In this post, we will cover how to build a simple PDF viewer application using Python. The viewer allows users to open PDF documents, navigate between pages, and view page contents.


We will utilize Python's Tkinter library to create the graphical user interface (GUI). Tkinter comes bundled with Python and provides widgets to display windows, buttons, labels and other interface elements.


To parse and render PDF content, we will use the PDFMiner library. PDFMiner allows extracting text, metadata and images from PDF files programmatically.

But before starting you have to download the necessary libraires from this link : Click Here !


Let's break down the key aspects of the code:


The GUI

We initialize a Tk root window and add menu, frames and widgets like canvas, buttons and labels. Tkinter handles laying out and displaying these elements.

We also add horizontal and vertical scrollbars to the canvas for panning large pages. Button icons are loaded as images to avoid plain text buttons.


def __init__(self, master):
    # Initialize variables
    self.path = None
    self.fileisopen = False
    self.author = None
    self.name = None
    self.current_page = 0
    self.numPages = None

    # Create main window
    self.master = master
    self.master.title('PDF Viewer')
    self.master.geometry('580x520+440+180')
    self.master.resizable(width=0, height=0)
    self.master.iconbitmap('pdf_file_icon.ico')

    # Create menu
    self.menu = Menu(self.master)
    self.master.config(menu=self.menu)
    self.filemenu = Menu(self.menu)
    self.menu.add_cascade(label="File", menu=self.filemenu)
    self.filemenu.add_command(label="Open File", command=self.open_file)
    self.filemenu.add_command(label="Exit", command=self.master.destroy)

    # Create frames
    self.top_frame = ttk.Frame(self.master, width=580, height=460)
    self.top_frame.grid(row=0, column=0)
    self.top_frame.grid_propagate(False)

    self.bottom_frame = ttk.Frame(self.master, width=580, height=50)
    self.bottom_frame.grid(row=1, column=0)
    self.bottom_frame.grid_propagate(False)

    # Create scrollbars and canvas
    self.scrolly = Scrollbar(self.top_frame, orient=VERTICAL)
    self.scrolly.grid(row=0, column=1, sticky=(N, S))
    self.scrollx = Scrollbar(self.top_frame, orient=HORIZONTAL)
    self.scrollx.grid(row=1, column=0, sticky=(W, E))

    self.output = Canvas(self.top_frame, bg='#ECE8F3', width=560, height=435)
    self.output.configure(yscrollcommand=self.scrolly.set, xscrollcommand=self.scrollx.set)
    self.output.grid(row=0, column=0)
    self.scrolly.config(command=self.output.yview)
    self.scrollx.config(command=self.output.xview)

    # Load button icons
    self.uparrow_icon = PhotoImage(file='uparrow.png').subsample(3, 3)
    self.downarrow_icon = PhotoImage(file='downarrow.png').subsample(3, 3)

    # Create buttons and page label
    self.upbutton = ttk.Button(self.bottom_frame, image=self.uparrow_icon, command=self.previous_page)
    self.upbutton.grid(row=0, column=1, padx=(270, 5), pady=8)
    self.downbutton = ttk.Button(self.bottom_frame, image=self.downarrow_icon, command=self.next_page)
    self.downbutton.grid(row=0, column=3, pady=8)
    self.page_label = ttk.Label(self.bottom_frame, text='page')
    self.page_label.grid(row=0, column=4, padx=5)


Working with PDFs

The PDFMiner class handles opening PDF files, extracting metadata and returning page images. We display the first page and track the current page number.


def open_file(self):
    # Open file dialog and select PDF file
    filepath = filedialog.askopenfilename(title='Select a PDF file', initialdir=os.getcwd(), filetypes=(('PDF', '*.pdf'),))
    if filepath:
        # If file selected, set path and extract file name
        self.path = filepath
        self.name = os.path.basename(self.path)[:-4]
        # Initialize PDFMiner with selected file
        self.miner = PDFMiner(self.path)
        # Get metadata and number of pages
        data, self.numPages = self.miner.get_metadata()
        self.current_page = 0
        if self.numPages:
            # If pages found, update variables and display first page
            self.author = data.get('author')
            self.fileisopen = True
            self.display_page()
            self.master.title(self.name)
def display_page(self):
    if 0 <= self.current_page < self.numPages:
        # Display current page
        self.img_file = self.miner.get_page(self.current_page)
        self.output.delete("all")
        self.output.create_image(0, 0, anchor='nw', image=self.img_file)
        self.page_label.config(text=f'{self.current_page + 1} of {self.numPages}')
        self.output.config(scrollregion=self.output.bbox("all"))


Navigation

Previous and next buttons call methods to increment/decrement the page number and re-display the new page image on the canvas. Page labels update to show the page count.


def next_page(self):
    if self.fileisopen and self.current_page < self.numPages - 1:
        # Display next page if available
        self.current_page += 1
        self.display_page()

def previous_page(self):
    if self.fileisopen and self.current_page > 0:
        # Display previous page if available
        self.current_page -= 1
        self.display_page()


Putting it Together

A main viewer class initializes the GUI, loads first page etc. The root mainloop runs the interface. Opening files extracts metadata before display.


from tkinter import *
from tkinter import ttk, filedialog
import os
from miner import PDFMiner

class PDFViewer:
    def __init__(self, master):
        # Initialize variables
        self.path = None
        self.fileisopen = False
        self.author = None
        self.name = None
        self.current_page = 0
        self.numPages = None

        # Create main window
        self.master = master
        self.master.title('PDF Viewer')
        self.master.geometry('580x520+440+180')
        self.master.resizable(width=0, height=0)
        self.master.iconbitmap('pdf_file_icon.ico')

        # Create menu
        self.menu = Menu(self.master)
        self.master.config(menu=self.menu)
        self.filemenu = Menu(self.menu)
        self.menu.add_cascade(label="File", menu=self.filemenu)
        self.filemenu.add_command(label="Open File", command=self.open_file)
        self.filemenu.add_command(label="Exit", command=self.master.destroy)

        # Create frames
        self.top_frame = ttk.Frame(self.master, width=580, height=460)
        self.top_frame.grid(row=0, column=0)
        self.top_frame.grid_propagate(False)

        self.bottom_frame = ttk.Frame(self.master, width=580, height=50)
        self.bottom_frame.grid(row=1, column=0)
        self.bottom_frame.grid_propagate(False)

        # Create scrollbars and canvas
        self.scrolly = Scrollbar(self.top_frame, orient=VERTICAL)
        self.scrolly.grid(row=0, column=1, sticky=(N, S))
        self.scrollx = Scrollbar(self.top_frame, orient=HORIZONTAL)
        self.scrollx.grid(row=1, column=0, sticky=(W, E))

        self.output = Canvas(self.top_frame, bg='#ECE8F3', width=560, height=435)
        self.output.configure(yscrollcommand=self.scrolly.set, xscrollcommand=self.scrollx.set)
        self.output.grid(row=0, column=0)
        self.scrolly.config(command=self.output.yview)
        self.scrollx.config(command=self.output.xview)

        # Load button icons
        self.uparrow_icon = PhotoImage(file='uparrow.png').subsample(3, 3)
        self.downarrow_icon = PhotoImage(file='downarrow.png').subsample(3, 3)

        # Create buttons and page label
        self.upbutton = ttk.Button(self.bottom_frame, image=self.uparrow_icon, command=self.previous_page)
        self.upbutton.grid(row=0, column=1, padx=(270, 5), pady=8)
        self.downbutton = ttk.Button(self.bottom_frame, image=self.downarrow_icon, command=self.next_page)
        self.downbutton.grid(row=0, column=3, pady=8)
        self.page_label = ttk.Label(self.bottom_frame, text='page')
        self.page_label.grid(row=0, column=4, padx=5)

    def open_file(self):
        # Open file dialog and select PDF file
        filepath = filedialog.askopenfilename(title='Select a PDF file', initialdir=os.getcwd(), filetypes=(('PDF', '*.pdf'),))
        if filepath:
            # If file selected, set path and extract file name
            self.path = filepath
            self.name = os.path.basename(self.path)[:-4]
            # Initialize PDFMiner with selected file
            self.miner = PDFMiner(self.path)
            # Get metadata and number of pages
            data, self.numPages = self.miner.get_metadata()
            self.current_page = 0
            if self.numPages:
                # If pages found, update variables and display first page
                self.author = data.get('author')
                self.fileisopen = True
                self.display_page()
                self.master.title(self.name)

    def display_page(self):
        if 0 <= self.current_page < self.numPages:
            # Display current page
            self.img_file = self.miner.get_page(self.current_page)
            self.output.delete("all")
            self.output.create_image(0, 0, anchor='nw', image=self.img_file)
            self.page_label.config(text=f'{self.current_page + 1} of {self.numPages}')
            self.output.config(scrollregion=self.output.bbox("all"))

    def next_page(self):
        if self.fileisopen and self.current_page < self.numPages - 1:
            # Display next page if available
            self.current_page += 1
            self.display_page()

    def previous_page(self):
        if self.fileisopen and self.current_page > 0:
            # Display previous page if available
            self.current_page -= 1
            self.display_page()

root = Tk()
app = PDFViewer(root)
root.mainloop()


The Output 


With just 100+ lines of Python code and minimal dependencies, we have a basic multi-page PDF viewer up and running! Tkinter makes building simple GUI apps very approachable.


Let me know if any part of the implementation or explanation needs more clarity. Building little projects like this is a great way to get comfortable with Python's capabilities.