A lightweight offline PWA that computes centered crop and X/Y offset values for Novastar V-Can. Given a layer resolution and a source image resolution, it returns the exact values to enter in V-Can.
Live app: fiverecords.github.io/LedCropCalc
Working with LED walls and V-Can, you often need to display a standard source (like 1920×1080) on a layer with non-standard dimensions (832×1248, 1040×624, etc.). The crop values to keep the image centered and undistorted aren't obvious to calculate on the fly.
This tool does the math for you:
- Enter the layer (screen) resolution
- Enter the source (image) resolution
- Get the four V-Can crop values: X, Width, Y, Height
Tap any value to copy it to the clipboard.
The app is a PWA, so you install it directly from the browser — no App Store, no Google Play.
iPhone (Safari):
- Open the app URL in Safari
- Tap the Share button → "Add to Home Screen"
Android (Chrome):
- Open the app URL in Chrome
- Tap the menu (⋮) → "Install app" or "Add to Home Screen"
Once installed, the app runs offline. Useful for venues with no signal during setup.
Given screen W × H and source sW × sH:
- If the source is proportionally wider than the screen → crop the sides (X axis), keep full height
- If the source is proportionally taller → crop top/bottom (Y axis), keep full width
- If aspect ratios match → no crop needed
The axis that is not cropped is filled with the source's full dimension (V-Can expects explicit values there, not zero).
Plain HTML + CSS + vanilla JS. No framework, no build step, no dependencies. ~15 KB total. Service worker caches everything on first load for offline use.
MIT — do whatever you want with it.
Built for live event AV/lighting technicians. Not affiliated with Novastar.