DoodleDream

Overview

An interactive AI-powered coloring book app that lets users color pre-made templates or generate custom coloring pages from text prompts using DALL-E 3.

Key Features

• Hybrid asset strategy combining 10 instant-loading preset templates with unlimited DALL-E 3 AI generation
• Advanced HTML5 Canvas drawing with high-DPI display support and line art preservation layer
• Production-grade flood fill algorithm using stack-based approach to prevent stack overflow
• Comprehensive responsive design with adaptive UI for desktop, tablet, and mobile with landscape optimization
• Secure backend with rate limiting, CORS protection, input validation, and environment-based configuration

Challenges & Solutions

The project solved complex technical challenges including high-DPI display rendering with Device Pixel Ratio tracking and coordinate mapping, image processing to convert AI-generated images into proper line-art coloring pages with white pixel thresholding, unified touch and mouse coordinate mapping across different event systems, drawing tool interaction with line preservation requiring strategic overlay compositing, memory-efficient undo system with sliding window history, cross-origin image loading with CORS headers, and prompt engineering for DALL-E 3 to generate proper black-and-white line art instead of colored images.