image-preview.py

#!/usr/bin/env python3
"""w3mimgdisplay wrapper

Usage: image-preview.py w3mimgdisplay_path [ files ... ]

Only jpeg, jpg, png and gif files are processed.

Outputs the input lines for w3mimgdisplay except for the last line,
which contains the number of consumed arguments.

"""

from sys import argv
import re
import subprocess
import itertools
import os.path
from os import getenv

import sys, struct, fcntl, termios
def get_terminal_size():
    _, _, w, h = struct.unpack("HHHH",
                               fcntl.ioctl(sys.stderr.fileno(), # stderr is not redirected, unlike stdout
                                           termios.TIOCGWINSZ,
                                           struct.pack("HHHH",
                                                       0,0,0,0)))
    return w, h


def main():
    ##########  CONFIG BEGIN  ##########
    upper_margin  = 50
    max_height    = 300
    width         = 270
    images_in_row = 5
    max_rows      = 3
    border        = 5
    autodetect_size = bool(getenv("DISPLAY")) # are we in X or in tty?
    ##########   CONFIG END   ##########


    w3mimgdisplay = argv.pop(1)
    argv.pop(0)

    # calculate how many images we can fit horizontally
    if autodetect_size:
        term_w, term_h = get_terminal_size()
        term_h -= upper_margin
        images_in_row = term_w // (width + border)
        max_rows = term_h // (max_height + border)


    # get as many images, as we can display, while removing non-images
    consumed_arg_count = 0
    files = []
    for file in argv:
        consumed_arg_count += 1
        if (os.path.isfile(file) and
            re.search(r"\.jpe?g$|\.png$|\.bmp$|\.gif$",
                      file, re.IGNORECASE)):
            files.append(file)
            if len(files) >= images_in_row * max_rows:
                break

    if not files:
        exit(1)

    # calculate the maximum image width that will still let us fit images_in_row images
    if autodetect_size:
        width = term_w // min(images_in_row, len(files)) - border
        if len(files) <= images_in_row:
            max_height = term_h
        else:
            # do not scale later to fit the image vertically
            autodetect_size = False

    column = 0
    row = 0
    for file in files:
        w3m = subprocess.Popen([w3mimgdisplay],
                               stdin=subprocess.PIPE,
                               stdout=subprocess.PIPE)
        result = w3m.communicate("5;{0}".format(file).encode())[0].decode()
        if result.strip():
            w, h = [int(string)
                    for string
                    in result.split()]
            w_scaled = min(width, w)
            h_scaled = (w_scaled * h) // w
            if autodetect_size and h_scaled > term_h:
                h_scaled = term_h
                w_scaled = (h_scaled * w) // h
            print("2;3;\n0;1;{x};{y};{w};{h};0;0;0;{h_max};{path}\n4;\n3;".format(
                x = column * (width + border),
                y = upper_margin + row * (max_height + border),
                w = w_scaled,
                h = h_scaled,
                h_max = max_height,
                path = file))
            column = (column+1) % images_in_row
            if column == 0:
                row += 1
    print(consumed_arg_count)

if __name__ == "__main__":
    main()