Add drawable-interline-spacing (#104)

src/drawables/drawable-interline-spacing.ts

@@ -0,0 +1,17 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/magick-wasm.
+// Licensed under the Apache License, Version 2.0.
+
+import { IDrawable } from "./drawable";
+import { IDrawingWand } from "./drawing-wand";
+
+export class DrawableInterlineSpacing implements IDrawable {
+    private readonly _interlineSpacing: number;
+
+    constructor(interlineSpacing: number) {
+        this._interlineSpacing = interlineSpacing;
+    }
+
+    draw(wand: IDrawingWand): void {
+        wand.interlineSpacing(this._interlineSpacing);
+    }
+}

src/drawables/drawing-wand.ts

@@ -22,6 +22,7 @@ export interface IDrawingWand extends IDisposable {
     font(family: string): void;
     fontPointSize(value: number): void;
     gravity(value: Gravity): void;
+    interlineSpacing(value: number): void;
     kerning(value: number): void;
     rectangle(upperLeftX: number, upperLeftY: number, lowerRightX: number, lowerRightY: number): void;
     roundRectangle(upperLeftX: number, upperLeftY: number, lowerRightX: number, lowerRightY: number, cornerWidth: number, cornerHeight: number): void;
@@ -88,6 +89,12 @@ export class DrawingWand extends NativeInstance implements IDrawingWand {
         });
     }
 
+    interlineSpacing(value: number): void {
+        Exception.usePointer(exception => {
+            ImageMagick._api._DrawingWand_TextInterlineSpacing(this._instance, value, exception);
+        });
+    }
+
     kerning(value: number): void {
         Exception.usePointer(exception => {
             ImageMagick._api._DrawingWand_TextKerning(this._instance, value, exception);

src/index.ts

@@ -26,6 +26,7 @@ export * from './drawables/drawable-fill-opacity';
 export * from './drawables/drawable-font-point-size';
 export * from './drawables/drawable-font';
 export * from './drawables/drawable-gravity';
+export * from './drawables/drawable-interline-spacing';
 export * from './drawables/drawable-kerning';
 export * from './drawables/drawable-rectangle';
 export * from './drawables/drawable-round-rectangle';

tests/drawables/drawable-interline-spacing.spec.ts

@@ -0,0 +1,40 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/magick-wasm.
+// Licensed under the Apache License, Version 2.0.
+
+import { DrawableText } from "../../src/drawables/drawable-text";
+import { DrawableInterlineSpacing } from "../../src/drawables/drawable-interline-spacing";
+import { DrawableFillColor } from "../../src/drawables/drawable-fill-color";
+import { DrawableFont } from "../../src/drawables/drawable-font";
+import { DrawableFontPointSize } from "../../src/drawables/drawable-font-point-size";
+import { MagickColor } from "../../src/magick-color";
+import { TestFonts } from "../test-fonts";
+import { TestImages } from "../test-images";
+
+describe("DrawableInterlineSpacing", () => {
+    it("should write text with increased interline spacing", () => {
+        TestImages.emptyCanvas.use((image) => {
+            image.draw([
+                new DrawableFont(TestFonts.kaushanScriptRegularTtf.name),
+                new DrawableFontPointSize(50),
+                new DrawableInterlineSpacing(10),
+                new DrawableFillColor(new MagickColor("pink")),
+                new DrawableText(50, 50, "I\nI"),
+            ]);
+
+            expect(image).toHavePixelWithColor(60, 131, "#ffc0cbff");
+        });
+    });
+
+    it("should write text with default interline spacing", () => {
+        TestImages.emptyCanvas.use((image) => {
+            image.draw([
+                new DrawableFont(TestFonts.kaushanScriptRegularTtf.name),
+                new DrawableFontPointSize(50),
+                new DrawableFillColor(new MagickColor("pink")),
+                new DrawableText(50, 50, "I\nI"),
+            ]);
+
+            expect(image).toHavePixelWithColor(60, 131, "#ffffffff");
+        });
+    });
+});