Jamal N's questions

我正在尝试实现一个拍照应用程序，我不需要完整的图片，我需要裁剪主图片的三张图片（用矩形表示），并保存它们以供以后处理。我使用的是 A4 纸张长宽比 (1:1.414)

@Composable
private fun CameraScreenContent(
    viewModel: ScanLabelViewModel,
    navController: NavController,
){
    Box(
        contentAlignment = Alignment.BottomCenter,
        modifier = Modifier
            .fillMaxSize()
            .background(Black)
    ) {

        val lifecycleOwner = LocalLifecycleOwner.current
        val context = LocalContext.current
        val cameraController: LifecycleCameraController = remember { LifecycleCameraController(context) }
        val previewView = remember { PreviewView(context) }

        val capturedImage = viewModel.capturedImage.collectAsState()


        AndroidView(
            modifier = Modifier
                .align(Alignment.TopCenter)
                .aspectRatio(1 / 1.414f)
                .fillMaxSize()
                .border(8.dp, Color(0x4A000000))
            ,
            factory = {
                previewView.apply {
                    setupCamera(
                        cameraController = cameraController,
                        lifecycleOwner = lifecycleOwner,
                        previewView = previewView,
                    )
                }
            }
        )


        Canvas(
            modifier = Modifier
                .align(Alignment.TopCenter)
                .aspectRatio(1 / 1.414f)
                .fillMaxSize()
        ) {
            viewModel.setCropsMesurements(size)
            //expediteur box
            drawRect(
                color = White,
                topLeft = Offset(size.width*6/24, size.height*3/29),
                size = Size((size.width/24)*11,(size.height/29)*4),
                style = Stroke(4f, pathEffect = PathEffect.dashPathEffect(floatArrayOf(10f,10f),0f))
            )
            //destinataire box
            drawRect(
                color = White,
                topLeft = Offset(size.width*1/24, size.height*7/29),
                size = Size((size.width/24)*9,(size.height/29)*4),
                style = Stroke(4f, pathEffect = PathEffect.dashPathEffect(floatArrayOf(10f,10f),0f))
            )
            //desciption box
            drawRect(
                color = White,
                topLeft = Offset(size.width*1/24, size.height*17/29),
                size = Size((size.width/24)*13,(size.height/29)*1),
                style = Stroke(4f, pathEffect = PathEffect.dashPathEffect(floatArrayOf(10f,10f),0f))
            )
        }


        Button(
            modifier = Modifier
                .padding(bottom = 32.dp)
                .align(Alignment.BottomCenter),
            shape = RoundedCornerShape(20.dp),
            colors = ButtonDefaults.buttonColors(
                contentColor = White
            ),
            border = BorderStroke(2.dp, Color(0x4DFFFFFF)),
            onClick = {
                viewModel.captureImage(cameraController)
                if (capturedImage.value != null){
                    viewModel.cropExpediteurImage()
                }
            }
        ){
            Text(text = "take picture",modifier = Modifier.padding(1.dp))
        }

    }
}

private fun setupCamera(
    cameraController: LifecycleCameraController,
    lifecycleOwner: LifecycleOwner,
    previewView: PreviewView,
) {
    cameraController.bindToLifecycle(lifecycleOwner)
    previewView.controller = cameraController
}

这是捕获图像功能

fun captureImage(
        cameraController: LifecycleCameraController,
        onImageCaptured: (File) -> Unit
    ) {
        val file = File(context.cacheDir, "${UUID.randomUUID()}.jpg")
        val outputOptions = ImageCapture.OutputFileOptions.Builder(file).build()

        cameraController.takePicture(
            outputOptions,
            ContextCompat.getMainExecutor(context),
            object : ImageCapture.OnImageSavedCallback {
                override fun onImageSaved(outputFileResults: ImageCapture.OutputFileResults) {
                    onImageCaptured(file)
                }

                override fun onError(exception: ImageCaptureException) {
                    println("Failed $exception")
                }
            }
        )
    }

我在这里尝试了很多建议的解决方案，但比例从来都不正确，我总是得到图片的小块，就像我裁剪预览而不是捕获的图像。