463 add pad function

src/filters/convolution.ts

@@ -4,8 +4,8 @@ import {
 } from 'ml-convolution';
 
 import { Image } from '../Image';
+import { extendBorders } from '../operations/extendBorders';
 import { getClamp } from '../utils/clamp';
-import { extendBorders } from '../utils/extendBorders';
 import { getIndex } from '../utils/getIndex';
 import { getOutputImage } from '../utils/getOutputImage';
 import { BorderType, getBorderInterpolation } from '../utils/interpolateBorder';

src/utils/__tests__/extendBorders.test.ts → src/operations/__tests__/extendBorders.test.ts

@@ -1,5 +1,28 @@
 import { extendBorders } from '../extendBorders';
 
+test('grey image with basic value', () => {
+  const image = testUtils.createGreyImage(`
+    1 2
+    3 4
+    5 6
+    7 8
+  `);
+
+  const newImage = extendBorders(image, {
+    horizontal: 1,
+    vertical: 1,
+    borderType: 'constant',
+  });
+  expect(newImage).toMatchImageData(` 
+    0 0 0 0
+    0 1 2 0 
+    0 3 4 0
+    0 5 6 0
+    0 7 8 0
+    0 0 0 0 
+  `);
+});
+
 test('grey image with wrap', () => {
   const image = testUtils.createGreyImage(`
     1 2 3 4
@@ -8,26 +31,24 @@ test('grey image with wrap', () => {
     4 5 6 7
     5 6 7 8
   `);
-
   const newImage = extendBorders(image, {
     horizontal: 2,
     vertical: 3,
     borderType: 'wrap',
   });
-
   expect(newImage).toMatchImageData(` 
-    5   6   3   4   5   6   3   4
-    6   7   4   5   6   7   4   5
-    7   8   5   6   7   8   5   6
-    3   4   1   2   3   4   1   2
-    4   5   2   3   4   5   2   3
-    5   6   3   4   5   6   3   4
-    6   7   4   5   6   7   4   5
-    7   8   5   6   7   8   5   6
-    3   4   1   2   3   4   1   2
-    4   5   2   3   4   5   2   3
-    5   6   3   4   5   6   3   4
-  `);
+  5   6   3   4   5   6   3   4
+  6   7   4   5   6   7   4   5
+  7   8   5   6   7   8   5   6
+  3   4   1   2   3   4   1   2
+  4   5   2   3   4   5   2   3
+  5   6   3   4   5   6   3   4
+  6   7   4   5   6   7   4   5
+  7   8   5   6   7   8   5   6
+  3   4   1   2   3   4   1   2
+  4   5   2   3   4   5   2   3
+  5   6   3   4   5   6   3   4
+`);
 });
 
 test('rgb image with default border type', () => {

src/utils/extendBorders.ts → src/operations/extendBorders.ts

@@ -1,11 +1,24 @@
 import { Image } from '../Image';
+import { BorderType, getBorderInterpolation } from '../utils/interpolateBorder';
 
-import { BorderType, getBorderInterpolation } from './interpolateBorder';
-
-interface ExtendBordersOptions {
+export interface ExtendBordersOptions {
+  /**
+   * Left and right border thickness.
+   */
   horizontal: number;
+  /**
+   *Top and bottom border thickness.
+   */
   vertical: number;
+  /**
+   * Specify how the borders should be handled.
+   * @default `'reflect101'`
+   */
   borderType?: BorderType;
+  /**
+   * Value of the border if BorderType is 'constant'.
+   * @default `0`
+   */
   borderValue?: number;
 }
 

src/operations/index.ts

@@ -13,3 +13,4 @@ export * from './operations.types';
 export * from './paintMaskOnImage';
 export * from './paintMaskOnMask';
 export * from './correctBackground';
+export * from './extendBorders';