i'm introducing compose desktop into a java/swing ...

# compose-desktop

[bj0]

i'm introducing compose desktop into a java/swing app and having trouble figure out how to load resources (an icon). In swing, this works: MyClass::class.java.getResource("/images/icon.png") , but if I try to use it in compose: painterResource("/images/icon.png") it throws an exception with Resource not found. I've tried with images/icon.png and ./images/icon.png. Does the path need to be different? The files are located in src/main/resources. I looked at the compose resource library but a lot of the code still uses the java resources as-is so i'm hesitant to convert over, and the project is currently kotlin("jvm"), not kotlin("multiplatform")

[bj0]

oddly, the IDEA compose preview window shows the icon fine

[romainguy]

That's because the preview window looks at the file system vs getResource that can resolve paths inside a jar

[Michael Paus]

Maybe that gets you further: https://www.jetbrains.com/help/kotlin-multiplatform-dev/compose-multiplatform-resources.html

[bj0]

I already read through that

[bj0]

the functions under "Using Java resources" is what i'm using

[Michael Paus]

The compose way of doing it is to add the dependency:

implementation(compose.components.resources)

Then put an image into the right folder like this, e.g.:

composeApp/src/commonMain/composeResources/drawable/picture_as_pdf_24px.xml

and then you can call it in your code like this:

Icon(painterResource(Res.drawable.picture_as_pdf_24px), null)

[bj0]

that's if its 100% compose, but it's a mix, so i need the Swing components to be able to load the resources the java way

[bj0]

that document says that it's possible to still use them as java resources in compose, I just can't seem to get that to work

[Alexander Maryanovsky]

I have something like this:

fun loadIconBytes(resourcePath: String): ByteArray {
    val stream = javaClass.getResourceAsStream(resourcePath) ?:
        throw MissingResourceException("Image for icon of $this not found", javaClass.name, resourcePath)
    return stream.use { it.readBytes() }
}

private val painterCache = mutableMapOf<String, Painter?>()


@OptIn(ExperimentalResourceApi::class)
@Composable
fun cachedResourcePainter(resourcePath: String): Painter? {
    return painterCache.getOrPut(resourcePath) {
        runCatching {
            val bytes = loadIconBytes(resourcePath)
            BitmapPainter(bytes.decodeToImageBitmap())
        }.getOrNull()
    }
}

@Composable
private fun ResourceImage(
    resourcePath: String,,
    modifier: Modifier = Modifier,
    contentDescription: String?,
    alignment: Alignment = Alignment.Center,
    contentScale: ContentScale = ContentScale.Fit,
    alpha: Float = DefaultAlpha,
    colorFilter: ColorFilter? = null
) {
    val painter = cachedResourcePainter(resourcePath)
    if (painter != null) {
        Image(
            painter = painter,
            contentDescription = contentDescription,
            modifier = modifier,
            alignment = alignment,
            contentScale = contentScale,
            alpha = alpha,
            colorFilter = colorFilter,
        )
    } else {
        Image(
            imageVector = MissingResourceImageVector,
            contentDescription = contentDescription,
            modifier = modifier,
            alignment = alignment,
            contentScale = contentScale,
            alpha = alpha,
            colorFilter = ColorFilter.tint(LocalContentColor.current.copy(alpha = LocalContentAlpha.current))
        )
    }
}

[Alexander Maryanovsky]

I’m not sure you can use the same resources both from Swing and as Compose resources, because the former needs to be in src/main/resources and the latter in src/main/composeResources.
@Konstantin Tskhovrebov knows for sure.

[bj0]

I'll try reading as resource like that and see if it works. As for the path, the docs say you can specify the resource path (in newer versions), but it does expect a specific subdirectory layout, which java code doesn't normally follow

[bj0]

using the stream directly worked, it must be searching the wrong classpath i guess?