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Mate Technologies
Mate Technologies

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🖼️ Build a Desktop Image-to-PDF Converter in Python (Tkinter + ttkbootstrap)

#desktopapp #productivity #opensource #devcommunity

A practical Python project to build a modern desktop GUI app that converts multiple images into a single PDF file — with batch processing, file ordering, and a clean UI.

We’ll build CANVAPDF LITE, a lightweight offline tool using:

Tkinter (GUI)
ttkbootstrap (modern UI styling)
Pillow (image processing)
threading + queue (smooth background processing)

🔗 Pro Version / Source & Upgrade:
https://matetools.gumroad.com/l/canva-pdf-pro

🚀 What You Will Build

By the end of this tutorial, you’ll have:

A desktop GUI app for image-to-PDF conversion
Drag-free file management (add files/folders)
Manual ordering system (move up/down)
Background processing (no UI freezing)
Live progress tracking
About window + menu system
🧠 Project Architecture Overview

This app is structured into clear sections:

UI Layer (Tkinter + ttkbootstrap)
File Management System
Image Processing Engine (Pillow)
Thread Worker (background task)
Queue-based UI updater
📦 Step 1: Install Dependencies

pip install pillow ttkbootstrap
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⚙️ Step 2: Initialize the App

We start by setting up the main window using a modern theme:

app = tk.Tk()
style = tb.Style("superhero")

app.title("CANVAPDF LITE v1.1.0")
app.geometry("1100x680")
app.minsize(900, 650)
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👉 ttkbootstrap gives Tkinter a modern UI instantly.

📂 Step 3: File Handling System

We store selected images globally:

selected_files = []
SUPPORTED_FORMATS = (".png", ".jpg", ".jpeg")
Add Files
files = filedialog.askopenfilenames(
    filetypes=[("Images", "*.png *.jpg *.jpeg")]
)
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Add Folder (Batch Import)

We scan directories using os.walk():

for root, _, files in os.walk(folder):
    for name in files:
        p = Path(root) / name
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🧾 Step 4: Display File List in UI

We update the listbox dynamically:

file_listbox.delete(0, "end")

for f in selected_files:
    file_listbox.insert("end", os.path.basename(str(f)))
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🔼 Step 5: Move Files Up & Down

We allow manual ordering:

selected_files[i], selected_files[i - 1] = selected_files[i - 1], selected_files[i]
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This is useful when ordering pages in the final PDF.

🖼️ Step 6: Image to PDF Conversion Engine

Each image is opened and converted:

def open_image(path):
    return Image.open(path).convert("RGB")
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Then we combine everything:

images[0].save(
    save_path,
    save_all=True,
    append_images=images[1:]
)
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👉 This is the core of the PDF generator.

🧵 Step 7: Run Processing in Background Thread

To avoid UI freezing:

threading.Thread(target=worker, daemon=True).start()
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Why this matters:

Tkinter runs on a single thread
Heavy tasks freeze UI unless threaded
📊 Step 8: Live Progress Updates (Queue System)

We safely update UI from worker thread:

ui_queue.put((cmd, data))

Then UI listens every 100ms:

app.after(100, process_queue)
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⛔ Step 9: Stop Functionality

We allow canceling the process:

stop_event.set()
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This helps users stop long conversions safely.

🎨 Step 10: Modern UI Features

Using ttkbootstrap we add:

Buttons with styles
Progress bars
Status indicators
Clean layout system

Example:

tb.Button(actions, text="🚀 Generate PDF", bootstyle="success")
ℹ️ Step 11: About Window

We added a full About dialog:

App info
Features list
Store link button
🛒 Project Link (Pro Version)

👉 Upgrade / Download / Support:
https://matetools.gumroad.com/l/canva-pdf-pro

🎯 Final Result

You now have a fully working:

✔ Desktop PDF generator
✔ Batch image importer
✔ Reorder system
✔ Thread-safe GUI
✔ Modern Tkinter UI

🧠 What You Learned
Tkinter GUI structure
File system integration
Pillow image processing
Multithreading in desktop apps
Queue-based UI updates
Modern Python desktop design patterns

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