Folha

A modern, canvas-based text editor built with Wails, Go, and vanilla JavaScript.

Features

Core Editor Functionality

• Canvas-based rendering for high performance and precise text display
• Intelligent text wrapping with word-boundary detection
• Responsive design that adapts to window resizing
• Monospace font rendering with configurable spacing and size
• Line-based editing with support for multi-line documents

Text Selection

• Mouse selection: Click and drag to select text across multiple lines
• Keyboard selection: Use Shift + Arrow keys to extend selections
• Multi-line support: Seamless selection across wrapped and logical lines
• Visual feedback: Blue highlighting for selected text regions
• Smart positioning: Handles both logical and visual text coordinates

Cursor Navigation

• Arrow key navigation: Move cursor in all directions
• Word wrapping awareness: Cursor movement respects wrapped lines
• Line jumping: Navigate between logical lines and visual wrapped lines
• Precise positioning: Accurate cursor placement in wrapped text

Keyboard Shortcuts

• Ctrl + A: Select all text
• Ctrl + C: Copy selected text to clipboard
• Ctrl + X: Cut selected text to clipboard
• Ctrl + V: Paste text from clipboard
• Ctrl + O: Opens file dialog to load file
• Ctrl + S: Opens save dialog to save current content
• Shift + Arrows: Extend text selection
• Backspace/Delete: Remove characters or selected text
• Enter: Create new lines
• Tab: Insert spaces (2-space indentation)

Text Editing

• Character insertion: Type to add text at cursor position
• Text deletion: Backspace and Delete key support
• Selection replacement: Typing replaces selected text
• Multi-line editing: Full support for paragraphs and line breaks
• Unicode support: Handle international characters and emojis

Cross-Platform

• Desktop application: Native performance with web technologies
• Windows, macOS, Linux: Full cross-platform support via Wails
• System integration: Native clipboard access and file operations

Technical Architecture

Frontend (JavaScript)

• Editor Class: Core text editing engine with canvas rendering
• Cursor Class: Intelligent cursor positioning and movement
• KeyPressMonitor: Comprehensive keyboard and mouse input handling
• Selection System: Advanced text selection with visual feedback

Backend (Go)

• Wails framework: Go backend with JavaScript frontend
• Native OS integration: Clipboard access and system operations
• Hot reload: Fast development with live code updates

Getting Started

Prerequisites

• Go 1.18 or later
• Node.js 16 or later
• Wails CLI tool

Installation

# Install Wails CLI
go install github.com/wailsapp/wails/v2/cmd/wails@latest

# Clone the repository
git clone <repository-url>
cd folha

# Install dependencies
wails build

Development

# Run in development mode with hot reload
wails dev

This starts a development server with hot reload. Access the browser version at http://localhost:34115 for debugging.

Building

# Build for production
wails build

Creates a distributable application in the build/ directory.

Configuration

Configure the project by editing wails.json. See the Wails documentation for all available options.

Architecture Details

The editor uses a sophisticated coordinate system that handles both:

• Logical positions: Actual character positions in the document
• Visual positions: Positions in wrapped/displayed lines

This dual-coordinate system ensures accurate cursor placement and text selection even when lines wrap to multiple visual lines.

Future Enhancements

• Syntax highlighting
• Multiple cursors
• Find and replace
• Undo/redo system
• File operations (open, save) [x]
• Themes and customization
• Plugin system