acldvppRotate

Applicability

Function Usage

Description: rotates an image counterclockwise.

Figure 1 Rotation diagram

Prototype

Each operator has two-phase API calls. First, acldvppRotateGetWorkspaceSize is called to calculate the required workspace size based on the computation process. Then, acldvppRotate is called to perform computation. The two-phase APIs are as follows:

• First-phase API:

  1	acldvppStatus acldvppRotateGetWorkspaceSize(const aclTensor *self, float angle, uint32_t interpolationMode, bool expand, const aclIntArray *center, uint32_t paddingMode, const aclFloatArray *fill, aclTensor *out, uint64_t *workspaceSize, aclOpExecutor **executor)

• Second-phase API:

  1	acldvppStatus acldvppRotate(void *workspace, uint64_t workspaceSize, aclOpExecutor *executor, aclrtStream stream)

acldvppRotateWorkspaceSize

• Parameters:
  • self: input tensor of the operator, which is of the aclTensor type created by calling aclCreateTensor (the tensor data is stored on the device). The value of dataType of the input tensor can be UINT8 or FLOAT, the value of Format can be NCHW or NHWC, and non-contiguous tensors are not supported. The value of N can be 1 or left empty, and the value of C can be 1 or 3 (1: input GRAY image; 3: input RGB image).
  • angle: rotation angle, in degrees. The rotation direction is counterclockwise.
  • expand: whether to extend the image. The values are as follows:
    • True: extends the image size to accommodate the rotated image. Note that the image is rotated around its center without translation during the extension.

      When expand is set to True, the output width and height are calculated as follows:

      The coordinates of the four vertices of the image are substituted into the following rotation matrix formula. Then the maximum distances in the horizontal and vertical directions are calculated as the width and height of the output image.

      

    • False: The image size remains unchanged.
  • center: rotation center.

    When expand is set to False, if center is set to nullptr, the image is rotated around its center point. If center is set to other values, the image is rotated around the center point set. The coordinates of center are set with the upper left corner of the image as the origin point.

    When expand is set to True, the center setting does not take effect, and the image is rotated around its center point.

  • interpolationMode: the interpolation algorithm. The values of this parameter are as follows:
    • 0: bilinear
    • 1: nearest neighbour
  • paddingMode: padding mode. The options are as follows:
    • 0: CONSTANT, indicating that a constant pad value will be used.
    • 1: EDGE, indicating repeating of the last element. For example, aaaaaa|a*****h|hhhhhhh, where * indicates any image element.
  • fill: an array with length of 3, used to set the value to be filled in each channel. This parameter is of the aclFloatArray type created by calling aclCreateFloatArray. This parameter is valid only when paddingMode is set to CONSTANT. If C is set to 1 (indicating a GRAY image), set fill[0]. If C is set to 3 (indicating an RGB image), set fill[0] for color red, fill[1] for color green, and fill[2] for color blue.
  • out: output tensor of the operator, which is of the aclTensor type created by calling aclCreateTensor (the tensor data is stored on the device). The value of dataType of the output tensor can be UINT8 or FLOAT, the value of Format can be NCHW or NHWC, and non-contiguous tensors are not supported. The value of N can only be 1, the value of C can be 1 or 3 (1: GRAY image; 3: RGB image), and the values of dataType and Format must be the same as those of self.
  • workspaceSize: size of the workspace to be allocated on the device.
  • executor: operator executor, containing the operator computation process.
• Returns:

  acldvppStatus status code. For details, see acldvpp Return Codes.

acldvppRotate

• Parameters:
  • workspace: address of the device memory allocated by calling aclrtMalloc. The size of the device memory is specified by workspaceSize.
  • workspaceSize: The value must be the same as that obtained by calling acldvppRotateGetWorkspaceSize.
  • executor: op executor, which contains the operator computation process and is the same as the executor of the acldvppRotateGetWorkspaceSize API.
  • stream: stream for executing a task, which can be a created stream for saving resources or newly created by calling aclrtCreateStream.
• Returns:

  acldvppStatus status code. For details, see acldvpp Return Codes.

Constraints

• The supported image resolution ranges from 6 x 4 to 32768 x 32768.
• The input and output formats must be the same.