Android:如何使用 CameraX 裁剪图像？

Question

我想拍摄一张照片，并使用 CameraX 从中心裁剪出一个 25x25 dp 的正方形。我读到可以使用 ImageCapture 进行裁剪，但不幸的是到目前为止几乎没有类似的示例。

val imageCaptureConfig = ImageCaptureConfig.Builder().apply {
    setTargetAspectRatio(Rational(1, 1))
    setCaptureMode(ImageCapture.CaptureMode.MIN_LATENCY)
}.build()

val imageCapture = ImageCapture(imageCaptureConfig)
btn_take_photo.setOnClickListener {
    imageCapture.takePicture(
        object : ImageCapture.OnImageCapturedListener() {
            override fun onCaptureSuccess(image: ImageProxy?, rotationDegrees: Int) {
                super.onCaptureSuccess(image, rotationDegrees)

                // image manipulation here?
            }
        }
    )
}

Answer 1

您可以使用此功能在捕获图像后裁剪图像:

private fun cropImage(bitmap: Bitmap, frame: View, reference: View): ByteArray {
        val heightOriginal = frame.height
        val widthOriginal = frame.width
        val heightFrame = reference.height
        val widthFrame = reference.width
        val leftFrame = reference.left
        val topFrame = reference.top
        val heightReal = bitmap.height
        val widthReal = bitmap.width
        val widthFinal = widthFrame * widthReal / widthOriginal
        val heightFinal = heightFrame * heightReal / heightOriginal
        val leftFinal = leftFrame * widthReal / widthOriginal
        val topFinal = topFrame * heightReal / heightOriginal
        val bitmapFinal = Bitmap.createBitmap(
            bitmap,
            leftFinal, topFinal, widthFinal, heightFinal
        )
        val stream = ByteArrayOutputStream()
        bitmapFinal.compress(
            Bitmap.CompressFormat.JPEG,
            100,
            stream
        ) //100 is the best quality possibe
        return stream.toByteArray()
    }

裁剪图像，引用 View 父级(如框架)和 View 子级(如最终引用)

• 参数位图要裁剪的图像
• param frame 设置图像的位置
• param reference 引用帧来裁剪图像
• 返回已裁剪的图像