Create and access images

This example shows how to create images, retrieve their dimensions and data type, save them, and access the images as NumPy arrays:

def create_and_access_images():
        """
        Demonstrates creation of image and accessing its data.
        """

        # newimage command is used to create new images
        img1 = pi.newimage(ImageDataType.UINT8, 10, 20, 30)
        print(f"Width = {img1.get_width()}")
        print(f"Height = {img1.get_height()}")
        print(f"Depth = {img1.get_depth()}")
        print(f"Data type = {img1.get_data_type()}")
        print(f"All in one: {img1}")

        # newlike command can be used to create new image that is similar to existing image,
        # This line creates second image that has the same dimensions than img1 and pixel
        # data type UINT16.
        img2 = pi.newlike(img1, ImageDataType.UINT16)
        print(f"img2 is {img2}")

        # This line creates second image that has the same pixel data type than img1,
        # but its dimensions are 50x50x50.
        img3 = pi.newlike(img1, ImageDataType.UNKNOWN, 50, 50, 50)
        print(f"img3 is {img3}")

        # The data in the image can be retrieved as a NumPy array
        data = img1.get_data()
        print(f"When converted to a NumPy array, the shape of the image is {data.shape} and data type is {data.dtype}.")

        # Image data can also be set from a NumPy array
        data = np.eye(100, 100)
        img1.set_data(data)

        # This writes img1 to disk as a .raw file.
        # The dimensions of the image and the .raw suffix are automatically appended to
        # the image name given as second argument.
        pi.writeraw(img1, output_file("img1"))

        # NumPy arrays can be used directly as input in commands.
        # Changes made by Pi2 are NOT reflected in the NumPy arrays as
        # in some cases that would require re-shaping of the arrays, and that
        # does not seem to be wise...
        pi.writetif(data, output_file("numpy_array_tif"))

Output shown by the code above:

Width = 10
Height = 20
Depth = 30
Data type = uint8
All in one: (10, 20, 30), uint8
img2 is (10, 20, 30), uint16
img3 is (50, 50, 50), uint8
When converted to a NumPy array, the shape of the image is (20, 10, 30) and data type is uint8.