主页 / coding / 问题 / 78582738
Accepted
Jamal N
Asked: 2024-06-06 01:49:59 +0800 CST

Jetpack Compsoe Camerax 图像捕获并裁剪 3 个矩形

  • 772

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)

在此输入图像描述

@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。

1 个回答

  1. Best Answer

    尝试这个，

      @Composable
    private fun CameraScreenContent() {
        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()
            ) {
                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 = {
                    captureImage(
                        cameraController = cameraController,
                        onImageCaptured = {
                            val bitmap = fileToBitmap(it) ?: return@captureImage
// I tried with the emulator and when it takes the image it is rotated so I had to set it right.
                            val rotatedBitmap = rotateBitmap(bitmap, 90f)
                            // Here you have images
                            processImage(rotatedBitmap).toMutableList()
                        },
                        context = context
                    )
                },
                content = { Text(text = "Capture") }
            )
        }
    }

    你还需要这些功能

    fun rotateBitmap(bitmap: Bitmap, degrees: Float): Bitmap {
    val matrix = Matrix()
    matrix.postRotate(degrees)
    return Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
}

fun cropBitmap(original: Bitmap, rect: Rect): Bitmap {
    return Bitmap.createBitmap(original, rect.left, rect.top, rect.width(), rect.height())
}

fun processImage(original: Bitmap): List<Bitmap> {
    val canvasWidth = original.width.toFloat()
    val canvasHeight = original.height.toFloat()

    val firstRect = Rect(
        (canvasWidth * 6 / 24).toInt(),
        (canvasHeight * 3 / 29).toInt(),
        (canvasWidth * 17 / 24).toInt(),
        (canvasHeight * 7 / 29).toInt()
    )

    val secondRect = Rect(
        (canvasWidth * 1 / 24).toInt(),
        (canvasHeight * 7 / 29).toInt(),
        (canvasWidth * 10 / 24).toInt(),
        (canvasHeight * 11 / 29).toInt()
    )

    val thirdRect = Rect(
        (canvasWidth * 1 / 24).toInt(),
        (canvasHeight * 17 / 29).toInt(),
        (canvasWidth * 14 / 24).toInt(),
        (canvasHeight * 18 / 29).toInt()
    )

    val firstBitmap = cropBitmap(original, firstRect)
    val secondBitmap = cropBitmap(original, secondRect)
    val thirdBitmap = cropBitmap(original, thirdRect)

    return listOf(firstBitmap, secondBitmap, thirdBitmap)
}

fun fileToBitmap(file: File): Bitmap? {
    return try {
        val inputStream = FileInputStream(file)
        val bitmap = BitmapFactory.decodeStream(inputStream)
        inputStream.close()
        bitmap
    } catch (e: IOException) {
        e.printStackTrace()
        null
    }
}
    • 1

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