Expose vips_text to create an image containing rendered text (#3252)

test/unit/text.js

@@ -0,0 +1,297 @@
+'use strict';
+
+const assert = require('assert');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+describe('Text to image', () => {
+  it('text with default values', async () => {
+    const output = fixtures.path('output.text-default.png');
+    const text = sharp({
+      text: {
+        text: 'Hello, world !'
+      }
+    });
+    const info = await text.png().toFile(output);
+    assert.strictEqual('png', info.format);
+    assert.strictEqual(3, info.channels);
+    assert.strictEqual(false, info.premultiplied);
+    assert.ok(info.width > 10);
+    assert.ok(info.height > 8);
+    const metadata = await sharp(output).metadata();
+    assert.strictEqual('uchar', metadata.depth);
+    assert.strictEqual('srgb', metadata.space);
+    assert.strictEqual(72, metadata.density);
+    const stats = await sharp(output).stats();
+    assert.strictEqual(0, stats.channels[0].min);
+    assert.strictEqual(255, stats.channels[0].max);
+    assert.strictEqual(0, stats.channels[1].min);
+    assert.strictEqual(255, stats.channels[1].max);
+    assert.strictEqual(0, stats.channels[2].min);
+    assert.strictEqual(255, stats.channels[2].max);
+    assert.ok(info.textAutofitDpi > 0);
+  });
+
+  it('text with width and height', function (done) {
+    const output = fixtures.path('output.text-width-height.png');
+    const maxWidth = 500;
+    const maxHeight = 500;
+    const text = sharp({
+      text: {
+        text: 'Hello, world!',
+        width: maxWidth,
+        height: maxHeight
+      }
+    });
+    text.toFile(output, function (err, info) {
+      if (err) throw err;
+      assert.strictEqual('png', info.format);
+      assert.strictEqual(3, info.channels);
+      assert.ok(info.width > 10 && info.width <= maxWidth);
+      assert.ok(info.height > 10 && info.height <= maxHeight);
+      assert.ok(Math.abs(info.width - maxWidth) < 50);
+      assert.ok(info.textAutofitDpi > 0);
+      done();
+    });
+  });
+
+  it('text with dpi', function (done) {
+    const output = fixtures.path('output.text-dpi.png');
+    const dpi = 300;
+    const text = sharp({
+      text: {
+        text: 'Hello, world!',
+        dpi: dpi
+      }
+    });
+    text.toFile(output, function (err, info) {
+      if (err) throw err;
+      assert.strictEqual('png', info.format);
+      sharp(output).metadata(function (err, metadata) {
+        if (err) throw err;
+        assert.strictEqual(dpi, metadata.density);
+        done();
+      });
+    });
+  });
+
+  it('text with color and pango markup', function (done) {
+    const output = fixtures.path('output.text-color-pango.png');
+    const dpi = 300;
+    const text = sharp({
+      text: {
+        text: '<span foreground="red" font="100">red</span><span font="50" background="cyan">blue</span>',
+        rgba: true,
+        dpi: dpi
+      }
+    });
+    text.toFile(output, function (err, info) {
+      if (err) throw err;
+      assert.strictEqual('png', info.format);
+      assert.strictEqual(4, info.channels);
+      sharp(output).metadata(function (err, metadata) {
+        if (err) throw err;
+        assert.strictEqual(dpi, metadata.density);
+        assert.strictEqual('uchar', metadata.depth);
+        assert.strictEqual(true, metadata.hasAlpha);
+        done();
+      });
+    });
+  });
+
+  it('text with font', function (done) {
+    const output = fixtures.path('output.text-with-font.png');
+    const text = sharp({
+      text: {
+        text: 'Hello, world!',
+        font: 'sans 100'
+      }
+    });
+    text.toFile(output, function (err, info) {
+      if (err) throw err;
+      assert.strictEqual('png', info.format);
+      assert.strictEqual(3, info.channels);
+      assert.ok(info.width > 30);
+      assert.ok(info.height > 10);
+      done();
+    });
+  });
+
+  it('text with justify and composite', done => {
+    const output = fixtures.path('output.text-composite.png');
+    const width = 500;
+    const dpi = 300;
+    const text = sharp(fixtures.inputJpg)
+      .resize(width)
+      .composite([{
+        input: {
+          text: {
+            text: '<span foreground="#ffff00">Watermark</span> <span foreground="white"><i>is cool</i></span>',
+            width: 300,
+            height: 300,
+            justify: true,
+            align: 'right',
+            spacing: 50,
+            rgba: true
+          }
+        },
+        gravity: 'northeast'
+      }, {
+        input: {
+          text: {
+            text: '<span background="cyan">cool</span>',
+            font: 'sans 30',
+            dpi: dpi,
+            rgba: true
+          }
+        },
+        left: 30,
+        top: 250
+      }]);
+    text.toFile(output, function (err, info) {
+      if (err) throw err;
+      assert.strictEqual('png', info.format);
+      assert.strictEqual(4, info.channels);
+      assert.strictEqual(width, info.width);
+      assert.strictEqual(true, info.premultiplied);
+      sharp(output).metadata(function (err, metadata) {
+        if (err) throw err;
+        assert.strictEqual('srgb', metadata.space);
+        assert.strictEqual('uchar', metadata.depth);
+        assert.strictEqual(true, metadata.hasAlpha);
+        done();
+      });
+    });
+  });
+
+  it('bad text input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+        }
+      });
+    });
+  });
+
+  it('fontfile input', function () {
+    // Added for code coverage
+    sharp({
+      text: {
+        text: 'text',
+        fontfile: 'UnknownFont.ttf'
+      }
+    });
+  });
+
+  it('bad font input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          font: 12
+        }
+      });
+    });
+  });
+
+  it('bad fontfile input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          fontfile: true
+        }
+      });
+    });
+  });
+
+  it('bad width input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          width: 'bad'
+        }
+      });
+    });
+  });
+
+  it('bad height input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          height: 'bad'
+        }
+      });
+    });
+  });
+
+  it('bad align input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          align: 'unknown'
+        }
+      });
+    });
+  });
+
+  it('bad justify input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          justify: 'unknown'
+        }
+      });
+    });
+  });
+
+  it('bad dpi input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          dpi: -10
+        }
+      });
+    });
+  });
+
+  it('bad rgba input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          rgba: -10
+        }
+      });
+    });
+  });
+
+  it('bad spacing input', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          spacing: 'number expected'
+        }
+      });
+    });
+  });
+
+  it('only height or dpi not both', function () {
+    assert.throws(function () {
+      sharp({
+        text: {
+          text: 'text',
+          height: 400,
+          dpi: 100
+        }
+      });
+    });
+  });
+});