Expose libvips' median filter operation (#1161)

test/fixtures/index.js

@@ -69,6 +69,8 @@ module.exports = {
   inputJpgOverlayLayer2: getPath('alpha-layer-2-ink.jpg'),
   inputJpgTruncated: getPath('truncated.jpg'), // head -c 10000 2569067123_aca715a2ee_o.jpg > truncated.jpg
   inputJpgCenteredImage: getPath('centered_image.jpeg'),
+  inputJpgRandom: getPath('random.jpg'), // convert -size 200x200 xc:   +noise Random   random.jpg
+  inputJpgThRandom: getPath('thRandom.jpg'), // convert random.jpg  -channel G -threshold 5% -separate +channel -negate thRandom.jpg
 
   inputPng: getPath('50020484-00001.png'), // http://c.searspartsdirect.com/lis_png/PLDM/50020484-00001.png
   inputPngWithTransparency: getPath('blackbug.png'), // public domain

test/unit/median.js

@@ -0,0 +1,72 @@
+'use strict';
+
+const assert = require('assert');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+describe('Median filter', function () {
+  it('1x1 window', function (done) {
+    sharp(fixtures.inputJpgThRandom)
+      .median(1)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_1.jpg'), data, done);
+      });
+  });
+
+  it('3x3 window', function (done) {
+    sharp(fixtures.inputJpgThRandom)
+      .median(3)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_3.jpg'), data, done);
+      });
+  });
+  it('5x5 window', function (done) {
+    sharp(fixtures.inputJpgThRandom)
+      .median(5)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_5.jpg'), data, done);
+      });
+  });
+
+  it('color image', function (done) {
+    sharp(fixtures.inputJpgRandom)
+      .median(5)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_color.jpg'), data, done);
+      });
+  });
+
+  it('no windows size', function (done) {
+    sharp(fixtures.inputJpgThRandom)
+      .median()
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('jpeg', info.format);
+        assert.strictEqual(200, info.width);
+        assert.strictEqual(200, info.height);
+        fixtures.assertSimilar(fixtures.expected('median_3.jpg'), data, done);
+      });
+  });
+  it('invalid radius', function () {
+    assert.throws(function () {
+      sharp(fixtures.inputJpg).median(0.1);
+    });
+  });
+});