开门见山，直接上码

package com.satis.compose.get.widget

import android.graphics.Bitmap
import android.graphics.Canvas
import android.view.View
import android.view.ViewGroup
import android.view.ViewTreeObserver
import android.widget.FrameLayout
import androidx.compose.material.Surface
import androidx.compose.runtime.Composable
import androidx.compose.runtime.MutableState
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.geometry.Rect
import androidx.compose.ui.layout.boundsInRoot
import androidx.compose.ui.layout.onGloballyPositioned
import androidx.compose.ui.platform.ComposeView
import androidx.compose.ui.viewinterop.AndroidView

/**
* @author sunshaobei on 2022/9/9
* Compose 对包裹控件截图
*/

data class CaptureState(
  val capture: Boolean = false
)

fun MutableState<CaptureState>.capture() {
  this.value = this.value.copy(capture = true)
}

private fun MutableState<CaptureState>.captureComplete() {
  this.value = this.value.copy(capture = false)
}

@Composable
fun rememberCaptureController(): MutableState<CaptureState> {
  return remember {
      mutableStateOf(CaptureState(capture = false))
  }
}

@Composable
fun ComposeCapture(
  captureController: MutableState<CaptureState> = rememberCaptureController(),
  onSaveBitmap: (Bitmap?) -> Unit,
  content: @Composable () -> Unit
) {
  var bounds = remember {
      mutableStateOf<Rect?>(null)
  }
  //依据状态值 选择是否使用AndroidView进行展示获取截图
  if (captureController.value.capture) {
      CaptureView(captureController = captureController, onSaveBitmap = onSaveBitmap,bounds = bounds,content = content)
  } else {
      Surface(modifier = Modifier.onGloballyPositioned {
          bounds.value = it.boundsInRoot()
      },content = content)

  }
}

@Composable
private fun CaptureView(
  captureController: MutableState<CaptureState>,
  bounds: MutableState<Rect?>,
  onSaveBitmap: ((Bitmap?) -> Unit)? = null,
  content: @Composable () -> Unit
) {
  AndroidView(factory = {
      FrameLayout(it).apply {
          layoutParams = ViewGroup.LayoutParams(
              (bounds.value!!.right - bounds.value!!.left).toInt(),
              (bounds.value!!.bottom - bounds.value!!.top).toInt()
          )
          val composeView = ComposeView(it).apply {
              setContent {
                  content()
              }
          }
          drawListener(composeView,this,captureController,onSaveBitmap)
          addView(
              composeView, ViewGroup.LayoutParams(
                  ViewGroup.LayoutParams.MATCH_PARENT,
                  ViewGroup.LayoutParams.MATCH_PARENT
              )
          )

      }
  })
}

private fun drawListener(
  composeView: View, viewGroup: ViewGroup,
  captureController: MutableState<CaptureState>,
  onSaveBitmap: ((Bitmap?) -> Unit)? = null,
) {
  val drawListener = object : ViewTreeObserver.OnDrawListener {
      var remove = false
      override fun onDraw() {
          if (composeView.width > 0) {
              if (!remove) {
                  // View 绘制第一帧 开始截图并移除 监听，随后切换截图状态 回到Compose组件
                  remove = true
                  composeView.post {
                      val bitmap = getViewGroupBitmap(viewGroup)
                      // 切换状态 回到Compose
                      captureController.captureComplete()
                      onSaveBitmap?.invoke(bitmap)
                      composeView.viewTreeObserver.removeOnDrawListener(this)
                  }
              }

          }
      }
  }
  composeView.viewTreeObserver.addOnDrawListener(drawListener)
}

/**
* @param viewGroup viewGroup
* @return Bitmap
*/
private fun getViewGroupBitmap(viewGroup: ViewGroup): Bitmap? {
  val bitmap = Bitmap.createBitmap(viewGroup.width, viewGroup.height, Bitmap.Config.ARGB_8888)
  val canvas = Canvas(bitmap)
  viewGroup.draw(canvas)
  return bitmap
}

由于官方并没有提供在Compose中截图的方式，所以改变了下思路，由状态切换为 AndroidView进行截图，截图后切换回Compose展示

具体使用如下

@Compose
fun testCaptur(){
        //截图控制器
        val captureController = rememberCaptureController()
       Column(horizontalAlignment = Alignment.CenterHorizontally) {
             ComposeCapture(
                   captureController = captureController,
                   onSaveBitmap = {
                          //Todo 返回截图的 bitmap
                   }) {
                            Column(
                                   horizontalAlignment = Alignment.CenterHorizontally
                            ) {
                                Image(
                                     painter = painterResource(id = R.drawable.wechat),
                                      contentDescription = null
                                )
                               Text(text = "测试截图bitmap")
                               Text(text = "测试截图bitmap")
                               Text(text = "测试截图bitmap")
                               Text(text = "测试截图bitmap")
                     }
           }
           Button(
                  onClick = { 
                        //触发截图
                        captureController.capture()
                    }
            ) {
               Text(text = "save")
             }
    }
}