ACWW Letter Editor

A Qt5 application for editing letters in Animal Crossing: Wild World save files. Extracts stationery and fonts from the ROM for authentic preview rendering.

Features

• Open and read ACWW save files (*.sav)
• View and edit letters from all 4 player slots
• Browse letters stored in:
  • Player inventory (backpack) - 20 slots
  • Mailbox - 20 slots
  • Bank storage - 75 slots
• Extracts all 64 letter stationery backgrounds from the ROM
• Extracts the game font (fontA - 16x16 variable-width glyphs)
• Live preview of letter text on selected stationery
• Direct text editing on the canvas (click and type)
• Supports basic editing: arrow keys, backspace, delete, enter for newlines

Requirements

• C++17 compiler (g++ or clang++)
• Qt5 (Core, Gui, Qml, Quick, QuickControls2)
• CMake 3.16+ or qmake

Installing Qt5

Ubuntu/Debian:

sudo apt install qtbase5-dev qtdeclarative5-dev qml-module-qtquick-controls2 qml-module-qtquick-dialogs qml-module-qtgraphicaleffects qt5-qmake

Fedora:

sudo dnf install qt5-qtbase-devel qt5-qtdeclarative-devel qt5-qtquickcontrols2-devel qt5-qtgraphicaleffects

Arch Linux:

sudo pacman -S qt5-base qt5-declarative qt5-quickcontrols2 qt5-graphicaleffects

macOS (Homebrew):

brew install qt@5

Building

Using CMake:

mkdir build && cd build
cmake ..
make

Using qmake:

qmake letter-editor.pro
make

Usage

1. Run the application: ./letter-editor
2. Use File → Open ROM to load your ACWW ROM file (*.nds) - this extracts stationery and fonts
3. Use File → Open Save to load your save file (*.sav)
4. Select a player and letter location (Inventory, Mailbox, or Bank Storage)
5. Select a letter slot to view/edit
6. Click on the letter canvas to edit text directly
7. Use arrow keys to navigate, Backspace/Delete to remove characters, Enter for newlines
8. Change stationery, recipient/sender info, and attached items as needed
9. Save changes back to the save file

File Structure

src/
├── main.cpp                # Application entry point, registers QML types
├── backend.h/cpp           # Main backend - ROM/save loading, letter management
├── lettercanvasitem.h/cpp  # QQuickPaintedItem for letter preview rendering
├── savefile.h/cpp          # Save file parser and writer
├── letter.h/cpp            # Letter data structure
├── stationery_loader.h/cpp # Extracts stationery backgrounds from ROM
├── font_loader.h/cpp       # Extracts font glyphs from ROM
├── icon_loader.h/cpp       # Extracts inventory item icons from ROM
├── nds_rom.h/cpp           # NDS ROM parser (NitroFS)
├── lz77.h/cpp              # LZ77 decompression
├── itemdatabase.h/cpp      # Item ID to name mapping
└── acww_encoding.h         # Character encoding lookup tables

qml/
├── main.qml                # Main application window
├── SaveBrowser.qml         # Save file browser panel
├── components/             # Reusable UI components
└── dialogs/                # Dialog windows

Save File Format

ACWW save files contain letter data at specific memory offsets. Each letter is 244 bytes (0xF4) and includes:

Offset	Size	Description
0x30	15 bytes	Subject line
0x48	99 bytes	Letter body
0xC8	25 bytes	Signature
0xE9	1 byte	Stationery paper ID
0xEA	2 bytes	Attached item ID

The application uses ACWW's custom character encoding table to decode the text.

License

This project is provided for educational and personal use for interacting with your own save files.