'll try and bake this into a nightly to test, as its the second report of it.

As for double-clicking, we can change the association. Create a batch file, then right-click on a .db file, select 'Properties', then click 'Change', then find the batch file. The batch file would be:

set QT_AUTO_SCREEN_SCALE_FACTOR=1
c:
cd "c:\program files\db4s"
call "DB Browser for SQLite.exe" %1

So you'd need the %1 to pass in the filename. Think you'll need the 'call' bit, otherwise the command-prompt window hangs around until you close DB4S, which can be annoying. Haven't tested this though...
Obviously change the directory after the CD command to wherever you have DB4S installed...

[justinclift]

It could also be set in Windows itself, to apply to everything. It should then apply automatically to all Qt applications

Whether or not that's a helpful thing is the next question... 😄

[gitblit]

Great idea @justinclift. I'll give that a go and see if it breaks any of the other QT apps I might have.

[chrisjlocke]

@gitblit - I assume all was good?

@justinclift - To close this issue, is this something we'd have to add to the DB4S code, or just something the user would have to run pre-running DB4S? (stick it in a batch file, etc).

[gitblit]

@chrisjlocke all good! I am using the global environment variable workaround with success!

[justinclift]

@gitblit Thanks for the confirmation, that's really helpful. People have mentioned scaling issues with DB4S with HiDPI monitors on Windows before, so having a potential solution is a definite win.

@chrisjlocke Now that it's been confirmed to work, we should probably look at setting that environment variable (or an equivalent Qt setting) at startup time. Not sure if it'll need to be set just for Windows, or if it's safe to set on all platforms, etc.

@MKleusberg Setting the QT_AUTO_SCREEN_SCALE_FACTOR variable (with a value of 1) at start up on Windows is probably safe, yeah?

[chrisjlocke]

Setting the variable (with a value of 1) at start up on Windows is probably safe, yeah?

The only 'gotcha' is that as its an environment variable, it'll affect other Qt programs until Windows is restarted or that variable is changed. If its going to be implemented, I'd suggest a command-line switch so that it could be turned off - so set on by default /unless/ a command-switch of --noAutoScreenScaleFactor (as an example) is present...
It might only affect one person out of a million but .... well, just thinking out loud....

[justinclift]

The only 'gotcha' is that as its an environment variable, it'll affect other Qt programs until Windows ...

I was meaning more "add it to the DB4S environment for this run of the application", rather than "add it to the system wide environment for everyone". 😄

[justinclift]

@MKleusberg Ping?

[scottfurry]

Piling on to conversation.
Ref: https://doc.qt.io/qt-5/highdpi.html

See section "Migrate Existing Applications".