From b97f65cb50ab6cad95e1fea2047b69536fa02d93 Mon Sep 17 00:00:00 2001
From: Pepijn Peeters <me@pepijnpeeters.nl>
Date: Mon, 5 Feb 2024 15:41:59 +0100
Subject: [PATCH] Added gaussianBlur to MagickImage.

---
 src/magick-image.ts                      | 34 ++++++++++++++++++++
 tests/magick-image/gaussian-blur.spec.ts | 40 ++++++++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 tests/magick-image/gaussian-blur.spec.ts

diff --git a/src/magick-image.ts b/src/magick-image.ts
index e04ef390..d1c777a5 100644
--- a/src/magick-image.ts
+++ b/src/magick-image.ts
@@ -938,6 +938,27 @@ export interface IMagickImage extends IDisposable {
      */
     flop(): void;
 
+    /**
+     * Gaussian blur image.
+     * @param radius - The number of neighbor pixels to be included in the convolution.
+     */
+    gaussianBlur(radius: number): void;
+
+    /**
+     * Gaussian blur image.
+     * @param radius - The number of neighbor pixels to be included in the convolution.
+     * @param sigma - The standard deviation of the gaussian bell curve.
+    */
+    gaussianBlur(radius: number, sigma: number): void;
+
+   /**
+    * Gaussian blur image.
+    * @param radius - The number of neighbor pixels to be included in the convolution.
+    * @param sigma - The standard deviation of the gaussian bell curve.
+    * @param sigma - The channel(s) to blur.
+    */
+    gaussianBlur(radius: number, sigma: number, channels: Channels): void;
+
     /**
      * Returns the value of the artifact with the specified name.
      * @param name - The name of the artifact.
@@ -2432,6 +2453,19 @@ export class MagickImage extends NativeInstance implements IMagickImage {
         });
     }
 
+    gaussianBlur(radius: number): void;
+    gaussianBlur(radius: number, sigma: number): void;
+    gaussianBlur(radius: number, sigma: number, channels: Channels): void;
+    gaussianBlur(radius: number, sigmaOrUndefined?: number, channelsOrUndefined?: Channels): void {
+        const sigma = this.valueOrDefault(sigmaOrUndefined, 1.0);
+        const channels = this.valueOrDefault(channelsOrUndefined, Channels.Undefined);
+
+        this.useException(exception => {
+            const instance = ImageMagick._api._MagickImage_GaussianBlur(this._instance, radius, sigma, channels, exception.ptr);
+            this._setInstance(instance, exception);
+        });
+    }
+
     getArtifact(name: string): string | null {
         return _withString(name, namePtr => {
             const value = ImageMagick._api._MagickImage_GetArtifact(this._instance, namePtr);
diff --git a/tests/magick-image/gaussian-blur.spec.ts b/tests/magick-image/gaussian-blur.spec.ts
new file mode 100644
index 00000000..5bd8b811
--- /dev/null
+++ b/tests/magick-image/gaussian-blur.spec.ts
@@ -0,0 +1,40 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/magick-wasm.
+// Licensed under the Apache License, Version 2.0.
+
+import { Channels } from '@src/enums/channels';
+import { ErrorMetric } from '@src/enums/error-metric';
+import { TestImages } from '@test/test-images';
+
+describe('MagickImage#gaussianBlur', () => {
+    it('should gaussian blur the image', () => {
+        TestImages.Builtin.wizard.use(image => {
+            image.clone(other => {
+                image.gaussianBlur(5.5, 10.2);
+                other.blur(5.5, 10.2);
+
+                const difference = other.compare(image, ErrorMetric.RootMeanSquared);
+                expect(difference).toBeCloseTo(0.000665, 6);
+            })
+        });
+    });
+
+    it('should use the correct default sigma', () => {
+        TestImages.Builtin.wizard.use(image => {
+            image.clone(other => {
+                image.gaussianBlur(4.2);
+                other.gaussianBlur(4.2, 1.0);
+
+                const difference = other.compare(image, ErrorMetric.RootMeanSquared);
+                expect(difference).toEqual(0);
+            });
+        });
+    });
+
+    it('should only blur the specified channels', () => {
+        TestImages.Builtin.wizard.use(image => {
+            image.gaussianBlur(4.2, 1, Channels.Green);
+
+            expect(image).toHavePixelWithColor(120, 200, '#185338ff');
+        });
+    });
+});