Question

我想拍照，并使用CameraX从中心裁剪出25x25 dp的正方形。我已经读到可以使用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

您可以在捕获图像后使用此功能裁剪图像：

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()
    }

以参考图像的形式裁剪图像，像是框架的父视图，而像最终参考的子视图则是

参数bitmap要裁剪的图像
参数frame设置图像的位置
参数reference框架为裁剪图像提供参考
return图像已经裁剪

Answer 2

您可以将图像转换为位图，然后进行裁剪。

Bitmap cropImage(Image image, int rotationDegree, int xOffset, int yOffset, int cropWidth, int cropHeight) {
    // 1 - Convert image to Bitmap
    ByteBuffer buffer = image.getPlanes()[0].getBuffer();
    byte[] bytes = new byte[buffer.remaining()];
    buffer.get(bytes);
    Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);

    // 2 - Rotate the Bitmap
    if(rotationDegree != 0) {
        Matrix rotationMatrix = new Matrix();
        rotationMatrix.postRotate(rotationDegree);
        bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), rotationMatrix, true);
    }

    // 3 - Crop the Bitmap
    bitmap = Bitmap.createBitmap(bitmap, xOffset, yOffset, cropWidth, cropHeight);

    return bitmap;
}

Answer 3

您可以从图像中获取飞机并手动裁剪它们：

private fun cropByteArray(array : ByteArray, cropRect: Rect): ByteArray {
    val croppedArray = ByteArray(cropRect.width()*cropRect.height())
    val imageWidth = 640
    var i = 0
    array.forEachIndexed { index, byte ->
        val x = index % imageWidth
        val y = index / imageWidth

        if (cropRect.left <= x && x < cropRect.right && cropRect.top <= y && y < cropRect.bottom) {
            croppedArray[i] = byte
            i++
        }
    }
    return croppedArray
}

......

val buffer = image.planes[0].buffer
val imageByteArray = buffer.toByteArray()
val data = cropByteArray(imageByteArray, cropRect)

Android：如何使用CameraX裁剪图像？

3 个答案: