| ID | Feature Description | Requirements | Citations |
|---|---|---|---|
| F.1 | Drawing Canvas | Support drawing on a blank canvas or imported photos (doodling on pictures).1 | 1 |
| F.2 | Core Utility Tools | Provide universally accessible Undo and Redo functions.1 | 1 |
| F.3 | Magical Brush Set | Must include a portfolio of high-impact brush effects (24+ options).1 Core effects required: Glow, Neon, Star Sparkles/Glitter, Fireworks, Rainbow, Crayon, Spray, and Ribbon.1 | 1 |
| F.4 | Movie Mode (Time-Lapse) | Automatically record the drawing procedure in the background and allow users to play back the drawing process as a short film/animation.1 | 1 |
| F.5 | Art Management | A built-in Art Gallery must securely store both completed drawings and the associated 'Movie Mode' animation procedures.1 | 1 |
| F.6 | Coloring Efficiency | Must include a "Magical pattern paint bucket" (Fill tool) for quickly coloring large areas, accommodating older children (ages 6–8).3 | 3 |
| ID | Feature Description | Requirements | Citations |
|---|---|---|---|
| U.1 | Ergonomic Design | All interactive elements (buttons, icons) must be large and easily tappable, adhering to a minimum physical target size of 2cm x 2cm.4 Provide generous spacing between buttons to prevent accidental activation.4 | 4 |
| U.2 | Interface Clarity | Design must be simple, unambiguous, and uncluttered, with minimal reliance on text in favor of large, clear icons and visual cues.1 | 1 |
| U.3 | Feedback & Engagement | Provide immediate, positive Multi-Sensory Feedback (visual cues, fun animations, and positive sounds) for all key actions (e.g., brush selection, saving).5 | 5 |
| U.4 | Color Experience | The default/prominent brush should utilize an automatic color cycling effect (the "Rainbow" brush), as this "surprise" element is highly engaging for young users and reduces cognitive load.2 | 2 |
| U.5 | Guidance | Use brief visual and audio demonstrations upon first use to show how to draw or interact, reducing the need for explicit instructions.7 | 7 |
| ID | Constraint Category | Requirements | Citations |
|---|---|---|---|
| NF.1 | Monetization Policy | Application must be completely free and permanently ad-free (no in-app advertising, banner ads, or pop-up ads).2 | 2 |
| NF.2 | Technical Connectivity | Application must be fully functional and robust in Offline mode (no Wi-Fi/Internet required).1 | 1 |
| NF.3 | Glow/Neon Implementation | Luminous effects must be implemented using optimized shaders (not standard particles), utilizing additive blending and a global screen-space Bloom filter to create a convincing soft, light-emitting halo.8 | 8 |
| NF.4 | Glitter/Sparkle Implementation | Glitter/Sparkle must be implemented using shader-based dynamic reflection simulation (e.g., Dot Product with noise) for high mobile performance.9 The effect must leverage HDR colors and the Bloom filter to create realistic, dynamic sparkle.9 | 9 |
| NF.5 | Brush Micro-Interactions | Specific brushes (e.g., Ribbon, Star) should integrate micro-animations or subtle movement (organic animation) to increase the "magic" and sensory engagement.11 | 11 |