Product Specification: Client-Side HEIC to JPG Converter

1. Overview

A high-performance, browser-based utility that decodes HEIC (High Efficiency Image Container) files and encodes them into JPEG format. The application is built to prioritize user privacy by ensuring zero server-side interaction.

2. Technical Stack

• Core Processing: heic2any library (for decoding) + Native Canvas API (for encoding).
• Frontend: HTML5, Tailwind CSS for styling, Alpine.js for lightweight state management.
• Bundling: Vite.
• PWA Capabilities: Service Workers to cache the app, allowing full offline functionality.

3. UI/UX Design

• Color Palette: Professional, clean, and minimalist. Uses high-contrast grays, deep whites, and a primary "Action Blue" (#2563eb) for CTA buttons.
• Layout Structure:
  • Header: Simple, descriptive H1, tagline.
  • Dropzone: A large, dashed-border area with icon feedback (hover states).
  • Control Panel: Floating sidebar or top bar to toggle output quality (0.1–1.0) and metadata settings.
  • Results Grid: A responsive list view showing a thumbnail, original filename, status (Processing/Done), and individual download buttons.
  • Batch Actions: Sticky footer containing "Download All as ZIP" and "Clear All" buttons.
• Animations: Subtle fade-ins for thumbnails, a progress bar using SVG stroke-dashoffset for each file, and a success checkmark animation upon completion.

4. Feature List

1. Drag-and-Drop Interface: Multi-file support utilizing the File System Access API.
2. Quality Control Slider: Allows users to determine JPEG compression ratios (default 0.92).
3. Batch Processing: Uses Web Workers to process images in parallel without freezing the main UI thread.
4. ZIP Compression: Uses JSZip to bundle all converted images into a single file for bulk downloads.
5. Metadata Toggle: A checkbox to either keep or strip EXIF, GPS, and orientation tags.
6. Live Preview: A modal window to view the original HEIC versus the converted JPEG before saving.
7. Responsive Design: Fully mobile-optimized layout (allows iPhone users to convert photos directly from the Files app in the browser).
8. Failure Handling: Clearly display errors for corrupted files (e.g., "Unable to decode, file may be corrupted").

5. Performance Goals

• Time to Interactive: < 2 seconds.
• Conversion Speed: Average < 500ms per image on mid-range devices.
• Memory Management: Clear Object URLs and revoke memory caches immediately after a file is downloaded to prevent memory leaks.