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I Built a Browser-Based HEIC PDF/PNG Converter: How It Works (and Why Office Workers Might Love It)

 This is a small side project I built to solve a daily annoyance — and it unexpectedly became a useful productivity tool for colleagues. Here’s the technical breakdown, along with practical office tips for handling HEIC files more efficiently.

🌱 Why This Project Exists

  • If you work with photos on Windows, you've probably run into this:
  • You receive HEIC images from iPhone users
  • Windows can't open them by default
  • Online converters have limits, watermarks, ads, or require uploads
  • Corporate networks often block file-upload tools (security concerns)
    I kept running into this in my own job. So on a weekend, I built a fully browser-based HEIC → PDF/PNG converter that:

  • runs entirely offline

  • processes files inside the browser (not uploaded anywhere)

  • supports batch conversion

  • is free, unrestricted, no watermark
    The tool:
    👉 https://heictopng.net
    I shared it with teammates and realized many office workflows became smoother. So here’s how it works under the hood — and how you can streamline your day-to-day tasks using simple file-conversion hacks.

🛠 Tech Breakdown: How It Works in the Browser

1. HEIC Decoding with Browser-Compatible Libraries
HEIC is based on HEIF + HEVC compression (H.265). Browsers don’t natively decode it yet, so I used:

  • WASM-based HEIC decoder
  • Canvas to reconstruct raster images
  • Blob / File API for final export Pseudocode: const heicFile = input.files[0]; const decoded = await decodeHeic(heicFile); const canvas = drawToCanvas(decoded); const blob = await exportAs(blobType); All processing happens inside the browser's memory.

2. PDF Generation Without a Server

To export PDF in-browser:

  • Render image → Canvas
  • Use a lightweight JS PDF generator
  • Embed image at native resolution
  • Export via No server. No upload. No tracking.

3. Performance Optimizations
I focused on:

  • lazy decoding for large HEIC sets
  • web workers to prevent UI freezing -** canvas recycling** to lower memory use
  • instant preview → improves perceived speed Even 20–30 images process smoothly on mid-range laptops.

🧩 Side Project Lessons Learned

1. Building tools for yourself is underrated
I made this tool for my own workflow, not for users — ironically, that’s precisely why people like it.

2. “Offline-first” is a feature now
Many devs and office teams avoid upload tools for privacy reasons.

3. People prefer tiny utilities over complex software
A single-purpose tool often outperforms complex “suite” products.

💼 Productivity Tips: Handling HEIC Files in Office Workflows

Office workers often don't know these tricks — adding them increases the utility of your post and avoids looking like an ad.

Tip 1 — Convert HEIC to PDF before sending to corporate clients
Because:

  • PDFs preserve layout
  • They display properly on all devices
  • No risk of “Client can't open the file” emails If you use many mobile photos in reports, convert them first, then drag into Word/PowerPoint.

Tip 2 — Batch rename images for documentation
Windows shortcut:
F2 → rename first file → then press Tab to rename the next.
Combine it with batch conversion for clean report images.

Tip 3 — Paste converted PNGs directly into Office (no quality loss)
PNG preserves clarity better than JPEG.
If you’re making:

  • bug reports
  • product demos
  • documentation
  • training slides → Use PNG, not JPG.

Tip 4 — Save PDFs directly to OneDrive / SharePoint for easy collaboration
Useful workflow:

  1. Convert HEIC → PDF offline
  2. Drag into SharePoint
  3. Colleagues preview without downloading Minimal friction.

🚀 What’s Next?

I plan to add:

  • Drag-in folder support
  • HEIC metadata extraction
  • Safari iOS support improvements
  • Dark mode If you have ideas or run into edge cases, I’d love to hear your thoughts!

🔗 Try the Demo (Offline-capable)

https://heictopng.net
I built this mainly for my own use, but if it helps you or your teammates, that’s awesome.
Happy to answer any implementation questions!

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