Added toString to Density.

src/types/density.ts

@@ -57,4 +57,30 @@ export class Density {
      * Gets the units.
      */
     readonly units: DensityUnit;
+
+    /**
+     * Returns a string that represents the current {@link Density} object.
+     */
+    toString(units?: DensityUnit): string {
+        if (units == this.units || units === DensityUnit.Undefined || units === undefined)
+            return Density.toString(this.x, this.y, units ?? DensityUnit.Undefined);
+        else if (this.units == DensityUnit.PixelsPerCentimeter && units == DensityUnit.PixelsPerInch)
+            return Density.toString(this.x * 2.54, this.y * 2.54, units);
+        else
+            return Density.toString(this.x / 2.54, this.y / 2.54, units);
+    }
+
+    private static toString(x: number, y: number, units: DensityUnit): string {
+        let result = `${x}x${y}`;
+        switch (units) {
+            case DensityUnit.PixelsPerCentimeter:
+                result += 'cm';
+                break;
+            case DensityUnit.PixelsPerInch:
+                result += 'inch';
+                break;
+        }
+
+        return result;
+    }
 }

tests/types/density/to-string.spec.ts

@@ -0,0 +1,34 @@
+/*
+  Copyright Dirk Lemstra https://github.com/dlemstra/magick-wasm.
+  Licensed under the Apache License, Version 2.0.
+*/
+
+import { Density } from '@src/types/density';
+import { DensityUnit } from '@src/enums/density-unit';
+
+describe('Density#toString', () => {
+    it('should use undefined density units by default', () => {
+        const density = new Density(4, 2, DensityUnit.PixelsPerCentimeter);
+        expect(density.toString()).toBe('4x2');
+    });
+
+    it('should  add cm when density unit matches', () => {
+        const density = new Density(4, 2, DensityUnit.PixelsPerCentimeter);
+        expect(density.toString(DensityUnit.PixelsPerCentimeter)).toBe('4x2cm');
+    });
+
+    it('should add inch when density unit matches', () => {
+        const density = new Density(4, 2, DensityUnit.PixelsPerInch);
+        expect(density.toString(DensityUnit.PixelsPerInch)).toBe('4x2inch');
+    });
+
+    it('should convert cm to inch', () => {
+        const density = new Density(4, 2, DensityUnit.PixelsPerCentimeter);
+        expect(density.toString(DensityUnit.PixelsPerInch)).toBe('10.16x5.08inch');
+    });
+
+    it('should convert inch to cm', () => {
+        const density = new Density(4, 2, DensityUnit.PixelsPerInch);
+        expect(density.toString(DensityUnit.PixelsPerCentimeter)).toBe('1.574803149606299x0.7874015748031495cm');
+    });
+});