[macOS] [gain_gui] Wrong Cursor Position

[apalm]

OS: macOS 12.2.1
DAW: REAPER 6.49

First of all, thank you for building this framework. It looks very cool.

I wanted to try out gain_gui, so I built it using cargo xtask bundle gain_gui --release --bundle-vst3, then copied target/gain_gui.vst3 to /Library/Audio/Plug-Ins/VST3.

While the plugin works, the cursor position appears to be off. This is most obvious with the slider, which isn't draggable unless I drag on a specific spot below the handle. Maybe a scaling issue?

Screen.Recording.2022-02-25.at.18.28.20.mov

I understand that this stuff hasn't been tested on macOS, so feel free to close this issue if it's not actionable :)

[robbert-vdh]

I don't have a Mac to test this on, but presumably this is baseview not translating the coordinates correctly (these lines in the original upstream baseview). REAPER embeds the parent window into another top level window, and from the screenshot it looks like the mouse coordinates used by baseview are relative to some part of that top level window, and not to the parent window passed to the plugin. Have you created a ticket on the baseview repo for this yet? egui-baseview just passes through the mouse coordinates as provided by baseview, so the issue has to be on baseview's side.

[apalm]

I see. No, I've not created a ticket; will create a minimal repro and do so. Thank you!

[apalm]

So, while creating my minimal repro, I noticed that if I used WindowScalePolicy::ScaleFactor(1.0) like nih_plug_egui, I saw the same issue exhibited in gain_gui. However, if I instead used WindowScalePolicy::SystemScaleFactor, the issue went away.

My minimal repro with WindowScalePolicy::ScaleFactor(1.0):

Screen.Recording.2022-02-27.at.00.31.56.mov

My minimal repro with WindowScalePolicy::SystemScaleFactor:

Screen.Recording.2022-02-27.at.00.30.57.mov

gain_gui with WindowScalePolicy::SystemScaleFactor:

Screen.Recording.2022-02-27.at.00.34.01.mov

So I think it makes sense to use WindowScalePolicy::SystemScaleFactor?

[robbert-vdh]

Ah, good catch. Macs with their HiDPI screens. 😉

Hadn't really considered HiDPI yet since baseview doesn't support window resizing (and I already have two open PRs there), but I'll add this in the meantime. The host should be able to override this with IPlugViewContentScaleSupport::setContentScaleFactor() once that is in place. I added the change in b40c43a.

[theor]

for the sake of documenting it : bitwig has an option to scale plugin interfaces. when enabled, the same issue happens. disabling it fixes it.