fix-perspective

Computes and applies perspective correction given 4 corners

Based on the following sources:

• http://codepen.io/fta/pen/JoGybG?editors=111
• http://codepen.io/fta/full/JoGybG/
• http://franklinta.com/2014/09/08/computing-css-matrix3d-transforms/

Given 4 starting points and 4 end points calculates transformation function (and matrix) that transforms any starting point. Usually used to remove perspective distortion.

// from, to are arrays with 4 points each (x, y)
var from = [{ 
    x: 100,
    y: 20
}, {
    x: 200,
    y: 50
}, ...];
var to = [{ 
    x: 20,
    y: 0
}, {
    x: 100,
    y: 0
}, ...];
var fixPerspective = require('fix-perspective');
var transformation = fixPerspective(from, to);
// any point in the original (FROM) coordinate system
var out = transformation(100, 60);
// out = { x: ..., y: ... };
// the transformation matrix (4x4) is available as transformation.H

Small print

Author: Gleb Bahmutov © 2015

• @bahmutov
• glebbahmutov.com
• blog

License: MIT - do anything with the code, but don't blame uTest if it does not work.

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Support: if you find any problems with this module, email / tweet / open issue on Github