memory_file_bitmap.py

"""Writes/Reads a bitmap to/from memory.

Topics:
    * c4d.storage.ByteSeq
    * c4d.storage.MemoryFileStruct
    * c4d.storage.HyperFile
    * HyperFile.WriteImage()
"""
__author__ = "Ferdinand Hoppe"
__copyright__ = "Copyright (C) 2026 MAXON Computer GmbH"
__license__ = "Apache-2.0 License"
__version__ = "R13"

import c4d


def WriteBitmap(bmp, format=c4d.FILTER_B3D, settings=c4d.BaseContainer()):
    """Write an hyper file image to a buffer object.

    Args:
        bmp: The image to convert into a buffer object
        format: The filter type. Defaults to c4d.FILTER_B3D.
        settings: Optional settings. Defaults to c4d.BaseContainer().

    Returns:
        The byte sequence or None
    """

    # Creates a MemoryFile, data will be written in
    mfs = c4d.storage.MemoryFileStruct()
    mfs.SetMemoryWriteMode()

    # Initializes a HyperFile
    hf = c4d.storage.HyperFile()

    # Opens the HyperFile, with the MemoryFile used
    if not hf.Open(0, mfs, c4d.FILEOPEN_WRITE, c4d.FILEDIALOG_NONE):
        raise RuntimeError("Failed to open the HyperFile.")

    # Writes the bitmap
    if not hf.WriteImage(bmp, format, settings):
        raise RuntimeError("Failed to write image in the HyperFile.")

    # Closes the HyperFile, data are now in our MemoryFile
    hf.Close()

    # Returns the data stored in the MemoryFile
    byteseq, size = mfs.GetData()
    return byteseq, size


def ReadBitmap(byteseq):
    """Creates a bitmap from a buffer object.

    Args:
        byteseq: The buffer object.

    Returns:
        The image if succeeded, otherwise False
    """
    # Initializes our HyperFile, MemoryFile and bmp where data will be stored
    hf = c4d.storage.HyperFile()
    mfs = c4d.storage.MemoryFileStruct()
    bmp = None

    # Defines the memory address to read, and the size of this block
    mfs.SetMemoryReadMode(byteseq, len(byteseq))

    # Opens the hyperfile, with the MemoryFile used
    if not hf.Open(0, mfs, c4d.FILEOPEN_READ, c4d.FILEDIALOG_NONE):
        raise RuntimeError("Failed to open the HyperFile.")

    # Reads the bitmap
    bmp = hf.ReadImage()

    # Closes the HyperFile
    hf.Close()

    return bmp


def main():
    # Opens a Dialog to choose a picture file
    path = c4d.storage.LoadDialog(type=c4d.FILESELECTTYPE_IMAGES, title="Please Choose an Image:")
    if not path:
        return

    # Creates and initialize selected image
    img = c4d.bitmaps.BaseBitmap()
    if img is None:
        raise RuntimeError("Failed to create a BaseBitmap.")

    # If initialization went wrong, display an error
    if img.InitWith(path)[0] != c4d.IMAGERESULT_OK:
        raise RuntimeError("Cannot load image \"" + path + "\".")

    # Saves BaseBitmap with a HyperFile and retrieve the byte sequence
    byteseq, size = WriteBitmap(img)

    # Reads BaseBitmap from the byte sequence
    bmp = ReadBitmap(byteseq)

    # Displays the bitmap in the Picture Viewer
    c4d.bitmaps.ShowBitmap(bmp)


if __name__ == '__main__':
    main()