Kotlin Desktop: Canvas, Path & Pointer Input Drawing App | Lesson 11

Build a freehand drawing app with Kotlin Compose Desktop! Learn how to use the Canvas composable, draw paths with moveTo/lineTo, apply smooth stroke styles with StrokeCap.Round, and capture pointer input with detectDragGestures. Includes a color palette, adjustable stroke width, undo, and clear. What You'll Learn: - Canvas composable with DrawScope for custom 2D drawing - Path API with moveTo and lineTo for building freehand strokes - Stroke styles: StrokeCap.Round, StrokeJoin.Round for smooth lines - pointerInput modifier with detectDragGestures for gesture handling - mutableStateListOf for reactive stroke list management - Color palette with CircleShape selection indicators - Slider for adjustable stroke width - Undo (removeLast) and clear operations Timestamps: 0:00 - Introduction 0:15 - Preview: What We're Building 0:45 - Project Setup (Gradle, Compose Dependencies) 2:14 - Stroke Model (DrawingStroke Data Class) 3:42 - Drawing Canvas (Canvas, Path, Pointer Input) 6:01 - Drawing App (Toolbar, State Management) 8:20 - Main & Compile 10:10 - Live Demo: Drawing App in Action 11:50 - Recap & Key Takeaways 12:50 - Thanks for Watching Key Takeaways: 1. Canvas — Canvas composable gives you a DrawScope for custom 2D rendering 2. Path — Path.moveTo/lineTo builds shapes, drawPath renders them on the canvas 3. Stroke — StrokeCap.Round and StrokeJoin.Round create smooth freehand lines 4. Input — pointerInput with detectDragGestures captures freehand drawing gestures 5. Undo — mutableStateListOf with removeLast provides simple undo functionality Previous Lesson: Lesson 10: Drag & Drop https://youtube.com/... Next Lesson: Lesson 12: Animations (coming soon) Tech Stack: Kotlin 2.1, Compose Multiplatform 1.7.3, Material3 Canvas API, Pointer Input, DrawScope Gradle 8.10, JVM 17+ Source Code: https://github.com/GoCelesteAI/kotlin_desktop_canvas_drawing Taught by CelesteAI If you found this helpful, please like and subscribe for more Kotlin Desktop tutorials! #kotlin #compose #desktop #material3 #canvas #drawing #path #pointerInput #tutorial #programming