Paint Application (C#)

A desktop drawing application built with C# and Windows Forms, inspired by the classic Microsoft Paint experience.

This project started as a hands-on challenge while learning C#, but it grew into a feature-rich WinForms app that covers drawing tools, shape rendering, text, image editing actions, selection workflows, and basic canvas manipulation. It was a practical way to learn event-driven programming, graphics rendering, and desktop UI development.

Features

Drawing Tools

• Pencil / freehand drawing
• Eraser
• Airbrush
• Straight line tool
• Curve support
• Text tool

Shapes

• Rectangle
• Ellipse / oval
• Triangle
• Right triangle
• Polygon
• Diamond
• Pentagon
• Hexagon
• Right / left / up / down arrows
• Four-point, five-point, and six-point stars
• Rounded rectangle callout
• Oval callout
• Cloud callout
• Heart
• Lightning

Editing & Canvas Actions

• Foreground and background color selection
• Custom color editing
• Adjustable pen/brush size
• Fill and outline behavior
• Color picker
• Fill bucket
• Open image
• Insert image onto canvas
• Save drawing
• Undo / redo
• Zoom in / zoom out
• Crop
• Flip horizontally / vertically
• Rotate left / right
• New canvas

Selection Support

• Rectangular selection
• Free-form selection
• Resize/move workflow for selected content

Screenshots

Demo GIF

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Why I Built This

This was one of my early C# projects and an important milestone in my learning journey. I wanted to build something interactive that would help me understand how desktop applications respond to user input in real time.

The goal was not just to recreate a simple paint program, but to explore:

• Event-driven programming in WinForms
• Mouse-based drawing interactions
• Rendering graphics with System.Drawing
• Managing drawing state across tools
• Building a more complete desktop UI with multiple editing actions

Tech Stack

• Language: C#
• Framework: .NET Framework 4.8
• UI: Windows Forms (WinForms)
• Graphics: System.Drawing
• Project Type: Desktop application

Architecture Overview

The project is organized as a classic WinForms desktop app with drawing-specific helper classes.

Main Components

• Form1.cs
  Contains the main UI logic, event handling, tool state, mouse interaction flow, canvas actions, and command behavior.

• Draw.cs
  Encapsulates shape rendering logic for lines, polygons, arrows, stars, and custom callout-style shapes.

• DoubleBufferedPanel.cs
  Enables double buffering to reduce flicker while drawing and repainting the canvas.

• TinySquare.cs
  Supports selection/resize handles for interactive editing.

Rendering Model

The app uses Bitmap, Graphics, mouse events, and control repainting to provide a drawing surface that updates in real time as the user interacts with the canvas.

What I Learned

Working on this project helped me build confidence in:

• WinForms UI design
• Handling MouseDown, MouseMove, and MouseUp
• Drawing with Graphics, Pen, Brush, and Bitmap
• Building reusable drawing logic
• Managing application state across multiple tools
• Supporting editing actions like crop, rotate, flip, and zoom
• Improving UI responsiveness with double buffering

Getting Started

Prerequisites

• Windows
• Visual Studio
• .NET Framework 4.8 targeting pack