Added gammaCorrect to MagickImage.

Author: Peeterush

src/magick-image.ts

@@ -961,6 +961,19 @@ export interface IMagickImage extends IDisposable {
      */
     flop(): void;
 
+    /**
+     * Gamma correct image.
+     * @param gamma - The image gamma.
+     */
+    gammaCorrect(gamma: number): void;
+
+    /**
+     * Gamma correct image.
+     * @param gamma - The image gamma for the channel.
+     * @param channels - The channel(s) to gamma correct.
+     */
+    gammaCorrect(gamma: number, channels: Channels): void;
+
     /**
      * Gaussian blur image.
      * @param radius - The number of neighbor pixels to be included in the convolution.
@@ -2488,6 +2501,19 @@ export class MagickImage extends NativeInstance implements IMagickImage {
         });
     }
 
+    gammaCorrect(gamma: number): void;
+    gammaCorrect(gamma: number, channels: Channels): void;
+    gammaCorrect(gamma: number, channelsOrUndefined?: Channels): void {
+        const channels = this.valueOrDefault(
+            channelsOrUndefined,
+            Channels.Undefined
+        );
+
+        this.useExceptionPointer((exception) => {
+            ImageMagick._api._MagickImage_GammaCorrect(this._instance, gamma, channels, exception);
+        });
+    }
+
     gaussianBlur(radius: number): void;
     gaussianBlur(radius: number, sigma: number): void;
     gaussianBlur(radius: number, sigma: number, channels: Channels): void;

tests/magick-image/gamma-correct.spec.ts

@@ -0,0 +1,30 @@
+// 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#gammaCorrect', () => {
+    it('should gamma correct the image', () => {
+        TestImages.Builtin.rose.use(image => {
+            image.clone(other => {
+                other.gammaCorrect(2);
+
+                const difference = image.compare(other, ErrorMetric.RootMeanSquared);
+                expect(difference).toBeCloseTo(0.21576);
+            });
+        });
+    });
+
+    it('should gamma correct the specified channels', () => {
+        TestImages.Builtin.rose.use(image => {
+            image.clone(other => {
+                other.gammaCorrect(2, Channels.Red);
+
+                const difference = image.compare(other, ErrorMetric.RootMeanSquared);
+                expect(difference).toBeCloseTo(0.10594);
+            });
+        });
+    });
+});