Scaling UI of hosted plugin

General JUCE discussion
1

I’m building a sequencer plugin that is able to host other plugins and have hit a snag with UI scaling.

I cant seem to find a way to scale the UI of hosted plugins that works. I have tried:

  • Applying a transform directly to the hosted plugin’s AudioProcessorEditor
  • Applying a transform to a parent component of the hosted plugin’s AudioProcessorEditor
  • Setting the scale with setScaleFactor on the hosted plugin’s AudioProcessorEditor
  • Calling Desktop::setGlobalScaleFactor()

In all cases the hosted plugin’s editor quickly flashes (unscaled) on screen and then disappears.

I have tested with a few of DAWs and the behaviour is the same.

Update:

After some further testing I have figured out that only AU plugins flash and disappear when scaled. VST plugins will render unscaled.

1 Like
2

Bump. Perhaps someone from the JUCE team could weigh in on this?

3

Have you looked at the HostPluginDemo in the JUCE repo? Does that work properly for you?

4

I’m not sure you can scale the plugin as the host. I think it’s up to the plugin to scale itself, and for the host to adapt if its size changes.

This is from my experience working on a plugin host. I’ve also never seen a DAW that scales plugin editors. I could be wrong though…

1 Like
5

not all plugins are made with JUCE, not all plugins support being rescaled at all.
But most of all, it’s the end-user who decides on a system-wide basis what DPI they are comfortable with. It’s would not be best practice (regarding accessibility etc) for a DAW to ignore the user’s preferences regarding DPI.

6

Thanks for the feedback.

I’m aware that not all plugins are built with JUCE, but the AudioProcessorEditor object created by a AudioPluginInstance does allow you to set a scale transform … it just doesn’t work.

I wonder if this is by design or not?

7

Hi @rbuskov

Did you ever get to the bottom of this?

Cheers

Andy

8

I’m 99% sure there is no way to apply an arbitrary scale to another window. On Windows, you can mark the HWND as DPI aware or not, I think that’s the only option.

9

Thanks @RolandMR

I think you are right, we are trying to embed the plugin editor component in another component, the only way seems to be to create a heavyweight window and set it to be DPI unaware. Embedding in a juce component and trying to scale just doesn’t work.