WinPDF 📄✨

A lightweight, modern PDF reader and viewer designed natively for Windows 11 using WinUI 3, Windows App SDK, and .NET 9.

WinPDF leverages native Windows desktop capabilities, offering a fluent interface with dynamic Mica backdrops, multi-document tabbed navigation, drag-and-drop support, and hardware-accelerated PDF rendering.

⚠️ Status: Work in Progress (Active Development)
Core viewer, tab architecture, and drag-and-drop operations are implemented. Annotation, deep search, and AI-driven document features are planned.

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🌟 Highlights & Current Features

• Fluent Windows 11 Design System:
  • Native custom TitleBar integration (ExtendsContentIntoTitleBar).
  • Dynamic Mica / Mica Alt system backdrop with theme-aware configuration (SystemBackdropConfiguration).
• Multi-Tabbed Workspace:
  • Tabbed document interface powered by TabView and MVVM architecture.
  • Dedicated Home tab for quick actions and separate, isolated tabs for loaded PDFs.
• Native PDF Rendering Pipeline:
  • Utilizes the native Windows.Data.Pdf.PdfDocument API.
  • Streams page bitmaps directly via InMemoryRandomAccessStream for smooth vertical scrolling using ItemsRepeater.
  • Zoom and pan gestures supported via ScrollView manipulation modes.
• Drag-and-Drop & Picker Workflows:
  • Full drag-and-drop capability from Windows File Explorer directly onto the canvas or Home view.
  • Asynchronous file pickers supporting single and multiple document loading.
• MVVM Architecture:
  • Built using CommunityToolkit.Mvvm (ObservableObject, IRelayCommand, custom event/drag-drop contexts).

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📸 Architecture & UI Overview

                      +-----------------------------+
                      |   MainWindow (Mica/Tabs)    |
                      +--------------+--------------+
                                     |
               +---------------------+---------------------+
               |                                           |
               v                                           v
      +-----------------+                         +-----------------+
      |    HomePage     |                         |     PDFPage     |
      | (Quick Actions, |                         | (Document View, |
      |  File Picker,   |                         |  ItemsRepeater, |
      |  Drag-and-Drop) |                         |  Page Nav Tree) |
      +-----------------+                         +--------+--------+
                                                           |
                                                           v
                                              +-------------------------+
                                              |    PDFRenderer Engine   |
                                              |  (Windows.Data.Pdf ->   |
                                              |     Bitmap Streams)     |
                                              +-------------------------+

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🛠️ Tech Stack & Dependencies

• Platform: Windows App SDK (WinUI 3)
• Framework: .NET 9.0 (net9.0-windows10.0.26100.0)
• Libraries & Packages:
  • CommunityToolkit.Mvvm (8.4.0) — Modern MVVM patterns
  • Microsoft.WindowsAppSDK (1.7.x) — Modern Windows desktop controls & runtime
  • Microsoft.Graphics.Win2D (1.3.2) — Hardware-accelerated graphics
  • Microsoft.Xaml.Behaviors.WinUI.Managed (3.0.0) — XAML Interaction & Behaviors

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📁 Project Structure

WinPDF/
├── App.xaml / .cs               # Application entry point & resource definitions
├── MainWindow.xaml / .cs        # Root window, Mica backdrop & TabView management
├── Helpers/                     # Win32 Dispatcher Queue helpers
├── Models/                      # Tab, Document, and Event Context data structures
├── Services/
│   ├── FileOperationService.cs  # Windows Storage Pickers wrapper
│   ├── InteractionServices.cs   # Dialog & notification services
│   ├── NavigationService.cs     # Frame navigation logic
│   └── PDFRenderer.cs           # PDF stream decoding and bitmap conversion
├── ViewModels/
│   ├── MainViewModel.cs         # Tab collection and tab lifecycle commands
│   ├── HomeViewModel.cs         # Drag-and-drop and document open workflows
│   └── TabViewModel.cs          # Tab metadata and encapsulated Frame states
└── Views/
    ├── HomePage.xaml            # Welcome screen with drop target
    └── PDFPage.xaml             # PDF document view & section tree panel

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🚀 Getting Started

Prerequisites

• Windows 10 (Version 1809 / Build 17763 or newer) or Windows 11 (Recommended).
• Visual Studio 2022 (v17.12+) with:
  • .NET Desktop Development workload.
  • Windows App SDK C# Templates installed.

Build and Run

1. Clone this repository:

   git clone https://github.com/yourusername/WinPDF.git

2. Open WinPDF.sln in Visual Studio.
3. Select your platform target (x64, ARM64, or x86) and build configuration (Debug or Release).
4. Set WinPDF (Package) or WinPDF (Unpackaged) as the startup project and press F5.

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🗺️ Roadmap

• Multi-tabbed window infrastructure (TabView).
• Mica & Mica Alt system backdrop support.
• Native PDF decoding into virtualized image repeaters.
• Drag & drop integration for document loading.
• Table of contents / Bookmarks extraction into the sidebar TreeView.
• Text extraction, selection, and in-document search.
• Highlight and annotation tools.
• Document summarization with AI integration.

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📄 License

This project is licensed under the GNU General Public License v3.0.