Structure

Overview

The overall structure of HP Booklet program is setting a filter in pipe-filter progress.

The core routines are implemented with Manuscript class and Modifier. The Modifier class acts as a filter of data. It combines, rearranges, deletes, adds new objects to pages and return manuscript. The features in this project, (Signature, Toimage, Imposition, PrintingMark, Note), are implemented with single class which are children of Modifier. Those class are categorized two types, Converter and Template.

• Converter: This class is about the conversion of file and page. Rearrange, delete, transformation, change page type are example. Major difference with Template is that this class does not contain merge and additional template pdfs.

• Template: This class is about the template imposition of manuscript. There are two direction of merging, imposing the manuscript on template or vice verse.

Core structure

python Bone structure

from booklet.manuscript import Manuscript
from booklet.modifiers import *

manuscript = Manuscript(file, output_directory, file_name)

modifier1 = ToImage()
modifier2 = Signature()
modifier3 = Imposition()

modifiern = PrintingMark()

modifiers = [modifier1, modifier2, modifier3, ..., modifiern]

for modifier in modifiers:
    manuscript.register_modifier(modifier)

manuscript.update("all")
manuscript.save_to_file()

Implemented modifiers are

• Signature(Converter)

• ToImage(Converter)

• Imposition(Template)

• Printing Mark(Template)

Modifier

Converter Class

There is nothing to describe about this class. It is just an warrper of Modifier to match a children layer with Template.

Template Class

It was intended to load external pdf file in inital stage of class object. However, with external libraries, like reportlab, we can combine template pdf generation code in class.

All the variables and calculations must be prepared after __init__ method is called. New features are needed to implement 3 methods

• rule(self, i:int): Return imposed manuscript pages of the given template page. For example, if k th template page cotains 2, 4, 7, 9 pages of manuscript.

  python3

  rule(k) # [2, 4, 7, 9]
  

• position(self, i:int): Return position of the given manuscript page on template page. tuple[float, float].

• generate_template(self, manuscript:Manuscript) : Return template pdf and its connected tempfile object.

Template do method

python3

def do(self, index:int, manuscript: Manuscript, file_mode:str = "safe"):

    if not self.on:
        pass
    else:
        new_pdf, new_file = self.get_new_pdf(index, manuscript.tem_directory.name, file_mode)
        try:
            getattr(self, "pdf")
            template_pdf = self.pdf
        except:
            template_pdf, tem_byte = self.generate_template(manuscript)
        for i, template in enumerate(template_pdf.pages):
            manu_pages = self.index_mapping(manuscript, i, len(template_pdf.pages))
            for j in manu_pages:
                page = manuscript.pages[j]
                x, y = self.position_mapping(manuscript, j, manuscript.file_pages)
                page.addTransformation(
                    pypdf.Transformation().translate(tx=x, ty=y)
                )
                upper = float(page.mediaBox[2])
                right = float(page.mediaBox[3])
                page.mediaBox.setUpperRight((upper + x, right + y))

                template.merge_page(page)
                new_pdf.add_page(template)

        new_pdf.write(new_file)
        manuscript.pdf_update(new_pdf, new_file)

Example feature Imposition

python3

def rule(
    self, i: int
) -> list:  # i = template page, list = manuscript pages unordered
    _i = i * self.pages_per_template
    _f = (i + 1) * self.pages_per_template
    return list(range(_i, _f))

def position(self, i: int) -> tuple[float, float]:  # manuscript page
    index = i % self.pages_per_template
    column = self.layout[1]
    row = self.layout[0]

    x = (index) % column
    y = row - floor((index) / column) - 1
    x_pos = (self.manuscript_format[0] + self.gap) * x - (
        self.gap if x > column - 1 else 0
    )
    y_pos = (self.manuscript_format[1] + self.gap) * y - (
        self.gap if y > row - 1 else 0
    )

    return (x_pos, y_pos)

See details in API reference and source repository.