lifesized

Overview

An Electron module for displaying objects in physically accurate sizes on screens.

Downloadable versions of the Demos are available for Macs.

I hope this module and its uses will convince browser makers to provide this as a native API or at least to Electron in its core

Installation

npm install --save lifesized

Usage

var lifesized = require('lifesized');

// Get the pixels per inch of the display the current render process' BrowserWindow
// is mostly overlayed on
var pixelsPerInch = lifesized.ppi();

See the Demos and their source for a working example.

API

lifesized.ppi(display)

Get the Pixels Per Inch of a display.

• display (optional*) - The Display who's PPI you want. If not provided it use the display the current BrowserWindow is most over.

Returns: (Number) The displays Pixels Per Inch.

lifesized.scale(objectRealSize, objectPixelSize, display)

Calculate how much you have to scale an object in an image to make it appear life sized on the screen.

• objectRealSize (Number) Real size of an object in inches
• objectPixelSize (Number) Size of the object in an image in pixels
• display (optional*) The Display you want to show the object on. If not provided it use the display the current BrowserWindow is most over.

Returns: (Number) Scale factor to use to scale images (1.0 === 100%)

* Some OSs display windows on multiple displays at once when a Window spans more than one display, some do not. We use the best guest using Electron's screen.getDisplayMatching(rect)

Demos

To run the coins app that shows this off do the following:

• Get the code and npm install things

      git clone [e-mail]:francoislaberge/lifesized.git
      cd lifesized
      npm Install
  

• Launch the coins demo

      npm run coins
  

• Get some coins and verify that they are the same size in real life as they are on screen.

• Run other demos via npm run shaqs-hands or npm run ruler

Limitations

• Only accurate on OSX right now, falls back to a sane default of 72 pixels/inch (Pull Requests welcome, I will add Windows/Linux support as soon as I can)
• Doesn't currently detect when a BrowserWindow's Display changes (This should be detectable, will add ASAP)

Contributing

git clone [e-mail]:francoislaberge/lifesized.git
cd lifesized
yarn install

See the Todos for planned work if you want to chip in.