Basic Animation with Object Pascal (Beginner Tutorial)

In this kid-friendly tutorial, we build a bouncing ball animation in Object Pascal using the Lazarus IDE on Linux. You’ll learn how GUI apps update over time with a Timer, how to move shapes on a form, and how to make the ball bounce off the window edges—all in under 10 minutes. 🎯 What you’ll learn * Add and configure GUI components: TShape (circle) and TTimer * Change properties (color, width/height, position) and captions * Write an OnTimer event to update position every few ms * Use form coordinates (Top, Left, Width, Height, ClientHeight, ClientWidth) * Implement edge collisions (reverse direction at boundaries) * Control animation speed (timer interval vs. pixels per tick) * Keep state with private fields (e.g., moving up/right booleans) Who it’s for OWL Scholars, kids learning to code, teachers, and beginners curious about Pascal + Lazarus on Linux. 🧰 Prereqs * You watched “Build Your First Pascal GUI” (button + textbox + message) * Basic comfort with variables, conditionals, and events ⏱️ Chapters 00:00 Intro & goal (animate a shape) 00:40 New Lazarus Application (GUI template) 01:10 Add TShape (circle, size, color) 01:55 Add TTimer (20 ms → animation frames) 02:30 Create Timer1Timer event 03:00 Move the ball vertically (Top ±= step) 04:10 Bounce at top/bottom (ClientHeight run check) 05:30 Tune speed (interval vs. step size) 06:20 Add horizontal movement (Left ±= step) 07:10 Bounce at left/right (ClientWidth run check) 08:15 Resize the window — animation still works 08:45 Save project structure (new folder per GUI app) 09:05 What’s next: GUI Guessing Game 🎒 Try this (Homework) * Add a speed slider (1–10) that changes step size live * Randomize start direction and ball color on run * Show a hit counter label (how many wall bounces) * Add a Pause/Play button (enable/disable Timer1) * Spawn a second ball with its own direction flags 🏷️ Tags / Hashtags #LazarusIDE #FreePascal #ObjectPascal #PascalProgramming #GUIProgramming #Animation #TTimer #TShape #KidsWhoCode #BeginnerProgramming #OpenWiseLearning #STEMEducation #LinuxCoding #FedoraLinux