feat: add options to mean, median and variance

src/compute/__tests__/mean.test.ts

@@ -1,3 +1,4 @@
+import { Point } from '../../geometry';
 import { mean } from '../mean';
 
 test('5x1 RGB image', () => {
@@ -65,3 +66,27 @@ test('mean from points in rgba image', () => {
 
   expect(result).toStrictEqual([1, 2, 3, 0]);
 });
+test('must throw if array is empty', () => {
+  const image = testUtils.createRgbaImage([
+    [1, 2, 3, 0],
+    [1, 2, 3, 0],
+  ]);
+  const points: Point[] = [];
+
+  expect(() => {
+    const result = image.mean({ points });
+    return result;
+  }).toThrow('Array of coordinates is empty.');
+});
+test("must throw if point's coordinates are invalid.", () => {
+  const image = testUtils.createRgbaImage([
+    [1, 2, 3, 0],
+    [1, 2, 3, 0],
+  ]);
+  const points: Point[] = [{ column: 0, row: 2 }];
+
+  expect(() => {
+    const result = image.mean({ points });
+    return result;
+  }).toThrow('Invalid coordinate: {column: 0, row: 2}');
+});

src/compute/__tests__/median.test.ts

@@ -1,3 +1,4 @@
+import { Point } from '../../geometry';
 import { median } from '../median';
 
 test('5x1 RGB image', () => {
@@ -54,6 +55,7 @@ test('median from points', () => {
 
   expect(result).toStrictEqual([2]);
 });
+
 test('median from points on rgba image', () => {
   const image = testUtils.createRgbaImage([
     [1, 2, 2, 2],
@@ -68,3 +70,27 @@ test('median from points on rgba image', () => {
 
   expect(result).toStrictEqual([1, 2, 2, 2]);
 });
+
+test('must throw if array is empty', () => {
+  const image = testUtils.createRgbaImage([
+    [1, 2, 2, 2],
+    [1, 2, 3, 2],
+  ]);
+  const points: Point[] = [];
+  expect(() => {
+    const result = image.median({ points });
+    return result;
+  }).toThrow('Array of coordinates is empty.');
+});
+
+test("must throw if point's coordinates are invalid", () => {
+  const image = testUtils.createRgbaImage([
+    [1, 2, 2, 2],
+    [1, 2, 3, 2],
+  ]);
+  const points: Point[] = [{ column: 0, row: 2 }];
+  expect(() => {
+    const result = image.median({ points });
+    return result;
+  }).toThrow('Invalid coordinate: {column: 0, row: 2}');
+});

src/compute/__tests__/variance.test.ts

@@ -1,3 +1,4 @@
+import { Point } from '../../geometry';
 import { variance } from '../variance';
 
 test('1x1 RGB image', () => {
@@ -34,3 +35,25 @@ test('variance from points', () => {
 
   expect(result).toStrictEqual([125]);
 });
+test('must throw if array is empty', () => {
+  const image = testUtils.createRgbaImage([
+    [1, 2, 2, 2],
+    [1, 2, 3, 2],
+  ]);
+  const points: Point[] = [];
+  expect(() => {
+    const result = image.median({ points });
+    return result;
+  }).toThrow('Array of coordinates is empty.');
+});
+test("must throw if point's coordinates are invalid", () => {
+  const image = testUtils.createGreyImage([
+    [1, 2, 2, 2],
+    [1, 2, 3, 2],
+  ]);
+  const points: Point[] = [{ column: 0, row: 2 }];
+  expect(() => {
+    const result = image.median({ points });
+    return result;
+  }).toThrow('Invalid coordinate: {column: 0, row: 2}');
+});

src/compute/mean.ts

@@ -18,11 +18,17 @@ export interface MeanOptions {
 export function mean(image: Image, options?: MeanOptions): number[] {
   const pixelSum = new Array<number>(image.channels).fill(0);
   const nbValues = options ? options.points.length : image.size;
-  if (nbValues === 0) throw new RangeError('Invalid number of points.');
+  if (nbValues === 0) throw new RangeError('Array of coordinates is empty.');
   if (options) {
     for (const point of options.points) {
+      const index = point.row * image.width + point.column;
       for (let channel = 0; channel < image.channels; channel++) {
-        pixelSum[channel] += image.getValueByPoint(point, channel);
+        if (index >= image.size || index < 0) {
+          throw new RangeError(
+            `Invalid coordinate: {column: ${point.column}, row: ${point.row}}.`,
+          );
+        }
+        pixelSum[channel] += image.getValueByIndex(index, channel);
       }
     }
   } else {

src/compute/median.ts

@@ -19,12 +19,19 @@ export interface MedianOptions {
 export function median(image: Image, options?: MedianOptions): number[] {
   const pixel = new Array<number>(image.channels).fill(0);
   if (options) {
+    //console.log(options.points.length);
     if (options.points.length === 0) {
-      throw new RangeError('Invalid number of points.');
+      throw new RangeError('Array of coordinates is empty.');
     }
     for (let i = 0; i < image.channels; i++) {
       const channel: number[] = [];
       for (const point of options.points) {
+        const index = point.row * image.width + point.column;
+        if (index < 0 || index >= image.size) {
+          throw new RangeError(
+            `Invalid coordinate: {column: ${point.column}, row: ${point.row}}.`,
+          );
+        }
         channel.push(image.getValueByPoint(point, i));
       }
       pixel[i] = quickMedian(channel);