Hi, can I export some already painted composable (...

# compose-desktop

[Krystian Kaniowski]

Hi, can I export some already painted composable (or a moment before) into file or clipboard when application is launched? Plus can I do it (it can be just standard @preview) without launching application using for example gradle task?

[Krystian Kaniowski]

I want something more smart than print screen 😉

[Krystian Kaniowski]

ahh I can see similar topic https://kotlinlang.slack.com/archives/C01D6HTPATV/p1662544404571979

[spierce7]

ImageComposeScene is the way to do this. It’s pretty easy to use, but it does have a bug if you are hitting this from multiple threads at the same time. I’ve worked around it in the mean time with a lock.

Rendering the image is where 95% of the work is done in the screenshoting process, which happens outside of the mutex.

private val IMAGE_COMPOSE_SCENE_MUTEX = Mutex()

/**
 * Because of a bug, ImageComposeScene has issues while being run in parallel, even though they shouldn't impact each
 * other. Most of the work seems to be done outside the scene when the image is rendered anyway, so not much is
 * lost by protecting this with a mutex.
 *
 * <https://github.com/JetBrains/compose-jb/issues/1396>
 */
suspend fun SafeImageComposeScene(
    width: Int,
    height: Int,
    density: Density = Density(1f),
    coroutineContext: CoroutineContext = Dispatchers.Unconfined,
    content: @Composable () -> Unit = {},
): ImageComposeScene {
    return IMAGE_COMPOSE_SCENE_MUTEX.withLock {
        ImageComposeScene(
            width = width,
            height = height,
            density = density,
            coroutineContext = coroutineContext,
            content = content
        )
    }
}