plakativ/plakativ.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Plakativ allows to create posters bigger than the page size one's own printer
# is able to print on by enlarging the input PDF, cutting it into smaller
# pieces and putting each of them onto a paper size that can be printed
# normally. The result can then be glued together into a bigger poster.
#
# Copyright (C) 2019 Johannes 'josch' Schauer
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License version 3 as published by the
# Free Software Foundation.

from collections import OrderedDict
import math
import fitz
import sys
import argparse
import os.path
import platform
from enum import Enum
from io import BytesIO
import logging

have_img2pdf = True
try:
    import img2pdf
except ImportError:
    have_img2pdf = False

have_tkinter = True
try:
    import tkinter
    import tkinter.filedialog
    import tkinter.messagebox
except ImportError:
    have_tkinter = False

    class dummy:
        def __init__(self, *args, **kwargs):
            raise Exception("this functionality needs tkinter")

    tkinter = type("", (), {})()
    tkinter.Frame = dummy
    tkinter.Menubutton = dummy
    tkinter.LabelFrame = dummy

VERSION = "0.3"

PAGE_SIZES = OrderedDict(
    [
        ("custom", (None, None)),
        ("A0 (841 mm × 1189 mm)", (841, 1189)),
        ("A1 (594 mm × 841 mm)", (594, 841)),
        ("A2 (420 mm × 594 mm)", (420, 594)),
        ("A3 (297 mm × 420 mm)", (297, 420)),
        ("A4 (210 mm × 297 mm)", (210, 297)),
        ("A5 (148 mm × 210 mm)", (148, 210)),
        ("Letter (8.5 in × 11 in)", (215.9, 279.4)),
        ("Legal (8.5 in × 14 in)", (215.9, 355.6)),
        ("Tabloid (11 in × 17 in)", (279.4, 431.8)),
    ]
)
papersizes = {
    "letter": "8.5inx11in",
    "a0": "841mmx1189mm",
    "a1": "594mmx841mm",
    "a2": "420mmx594mm",
    "a3": "297mmx420mm",
    "a4": "210mmx297mm",
    "a5": "148mmx210mm",
    "a6": "105mmx148mm",
    "legal": "8.5inx14in",
    "tabloid": "11inx17in",
}
papernames = {
    "letter": "Letter",
    "a0": "A0",
    "a1": "A1",
    "a2": "A2",
    "a3": "A3",
    "a4": "A4",
    "a5": "A5",
    "a6": "A6",
    "legal": "Legal",
    "tabloid": "Tabloid",
}

Unit = Enum("Unit", "pt cm mm inch")


def mm_to_pt(length):
    return (72.0 * length) / 25.4


def cm_to_mm(length):
    return length * 10.0


def in_to_mm(length):
    return length * 25.4


def pt_to_mm(length):
    return (25.4 * length) / 72.0


class PlakativException(Exception):
    pass


class PageNrOutOfRangeException(PlakativException):
    pass


class LayoutNotComputedException(PlakativException):
    pass


def simple_cover(n, m, x, y):
    pages_x_portrait = math.ceil(n / x)
    pages_y_portrait = math.ceil(m / y)
    pages_x_landscape = math.ceil(n / y)
    pages_y_landscape = math.ceil(m / x)
    if pages_x_portrait * pages_y_portrait <= pages_x_landscape * pages_y_landscape:
        pages_x = pages_x_portrait
        pages_y = pages_y_portrait
        portrait = True
        size = pages_x * x, pages_y * y
    else:
        pages_x = pages_x_landscape
        pages_y = pages_y_landscape
        portrait = False
        size = pages_x * y, pages_y * x
    config = list()
    for py in range(pages_y):
        for px in range(pages_x):
            if portrait:
                posx = px * x
                posy = py * y
            else:
                posx = px * y
                posy = py * x
            config.append((posx, posy, portrait))
    return config, size


# the function complex_cover() is based on a heuristic proposed by
# stackoverflow user m69 https://stackoverflow.com/users/4907604/m69 as a reply
# to this question https://stackoverflow.com/questions/39306507
#
# In addition to computing the number of required rectangles it also returns
# the position of the rectangles.
#
# In contrast to the solution by m69 this algorithm mandates at least one page
# in each corner of the result. This means that the minimum solution size is
# four. The advantage is, that the layout computed by this algorithm will
# always be completely be inside the poster without leaving the poster area.
# This in turn will make assembling the poster easier.
#
# This heuristic is not optimal. We always use a regular simple cover for the
# hole in the center (if it exists) but there are situations where the hole in
# the center should be covered by a complex cover instead. We do not consider
# this improvement because:
#   - it's required very seldom
#   - it makes the resulting layout more complicated to glue together
#   - there is no proof that the improved version is optimal either
#   - we save some cpu cycles
def complex_cover(n, m, x, y):
    # each tuple-entry represents one of the corners of the poster
    # upper-left, upper-right, lower-right, lower-left
    portrait = (
        (True, True, True, False),
        (True, True, False, False),
        (True, False, True, False),
        (True, False, False, True),
        (True, False, False, False),
    )
    X = lambda r, d: x if portrait[r][d] else y
    Y = lambda r, d: y if portrait[r][d] else x
    if x == y:
        # if page sizes are square, only one rotation has to be checked
        num_rotations = 1
    elif n == m:
        # if the poster size is a square, rotation 4 and 5 (which are itself
        # just rotations of rotations 2 and 1, respectively) do not need to be
        # checked
        num_rotations = 3
    else:
        num_rotations = 5
    minimum = math.ceil((n * m) / (x * y))
    config, _ = simple_cover(n, m, x, y)
    cover = len(config)
    if cover == minimum:
        return config

    for r in range(num_rotations):
        # w0 -> width of upper left corner pages
        for w0 in range(1, math.ceil(n / X(r, 0))):
            # w1 -> width of upper right corner pages
            w1 = math.ceil((n - w0 * X(r, 0)) / X(r, 1))
            if w1 < 0:
                w1 = 0
            # h0 -> height of upper left corner pages
            for h0 in range(1, math.ceil(m / Y(r, 0))):
                # h3 -> height of lower left corner pages
                h3 = math.ceil((m - h0 * Y(r, 0)) / Y(r, 3))
                if h3 < 0:
                    h3 = 0
                # w2 -> width of lower right corner pages
                for w2 in range(1, math.ceil(n / X(r, 2))):
                    # w3 -> width of lower left corner pages
                    w3 = math.ceil((n - w2 * X(r, 2)) / X(r, 3))
                    if w3 < 0:
                        w3 = 0
                    # h2 -> height of lower right corner pages
                    for h2 in range(1, math.ceil(m / Y(r, 2))):
                        # h1 -> height of upper right corner pages
                        h1 = math.ceil((m - h2 * Y(r, 2)) / Y(r, 1))
                        if h1 < 0:
                            h1 = 0
                        newconfig = list()
                        # upper-left (w0,h0)
                        for i in range(w0):
                            for j in range(h0):
                                newconfig.append(
                                    (i * X(r, 0), j * Y(r, 0), portrait[r][0])
                                )
                        # upper-right (w1,h1)
                        for i in range(w1):
                            for j in range(h1):
                                newconfig.append(
                                    (
                                        n - w1 * X(r, 1) + i * X(r, 1),
                                        j * Y(r, 1),
                                        portrait[r][1],
                                    )
                                )
                        # lower-right (w2,h2)
                        for i in range(w2):
                            for j in range(h2):
                                newconfig.append(
                                    (
                                        n - w2 * X(r, 2) + i * X(r, 2),
                                        m - h2 * Y(r, 2) + j * Y(r, 2),
                                        portrait[r][2],
                                    )
                                )
                        # lower-left (w3,h3)
                        for i in range(w3):
                            for j in range(h3):
                                newconfig.append(
                                    (
                                        i * X(r, 3),
                                        m - h3 * Y(r, 3) + j * Y(r, 3),
                                        portrait[r][3],
                                    )
                                )

                        # if neither rectangle 0 overlaps with rectangle 2 nor
                        # does rectangle 1 overlap with rectangle 3 in the center,
                        # then a center cover has to be added
                        X4 = n - w0 * X(r, 0) - w2 * X(r, 2)
                        Y4 = m - h1 * Y(r, 1) - h3 * Y(r, 3)
                        simple_config = []
                        if X4 > 0 and Y4 > 0:
                            simple_config, (sx, sy) = simple_cover(X4, Y4, x, y)
                            # shift the results such that they are in the center
                            for (cx, cy, p) in simple_config:
                                newconfig.append(
                                    (
                                        w0 * X(r, 0) + (X4 - sx) / 2 + cx,
                                        h1 * Y(r, 1) + (Y4 - sy) / 2 + cy,
                                        p,
                                    )
                                )
                        else:
                            X4 = n - w1 * X(r, 1) - w3 * X(r, 3)
                            Y4 = m - h0 * Y(r, 0) - h2 * Y(r, 2)
                            if X4 > 0 and Y4 > 0:
                                simple_config, (sx, sy) = simple_cover(X4, Y4, x, y)
                                # shift the results such that they are in the center
                                for (cx, cy, p) in simple_config:
                                    newconfig.append(
                                        (
                                            w3 * X(r, 3) + (X4 - sx) / 2 + cx,
                                            h0 * Y(r, 0) + (Y4 - sy) / 2 + cy,
                                            p,
                                        )
                                    )
                        total = len(newconfig)
                        # shortcut to cut computation short in case a
                        # solution with the minimal possible number of
                        # pages is found
                        if total == minimum:
                            return newconfig
                        if total < cover:
                            cover = total
                            config = newconfig
    return config


class Plakativ:
    def __init__(self, doc=None, pagenr=0):
        self.doc = doc
        if self.doc is None:
            # either we didn't have img2pdf or opening the input with img2pdf
            # failed
            if hasattr(infile, "read"):
                self.doc = fitz.open(stream=infile, filetype="application/pdf")
            else:
                self.doc = fitz.open(filename=infile)
        self.pagenr = pagenr

    # set page number -- first page is 0
    def set_input_pagenr(self, pagenr):
        if pagenr < 0 or pagenr >= len(self.doc):
            raise PageNrOutOfRangeException(
                "%d is not between 0 and %d (inclusive)" % (pagenr, len(self.doc))
            )

        self.pagenr = pagenr

    def get_input_pagenums(self):
        return len(self.doc)

    def get_input_page_size(self):
        width = self.doc[self.pagenr].getDisplayList().rect.width
        height = self.doc[self.pagenr].getDisplayList().rect.height
        return (width, height)

    def get_image(self, zoom):
        mat_0 = fitz.Matrix(zoom, zoom)
        pix = (
            self.doc[self.pagenr].getDisplayList().getPixmap(matrix=mat_0, alpha=False)
        )
        # the getImageData() function was only introduced in pymupdf 1.14.5
        if hasattr(pix, "getImageData"):
            return pix.getImageData("ppm")
        else:
            # this is essentially the same thing that the getImageData()
            # function does
            return pix._getImageData(2)  # 2 stands for pgm/ppm/pbm

    def compute_layout(
        self,
        mode,
        postersize=None,
        mult=None,
        npages=None,
        pagesize=(210, 297),
        border=(0, 0, 0, 0),
        strategy="simple",
    ):
        border_top, border_right, border_bottom, border_left = border

        self.layout = {
            "output_pagesize": pagesize,
            "border_top": border_top,
            "border_right": border_right,
            "border_bottom": border_bottom,
            "border_left": border_left,
        }

        printable_width = self.layout["output_pagesize"][0] - (
            border_left + border_right
        )
        printable_height = self.layout["output_pagesize"][1] - (
            border_top + border_bottom
        )
        inpage_width = pt_to_mm(self.doc[self.pagenr].getDisplayList().rect.width)
        inpage_height = pt_to_mm(self.doc[self.pagenr].getDisplayList().rect.height)

        if mode in ["size", "mult"]:
            if mode == "size":
                # fit the input page size into the selected postersize
                width_portrait = postersize[0]
                height_portrait = (width_portrait * inpage_height) / inpage_width
                if height_portrait > postersize[1]:
                    height_portrait = postersize[1]
                    width_portrait = (height_portrait * inpage_width) / inpage_height
                area_portrait = width_portrait * height_portrait
                width_landscape = postersize[1]
                height_landscape = (width_landscape * inpage_height) / inpage_width
                if height_landscape > postersize[0]:
                    height_landscape = postersize[0]
                    width_landscape = (height_landscape * inpage_width) / inpage_height
                area_landscape = width_landscape * height_landscape
                if area_portrait > area_landscape:
                    poster_width, poster_height = width_portrait, height_portrait
                else:
                    poster_width, poster_height = width_landscape, height_landscape
            elif mode == "mult":
                area = inpage_width * inpage_height * mult
                poster_width = math.sqrt(area * inpage_width / inpage_height)
                poster_height = math.sqrt(area * inpage_height / inpage_width)
            else:
                raise Exception("unsupported mode: %s" % mode)
        elif mode == "npages":
            # stupid bruteforce algorithm to determine the largest printable
            # postersize with N pages
            best_area = 0
            best = None
            for x in range(1, npages + 1):
                for y in range(1, npages + 1):
                    if x * y > npages:
                        continue
                    width_portrait = x * printable_width
                    height_portrait = y * printable_height

                    poster_width = width_portrait
                    poster_height = (poster_width * inpage_height) / inpage_width
                    if poster_height > height_portrait:
                        poster_height = height_portrait
                        poster_width = (poster_height * inpage_width) / inpage_height

                    area_portrait = poster_width * poster_height

                    if area_portrait > best_area:
                        best_area = area_portrait
                        best = (poster_width, poster_height)

                    width_landscape = x * printable_height
                    height_landscape = y * printable_width

                    poster_width = width_landscape
                    poster_height = (poster_width * inpage_height) / inpage_width
                    if poster_height > height_landscape:
                        poster_height = height_landscape
                        poster_width = (poster_height * inpage_width) / inpage_height

                    area_landscape = poster_width * poster_height

                    if area_landscape > best_area:
                        best_area = area_landscape
                        best = (poster_width, poster_height)

            poster_width, poster_height = best

            if strategy == "complex":
                # bisect poster sizes until we find the largest size that can
                # be printed given the available number of pages

                # we already know the maximum size for a solution utilizing the
                # simple cover algorithm, so this will be the minimum known
                # poster size
                min_area_mult = (poster_width * poster_height) / (
                    inpage_width * inpage_height
                )
                # to avoid floating point errors later
                min_area_mult *= 0.9999
                min_area_npages = len(
                    complex_cover(
                        poster_width, poster_height, printable_width, printable_height
                    )
                )

                # the maximum possible size is a poster of the area created by
                # multiplying the individual page areas by the maximum number
                # of pages available
                max_area_mult = (npages * printable_width * printable_height) / (
                    inpage_width * inpage_height
                )
                max_area_npages = len(
                    complex_cover(
                        math.sqrt(max_area_mult) * inpage_width,
                        math.sqrt(max_area_mult) * inpage_height,
                        printable_width,
                        printable_height,
                    )
                )

                while True:
                    if abs(min_area_mult - max_area_mult) < 0.001:
                        break
                    new_area_mult = (min_area_mult + max_area_mult) / 2
                    new_area_npages = len(
                        complex_cover(
                            math.sqrt(new_area_mult) * inpage_width,
                            math.sqrt(new_area_mult) * inpage_height,
                            printable_width,
                            printable_height,
                        )
                    )
                    if new_area_npages > npages:
                        max_area_mult = new_area_mult
                    else:
                        min_area_mult = new_area_mult

                poster_width = inpage_width * math.sqrt(min_area_mult)
                poster_height = inpage_height * math.sqrt(min_area_mult)

        else:
            raise Exception("unsupported mode: %s" % mode)

        pages_x_portrait = math.ceil(poster_width / printable_width)
        pages_y_portrait = math.ceil(poster_height / printable_height)

        pages_x_landscape = math.ceil(poster_width / printable_height)
        pages_y_landscape = math.ceil(poster_height / printable_width)

        portrait = True
        if pages_x_portrait * pages_y_portrait > pages_x_landscape * pages_y_landscape:
            portrait = False

        if portrait:
            pages_x = pages_x_portrait
            pages_y = pages_y_portrait
        else:
            pages_x = pages_x_landscape
            pages_y = pages_y_landscape

        # size of the bounding box of all pages after they have been glued together
        if portrait:
            self.layout["overallsize"] = (
                pages_x * printable_width + (border_right + border_left),
                pages_y * printable_height + (border_top + border_bottom),
            )
        else:
            self.layout["overallsize"] = (
                pages_x * printable_height + (border_top + border_bottom),
                pages_y * printable_width + (border_right + border_left),
            )

        # position of the poster relative to upper left corner of layout["overallsize"]
        if portrait:
            self.layout["posterpos"] = (
                border_left + (pages_x * printable_width - poster_width) / 2,
                border_top + (pages_y * printable_height - poster_height) / 2,
            )
        else:
            self.layout["posterpos"] = (
                border_bottom + (pages_x * printable_height - poster_width) / 2,
                border_right + (pages_y * printable_width - poster_height) / 2,
            )

        # positions are relative to self.layout["posterpos"]
        self.layout["positions"] = []
        for y in range(pages_y):
            for x in range(pages_x):
                if portrait:
                    posx = (
                        x * printable_width
                        - (pages_x * printable_width - poster_width) / 2
                    )
                    posy = (
                        y * printable_height
                        - (pages_y * printable_height - poster_height) / 2
                    )
                else:
                    posx = (
                        x * printable_height
                        - (pages_x * printable_height - poster_width) / 2
                    )
                    posy = (
                        y * printable_width
                        - (pages_y * printable_width - poster_height) / 2
                    )
                self.layout["positions"].append((posx, posy, portrait))

        if strategy == "complex":
            positions_complex = complex_cover(
                poster_width, poster_height, printable_width, printable_height
            )

            if len(positions_complex) < len(self.layout["positions"]):
                self.layout["positions"] = positions_complex
                # figure out the borders around the final poster by analyzing
                # the computed positions and storing the largest border size in
                # each dimension
                poster_top = poster_right = poster_bottom = poster_left = 0
                for (posx, posy, p) in self.layout["positions"]:
                    if p:
                        top = posy - border_top
                        if top < 0 and -top > poster_top:
                            poster_top = -top
                        right = posx + printable_width + border_right - poster_width
                        if right > 0 and right > poster_right:
                            poster_right = right
                        bottom = posy + printable_height + border_bottom - poster_height
                        if bottom > 0 and bottom > poster_bottom:
                            poster_bottom = bottom
                        left = posx - border_left
                        if left < 0 and -left > poster_left:
                            poster_left = -left
                    else:
                        top = posy - border_left
                        if top < 0 and -top > poster_top:
                            poster_top = -top
                        right = posx + printable_height + border_top - poster_width
                        if right > 0 and right > poster_right:
                            poster_right = right
                        bottom = posy + printable_width + border_right - poster_height
                        if bottom > 0 and bottom > poster_bottom:
                            poster_bottom = bottom
                        left = posx - border_bottom
                        if left < 0 and -left > poster_left:
                            poster_left = -left
                self.layout["overallsize"] = (
                    poster_width + poster_left + poster_right,
                    poster_height + poster_top + poster_bottom,
                )

                self.layout["posterpos"] = (poster_left, poster_top)

        # size of output poster is always proportional to size of input page
        self.layout["postersize"] = poster_width, poster_height

        if mode == "size":
            mult = (poster_width * poster_height) / (inpage_width * inpage_height)
            npages = len(self.layout["positions"])
        elif mode == "mult":
            postersize = poster_width, poster_height
            npages = len(self.layout["positions"])
        elif mode == "npages":
            postersize = poster_width, poster_height
            mult = (poster_width * poster_height) / (inpage_width * inpage_height)
        else:
            raise Exception("unsupported mode: %s" % mode)

        return postersize, mult, npages

    def render(self, outfile, cover=False, guides=False, numbers=False, border=False):
        if not hasattr(self, "layout"):
            raise LayoutNotComputedException()

        inpage_width = pt_to_mm(self.doc[self.pagenr].getDisplayList().rect.width)

        outdoc = fitz.open()

        if cover:
            # factor to convert from output poster dimensions (given in mm) into
            # pdf dimensions (given in pt)
            zoom_1 = min(
                mm_to_pt(
                    self.layout["output_pagesize"][0]
                    - 2 * max(self.layout["border_left"], self.layout["border_right"])
                )
                / (self.layout["overallsize"][0]),
                mm_to_pt(
                    self.layout["output_pagesize"][1]
                    - 2 * max(self.layout["border_top"], self.layout["border_bottom"])
                )
                / (self.layout["overallsize"][1]),
            )
            page = outdoc.newPage(
                -1,  # insert after last page
                width=mm_to_pt(self.layout["output_pagesize"][0]),
                height=mm_to_pt(self.layout["output_pagesize"][1]),
            )
            for i, (x, y, portrait) in enumerate(self.layout["positions"]):
                x0 = (x + self.layout["posterpos"][0]) * zoom_1 + (
                    mm_to_pt(self.layout["output_pagesize"][0])
                    - zoom_1 * self.layout["overallsize"][0]
                ) / 2
                y0 = (y + self.layout["posterpos"][1]) * zoom_1 + (
                    mm_to_pt(self.layout["output_pagesize"][1])
                    - zoom_1 * self.layout["overallsize"][1]
                ) / 2
                if portrait:
                    page_width = self.layout["output_pagesize"][0] * zoom_1
                    page_height = self.layout["output_pagesize"][1] * zoom_1
                    top = self.layout["border_top"] * zoom_1
                    right = self.layout["border_right"] * zoom_1
                    bottom = self.layout["border_bottom"] * zoom_1
                    left = self.layout["border_left"] * zoom_1
                else:
                    # page is rotated 90 degrees clockwise
                    page_width = self.layout["output_pagesize"][1] * zoom_1
                    page_height = self.layout["output_pagesize"][0] * zoom_1
                    top = self.layout["border_left"] * zoom_1
                    right = self.layout["border_top"] * zoom_1
                    bottom = self.layout["border_right"] * zoom_1
                    left = self.layout["border_bottom"] * zoom_1
                # inner rectangle
                shape = page.newShape()
                shape.drawRect(
                    fitz.Rect(
                        x0,
                        y0,
                        x0 + page_width - left - right,
                        y0 + page_height - top - bottom,
                    )
                )
                shape.finish(color=(0, 0, 1))
                # outer rectangle
                shape.drawRect(
                    fitz.Rect(
                        x0 - left,
                        y0 - top,
                        x0 - left + page_width,
                        y0 - top + page_height,
                    )
                )
                shape.finish(color=(1, 0, 0))
                shape.insertTextbox(
                    fitz.Rect(
                        x0 + 5,
                        y0 + 5,
                        x0 + page_width - left - right - 5,
                        y0 + page_height - top - bottom - 5,
                    ),
                    "%d" % (i + 1),
                    fontsize=20,
                    color=(0, 0, 0),
                )
                shape.commit()

        for i, (x, y, portrait) in enumerate(self.layout["positions"]):
            if portrait:
                page_width = mm_to_pt(self.layout["output_pagesize"][0])
                page_height = mm_to_pt(self.layout["output_pagesize"][1])
            else:
                page_width = mm_to_pt(self.layout["output_pagesize"][1])
                page_height = mm_to_pt(self.layout["output_pagesize"][0])
            page = outdoc.newPage(
                -1, width=page_width, height=page_height  # insert after last page
            )

            if portrait:
                target_x = x - self.layout["border_left"]
                target_y = y - self.layout["border_top"]
                target_width = self.layout["output_pagesize"][0]
                target_height = self.layout["output_pagesize"][1]
            else:
                target_x = x - self.layout["border_bottom"]
                target_y = y - self.layout["border_left"]
                target_width = self.layout["output_pagesize"][1]
                target_height = self.layout["output_pagesize"][0]
            target_xoffset = 0
            target_yoffset = 0
            if target_x < 0:
                target_xoffset = -target_x
                target_width += target_x
                target_x = 0
            if target_y < 0:
                target_yoffset = -target_y
                target_height += target_y
                target_y = 0
            if target_x + target_width > self.layout["postersize"][0]:
                target_width = self.layout["postersize"][0] - target_x
            if target_y + target_height > self.layout["postersize"][1]:
                target_height = self.layout["postersize"][1] - target_y

            targetrect = fitz.Rect(
                mm_to_pt(target_xoffset),
                mm_to_pt(target_yoffset),
                mm_to_pt(target_xoffset + target_width),
                mm_to_pt(target_yoffset + target_height),
            )

            factor = inpage_width / self.layout["postersize"][0]
            sourcerect = fitz.Rect(
                mm_to_pt(factor * target_x),
                mm_to_pt(factor * target_y),
                mm_to_pt(factor * (target_x + target_width)),
                mm_to_pt(factor * (target_y + target_height)),
            )

            page.showPDFpage(
                targetrect,  # fill the whole page
                self.doc,  # input document
                self.pagenr,  # input page number
                clip=sourcerect,  # part of the input page to use
            )

            shape = page.newShape()
            if guides:
                if portrait:
                    shape.drawRect(
                        fitz.Rect(
                            mm_to_pt(self.layout["border_left"]),
                            mm_to_pt(self.layout["border_top"]),
                            page_width - mm_to_pt(self.layout["border_right"]),
                            page_height - mm_to_pt(self.layout["border_bottom"]),
                        )
                    )
                else:
                    shape.drawRect(
                        fitz.Rect(
                            mm_to_pt(self.layout["border_bottom"]),
                            mm_to_pt(self.layout["border_left"]),
                            page_width - mm_to_pt(self.layout["border_top"]),
                            page_height - mm_to_pt(self.layout["border_right"]),
                        )
                    )
                shape.finish(width=0.2, color=(0.5, 0.5, 0.5), dashes="[5 6 1 6] 0")
            if numbers:
                if portrait:
                    shape.insertTextbox(
                        fitz.Rect(
                            mm_to_pt(self.layout["border_left"]) + 5,
                            mm_to_pt(self.layout["border_top"]) + 5,
                            page_width - mm_to_pt(self.layout["border_right"]) - 5,
                            page_height - mm_to_pt(self.layout["border_bottom"]) - 5,
                        ),
                        "%d" % (i + 1),
                        fontsize=8,
                        color=(0.5, 0.5, 0.5),
                    )
                else:
                    shape.insertTextbox(
                        fitz.Rect(
                            mm_to_pt(self.layout["border_bottom"]) + 5,
                            mm_to_pt(self.layout["border_left"]) + 5,
                            page_width - mm_to_pt(self.layout["border_top"]) - 5,
                            page_height - mm_to_pt(self.layout["border_right"]) - 5,
                        ),
                        "%d" % (i + 1),
                        fontsize=8,
                        color=(0.5, 0.5, 0.5),
                    )
            if border:
                if portrait:
                    shape.drawRect(
                        fitz.Rect(
                            mm_to_pt(self.layout["border_left"] - x),
                            mm_to_pt(self.layout["border_top"] - y),
                            mm_to_pt(
                                self.layout["border_left"]
                                - x
                                + self.layout["postersize"][0]
                            ),
                            mm_to_pt(
                                self.layout["border_top"]
                                - y
                                + self.layout["postersize"][1]
                            ),
                        )
                    )
                else:
                    shape.drawRect(
                        fitz.Rect(
                            mm_to_pt(self.layout["border_bottom"] - x),
                            mm_to_pt(self.layout["border_left"] - y),
                            mm_to_pt(
                                self.layout["border_bottom"]
                                - x
                                + self.layout["postersize"][0]
                            ),
                            mm_to_pt(
                                self.layout["border_left"]
                                - y
                                + self.layout["postersize"][1]
                            ),
                        )
                    )
                shape.finish(width=0.2, color=(0.5, 0.5, 0.5), dashes="[1 1] 0")
            shape.commit()

        if hasattr(outfile, "write"):
            # outfile is an object with a write() method
            outfile.write(outdoc.write(garbage=4, deflate=True))
        else:
            # outfile is used as a filename
            outdoc.save(outfile, garbage=4, deflate=True)


# from Python 3.7 Lib/idlelib/configdialog.py
# Copyright 2015-2017 Terry Jan Reedy
# Python License
class VerticalScrolledFrame(tkinter.Frame):
    """A pure Tkinter vertically scrollable frame.

    * Use the 'interior' attribute to place widgets inside the scrollable frame
    * Construct and pack/place/grid normally
    * This frame only allows vertical scrolling
    """

    def __init__(self, parent, *args, **kw):
        tkinter.Frame.__init__(self, parent, *args, **kw)

        # Create a canvas object and a vertical scrollbar for scrolling it.
        vscrollbar = tkinter.Scrollbar(self, orient=tkinter.VERTICAL)
        vscrollbar.pack(fill=tkinter.Y, side=tkinter.RIGHT, expand=tkinter.FALSE)
        canvas = tkinter.Canvas(
            self,
            borderwidth=0,
            highlightthickness=0,
            yscrollcommand=vscrollbar.set,
            width=240,
        )
        canvas.pack(side=tkinter.LEFT, fill=tkinter.BOTH, expand=tkinter.TRUE)
        vscrollbar.config(command=canvas.yview)

        # Reset the view.
        canvas.xview_moveto(0)
        canvas.yview_moveto(0)

        # Create a frame inside the canvas which will be scrolled with it.
        self.interior = interior = tkinter.Frame(canvas)
        interior_id = canvas.create_window(0, 0, window=interior, anchor=tkinter.NW)

        # Track changes to the canvas and frame width and sync them,
        # also updating the scrollbar.
        def _configure_interior(event):
            # Update the scrollbars to match the size of the inner frame.
            size = (interior.winfo_reqwidth(), interior.winfo_reqheight())
            canvas.config(scrollregion="0 0 %s %s" % size)

        interior.bind("<Configure>", _configure_interior)

        def _configure_canvas(event):
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # Update the inner frame's width to fill the canvas.
                canvas.itemconfigure(interior_id, width=canvas.winfo_width())

        canvas.bind("<Configure>", _configure_canvas)

        return


# From Python 3.7 Lib/tkinter/__init__.py
# Copyright 2000 Fredrik Lundh
# Python License
#
# add support for 'state' and 'name' kwargs
# add support for updating list of options
class OptionMenu(tkinter.Menubutton):
    """OptionMenu which allows the user to select a value from a menu."""

    def __init__(self, master, variable, value, *values, **kwargs):
        """Construct an optionmenu widget with the parent MASTER, with
        the resource textvariable set to VARIABLE, the initially selected
        value VALUE, the other menu values VALUES and an additional
        keyword argument command."""
        kw = {
            "borderwidth": 2,
            "textvariable": variable,
            "indicatoron": 1,
            "relief": tkinter.RAISED,
            "anchor": "c",
            "highlightthickness": 2,
        }
        if "state" in kwargs:
            kw["state"] = kwargs["state"]
            del kwargs["state"]
        if "name" in kwargs:
            kw["name"] = kwargs["name"]
            del kwargs["name"]
        tkinter.Widget.__init__(self, master, "menubutton", kw)
        self.widgetName = "tk_optionMenu"
        self.callback = kwargs.get("command")
        self.variable = variable
        if "command" in kwargs:
            del kwargs["command"]
        if kwargs:
            raise tkinter.TclError("unknown option -" + list(kwargs.keys())[0])
        self.set_values([value] + list(values))

    def __getitem__(self, name):
        if name == "menu":
            return self.__menu
        return tkinter.Widget.__getitem__(self, name)

    def set_values(self, values):
        menu = self.__menu = tkinter.Menu(self, name="menu", tearoff=0)
        self.menuname = menu._w
        for v in values:
            menu.add_command(
                label=v, command=tkinter._setit(self.variable, v, self.callback)
            )
        self["menu"] = menu

    def destroy(self):
        """Destroy this widget and the associated menu."""
        tkinter.Menubutton.destroy(self)
        self.__menu = None


class Application(tkinter.Frame):
    def __init__(self, master=None):
        super().__init__(master)
        self.master = master
        self.master.title("plakativ")

        self.pack(fill=tkinter.BOTH, expand=tkinter.TRUE)

        self.canvas = tkinter.Canvas(self, bg="black")
        self.canvas.pack(fill=tkinter.BOTH, side=tkinter.LEFT, expand=tkinter.TRUE)
        self.canvas_size = self.canvas.winfo_width(), self.canvas.winfo_height()
        self.canvas.bind("<Configure>", self.on_resize)

        frame_right = tkinter.Frame(self)
        frame_right.pack(side=tkinter.TOP, expand=tkinter.TRUE, fill=tkinter.Y)

        top_frame = tkinter.Frame(frame_right)
        top_frame.pack(fill=tkinter.X)

        tkinter.Button(top_frame, text="Open PDF", command=self.on_open_button).pack(
            side=tkinter.LEFT, expand=tkinter.TRUE, fill=tkinter.X
        )
        tkinter.Button(top_frame, text="Help", state=tkinter.DISABLED).pack(
            side=tkinter.RIGHT, expand=tkinter.TRUE, fill=tkinter.X
        )

        frame1 = VerticalScrolledFrame(frame_right)
        frame1.pack(side=tkinter.TOP, expand=tkinter.TRUE, fill=tkinter.Y)

        self.input = InputWidget(frame1.interior)
        self.input.pack(fill=tkinter.X)
        self.input.set(1, (0, 0))
        if hasattr(self, "plakativ"):
            self.input.callback = self.on_input

        self.pagesize = PageSizeWidget(frame1.interior)
        self.pagesize.pack(fill=tkinter.X)
        self.pagesize.set(False, (210, 297))
        if hasattr(self, "plakativ"):
            self.pagesize.callback = self.on_pagesize

        self.bordersize = BorderSizeWidget(frame1.interior)
        self.bordersize.pack(fill=tkinter.X)
        self.bordersize.set(15.0, 15.0, 15.0, 15.0)
        if hasattr(self, "plakativ"):
            self.bordersize.callback = self.on_bordersize

        self.postersize = PostersizeWidget(frame1.interior)
        self.postersize.pack(fill=tkinter.X)
        self.postersize.set("size", (False, (594, 841)), 1.0, 1)
        if hasattr(self, "plakativ"):
            self.postersize.callback = self.on_postersize

        self.layouter = LayouterWidget(frame1.interior)
        self.layouter.pack(fill=tkinter.X)
        self.layouter.set("simple")
        if hasattr(self, "plakativ"):
            self.layouter.callback = self.on_layouter

        self.outopts = OutOptsWidget(frame1.interior)
        self.outopts.pack(fill=tkinter.X)

        option_group = tkinter.LabelFrame(frame1.interior, text="Program options")
        option_group.pack(fill=tkinter.X)

        tkinter.Label(option_group, text="Unit:", state=tkinter.DISABLED).grid(
            row=0, column=0, sticky=tkinter.W
        )
        unit = tkinter.StringVar()
        unit.set("mm")
        OptionMenu(option_group, unit, ["mm"], state=tkinter.DISABLED).grid(
            row=0, column=1, sticky=tkinter.W
        )

        tkinter.Label(option_group, text="Language:", state=tkinter.DISABLED).grid(
            row=1, column=0, sticky=tkinter.W
        )
        language = tkinter.StringVar()
        language.set("English")
        OptionMenu(option_group, language, ["English"], state=tkinter.DISABLED).grid(
            row=1, column=1, sticky=tkinter.W
        )

        bottom_frame = tkinter.Frame(frame_right)
        bottom_frame.pack(fill=tkinter.X)

        self.save_button = tkinter.Button(
            bottom_frame,
            text="Save PDF",
            command=self.on_save_button,
            state=tkinter.DISABLED,
        )
        self.save_button.pack(side=tkinter.LEFT, expand=tkinter.TRUE, fill=tkinter.X)

        quit_button = tkinter.Button(
            bottom_frame, text="Exit", command=self.master.destroy
        )
        quit_button.pack(side=tkinter.RIGHT, expand=tkinter.TRUE, fill=tkinter.X)

    def on_input(self, value):
        _, pagesize = self.pagesize.value
        pagenum, _ = value
        mode, (custom_size, size), mult, npages = self.postersize.value
        bordersize = self.bordersize.value
        strategy = self.layouter.value
        self.plakativ.set_input_pagenr(pagenum - 1)
        size, mult, npages = self.plakativ.compute_layout(
            mode, size, mult, npages, pagesize, bordersize, strategy
        )
        self.postersize.set(mode, (custom_size, size), mult, npages)
        self.draw()
        width, height = self.plakativ.get_input_page_size()
        return "%.02f" % pt_to_mm(width), "%.02f" % pt_to_mm(height)

    def on_pagesize(self, value):
        _, pagesize = value
        pagenum, _ = self.input.value
        mode, (custom_size, size), mult, npages = self.postersize.value
        bordersize = self.bordersize.value
        strategy = self.layouter.value
        self.plakativ.set_input_pagenr(pagenum - 1)
        size, mult, npages = self.plakativ.compute_layout(
            mode, size, mult, npages, pagesize, bordersize, strategy
        )
        self.postersize.set(mode, (custom_size, size), mult, npages)
        self.draw()

    def on_bordersize(self, value):
        _, pagesize = self.pagesize.value
        pagenum, _ = self.input.value
        mode, (custom_size, size), mult, npages = self.postersize.value
        strategy = self.layouter.value
        self.plakativ.set_input_pagenr(pagenum - 1)
        size, mult, npages = self.plakativ.compute_layout(
            mode, size, mult, npages, pagesize, value, strategy
        )
        self.postersize.set(mode, (custom_size, size), mult, npages)
        self.draw()

    def on_postersize(self, value):
        mode, (custom_size, size), mult, npages = value
        pagenum, _ = self.input.value
        _, pagesize = self.pagesize.value
        border = self.bordersize.value
        strategy = self.layouter.value
        self.plakativ.set_input_pagenr(pagenum - 1)
        size, mult, npages = self.plakativ.compute_layout(
            mode, size, mult, npages, pagesize, border, strategy
        )
        self.draw()
        return (mode, (custom_size, size), mult, npages)

    def on_layouter(self, value):
        _, pagesize = self.pagesize.value
        pagenum, _ = self.input.value
        mode, (custom_size, size), mult, npages = self.postersize.value
        border = self.bordersize.value
        self.plakativ.set_input_pagenr(pagenum - 1)
        size, mult, npages = self.plakativ.compute_layout(
            mode, size, mult, npages, pagesize, border, value
        )
        self.postersize.set(mode, (custom_size, size), mult, npages)
        self.draw()

    def on_resize(self, event):
        self.canvas_size = (event.width, event.height)
        self.draw()

    def draw(self):
        # clean canvas
        self.canvas.delete(tkinter.ALL)

        if not hasattr(self, "plakativ"):
            self.canvas.create_text(
                self.canvas_size[0] / 2,
                self.canvas_size[1] / 2,
                text='Click on the "Open PDF" button in the upper right.',
                fill="white",
            )
            return

        canvas_padding = 10

        width, height = self.plakativ.get_input_page_size()

        # factor to convert from input page dimensions (given in pt) into
        # canvas dimensions (given in pixels)
        zoom_0 = min(
            self.canvas_size[0]
            / width
            * self.plakativ.layout["postersize"][0]
            / (self.plakativ.layout["overallsize"][0] + canvas_padding),
            self.canvas_size[1]
            / height
            * self.plakativ.layout["postersize"][1]
            / (self.plakativ.layout["overallsize"][1] + canvas_padding),
        )

        img = self.plakativ.get_image(zoom_0)
        tkimg = tkinter.PhotoImage(data=img)

        # factor to convert from output poster dimensions (given in mm) into
        # canvas dimensions (given in pixels)
        zoom_1 = min(
            self.canvas_size[0]
            / (self.plakativ.layout["overallsize"][0] + canvas_padding),
            self.canvas_size[1]
            / (self.plakativ.layout["overallsize"][1] + canvas_padding),
        )

        # draw image on canvas
        self.canvas.create_image(
            (self.canvas_size[0] - zoom_1 * self.plakativ.layout["overallsize"][0]) / 2
            + zoom_1 * self.plakativ.layout["posterpos"][0],
            (self.canvas_size[1] - zoom_1 * self.plakativ.layout["overallsize"][1]) / 2
            + zoom_1 * self.plakativ.layout["posterpos"][1],
            anchor=tkinter.NW,
            image=tkimg,
        )
        self.canvas.image = tkimg

        # self.canvas.create_text(
        #    self.canvas_size[0] / 2,
        #    self.canvas_size[1] / 2,
        #    text="%d" % len(self.plakativ.layout["positions"]),
        #    fill="grey",
        #    font=("TkDefaultFont", 40),
        #    anchor=tkinter.CENTER,
        # )

        # draw rectangles
        # TODO: also draw numbers indicating the page number
        for (x, y, portrait) in self.plakativ.layout["positions"]:
            x0 = (x + self.plakativ.layout["posterpos"][0]) * zoom_1 + (
                self.canvas_size[0] - zoom_1 * self.plakativ.layout["overallsize"][0]
            ) / 2
            y0 = (y + self.plakativ.layout["posterpos"][1]) * zoom_1 + (
                self.canvas_size[1] - zoom_1 * self.plakativ.layout["overallsize"][1]
            ) / 2
            if portrait:
                page_width = self.plakativ.layout["output_pagesize"][0] * zoom_1
                page_height = self.plakativ.layout["output_pagesize"][1] * zoom_1
                top = self.plakativ.layout["border_top"] * zoom_1
                right = self.plakativ.layout["border_right"] * zoom_1
                bottom = self.plakativ.layout["border_bottom"] * zoom_1
                left = self.plakativ.layout["border_left"] * zoom_1
            else:
                # page is rotated 90 degrees clockwise
                page_width = self.plakativ.layout["output_pagesize"][1] * zoom_1
                page_height = self.plakativ.layout["output_pagesize"][0] * zoom_1
                top = self.plakativ.layout["border_left"] * zoom_1
                right = self.plakativ.layout["border_top"] * zoom_1
                bottom = self.plakativ.layout["border_right"] * zoom_1
                left = self.plakativ.layout["border_bottom"] * zoom_1
            # inner rectangle
            self.canvas.create_rectangle(
                x0,
                y0,
                x0 + page_width - left - right,
                y0 + page_height - top - bottom,
                outline="blue",
            )
            # outer rectangle
            self.canvas.create_rectangle(
                x0 - left,
                y0 - top,
                x0 - left + page_width,
                y0 - top + page_height,
                outline="red",
            )

        # filename = "out_%03d.ps" % len(self.plakativ.layout["positions"])
        # self.canvas.postscript(file=filename)
        # print("saved ", filename)

    def on_open_button(self):
        if have_img2pdf:
            filetypes = [
                ("all supported", "*.pdf *.png *.jpg *.jpeg *.gif *.tiff *.tif"),
                ("pdf documents", "*.pdf"),
                ("png images", "*.png"),
                ("jpg images", "*.jpg *.jpeg"),
                ("gif images", "*.gif"),
                ("tiff images", "*.tiff *.tif"),
                ("all files", "*"),
            ]
        else:
            filetypes = [
                ("pdf documents", "*.pdf"),
                ("all files", "*"),
            ]
        filename = tkinter.filedialog.askopenfilename(
            parent=self.master,
            title="Open either a PDF or a raster image",
            filetypes=filetypes
            # initialdir="/home/josch/git/plakativ",
            # initialfile="test.pdf",
        )
        if filename == ():
            return
        self.open_file(filename)

    def open_file(self, filename):
        self.filename = filename
        doc = None
        if have_img2pdf:
            # if we have img2pdf available we can encapsulate a raster image
            # into a PDF container
            data = None
            try:
                data = img2pdf.convert(self.filename)
            except img2pdf.AlphaChannelError:
                remove_alpha = tkinter.messagebox.askyesno(
                    title="Removing Alpha Channel",
                    message="PDF does not support alpha channels. Should the "
                    "alpha channel be removed? The resulting PDF might not be "
                    "lossless anymore.",
                )
                # remove alpha channel
                if remove_alpha:
                    from PIL import Image

                    img = Image.open(self.filename).convert("RGBA")
                    background = Image.new("RGBA", img.size, (255, 255, 255))
                    img = Image.alpha_composite(background, img)
                    with BytesIO() as output:
                        img.convert("RGB").save(output, format="PNG")
                        output.seek(0)
                        data = img2pdf.convert(output)
                else:
                    return
            except img2pdf.ImageOpenError:
                # img2pdf cannot handle this
                pass

            if data is not None:
                stream = BytesIO()
                stream.write(data)
                doc = fitz.open(stream=stream, filetype="application/pdf")
        if doc is None:
            # either we didn't have img2pdf or opening the input with img2pdf
            # failed
            doc = fitz.open(filename=self.filename)
        self.plakativ = Plakativ(doc)
        # compute the splitting with the current values
        mode, (custom_size, size), mult, npages = self.postersize.value
        _, pagesize = self.pagesize.value
        border = self.bordersize.value
        strategy = self.layouter.value
        size, mult, npages = self.plakativ.compute_layout(
            mode, size, mult, npages, pagesize, border, strategy
        )
        # update input widget
        width, height = self.plakativ.get_input_page_size()
        self.input.set(1, ("%.02f" % pt_to_mm(width), "%.02f" % pt_to_mm(height)))
        self.input.nametowidget("spinbox_pagenum").configure(
            to=self.plakativ.get_input_pagenums()
        )
        self.input.nametowidget("label_of_pagenum").configure(
            text="of %d" % self.plakativ.get_input_pagenums()
        )
        # update postersize widget
        self.postersize.set(mode, (custom_size, size), mult, npages)
        # draw preview in canvas
        self.draw()
        # enable save button
        self.save_button.configure(state=tkinter.NORMAL)
        # set callback function
        self.input.callback = self.on_input
        self.pagesize.callback = self.on_pagesize
        self.bordersize.callback = self.on_bordersize
        self.postersize.callback = self.on_postersize
        self.layouter.callback = self.on_layouter

    def on_save_button(self):
        base, ext = os.path.splitext(os.path.basename(self.filename))
        filename = tkinter.filedialog.asksaveasfilename(
            parent=self.master,
            title="Save as PDF",
            defaultextension=".pdf",
            filetypes=[("pdf documents", "*.pdf"), ("all files", "*")],
            initialdir=os.path.dirname(self.filename),
            initialfile=base + "_poster" + ext,
        )
        if filename == "":
            return
        self.plakativ.render(
            filename,
            cover=self.outopts.variables["cover"].get(),
            guides=self.outopts.variables["guides"].get(),
            numbers=self.outopts.variables["numbers"].get(),
            border=self.outopts.variables["border"].get(),
        )


class LayouterWidget(tkinter.LabelFrame):
    def __init__(self, parent, *args, **kw):
        tkinter.LabelFrame.__init__(self, parent, text="Layouter", *args, **kw)

        self.callback = None

        self.variables = {"strategy": tkinter.StringVar()}

        def callback(varname, idx, op):
            assert op == "w"
            self.on_strategy(self.variables["strategy"].get())

        self.variables["strategy"].trace("w", callback)

        layouter1 = tkinter.Radiobutton(
            self, text="Simple", variable=self.variables["strategy"], value="simple"
        )
        layouter1.pack(anchor=tkinter.W)
        layouter3 = tkinter.Radiobutton(
            self, text="Complex", variable=self.variables["strategy"], value="complex"
        )
        layouter3.pack(anchor=tkinter.W)

    def on_strategy(self, value):
        if getattr(self, "value", None) is None:
            return
        strategy = self.value
        self.set(value)

    def set(self, strategy):
        # before setting self.value, check if the effective value is different
        # from before or otherwise we do not need to execute the callback in
        # the end
        state_changed = True
        if getattr(self, "value", None) is not None:
            state_changed = self.value != strategy
        # execute callback if necessary
        if state_changed and self.callback is not None:
            pagesize = self.callback(strategy)
        self.value = strategy
        if self.variables["strategy"].get() != strategy:
            self.variables["strategy"].set(strategy)


class OutOptsWidget(tkinter.LabelFrame):
    def __init__(self, parent, *args, **kw):
        tkinter.LabelFrame.__init__(self, parent, text="Output options", *args, **kw)

        self.variables = {
            "guides": tkinter.IntVar(),
            "border": tkinter.IntVar(),
            "numbers": tkinter.IntVar(),
            "cover": tkinter.IntVar(),
        }

        tkinter.Checkbutton(
            self, text="Print cutting guides", variable=self.variables["guides"]
        ).pack(anchor=tkinter.W)
        tkinter.Checkbutton(
            self, text="Print poster border", variable=self.variables["border"]
        ).pack(anchor=tkinter.W)
        tkinter.Checkbutton(
            self, text="Print page number", variable=self.variables["numbers"]
        ).pack(anchor=tkinter.W)
        tkinter.Checkbutton(
            self, text="Print layout cover page", variable=self.variables["cover"]
        ).pack(anchor=tkinter.W)


class InputWidget(tkinter.LabelFrame):
    def __init__(self, parent, *args, **kw):
        tkinter.LabelFrame.__init__(self, parent, text="Input properties", *args, **kw)

        self.callback = None

        self.variables = {
            "pagenum": tkinter.IntVar(),
            "width": tkinter.StringVar(),
            "height": tkinter.StringVar(),
        }

        def callback(varname, idx, op):
            assert op == "w"
            self.on_pagenum(self.variables["pagenum"].get())

        self.variables["pagenum"].trace("w", callback)

        tkinter.Label(self, text="Use page").grid(row=0, column=0, sticky=tkinter.W)
        tkinter.Spinbox(
            self,
            increment=1,
            from_=1,
            to=100,
            width=3,
            name="spinbox_pagenum",
            textvariable=self.variables["pagenum"],
        ).grid(row=0, column=1, sticky=tkinter.W)
        tkinter.Label(self, text="of 1", name="label_of_pagenum").grid(
            row=0, column=2, sticky=tkinter.W
        )
        tkinter.Label(self, text="Width:").grid(row=1, column=0, sticky=tkinter.W)
        tkinter.Label(self, textvariable=self.variables["width"]).grid(
            row=1, column=1, sticky=tkinter.W
        )
        tkinter.Label(self, text="mm", name="size_label_width_mm").grid(
            row=1, column=2, sticky=tkinter.W
        )
        tkinter.Label(self, text="Height:").grid(row=2, column=0, sticky=tkinter.W)
        tkinter.Label(self, textvariable=self.variables["height"]).grid(
            row=2, column=1, sticky=tkinter.W
        )
        tkinter.Label(self, text="mm", name="size_label_height_mm").grid(
            row=2, column=2, sticky=tkinter.W
        )

    def on_pagenum(self, value):
        if getattr(self, "value", None) is None:
            return
        _, size = self.value
        self.set(value, size)

    def set(self, pagenum, pagesize):
        # before setting self.value, check if the effective value is different
        # from before or otherwise we do not need to execute the callback in
        # the end
        state_changed = True
        if getattr(self, "value", None) is not None:
            state_changed = self.value != (pagenum, pagesize)
        # execute callback if necessary
        if state_changed and self.callback is not None:
            pagesize = self.callback((pagenum, pagesize))
        self.value = (pagenum, pagesize)
        width, height = pagesize
        if self.variables["pagenum"].get() != pagenum:
            self.variables["pagenum"].set(pagenum)
        if self.variables["width"].get() != width:
            self.variables["width"].set(width)
        if self.variables["height"].get() != height:
            self.variables["height"].set(height)


class PageSizeWidget(tkinter.LabelFrame):
    def __init__(self, parent, *args, **kw):
        tkinter.LabelFrame.__init__(
            self, parent, text="Size of output pages", *args, **kw
        )

        self.callback = None

        self.variables = {
            "dropdown": tkinter.StringVar(),
            "width": tkinter.DoubleVar(),
            "height": tkinter.DoubleVar(),
        }

        for k, v in self.variables.items():
            # need to pass k and v as function arguments so that their value
            # does not get overwritten each loop iteration
            def callback(varname, idx, op, k_copy=k, v_copy=v):
                assert op == "w"
                getattr(self, "on_" + k_copy)(v_copy.get())

            v.trace("w", callback)

        OptionMenu(self, self.variables["dropdown"], *PAGE_SIZES.keys()).grid(
            row=1, column=0, columnspan=3, sticky=tkinter.W
        )

        tkinter.Label(
            self, text="Width:", state=tkinter.DISABLED, name="size_label_width"
        ).grid(row=2, column=0, sticky=tkinter.W)
        tkinter.Spinbox(
            self,
            format="%.2f",
            increment=0.01,
            from_=0,
            to=100,
            width=5,
            state=tkinter.DISABLED,
            name="spinbox_width",
            textvariable=self.variables["width"],
        ).grid(row=2, column=1, sticky=tkinter.W)
        tkinter.Label(
            self, text="mm", state=tkinter.DISABLED, name="size_label_width_mm"
        ).grid(row=2, column=2, sticky=tkinter.W)

        tkinter.Label(
            self, text="Height:", state=tkinter.DISABLED, name="size_label_height"
        ).grid(row=3, column=0, sticky=tkinter.W)
        tkinter.Spinbox(
            self,
            format="%.2f",
            increment=0.01,
            from_=0,
            to=100,
            width=5,
            state=tkinter.DISABLED,
            name="spinbox_height",
            textvariable=self.variables["height"],
        ).grid(row=3, column=1, sticky=tkinter.W)
        tkinter.Label(
            self, text="mm", state=tkinter.DISABLED, name="size_label_height_mm"
        ).grid(row=3, column=2, sticky=tkinter.W)

    def on_dropdown(self, value):
        custom_size, size = self.value
        if value == "custom":
            custom_size = True
        else:
            custom_size = False
            size = PAGE_SIZES[value]
        self.set(custom_size, size)

    def on_width(self, value):
        if getattr(self, "value", None) is None:
            return
        custom_size, (_, height) = self.value
        self.set(custom_size, (value, height))

    def on_height(self, value):
        if getattr(self, "value", None) is None:
            return
        custom_size, (width, _) = self.value
        self.set(custom_size, (width, value))

    def set(self, custom_size, pagesize):
        # before setting self.value, check if the effective value is different
        # from before or otherwise we do not need to execute the callback in
        # the end
        state_changed = True
        if getattr(self, "value", None) is not None:
            state_changed = self.value != (custom_size, pagesize)
        # execute callback if necessary
        if state_changed and self.callback is not None:
            self.callback((custom_size, pagesize))
        self.value = (custom_size, pagesize)
        width, height = pagesize
        if custom_size:
            self.nametowidget("size_label_width").configure(state=tkinter.NORMAL)
            self.nametowidget("spinbox_width").configure(state=tkinter.NORMAL)
            self.nametowidget("size_label_width_mm").configure(state=tkinter.NORMAL)
            self.nametowidget("size_label_height").configure(state=tkinter.NORMAL)
            self.nametowidget("spinbox_height").configure(state=tkinter.NORMAL)
            self.nametowidget("size_label_height_mm").configure(state=tkinter.NORMAL)
        else:
            self.nametowidget("size_label_width").configure(state=tkinter.DISABLED)
            self.nametowidget("spinbox_width").configure(state=tkinter.DISABLED)
            self.nametowidget("size_label_width_mm").configure(state=tkinter.DISABLED)
            self.nametowidget("size_label_height").configure(state=tkinter.DISABLED)
            self.nametowidget("spinbox_height").configure(state=tkinter.DISABLED)
            self.nametowidget("size_label_height_mm").configure(state=tkinter.DISABLED)
        # only set variables that changed to not trigger multiple variable tracers
        if custom_size:
            if self.variables["dropdown"].get() != "custom":
                self.variables["dropdown"].set("custom")
        else:
            val = dict(zip(PAGE_SIZES.values(), PAGE_SIZES.keys()))[(width, height)]
            if self.variables["dropdown"].get() != val:
                self.variables["dropdown"].set(val)
        if self.variables["width"].get() != width:
            self.variables["width"].set(width)
        if self.variables["height"].get() != height:
            self.variables["height"].set(height)


class BorderSizeWidget(tkinter.LabelFrame):
    def __init__(self, parent, *args, **kw):
        tkinter.LabelFrame.__init__(
            self, parent, text="Output Borders/Overlap", *args, **kw
        )

        self.callback = None

        self.variables = dict()
        for i, (n, label) in enumerate(
            [
                ("top", "Top:"),
                ("right", "Right:"),
                ("bottom", "Bottom:"),
                ("left", "Left:"),
            ]
        ):
            self.variables[n] = tkinter.DoubleVar()
            # need to pass k and v as function arguments so that their value
            # does not get overwritten each loop iteration
            def callback(varname, idx, op, k_copy=n, v_copy=self.variables[n]):
                assert op == "w"
                getattr(self, "on_" + k_copy)(v_copy.get())

            self.variables[n].trace("w", callback)

            tkinter.Label(self, text=label).grid(row=i, column=0, sticky=tkinter.W)
            tkinter.Spinbox(
                self,
                format="%.2f",
                increment=1.0,
                from_=0,
                to=100,
                width=5,
                textvariable=self.variables[n],
            ).grid(row=i, column=1)
            tkinter.Label(self, text="mm").grid(row=i, column=2)

    def on_top(self, value):
        if getattr(self, "value", None) is None:
            return
        _, right, bottom, left = self.value
        self.set(value, right, bottom, left)

    def on_right(self, value):
        if getattr(self, "value", None) is None:
            return
        top, _, bottom, left = self.value
        self.set(top, value, bottom, left)

    def on_bottom(self, value):
        if getattr(self, "value", None) is None:
            return
        top, right, _, left = self.value
        self.set(top, right, value, left)

    def on_left(self, value):
        if getattr(self, "value", None) is None:
            return
        top, right, bottom, _ = self.value
        self.set(top, right, bottom, value)

    def set(self, top, right, bottom, left):
        # before setting self.value, check if the effective value is different
        # from before or otherwise we do not need to execute the callback in
        # the end
        state_changed = True
        if getattr(self, "value", None) is not None:
            state_changed = self.value != (top, right, bottom, left)
        # execute callback if necessary
        if state_changed and self.callback is not None:
            self.callback((top, right, bottom, left))
        self.value = top, right, bottom, left
        # only set variables that changed to not trigger multiple variable tracers
        if self.variables["top"].get() != top:
            self.variables["top"].set(top)
        if self.variables["right"].get() != right:
            self.variables["right"].set(right)
        if self.variables["bottom"].get() != bottom:
            self.variables["bottom"].set(bottom)
        if self.variables["left"].get() != left:
            self.variables["left"].set(left)


class PostersizeWidget(tkinter.LabelFrame):
    def __init__(self, parent, *args, **kw):
        tkinter.LabelFrame.__init__(self, parent, text="Poster Size", *args, **kw)

        self.callback = None

        self.variables = {
            "radio": tkinter.StringVar(),
            "dropdown": tkinter.StringVar(),
            "width": tkinter.DoubleVar(),
            "height": tkinter.DoubleVar(),
            "multiplier": tkinter.DoubleVar(),
            "pages": tkinter.IntVar(),
        }

        for k, v in self.variables.items():
            # need to pass k and v as function arguments so that their value
            # does not get overwritten each loop iteration
            def callback(varname, idx, op, k_copy=k, v_copy=v):
                assert op == "w"
                getattr(self, "on_" + k_copy)(v_copy.get())

            v.trace("w", callback)

        tkinter.Radiobutton(
            self,
            text="Fit into width/height",
            variable=self.variables["radio"],
            value="size",
            state=tkinter.DISABLED,
            name="size_radio",
        ).grid(row=0, column=0, columnspan=3, sticky=tkinter.W)

        OptionMenu(
            self,
            self.variables["dropdown"],
            *PAGE_SIZES.keys(),
            #            state=tkinter.DISABLED,
            name="size_dropdown",
        ).grid(row=1, column=0, columnspan=3, sticky=tkinter.W, padx=(27, 0))

        tkinter.Label(
            self, text="Width:", state=tkinter.DISABLED, name="size_label_width"
        ).grid(row=2, column=0, sticky=tkinter.W, padx=(27, 0))
        tkinter.Spinbox(
            self,
            format="%.2f",
            increment=0.1,
            from_=0,
            to=10000,
            width=5,
            textvariable=self.variables["width"],
            state=tkinter.DISABLED,
            name="size_spinbox_width",
        ).grid(row=2, column=1, sticky=tkinter.W)
        tkinter.Label(
            self, text="mm", state=tkinter.DISABLED, name="size_label_width_mm"
        ).grid(row=2, column=2, sticky=tkinter.W)

        tkinter.Label(
            self, text="Height:", state=tkinter.DISABLED, name="size_label_height"
        ).grid(row=3, column=0, sticky=tkinter.W, padx=(27, 0))
        tkinter.Spinbox(
            self,
            format="%.2f",
            increment=0.1,
            from_=0,
            to=10000,
            width=5,
            textvariable=self.variables["height"],
            state=tkinter.DISABLED,
            name="size_spinbox_height",
        ).grid(row=3, column=1, sticky=tkinter.W)
        tkinter.Label(
            self, text="mm", state=tkinter.DISABLED, name="size_label_height_mm"
        ).grid(row=3, column=2, sticky=tkinter.W)

        tkinter.Radiobutton(
            self,
            text="Factor of input page area",
            variable=self.variables["radio"],
            value="mult",
            state=tkinter.DISABLED,
            name="mult_radio",
        ).grid(row=4, column=0, columnspan=3, sticky=tkinter.W)
        tkinter.Label(
            self,
            text="Multiplier:",
            state=tkinter.DISABLED,
            name="mult_label_multiplier",
        ).grid(row=5, column=0, sticky=tkinter.W, padx=(27, 0))
        tkinter.Spinbox(
            self,
            format="%.2f",
            increment=0.01,
            from_=0,
            to=10000,
            width=6,
            textvariable=self.variables["multiplier"],
            state=tkinter.DISABLED,
            name="mult_spinbox_multiplier",
        ).grid(row=5, column=1, sticky=tkinter.W)

        tkinter.Radiobutton(
            self,
            text="Fit into X output pages",
            variable=self.variables["radio"],
            value="npages",
            state=tkinter.DISABLED,
            name="npages_radio",
        ).grid(row=6, column=0, columnspan=3, sticky=tkinter.W)
        tkinter.Label(
            self, text="# of pages:", state=tkinter.DISABLED, name="npages_label"
        ).grid(row=7, column=0, sticky=tkinter.W, padx=(27, 0))
        tkinter.Spinbox(
            self,
            increment=1,
            from_=1,
            to=10000,
            width=6,
            textvariable=self.variables["pages"],
            state=tkinter.DISABLED,
            name="npages_spinbox",
        ).grid(row=7, column=1, sticky=tkinter.W)

    def on_radio(self, value):
        _, size, mult, npages = self.value
        self.set(value, size, mult, npages)

    def on_dropdown(self, value):
        mode, (custom_size, size), mult, npages = self.value
        if value == "custom":
            custom_size = True
        else:
            custom_size = False
            size = PAGE_SIZES[value]
        self.set(mode, (custom_size, size), mult, npages)

    def on_width(self, value):
        if getattr(self, "value", None) is None:
            return
        mode, (custom_size, (_, height)), mult, npages = self.value
        self.set(mode, (custom_size, (value, height)), mult, npages)

    def on_height(self, value):
        if getattr(self, "value", None) is None:
            return
        mode, (custom_size, (width, _)), mult, npages = self.value
        self.set(mode, (custom_size, (width, value)), mult, npages)

    def on_multiplier(self, value):
        if getattr(self, "value", None) is None:
            return
        mode, size, _, npages = self.value
        self.set(mode, size, value, npages)

    def on_pages(self, value):
        if getattr(self, "value", None) is None:
            return
        mode, size, mult, _ = self.value
        self.set(mode, size, mult, value)

    def set(self, mode, size, mult, npages):
        # before setting self.value, check if the effective value is different
        # from before or otherwise we do not need to execute the callback in
        # the end
        state_changed = True
        if getattr(self, "value", None) is not None:
            if mode == self.value[0] == "size":
                state_changed = self.value[1][1] != size[1]
            elif mode == self.value[0] == "mult":
                state_changed = self.value[2] != mult
            elif mode == self.value[0] == "npages":
                state_changed = self.value[3] != npages
        # execute callback if necessary
        if state_changed and self.callback is not None:
            mode, size, mult, npages = self.callback((mode, size, mult, npages))
        self.value = (mode, size, mult, npages)
        custom_size, (width, height) = size
        # cycle through all widgets and set the state accordingly
        for k, v in self.children.items():
            if k.endswith("_radio"):
                v.configure(state=tkinter.NORMAL)
                continue
            if not k.startswith(mode + "_"):
                v.configure(state=tkinter.DISABLED)
                continue
            if k in ["size_dropdown", "size_radio"]:
                v.configure(state=tkinter.NORMAL)
                continue
            if mode != "size":
                v.configure(state=tkinter.NORMAL)
                continue
            if custom_size:
                v.configure(state=tkinter.NORMAL)
                continue
            v.configure(state=tkinter.DISABLED)
        # only set variables that changed to not trigger multiple variable tracers
        if custom_size or mode != "size":
            if self.variables["dropdown"].get() != "custom":
                self.variables["dropdown"].set("custom")
        else:
            val = dict(zip(PAGE_SIZES.values(), PAGE_SIZES.keys()))[(width, height)]
            if self.variables["dropdown"].get() != val:
                self.variables["dropdown"].set(val)
        if self.variables["radio"].get() != mode:
            self.variables["radio"].set(mode)
        if self.variables["width"].get() != width:
            self.variables["width"].set(width)
        if self.variables["height"].get() != height:
            self.variables["height"].set(height)
        if self.variables["multiplier"].get() != mult:
            self.variables["multiplier"].set(mult)
        if self.variables["pages"].get() != npages:
            self.variables["pages"].set(npages)


def compute_layout(
    infile,
    outfile,
    mode,
    size=None,
    mult=None,
    npages=None,
    pagenr=0,
    pagesize=(210, 297),
    border=(0, 0, 0, 0),
    strategy="simple",
    remove_alpha=False,
    cover=False,
    guides=False,
    numbers=False,
    poster_border=False,
):
    doc = None
    if hasattr(infile, "read"):
        # we have to slurp in the whole file because we potentially read it
        # in multiple times in case img2pdf is installed
        # also, mupdf needs to be able to seek(), so we need to slurp it in
        # anyways
        infile = BytesIO(infile.read())
    if have_img2pdf:
        # if we have img2pdf available we can encapsulate a raster image
        # into a PDF container
        data = None
        try:
            # FIXME: img2pdf should not use the root logger so that instead we
            #        can run logging.getLogger('img2pdf').setLevel(logging.CRITICAL)
            logging.getLogger().setLevel(logging.CRITICAL)
            data = img2pdf.convert(infile)
        except img2pdf.AlphaChannelError:
            if remove_alpha:
                # remove alpha channel
                from PIL import Image

                img = Image.open(infile).convert("RGBA")
                background = Image.new("RGBA", img.size, (255, 255, 255))
                img = Image.alpha_composite(background, img)
                with BytesIO() as output:
                    img.convert("RGB").save(output, format="PNG")
                    output.seek(0)
                    data = img2pdf.convert(output)
            else:
                print(
                    """
Plakativ is lossless by default. To automatically remove the alpha channel from
the input and place the image on a white background, use the --remove-alpha
option""",
                    file=sys.stderr,
                )
                exit(1)
        except img2pdf.ImageOpenError:
            # img2pdf cannot handle this
            pass

        if data is not None:
            stream = BytesIO()
            stream.write(data)
            doc = fitz.open(stream=stream, filetype="application/pdf")
    if doc is None:
        # either we didn't have img2pdf or opening the input with img2pdf
        # failed
        if hasattr(infile, "read"):
            doc = fitz.open(stream=infile, filetype="application/pdf")
        else:
            doc = fitz.open(filename=infile)
    plakativ = Plakativ(doc, pagenr)
    plakativ.compute_layout(mode, size, mult, npages, pagesize, border, strategy)
    plakativ.render(outfile, cover, guides, numbers, poster_border)
    doc.close()


def gui(filename=None):
    if not have_tkinter:
        raise Exception("the GUI requires tkinter")
    root = tkinter.Tk()
    app = Application(master=root)
    if filename is not None:
        app.open_file(filename)
    app.mainloop()


def parse_num(num, name):
    if num == "":
        raise argparse.ArgumentTypeError("%s is empty" % name)
    unit = None
    if num.endswith("pt"):
        unit = Unit.pt
    elif num.endswith("cm"):
        unit = Unit.cm
    elif num.endswith("mm"):
        unit = Unit.mm
    elif num.endswith("in"):
        unit = Unit.inch
    else:
        try:
            num = float(num)
        except ValueError:
            msg = (
                "%s is not a floating point number and doesn't have a "
                "valid unit: %s" % (name, num)
            )
            raise argparse.ArgumentTypeError(msg)
    if unit is None:
        unit = Unit.mm
    else:
        num = num[:-2]
        try:
            num = float(num)
        except ValueError:
            msg = "%s is not a floating point number: %s" % (name, num)
            raise argparse.ArgumentTypeError(msg)
    if num < 0:
        msg = "%s must not be negative: %s" % (name, num)
        raise argparse.ArgumentTypeError(msg)
    if unit == Unit.cm:
        num = cm_to_mm(num)
    elif unit == Unit.pt:
        num = pt_to_mm(num)
    elif unit == Unit.inch:
        num = in_to_mm(num)
    return num


def parse_borderarg(string):
    if ":" in string:
        vals = string.split(":")
        if len(vals) in [0, 1]:
            raise argparse.ArgumentTypeError("logic error")
        elif len(vals) == 2:
            t = b = parse_num(vals[0], "top/bottom border")
            r = l = parse_num(vals[1], "right/left border")
        elif len(vals) == 3:
            t = parse_num(vals[0], "top border")
            r = l = parse_num(vals[1], "right/left border")
            b = parse_num(vals[2], "bottom border")
        elif len(vals) == 4:
            t = parse_num(vals[0], "top border")
            r = parse_num(vals[1], "right border")
            b = parse_num(vals[2], "bottom border")
            l = parse_num(vals[3], "left border")
        else:
            raise argparse.ArgumentTypeError(
                "border option can not have more than four values"
            )
    else:
        if string == "":
            raise argparse.ArgumentTypeError("border option cannot be empty")
        val = parse_num(string, "border")
        t, r, b, l = val, val, val, val
    return t, r, b, l


def parse_pagesize_rectarg(string):
    if papersizes.get(string.lower()):
        string = papersizes[string.lower()]
    if "x" not in string:
        # if there is no separating "x" in the string, then the string is
        # interpreted as the width
        w = parse_num(string, "width")
        h = None
    else:
        w, h = string.split("x", 1)
        w = parse_num(w, "width")
        h = parse_num(h, "height")
    if w is None and h is None:
        raise argparse.ArgumentTypeError("at least one dimension must be specified")
    return w, h


def main():
    if len(sys.argv) == 1 and platform.system() != "Windows":
        print("""
You called plakativ without arguments. At least one of the options --size,
--factor or --maxpages is required for running plakativ on the command line.
But maybe you meant to run the plakativ GUI instead? On platforms other than
Windows, the default is to run the command line interface. To run the graphical
user interface, run plakativ with the --gui option instead.
""", file=sys.stderr)

    rendered_papersizes = ""
    for k, v in sorted(papersizes.items()):
        rendered_papersizes += "    %-8s %s\n" % (papernames[k], v)

    parser = argparse.ArgumentParser(
        formatter_class=argparse.RawDescriptionHelpFormatter,
        description="""\
Create large posters by printing and gluing together smaller pages.

This program is for situations when you want to create a large poster or banner
but do not have a printer that supports large sheets of paper. Plakativ allows
one to enlarge and split a PDF across multiple pages, creating another PDF with
pages of the desired printable size. After printing, the pages can be cut and
glued together to form a larger poster. Features:

  - lossless operation
  - no pixel artifacts when upscaling if PDF contains vector graphics
  - GUI with preview functionality
  - complex layouter to save paper
  - optimize by number of pages, output poster size or multiple of input area
  - support for raster images as input if img2pdf is available

Options:
""",
        epilog="""\
Poster size:
  There are three ways to set the size of the final poster. The desired method
  is selected using the mutually exclusive options --size, --factor and
  --maxpages. The --size option allows one to specify a width and height into
  which the input will be fitted, swapping width and height as necessary, to
  create the largest possible poster with those dimensions while keeping the
  aspect ratio of the input. The --factor option scales the area of the input
  by the given multiplier. If the input is a DIN A4 page, then a factor of 2
  will create a DIN A3 poster. The --maxpages option allows one to specify a
  maximum number of pages one is willing to print out and creates the largest
  possible poster that can possibly be created with the given number of pages.
  For example, printing a DIN A1 poster on DIN A4 pages with a border of 15 mm
  will require 15 pages with the simple layouter engine. With --maxpages=15 a
  slightly larger poster will be generated but will make better use of the
  available number of pages of paper. Using the complex layouter, an even
  bigger poster can be generated with just 15 pages of paper by changing the
  orientation of some of them.

Paper sizes:
  You can specify the short hand paper size names shown in the first column in
  the table below as arguments to the --pagesize and --imgsize options.  The
  width and height they are mapping to is shown in the second column.  Giving
  the value in the second column has the same effect as giving the short hand
  in the first column. The values are case insensitive.

%s

Borders, cutting and gluing:
  The border on each page set using the --border option has two purposes.
  Firstly, the border is useful for printers that do not support borderless
  printing. Secondly, the border is the area where the individual pages overlap
  and can be glued together. Before gluing, cut away the border area where the
  printer was unable to print on. As long as you stay within the distance set
  by the --border option, you don't need precision tools to do the cutting but
  can cut freehand using a pair of scissors. You only need to cut the borders
  from those edges that will end up being glued onto another piece of paper.
  By keeping even the area at the border your printer could not print on from
  the paper at the bottom you maintain a larger area for the glue.

Examples:

To run the tkinter GUI execute either:

    $ plakativ-gui
    $ plakativ --gui

To use plakativ without GUI from the command line you can run:

    $ plakativ --size A1 --output=poster.pdf input.pdf

This will create a file poster.pdf with multiple DIN A4 pages which, after
being cut and glued together will form a DIN A1 poster of the content on the
first page of input.pdf.

If img2pdf is available as a Python module, then plakativ can also use raster
images as input. Since img2pdf refuses to work on images with an alpha channel,
you can instruct plakativ to remove the alpha channel for you with the
--remove-alpha flag:

    $ plakativ --size A1 --output=poster.pdf --remove-alpha input.png

Written by Johannes 'josch' Schauer <josch@mister-muffin.de>

Report bugs at https://gitlab.mister-muffin.de/josch/plakativ/issues
"""
        % rendered_papersizes,
    )
    parser.add_argument(
        "-v",
        "--verbose",
        action="store_true",
        help="Makes the program operate in verbose mode, printing messages on "
        "standard error.",
    )
    parser.add_argument(
        "-V",
        "--version",
        action="version",
        version="%(prog)s " + VERSION,
        help="Prints version information and exits.",
    )
    gui_group = parser.add_mutually_exclusive_group(required=False)
    gui_group.add_argument(
        "--gui",
        dest="gui",
        action="store_true",
        help="run tkinter gui (default on Windows)",
    )
    gui_group.add_argument(
        "--nogui",
        dest="gui",
        action="store_false",
        help="don't run tkinter gui (default elsewhere)",
    )
    if platform.system() == "Windows":
        parser.set_defaults(gui=True)
    else:
        parser.set_defaults(gui=False)

    mode_group = parser.add_mutually_exclusive_group(required=False)
    mode_group.add_argument(
        "--size",
        metavar="LxL",
        dest="mode",
        type=parse_pagesize_rectarg,
        help="Poster width/height either as width times height or one of the "
        "known paper sizes (see below). Cannot be used together with --factor "
        "or --maxpages.",
    )
    mode_group.add_argument(
        "--factor",
        metavar="MULT",
        dest="mode",
        type=float,
        help="Poster size as multiple of input page area. Cannot be used "
        "together with --size or --maxpages.",
    )
    mode_group.add_argument(
        "--maxpages",
        metavar="NUM",
        dest="mode",
        type=int,
        help="Maximum possible poster size with the given number of pages. "
        "Cannot be used together with --size or --factor.",
    )

    parser.add_argument("-o", "--output", help="output filename (default: stdout)")
    parser.add_argument("input", nargs="?", help="input filename (default: stdin)")
    parser.add_argument(
        "--pagenum",
        type=int,
        default=1,
        help="Page number of input PDF to turn into a poster (default: 1)",
    )
    parser.add_argument(
        "--pagesize",
        metavar="LxL",
        type=parse_pagesize_rectarg,
        default=(210, 297),
        help="Width and height of the output pages or one of the known paper "
        "sizes (see below). This is the paper size that you are printing on "
        "with your printer (default: A4)",
    )
    parser.add_argument(
        "--border",
        metavar="L[:L[:L[:L]]]",
        type=parse_borderarg,
        default=(15, 15, 15, 15),
        help="The borders on each output page for gluing. This specifies how "
        "much the pages overlap each other. If your printer cannot print "
        "borderless, then this value should also be larger than the border up "
        "to which your printer is able to print. The default unit is mm. "
        "Other possible units are cm, in and pt. One value sets the border on "
        "all four sides. Multiple values are separated by a colon. With two "
        "values, the first value sets top and bottom border and the second "
        "value sets left and right border. With three values, the first value "
        "sets the top border, the second value the left and right border and "
        "the third value the bottom border. Four values set top, right, "
        "bottom and left borders in that order.",
    )
    parser.add_argument(
        "--layouter",
        choices=["simple", "complex"],
        default="simple",
        help="The algorithm arranging the individual pages making the poster. "
        "The simple layout has all pages in the same orientation. The complex "
        "layout is able to sometimes require less pages for the same poster "
        "size and is allowed to rotate pages.",
    )
    parser.add_argument(
        "--remove-alpha",
        action="store_true",
        help="When the input is a raster image instead of a PDF document, "
        "plakativ can remove the alpha channel for you. The resulting PDF "
        "poster might not be lossless anymore.",
    )
    parser.add_argument(
        "--cover-page",
        action="store_true",
        help="Add a cover page as the first page which shows the resulting "
        "layout. This is especially interesting for the complex layouter "
        "unless you like puzzles.",
    )
    parser.add_argument(
        "--cutting-guides",
        action="store_true",
        help="Print light-gray dashed lines that surround the visible part "
        "of each page and can help with easier cutting and gluing of the "
        "pages. This is generally only needed if the poster does not contain "
        "enough detail for accurate gluing.",
    )
    parser.add_argument(
        "--page-numbers",
        action="store_true",
        help="Print a small number of each page to uniquely identify each "
        "sheet. This is especially useful in combination with --cover-page "
        "because the numbers on the cover page correspond to the page numbers.",
    )
    parser.add_argument(
        "--poster-border",
        action="store_true",
        help="If the poster itself has a white background and it is important "
        "that the final result has precisely the desired poster size, then "
        "this option will print a light-gray dashed border around the whole "
        "poster, so that it can be accurately cut to the correct overall size.",
    )

    args = parser.parse_args()

    if args.gui:
        gui(args.input)
        sys.exit(0)

    if not args.input or args.input == "-":
        args.input = sys.stdin.buffer

    if not args.output or args.output == "-":
        args.output = sys.stdout.buffer

    if isinstance(args.mode, tuple):
        mode = "size"
    elif isinstance(args.mode, float):
        mode = "mult"
    elif isinstance(args.mode, int):
        mode = "npages"
    else:
        print(
            "Error: must supply one of --size, --factor or --maxpages\n",
            file=sys.stderr,
        )
        parser.print_usage(sys.stderr)
        sys.exit(1)

    compute_layout(
        args.input,
        args.output,
        mode,
        pagenr=args.pagenum - 1,  # zero based
        pagesize=args.pagesize,
        border=args.border,
        strategy=args.layouter,
        **{mode: args.mode},
        remove_alpha=args.remove_alpha,
        cover=args.cover_page,
        guides=args.cutting_guides,
        numbers=args.page_numbers,
        poster_border=args.poster_border,
    )


if __name__ == "__main__":
    main()

__all__ = ["Plakativ", "compute_layout", "simple_cover", "complex_cover"]