README

PdfToJPEG

A cross-platform desktop application built with Delphi FMX that converts PDF files into high-quality JPEG images — one image per page — with a live preview, conversion history, and a clean tabbed UI.

✨ Features

• 📄 PDF to JPEG conversion — renders each PDF page as a full-resolution JPEG image
• 🖼️ Live preview panel — thumbnail previews appear in real-time as pages are converted
• 📊 Conversion history — every conversion is logged to a local SQLite database and displayed in a sortable grid
• ⚙️ 2× render resolution — pages are rendered at double size for sharper output
• 🔄 Background threading — conversion runs on a background thread; the UI stays responsive throughout
• 🗄️ SQLite persistence — history is stored locally via FireDAC, no server required
• 🧱 Clean layered architecture — separated into Interfaces, Repository, Service, and Extractor units

🖥️ Video:

https://github.com/user-attachments/assets/be72af91-79ad-42ab-92e0-861011d52d12

🏗️ Architecture

The project follows a layered architecture with interface-based dependency injection:

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???          Main.View (FMX UI)     ???
?????????????????????????????????????????????????????????????????????????????????????????????????????????
             ???
     ??????????????????????????????????????????????????????
     ???  iHistoryService???  ?????????  THistoryService
     ?????????????????????????????????????????????????????????
             ???
     ????????????????????????????????????????????????????????????????????????
     ???  iHistoryRepository  ???  ?????????  THistoryRepository (FireDAC / SQLite)
     ????????????????????????????????????????????????????????????????????????

     ????????????????????????????????????????????????????????????
     ???  iPdfExtractor   ???  ?????????  TPdfExtractor (pdfium.dll)
     ????????????????????????????????????????????????????????????

     ????????????????????????????????????????????????????????????
     ???  API.Pdfium.Core ???  ?????????  Dynamic DLL loader for pdfium
     ????????????????????????????????????????????????????????????

     ????????????????????????????????????????????????????????????
     ???  API.Connection  ???  ?????????  TDMConnection (FireDAC DataModule)
     ????????????????????????????????????????????????????????????

Unit Overview

🚀 Getting Started

Prerequisites

• Delphi (tested with Delphi 12.3.3.3 Athens)
• FireMonkey (FMX) — included with Delphi
• FireDAC with SQLite driver — included with Delphi
• pdfium.dll — see below

Getting pdfium.dll

The app depends on Google's PDFium library for rendering.

1. Download a pre-built Windows binary from bblanchon/pdfium-binaries
2. Extract and place pdfium.dll in the same folder as your compiled executable
3. The app will show a warning on startup if the DLL is missing — conversion will be disabled

Build & Run

1. Clone the repository:
   bashCopy

   git clone https://github.com/mben-dz/PdfiumToJPEG.git

2. Open PdfToJPEG.dproj in Delphi
3. Build and run (F9)
4. Place pdfium.dll next to the compiled .exe

📖 Usage

1. Click Browse and select a PDF file
2. The output folder defaults to Pages_Output (relative to the exe); change it if needed
3. Click Convert
4. Watch the Preview tab populate with thumbnails as pages are rendered
5. Switch to the History tab to see a log of all past conversions

Output files are saved as Page_1.jpg, Page_2.jpg, etc. inside the chosen output folder.

🗄️ Database

Conversion history is stored in a SQLite database file at:

%DOCUMENTS%\PdfToJPEG_MBen.db

Schema:

CREATE TABLE ConversionHistory (
  Id             INTEGER PRIMARY KEY AUTOINCREMENT,
  FileName       TEXT,
  PageCount      INTEGER,
  ConversionDate DATETIME,
  OutputFolder   TEXT
);

📁 Project Structure

PdfToJPEG/
????????? PdfToJPEG.dpr          # Project file
????????? Main.View.pas           # Main FMX form
????????? Main.View.fmx           # Form layout
????????? API/
???   ????????? API.Connection.pas          # FireDAC DataModule
???   ????????? API.Interfaces.pas          # Interfaces & shared types
???   ????????? API.Pdfium.Core.pas         # pdfium.dll loader
???   ????????? API.PdfExtractor.pas        # PDF ??? JPEG renderer
???   ????????? API.History.Repository.pas  # SQLite repository
???   ????????? API.History.Service.pas     # History service
????????? README.md

🤝 Contributing

Contributions are welcome! Please open an issue first to discuss what you'd like to change.

1. Fork the repo
2. Create a feature branch (git checkout -b feature/my-feature)
3. Commit your changes (git commit -m 'Add my feature')
4. Push to the branch (git push origin feature/my-feature)
5. Open a Pull Request

📄 License

This project is licensed under the MIT License. See LICENSE for details.

🙏 Acknowledgements

• PDFium — PDF rendering engine by Google
• bblanchon/pdfium-binaries — pre-built PDFium Windows binaries
• Embarcadero Delphi — RAD IDE and FMX framework