A modern programming language that makes developers happier.

kotlinlang

I’m trying to display Compose ui elements on top of a SwingPanel. When I enable `compose.interop.blending` as specified in the documentation, my app crashes on launch with a SIGTRAP:
```Crashed Thread:        29  Java: AWT-EventQueue-0

Exception Type:        EXC_BREAKPOINT (SIGTRAP)
Exception Codes:       0x0000000000000001, 0x00000001937bdbf4

Termination Reason:    Namespace SIGNAL, Code 5 Trace/BPT trap: 5
Terminating Process:   exc handler [66685]

Application Specific Information:
Must only be used from the main thread```
Full crash report in :thread:

Untitled

Relevant bit of the stack trace:
```Thread 29 Crashed:: Java: AWT-EventQueue-0
0   AppKit                        	       0x1937bdbf4 -[NSWMWindowCoordinator performTransactionUsingBlock:] + 768
1   AppKit                        	       0x1935ed6a4 -[NSWindow(NSWMWindowManagement) window:didUpdateWithChangedProperties:] + 104
2   WindowManagement              	       0x2671bcf60 -[_WMWindow performUpdatesUsingBlock:] + 116
3   WindowManagement              	       0x2671bc3f0 -[_WMWindow setShadowProperties:] + 144
4   AppKit                        	       0x192bddaa0 _NSWindowSetShadowProperties + 692
5   libskiko-macos-arm64.dylib    	       0x1493fdfc0 Java_org_jetbrains_skiko_redrawer_MetalRedrawer_createMetalDevice + 724```

Filed youtrack <https://youtrack.jetbrains.com/issue/CMP-7352/SIGTRAP-from-AppKit-when-compose.interop.blending-is-enabled>

But the repro is so simple, I’m wondering if I’m just doing something wrong:
```fun main() {
  System.setProperty("compose.interop.blending", "true")
  singleWindowApplication { Box {} }
}```

Abnormal conditions that are a developer's fault should trigger a controlled exception (potentially with a useful error message).

Given this is a _native_ crash, I'd assume it's a bug, most likely in Compose (Skia/Skiko) or the JVM (Swing).

Would the mentioned workaround <https://github.com/JetBrains/compose-multiplatform/issues/4389#issuecomment-1970570215|here> be an option for you?

That issue doesn't seem related. I'm getting a crash even before adding a SwingPanel. Just setting the flag triggers a crash.

I meant this <https://github.com/JetBrains/compose-multiplatform/issues/4389#issuecomment-1972283661|workaround> to render into an image. Then you won’t need the flag. I once did something similar for JavaFX.

Ah I see. 

If I render the image into a SwingPanel I'd still need blending. Maybe I could render the image straight into compose somehow. 

Or if there's some solution out there for a transparent ComposePanel, I could place that in the SwingPanel over the map. I've experimented quite a bit and haven't been able to get a transparent ComposePanel to work though