Reaper Linux VST3 is stealing 8 pixels from me (FIXED)

[baconpaul]

Hi!

I'm one of the devs on surge (https://surge-synthesizer.github.io/) and we actually have the VST3 version of our plugin working on Linux. Reaper works almost perfectly with Linux VST3 and the nightly of Surge

But it seems when we display the VST3 in Linux, our plugin gets clipped by about 8 pixels. Almost like the whole thing is being drawn in a rect which is .offset(4,4) or something.

https://github.com/surge-synthesizer/surge/issues/1144

there's an issue with screenshots and so on.

Is there something about the Reaper VST3 implementation which changes the sizing? Is there something I should do in my code to compensate for this? Is this a reaper bug? (Is it a surge bug?)

These are all questions I'm not sure of the answer to, but the Reaper surge users tell me that this forum is super friendly and the devs are responsive, so I figured i would ask it over here and see if you have any ideas.

Thanks for your consideration!

Paul

[EvilDragon]

@Justin, would be really nice to give some input here. Thanks!

[Justin]

Hi thanks for bringing this to our attention!

I'm looking at the code now -- it appears your IPlugView::canResize() returns kResultTrue, meaning that the plug-in supports variable sizing. In this case, implementing IPlugView::checkSizeConstraint() would probably help?

[sub26nico]

Originally Posted by Justin

Hi thanks for bringing this to our attention!

I'm looking at the code now -- it appears your IPlugView::canResize() returns kResultTrue, meaning that the plug-in supports variable sizing. In this case, implementing IPlugView::checkSizeConstraint() would probably help?

Resizing now works (tested with the vst3) but the issue at the bottom (pixels missing) is still there.

[baconpaul]

Yeah the 8 pixel clip which only happens on linux is what’s confusing me. I send a resize message to go to a certain size, and I get sent to that certain size, then I get drawn about 8 pixels shy of that on linux only.

I’ll check that constraint API this week though and see if that helps; andupdate this thread if so. Thanks!

[baconpaul]

Alright here's what's happening

I put print statements in the place where I call IPlugFrame::resizeView and also where I get called back in IPlugFrame:nSize and IPlugFrame::checkSizeConstraint (which I have now implemented).

On macOS I get the following when I resize (which I do by doing "menu/zoom/zoom to 125%" in this case:

```
Asking to resize to 1130 677
checkSizeConstraint 0 1130 1130x677
onSize 0 1130 1130x677
```

whereas on Linux I get this

```
Asking to resize to 1130 677
checkSizeConstraint 0 1122 1122x669
onSize 0 1122 1122x669
```

so yeah, for some reason you are just taking 8 pixels away from my desired size. But only in Reaper. And only on Linux.

So I guess I could code defensively around this. looks like in checksizeconstraint I can overrule you to tell you the size I want, after I told you the size I want

Is that the right solution? Why does only linux and only reaper do this in the VST3? Before I write that bit of code (which is a bit painful of course because the size I requested is not handed to me just the size you want to give me), I want to make sure this is what you intended Reaper/Linux to do.

Thanks

[Justin]

Fixing on the REAPER side for the next builds

[SmajjL]

Originally Posted by EvilDragon

Originally Posted by baconpaul

Originally Posted by Justin

[baconpaul]

Awesome! Thank you!

[Justin]

Latest +dev build should fix this!

[sub26nico]

Originally Posted by Justin

Latest +dev build should fix this!

It works, thanks @Justin !

[acebone]

What a happy ending!