roboflex.util.png

Roboflex support for png compression to file and memory, and png decompression from memory.

Useful for compressing images over slow transports (wifi, etc).

System Dependencies

None! We build lodepng from source...

pip install

pip install roboflex.util.png

Import

import roboflex.util.png as rup

Nodes

There are two complementary nodes: PNGCompressor, which can turn rgb tensors into pngs in memory, and PNGDecompressor, which does the opposite. Useful either for writing rgb tensors to files, or compressing them.

# all parameters are optional
c = rup.PNGCompressor(

    # in the incoming message, where to find the rgb tensor
    image_key = "rgb",

    # in the outgoing message, where to place the jpeg data
    output_key = "png", 

    # If this is provided, will ALSO write jpeg files with this 
    # prefix, with a variation of the date and time as the suffix.
    filename_prefix = "",

    # name of the node
    name = "PNGCompressor",

    # prints internal info
    debug = False,
)

... and ...

c = rup.PNGDecompressor(

    # in the incoming message, where to find the png data as a blob
    input_key = "png",

    # in the outgoing message, where to place the rgb data as a tensor
    output_key = "rgb", 

    # name of the node
    name = "PNGDecompressor",

    # prints internal info
    debug = False,
)