sharp/test/unit/gamma.js

'use strict';

var assert = require('assert');

var sharp = require('../../index');
var fixtures = require('../fixtures');

sharp.cache(0);

describe('Gamma correction', function() {

  it('value of 0.0 (disabled)', function(done) {
    sharp(fixtures.inputJpgWithGammaHoliness)
      .resize(129, 111)
      .toBuffer(function(err, data, info) {
        assert.strictEqual('jpeg', info.format);
        assert.strictEqual(129, info.width);
        assert.strictEqual(111, info.height);
        fixtures.assertSimilar(fixtures.expected('gamma-0.0.jpg'), data, done);
      });
  });

  it('value of 2.2 (default)', function(done) {
    sharp(fixtures.inputJpgWithGammaHoliness)
      .resize(129, 111)
      .gamma()
      .toBuffer(function(err, data, info) {
        assert.strictEqual('jpeg', info.format);
        assert.strictEqual(129, info.width);
        assert.strictEqual(111, info.height);
        fixtures.assertSimilar(fixtures.expected('gamma-2.2.jpg'), data, done);
      });
  });

  it('value of 3.0', function(done) {
    sharp(fixtures.inputJpgWithGammaHoliness)
      .resize(129, 111)
      .gamma(3)
      .toBuffer(function(err, data, info) {
        assert.strictEqual('jpeg', info.format);
        assert.strictEqual(129, info.width);
        assert.strictEqual(111, info.height);
        fixtures.assertSimilar(fixtures.expected('gamma-3.0.jpg'), data, done);
      });
  });

  it('alpha transparency', function(done) {
    sharp(fixtures.inputPngOverlayLayer1)
      .resize(320)
      .gamma()
      .toBuffer(function(err, data, info) {
        assert.strictEqual('png', info.format);
        assert.strictEqual(320, info.width);
        fixtures.assertSimilar(fixtures.expected('gamma-alpha.jpg'), data, done);
      });
  });

  it('invalid value', function() {
    assert.throws(function() {
      sharp(fixtures.inputJpgWithGammaHoliness).gamma(4);
    });
  });

});