frame.set_window_size() is not consistent/broken across platforms.

[sourcebox]

According to my tests, it works as expected only on macOS. With Linux (Mint Cinnamon 20.3), it simply does nothing, on Windows 10, the resulting window size is wrong when called within setup() but correct when called from update().

[emilk]

What about when using winit directly? e.g. adapt https://github.com/rust-windowing/winit/blob/master/examples/min_max_size.rs to call window.set_inner_size(…) when pressing some keyboard key

[sourcebox]

What about when using winit directly? e.g. adapt https://github.com/rust-windowing/winit/blob/master/examples/min_max_size.rs to call window.set_inner_size(…) when pressing some keyboard key

This works as expected on Linux. macOS works anyway, so I don't need to test anything there. So Windows is still in question. It did not work within setup(), but this method was removed from the API recently.

[emilk]

Ok, so if it was only ever broken in setup? Then we can close this issue?

[sourcebox]

Ok, so if it was only ever broken in setup? Then we can close this issue?

It was broken in setup() for Windows. In Linux it is broken even in update().

[sourcebox]

Now that setup() is gone, is there another way to access the frame when you create the application instance (now with the new()method)?

[emilk]

You shouldn't need to - use NativeOptions. If that doesn't work, then let's fix that.

[emilk]

So just to be clear, on latest master, frame.set_window_size doesn't work on Linux, even though calling window.set_inner_size directly on the winit::Window works?

If that is correct, can you please investigate further?

frame.set_window_size is just be calling window.set_inner_size with a points->pixel conversion (see fn handle_app_output in egui-winit/src/epi.rs), so either the conversion is broken, or some window setting is different from the winit example.

[sourcebox]

I'm currently using commit 95efbbc from 2 days ago, That's the one with your DPI fix. When I use the debugger, frame.set_window_size() just sets self.output.window_size inside epi/src/lib.rs in line 311. There is no call to window.set_inner_size().

[emilk]

@sourcebox the call to set_inner_size is in handle_app_output

[sourcebox]

I had a closer look. window.set_inner_size() gets the correct size, but the call simply does nothing.

[sourcebox]

Now we come closer: it works if I set resizable to true in the NativeOptions.

[emilk]

So set_inner_size and resizable interact differently on Linux vs other platforms? Sounds like a bug that should be reported to (and fixed in) winit!

[sourcebox]

Done, see rust-windowing/winit#2242

[sourcebox]

As a workaround for Linux, initial_window_size, min_window_size and max_window_size could be set to the same value in the NativeOptions. Doing this in addition to frame.set_window_size() (needed at least for Windows, macOS not tested yet) will make it work on all 3 platforms.