Added textKerning to MagickSettings (#79).

src/settings/magick-settings.ts

@@ -39,6 +39,8 @@ export class MagickSettings {
 
     textInterlineSpacing?: number;
 
+    textKerning?: number;
+
     getDefine(name: string): string;
     getDefine(format: MagickFormat, name: string): string;
     getDefine(nameOrFormat: MagickFormat | string, name?: string): string {

src/settings/native-magick-settings.ts

@@ -64,6 +64,9 @@ export class NativeMagickSettings extends NativeInstance {
         if (settings.textInterlineSpacing !== undefined)
             this.setOption('interline-spacing', settings.textInterlineSpacing.toString());
 
+        if (settings.textKerning !== undefined)
+            this.setOption('kerning', settings.textKerning.toString());
+
         for (const option in settings._options)
             this.setOption(option, settings._options[option]);
     }

tests/settings/magick-settings/text-kerning.spec.ts

@@ -0,0 +1,25 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/magick-wasm.
+// Licensed under the Apache License, Version 2.0.
+
+import { ImageMagick } from '../../../src/image-magick';
+import { MagickReadSettings } from '../../../src/settings/magick-read-settings';
+import { TestFiles } from '../../test-files';
+import '../../custom-matcher';
+
+beforeAll(() => { ImageMagick._api = global.native; });
+
+describe('MagickSettings#textKerning', () => {
+    it.each([
+        [30, 373, 20],
+        [130, 1373, 20],
+    ])('should draw text with the expected kerning %s', (textKerning: number, width: number, height: number) => {
+        const settings = new MagickReadSettings();
+        settings.font = TestFiles.Fonts.kaushanScriptRegularTtf.name;
+        settings.textKerning = textKerning;
+
+        ImageMagick.read('label:magick-wasm', settings, (image) => {
+            expect(image.width).toBe(width);
+            expect(image.height).toBe(height);
+        });
+    });
+});