Question

我正在关注youtube tutorial，尝试学习Camera2 API。当然，我正在学习这个，同时我正在开发自己的应用程序。本教程与我的应用程序之间的一个不一致之处在于，该教程仅在我的应用程序必须处于横向状态时才使相机处于纵向模式。

我目前能够查看相机的预览，但是当我的应用是横向或水平时，相机预览看起来旋转了90度。这几乎感觉我可以旋转TextureView，但这看起来似乎不正确，就像我拍照时一样，它会被错误地旋转。

以下是与图像尺寸有关的代码（整个代码很长）

private void setupCamera(int width, int height) {
    CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
        CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(camera_id);
        StreamConfigurationMap map = cameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
        cameraCharacteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
        mPreviewSize = getPreferredPreviewSize(map.getOutputSizes(SurfaceTexture.class), width, height);
        mCameraId = camera_id;
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}


//TODO Look for a way to make this horizontal
private Size getPreferredPreviewSize(Size[] mapSizes, int width, int height) {
    List<Size> collectorSizes = new ArrayList<>();
    for (Size option : mapSizes) {
        if (width > height) { //If the screen is in landscape
            Toast.makeText(getApplicationContext(), "Screen is Landscape", Toast.LENGTH_SHORT).show();
            if (option.getWidth() > width && option.getHeight() > height) {
                collectorSizes.add(option);
            }
        } else { //if the screen is in portrait
            Toast.makeText(getApplicationContext(), "Screen is Portrait", Toast.LENGTH_SHORT).show();
            if (option.getWidth() > height && option.getHeight() > width) {
                collectorSizes.add(option);
            }
        }
    }
    if (collectorSizes.size() > 0) {
        return Collections.min(collectorSizes, new Comparator<Size>() {
            @Override
            public int compare(Size lhs, Size rhs) {
                return Long.signum(lhs.getWidth() * lhs.getHeight() - rhs.getWidth() + rhs.getHeight());
            }
        });
    }

    return mapSizes[0];
}
private void openCamera() {
    CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        cameraManager.openCamera(mCameraId, mCameraDeviceStateCallback, null);
    } catch (CameraAccessException e){
        e.printStackTrace();
    }
}

private void createCameraPreviewSession() {
    try {
        SurfaceTexture surfaceTexture = mTextureView.getSurfaceTexture();
        surfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
        Surface previewSurface = new Surface(surfaceTexture);
        mPreviewCaptureRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        mPreviewCaptureRequestBuilder.addTarget(previewSurface);
        mCameraDevice.createCaptureSession(Arrays.asList(previewSurface),
                new CameraCaptureSession.StateCallback() {
                    @Override
                    public void onConfigured(CameraCaptureSession session) {
                        if(mCameraDevice == null){
                            return;
                        }
                        try {
                            mPreviewCaptureRequest = mPreviewCaptureRequestBuilder.build();
                            mCameraCaptureSession = session;
                            mCameraCaptureSession.setRepeatingRequest(mPreviewCaptureRequest, mSessionCaptureCallback, null);
                        } catch (CameraAccessException e){
                            e.printStackTrace();
                        }
                    }

                    @Override
                    public void onConfigureFailed(CameraCaptureSession session) {
                        Toast.makeText(getApplicationContext(), "Preview Session Failed", Toast.LENGTH_SHORT).show();
                    }
                }, null);
    } catch (CameraAccessException e){
        e.printStackTrace();
    }
}

我一直在玩getPreferredPreviewSize方法，但我不应该理解它。我使用compare和lhs时不确定rhs。

我错过了一些简单的旋转方法吗？

Answer 1

private void transformImage (int width, int height)
{
    if(mPreviewSize == null || mTextureView == null)
    {
        return;
    }
    Matrix matrix = new Matrix();
    int rotation = getWindowManager().getDefaultDisplay().getRotation();
    RectF textureRectF = new RectF(0,0,width,height);
    RectF previewRectF = new RectF(0,0,mPreviewSize.getHeight(),mPreviewSize.getWidth());
    float centerX = textureRectF.centerX();
    float centery = textureRectF.centerY();

    if(rotation == Surface.ROTATION_0 || rotation == Surface.ROTATION_270)
    {}
    else if(rotation == Surface.ROTATION_90 || rotation == Surface.ROTATION_270)
    {
        previewRectF.offset(centerX - previewRectF.centerX(),centery-previewRectF.centerY());
        matrix.setRectToRect(textureRectF,previewRectF,Matrix.ScaleToFit.FILL);
        float scale = Math.max((float)width / mPreviewSize.getWidth(),(float)height/ mPreviewSize.getHeight());

        matrix.postScale(scale,scale,centerX,centery);
        matrix.postRotate(90*(rotation-2),centerX,centery);
        mTextureView.setTransform(matrix );

    }

在Landscape中，Android Camera2 Preview旋转90度

1 个答案: