Base64 Process

pybase64 is a Python library that provides Base64 encoding and decoding functionalities. It supports various encoding formats, including standard Base64, Base64 URL, and Base64 URL file name safe encoding. pybase64 is an enhanced version of the base64 module, offering more features and options.

In image processing, we often need to convert image data into Base64 encoded strings for use in web transmission. pybase64 provides a convenient interface for fast Base64 encoding and decoding operations, supporting various encoding formats to meet different needs.

• Common Issue: String vs Byte String?

  In Python, a string is a sequence of Unicode characters, while a byte string is a sequence of "bytes." In Base64 encoding, we typically use byte strings for encoding and decoding, as Base64 encoding operates on byte data.

img_to_b64

img_to_b64(img: np.ndarray, IMGTYP: Union[str, int, IMGTYP] = IMGTYP.JPEG) -> Union[bytes, None]

• Description: Converts a NumPy image array into a Base64 byte string.

• Parameters:

  • img (np.ndarray): The image array to convert.
  • IMGTYP (Union[str, int, IMGTYP]): The image type. Supported types are IMGTYP.JPEG and IMGTYP.PNG. Default is IMGTYP.JPEG.

• Return value:

  • bytes: The Base64 encoded byte string.

• Example:

  import capybara as cb
  
  img = cb.imread('lena.png')
  b64 = cb.img_to_b64(img, IMGTYP=cb.IMGTYP.PNG)

npy_to_b64

npy_to_b64(x: np.ndarray, dtype='float32') -> bytes

• Description: Converts a NumPy array into a Base64 byte string.

• Parameters:

  • x (np.ndarray): The NumPy array to convert.
  • dtype (str): The data type. Default is 'float32'.

• Return value:

  • bytes: The Base64 encoded byte string.

• Example:

  import capybara as cb
  import numpy as np
  
  x = np.random.rand(100, 100, 3)
  b64 = cb.npy_to_b64(x)

npy_to_b64str

npy_to_b64str(x: np.ndarray, dtype='float32', string_encode: str = 'utf-8') -> str

• Description: Converts a NumPy array into a Base64 string.

• Parameters:

  • x (np.ndarray): The NumPy array to convert.
  • dtype (str): The data type. Default is 'float32'.
  • string_encode (str): The string encoding. Default is 'utf-8'.

• Return value:

  • str: The Base64 encoded string.

• Example:

  import capybara as cb
  import numpy as np
  
  x = np.random.rand(100, 100, 3)
  
  b64str = cb.npy_to_b64str(x)

img_to_b64str

img_to_b64str(img: np.ndarray, IMGTYP: Union[str, int, IMGTYP] = IMGTYP.JPEG, string_encode: str = 'utf-8') -> Union[str, None]

• Description: Converts a NumPy image array into a Base64 string.

• Parameters:

  • img (np.ndarray): The image array to convert.
  • IMGTYP (Union[str, int, IMGTYP]): The image type. Supported types are IMGTYP.JPEG and IMGTYP.PNG. Default is IMGTYP.JPEG.
  • string_encode (str): The string encoding. Default is 'utf-8'.

• Return value:

  • str: The Base64 encoded string.

• Example:

  import capybara as cb
  
  img = cb.imread('lena.png')
  b64str = cb.img_to_b64str(img, IMGTYP=cb.IMGTYP.PNG)

b64_to_img

b64_to_img(b64: bytes) -> Union[np.ndarray, None]

• Description: Converts a Base64 byte string into a NumPy image array.

• Parameters:

  • b64 (bytes): The Base64 byte string to convert.

• Return value:

  • np.ndarray: The converted NumPy image array.

• Example:

  import capybara as cb
  
  b64 = cb.img_to_b64(cb.imread('lena.png'))
  img = cb.b64_to_img(b64)

b64str_to_img

b64str_to_img(b64str: Union[str, None], string_encode: str = 'utf-8') -> Union[np.ndarray, None]

• Description: Converts a Base64 string into a NumPy image array.

• Parameters:

  • b64str (Union[str, None]): The Base64 string to convert.
  • string_encode (str): The string encoding. Default is 'utf-8'.

• Return value:

  • np.ndarray: The converted NumPy image array.

• Example:

  import capybara as cb
  
  b64 = cb.img_to_b64(cb.imread('lena.png'))
  b64str = b64.decode('utf-8')
  img = cb.b64str_to_img(b64str)

b64_to_npy

b64_to_npy(x: bytes, dtype='float32') -> np.ndarray

• Description: Converts a Base64 byte string into a NumPy array.

• Parameters:

  • x (bytes): The Base64 byte string to convert.
  • dtype (str): The data type. Default is 'float32'.

• Return value:

  • np.ndarray: The converted NumPy array.

• Example:

  import capybara as cb
  
  b64 = cb.npy_to_b64(np.random.rand(100, 100, 3))
  x = cb.b64_to_npy(b64)

b64str_to_npy

b64str_to_npy(x: bytes, dtype='float32', string_encode: str = 'utf-8') -> np.ndarray

• Description: Converts a Base64 string into a NumPy array.

• Parameters:

  • x (bytes): The Base64 string to convert.
  • dtype (str): The data type. Default is 'float32'.
  • string_encode (str): The string encoding. Default is 'utf-8'.

• Return value:

  • np.ndarray: The converted NumPy array.

• Example:

  import capybara as cb
  
  b64 = cb.npy_to_b64(np.random.rand(100, 100, 3))
  x = cb.b64str_to_npy(b64.decode('utf-8'))