Camera2标量作物区域与传感器图像大小

Question

我正在为Galaxy S7编写一个应用程序，该应用程序显示实时Camera2预览，在该预览中，我希望使用以下方法控制缩放级别：

 captureRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomCropPreview);
 cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(), null, mBackgroundHandler);

对于所需的不同作物/缩放，Rect zoomCropPreview被更改。由于S7支持8的最大数字变焦，其传感器阵列大小为4032x3024，因此我很难确定Rect值。我已经看过reprocess.html的指导，但我被困住了。

例如，zoomCropPreview =(0,4032,3024)和(0,504,378)-8倍变焦一样会产生罚款。但其他区域，如(250,250,504,378)或(1512,1134,1008,756)则不起作用，即使它们的边界在传感器阵列内。以下是基于https://inducesmile.com/android/android-camera2-api-example-tutorial/的代码的摄像机预览部分

protected void createCameraPreview() {
        try {
        SurfaceTexture texture = textureView.getSurfaceTexture();
        assert texture != null;
        texture.setDefaultBufferSize(imageDimension.getWidth(), imageDimension.getHeight());
        Surface surface = new Surface(texture);
        captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        captureRequestBuilder.addTarget(surface);
        cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                //The camera is already closed
                if (null == cameraDevice) {
                    return;
                }
                // When the session is ready, we start displaying the preview.
                //try to change zoom
                captureRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomCropPreview);
                cameraCaptureSessions = cameraCaptureSession;
                updatePreview();                    //update preview screen
            }

            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
                Toast.makeText(AndroidCameraApi.this, "Configuration change", Toast.LENGTH_SHORT).show();
            }
        }, null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

如何确定scalar_crop_region的正确Rect值？

Answer 1

如果您查看地域的文档，它会告诉您

作物区域的宽度和高度不能分别设置为小于地面( activeArraySize.width / android.scaler.availableMaxDigitalZoom )和地面( activeArraySize.height / android.scaler.availableMaxDigitalZoom )。

文档还指出，它将根据硬件和诸如此类的内容进行圆整--您想要计算您的弹出区域的高度和宽度。从这些项目中，您可以计算左上角和右下角。这些角落将提供您的裁剪区域的面积。

float cropW = activeArraySize.width() / zoomLevel;
float cropH = activeArraySize.height() / zoomLevel;

// now we calculate the corners
int top = activeArraySize.centerY() - (int) (cropH / 2f);
int left = activeArraySize.centerX() - (int) (cropW / 2f);
int right = activeArraySize.centerX() + (int) (cropW / 2f);
int bottom = activeArraySize.centerY() + (int) (cropH / 2f);

记住，屏幕的左上角是0,0。把这个画出来，以便进一步澄清。