graph is blurry on high DPI macOS with Qt5

[Be-ing]

Environment

• QJackCtl Version: 0.9.6
• JACK Version: 1.9.20
• Operating System: macOS 11.5.2
• Installation: https://jackaudio.org/downloads

Steps To Reproduce

Open QJackCtl distributed with JACK on macOS and click the Graph button

Expected vs. actual behavior

The connection graph in the QJackCtl build shipped with the macOS version of JACK does not scale well for high DPI screens. Everything within the graph is blurry but the text at the top of the window scales okay:

[rncbc]

can't argue about macosx, but the Graph scales quite well and sharply on Linux X11/Wayland (Qt6.2)

[Be-ing]

This issue does not occur with QJackCtl from Homebrew which is built with Qt 6.2.2:

I think this can be fixed by setting the Qt::AA_EnableHighDpiScaling when building with Qt5. This was removed in Qt6; high DPI scaling is always enabled in Qt6.

[Be-ing]

The graphics are still blurry because they're all low resolution rasters.

[rncbc]

I think this can be fixed by setting the Qt::AA_EnableHighDpiScaling when building with Qt5.

maybe you wanna have a look around here:

qjackctl/src/qjackctl.cpp

Line 557 in e3c15c6

QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

• it's been enabled for Qt5 where applicable, and disabled for Qt6 for good measure.

[Be-ing]

Hmm, if that's already implemented then I'm nos sure what else could be the issue.

[rncbc]

issue (probably) lies on an old Qt5 perhaps?