code/pipwindow

#!/usr/bin/env python

import argparse

import png
import prix

# pipwindow

"""Tool to crop/expand an image to a rectangular window.
Come the revolution
this tool will allow the image and the window to be placed arbitrarily
(in particular the window can be bigger than the picture
and/or overlap it only partially) and
the image can be OpenGL style # border/repeat effects
(repeat, mirrored repeat, clamp,
fixed background colour, background colour from source file).
For now this tool only crops.
The window must be no greater than the image in
both x and y.
Coordinates are with (0,0) being the top-left
(as in ImageMagick).
"""


def copy_window(tl, br, inp, out):
    """Window the *inp* image and copy it to *out*.
    The window is an axis aligned rectangle with opposite corners
    at *tl* and *br* (each being an (x,y) pair).
    *inp* is the input file (a PNG image).
    *out* is the output file.
    """

    r = png.Reader(file=inp)
    _, _, rows, info = r.asDirect()

    image = png.Image(rows, info)
    image = prix.window(image, tl, br)

    image.write(out)


def main(argv=None):
    import sys

    if argv is None:
        argv = sys.argv
    argv = argv[1:]

    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--top", type=int)
    parser.add_argument("--left", type=int)
    parser.add_argument("--bottom", type=int)
    parser.add_argument("--right", type=int)
    parser.add_argument(
        "input", nargs="?", default="-", type=png.cli_open, metavar="PNG"
    )

    args = parser.parse_args(argv)

    return copy_window(
        (args.left, args.top),
        (args.right, args.bottom),
        args.input,
        png.binary_stdout(),
    )


if __name__ == "__main__":
    main()