Expose erode and dilate operations #4243

test/fixtures/index.js

@@ -128,6 +128,8 @@ module.exports = {
 
   inputJPGBig: getPath('flowers.jpeg'),
 
+  inputPngDotAndLines: getPath('dot-and-lines.png'),
+
   inputPngStripesV: getPath('stripesV.png'),
   inputPngStripesH: getPath('stripesH.png'),
 

test/types/sharp.test-d.ts

@@ -740,3 +740,8 @@ sharp([input, input], {
     valign: 'bottom'
   }
 });
+
+sharp().erode();
+sharp().erode(1);
+sharp().dilate();
+sharp().dilate(1);

test/unit/dilate.js

@@ -0,0 +1,38 @@
+'use strict';
+
+const assert = require('assert');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+describe('Dilate', function () {
+  it('dilate 1 png', function (done) {
+    sharp(fixtures.inputPngDotAndLines)
+      .dilate(1)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('png', info.format);
+        assert.strictEqual(100, info.width);
+        assert.strictEqual(100, info.height);
+        fixtures.assertSimilar(fixtures.expected('dilate-1.png'), data, done);
+      });
+  });
+
+  it('dilate 1 png - default width', function (done) {
+    sharp(fixtures.inputPngDotAndLines)
+      .dilate()
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('png', info.format);
+        assert.strictEqual(100, info.width);
+        assert.strictEqual(100, info.height);
+        fixtures.assertSimilar(fixtures.expected('dilate-1.png'), data, done);
+      });
+  });
+
+  it('invalid dilation width', function () {
+    assert.throws(function () {
+      sharp(fixtures.inputJpg).dilate(-1);
+    });
+  });
+});

test/unit/erode.js

@@ -0,0 +1,38 @@
+'use strict';
+
+const assert = require('assert');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+describe('Erode', function () {
+  it('erode 1 png', function (done) {
+    sharp(fixtures.inputPngDotAndLines)
+      .erode(1)
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('png', info.format);
+        assert.strictEqual(100, info.width);
+        assert.strictEqual(100, info.height);
+        fixtures.assertSimilar(fixtures.expected('erode-1.png'), data, done);
+      });
+  });
+
+  it('erode 1 png - default width', function (done) {
+    sharp(fixtures.inputPngDotAndLines)
+      .erode()
+      .toBuffer(function (err, data, info) {
+        if (err) throw err;
+        assert.strictEqual('png', info.format);
+        assert.strictEqual(100, info.width);
+        assert.strictEqual(100, info.height);
+        fixtures.assertSimilar(fixtures.expected('erode-1.png'), data, done);
+      });
+  });
+
+  it('invalid erosion width', function () {
+    assert.throws(function () {
+      sharp(fixtures.inputJpg).erode(-1);
+    });
+  });
+});