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Ensure 16-bit input images can be normalised
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@lovell
lovell committed Feb 3, 2016
1 parent e380576 commit 322aa60
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3 changes: 2 additions & 1 deletion docs/changelog.md
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Expand Up @@ -20,7 +20,8 @@
[#315](https://github.com/lovell/sharp/issues/315)
[@impomezia](https://github.com/impomezia)

* Ensure 16-bit input images can be embedded onto a transparent background.
* Ensure 16-bit input images can be normalised and embedded onto transparent backgrounds.
[#339](https://github.com/lovell/sharp/issues/339)
[#340](https://github.com/lovell/sharp/issues/340)
[@janaz](https://github.com/janaz)

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175 changes: 88 additions & 87 deletions test/unit/normalize.js
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Expand Up @@ -5,107 +5,108 @@ var assert = require('assert');
var sharp = require('../../index');
var fixtures = require('../fixtures');

var assertNormalized = function(data) {
var min = 255;
var max = 0;
for (var i = 0; i < data.length; i++) {
min = Math.min(min, data[i]);
max = Math.max(max, data[i]);
}
assert.strictEqual(0, min);
assert.strictEqual(255, max);
};

describe('Normalization', function () {

it('uses the same prototype for both spellings', function () {
it('uses the same prototype for both spellings', function() {
assert.strictEqual(sharp.prototype.normalize, sharp.prototype.normalise);
});

// Normalize is currently unavailable on Windows
if (process.platform !== 'win32') {
it('spreads rgb image values between 0 and 255', function(done) {
sharp(fixtures.inputJpgWithLowContrast)
.normalize()
.raw()
.toBuffer(function (err, data, info) {
if (err) throw err;
assertNormalized(data);
done();
});
});

it('spreads rgb image values between 0 and 255', function(done) {
sharp(fixtures.inputJpgWithLowContrast)
.normalize()
.raw()
.toBuffer(function (err, data, info) {
if (err) throw err;
var min = 255, max = 0, i;
for (i = 0; i < data.length; i += 3) {
min = Math.min(min, data[i], data[i + 1], data[i + 2]);
max = Math.max(max, data[i], data[i + 1], data[i + 2]);
}
assert.strictEqual(0, min);
assert.strictEqual(255, max);
done();
});
});
it('spreads grayscaled image values between 0 and 255', function(done) {
sharp(fixtures.inputJpgWithLowContrast)
.gamma()
.greyscale()
.normalize(true)
.raw()
.toBuffer(function (err, data, info) {
if (err) throw err;
assertNormalized(data);
done();
});
});

it('spreads grayscaled image values between 0 and 255', function(done) {
sharp(fixtures.inputJpgWithLowContrast)
.gamma()
.greyscale()
.normalize(true)
.raw()
.toBuffer(function (err, data, info) {
if (err) throw err;
var min = 255, max = 0, i;
for (i = 0; i < data.length; i++) {
min = Math.min(min, data[i]);
max = Math.max(max, data[i]);
}
assert.strictEqual(0, min);
assert.strictEqual(255, max);
done();
});
});
it('stretches greyscale images with alpha channel', function(done) {
sharp(fixtures.inputPngWithGreyAlpha)
.normalize()
.raw()
.toBuffer(function (err, data, info) {
if (err) throw err;
assertNormalized(data);
done();
});
});

it('stretches greyscale images with alpha channel', function (done) {
sharp(fixtures.inputPngWithGreyAlpha)
.normalize()
.raw()
.toBuffer(function (err, data, info) {
var min = 255, max = 0, i;
for (i = 0; i < data.length; i++) {
min = Math.min(min, data[i]);
max = Math.max(max, data[i]);
}
assert.strictEqual(0, min);
assert.strictEqual(255, max);
it('keeps an existing alpha channel', function(done) {
sharp(fixtures.inputPngWithTransparency)
.normalize()
.toBuffer(function (err, data) {
if (err) throw err;
sharp(data).metadata(function(err, metadata) {
if (err) return done(err);
assert.strictEqual(4, metadata.channels);
assert.strictEqual(true, metadata.hasAlpha);
assert.strictEqual('srgb', metadata.space);
done();
});
});
});
});

it('keeps an existing alpha channel', function (done) {
sharp(fixtures.inputPngWithTransparency)
.normalize()
.toBuffer(function (err, data) {
it('keeps the alpha channel of greyscale images intact', function(done) {
sharp(fixtures.inputPngWithGreyAlpha)
.normalize()
.toBuffer(function (err, data) {
if (err) throw err;
sharp(data).metadata(function(err, metadata) {
if (err) return done(err);
sharp(data).metadata(function(err, metadata) {
if (err) return done(err);
assert.strictEqual(4, metadata.channels);
assert.strictEqual(true, metadata.hasAlpha);
assert.strictEqual('srgb', metadata.space);
done();
});
assert.strictEqual(true, metadata.hasAlpha);
assert.strictEqual(4, metadata.channels);
assert.strictEqual('srgb', metadata.space);
done();
});
});
});
});

it('keeps the alpha channel of greyscale images intact', function (done) {
sharp(fixtures.inputPngWithGreyAlpha)
.normalize()
.toBuffer(function (err, data) {
if (err) return done(err);
sharp(data).metadata(function(err, metadata) {
if (err) return done(err);
assert.strictEqual(true, metadata.hasAlpha);
assert.strictEqual(4, metadata.channels);
assert.strictEqual('srgb', metadata.space);
done();
});
});
});
it('does not alter images with only one color', function(done) {
var output = fixtures.path('output.unmodified-png-with-one-color.png');
sharp(fixtures.inputPngWithOneColor)
.normalize()
.toFile(output, function(err, info) {
if (err) done(err);
fixtures.assertMaxColourDistance(output, fixtures.inputPngWithOneColor, 0);
done();
});
});

it('does not alter images with only one color', function (done) {
var output = fixtures.path('output.unmodified-png-with-one-color.png');
sharp(fixtures.inputPngWithOneColor)
.normalize()
.toFile(output, function(err, info) {
if (err) done(err);
fixtures.assertMaxColourDistance(output, fixtures.inputPngWithOneColor, 0);
done();
});
});
it('works with 16-bit RGBA images', function(done) {
sharp(fixtures.inputPngWithTransparency16bit)
.normalize()
.raw()
.toBuffer(function (err, data, info) {
if (err) throw err;
assertNormalized(data);
done();
});
});

}
});

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