Merge pull request #108 from TonyBrobston/scale-image-by

Scale image by

README.md

@@ -41,6 +41,7 @@ module.exports = {
   * `maxWidth`: the max width in pixels of the compressed output File, defaults to `image's original width`.
   * `quality`: degrades quality of File, values is between `0.01` and `1.00`, defaults to `0.50`.
   * `returnOriginalOnFailure`: a boolean that determines if `jpegasus` should return the original `File` on failure or if it should throw and the let the consumer handle the failure, defaults to `true`.
+  * `scaleImageBy`: a decimal to scale up or down the image width and height by, defaults to `1.00`.
 
 ## Contributors
 Thanks goes to these wonderful people:

src/services/optionService.ts

@@ -5,6 +5,7 @@ const override = (inputOptions: Options): Options => {
         allowCrossOriginResourceSharing: false,
         quality: 0.5,
         returnOriginalOnFailure: true,
+        scaleImageBy: 1.00,
         ...inputOptions,
     };
 };

src/services/scaleService.ts

@@ -1,21 +1,20 @@
+import {Options} from '../types/Options';
 import canvasService from './canvasService';
 import imageService from './imageService';
 
-import {Options} from '../types/Options';
+const determineScale = ({height, width}: HTMLImageElement, {maxHeight, maxWidth, scaleImageBy}: Options): number => {
+    if (scaleImageBy) {
+        const scaledHeight = scaleImageBy * height;
+        const scaledWidth = scaleImageBy * width;
+        const heightIsGreaterThanWidth = height > width;
 
-const determineScale = (image: HTMLImageElement, options: Options): number => {
-    const height = image.height;
-    const width = image.width;
-    const maxHeight = options.maxHeight;
-    const maxWidth = options.maxWidth;
-    const heightCanBeScaled = maxHeight && height > maxHeight;
-    const heightIsLargest = height > width;
-    const widthCanBeScaled = maxWidth && width > maxWidth;
+        if (heightIsGreaterThanWidth && maxHeight && (scaledHeight > maxHeight)) {
+            return maxHeight / height;
+        } else if (maxWidth && (scaledWidth > maxWidth)) {
+            return maxWidth / width;
+        }
 
-    if (maxHeight && heightCanBeScaled && heightIsLargest) {
-        return maxHeight / height;
-    } else if (maxWidth && widthCanBeScaled) {
-        return maxWidth / width;
+        return scaleImageBy;
     }
 
     return 1.00;

src/types/Options.ts

@@ -4,4 +4,5 @@ export interface Options {
     maxHeight?: number;
     maxWidth?: number;
     returnOriginalOnFailure?: boolean;
+    scaleImageBy?: number;
 }

tests/index.test.ts

@@ -25,6 +25,7 @@ describe('index', () => {
             maxWidth: 1000,
             quality: 0.05,
             returnOriginalOnFailure: true,
+            scaleImageBy: 1.00,
         };
         const canvas = document.createElement('canvas');
         fileService.validate = jest.fn(() => true);

tests/services/optionService.test.ts

@@ -7,6 +7,7 @@ describe('optionService', () => {
                 allowCrossOriginResourceSharing: false,
                 quality: 0.5,
                 returnOriginalOnFailure: true,
+                scaleImageBy: 1.00,
             },
             inputOptions: {},
             name: 'should not override any inputOptions',
@@ -18,13 +19,15 @@ describe('optionService', () => {
                 maxWidth: 4,
                 quality: 0.75,
                 returnOriginalOnFailure: false,
+                scaleImageBy: 0.49,
             },
             inputOptions: {
                 allowCrossOriginResourceSharing: true,
                 maxHeight: 5,
                 maxWidth: 4,
                 quality: 0.75,
                 returnOriginalOnFailure: false,
+                scaleImageBy: 0.49,
             },
             name: 'should override all inputOptions',
         },
@@ -33,6 +36,7 @@ describe('optionService', () => {
                 allowCrossOriginResourceSharing: true,
                 quality: 0.5,
                 returnOriginalOnFailure: true,
+                scaleImageBy: 1.00,
             },
             inputOptions: {
                 allowCrossOriginResourceSharing: true,

tests/services/scaleService.test.ts

@@ -3,6 +3,7 @@ import {Chance} from 'chance';
 import canvasService from '../../src/services/canvasService';
 import imageService from '../../src/services/imageService';
 import scaleService from '../../src/services/scaleService';
+import {Options} from '../../src/types/Options';
 
 jest.mock('../../src/services/imageService');
 jest.mock('../../src/services/canvasService');
@@ -20,18 +21,31 @@ describe('scaleService', () => {
                 height: chance.natural(),
                 width: chance.natural(),
             },
-            inputOptions: {},
+            inputOptions: {
+            } as Options,
             name: 'no inputOptions',
             scale: 1.00,
         },
+        {
+            image: {
+                height: chance.natural(),
+                width: chance.natural(),
+            },
+            inputOptions: {
+                scaleImageBy: 1.00,
+            } as Options,
+            name: 'default scaleImageBy inputOptions',
+            scale: 1.00,
+        },
         {
             image: {
                 height: 4000,
                 width: 3000,
             },
             inputOptions: {
                 maxHeight: 1200,
-            },
+                scaleImageBy: 1.00,
+            } as Options,
             name: 'maxHeight scale',
             scale: 0.30,
         },
@@ -42,7 +56,8 @@ describe('scaleService', () => {
             },
             inputOptions: {
                 maxWidth: 1200,
-            },
+                scaleImageBy: 1.00,
+            } as Options,
             name: 'maxWidth scale',
             scale: 0.40,
         },
@@ -53,7 +68,8 @@ describe('scaleService', () => {
             },
             inputOptions: {
                 maxHeight: 1200,
-            },
+                scaleImageBy: 1.00,
+            } as Options,
             name: 'no scale, height < maxHeight',
             scale: 1.00,
         },
@@ -64,7 +80,8 @@ describe('scaleService', () => {
             },
             inputOptions: {
                 maxWidth: 1200,
-            },
+                scaleImageBy: 1.00,
+            } as Options,
             name: 'no scale, width < maxWidth',
             scale: 1.00,
         },
@@ -76,7 +93,8 @@ describe('scaleService', () => {
             inputOptions: {
                 maxHeight: 600,
                 maxWidth: 600,
-            },
+                scaleImageBy: 1.00,
+            } as Options,
             name: 'maxHeight scale, width < height',
             scale: 0.50,
         },
@@ -88,18 +106,79 @@ describe('scaleService', () => {
             inputOptions: {
                 maxHeight: 600,
                 maxWidth: 600,
-            },
+                scaleImageBy: 1.00,
+            } as Options,
             name: 'maxWidth scale, height < width',
             scale: 0.50,
         },
+        {
+            image: {
+                height: 400,
+                scaleImageBy: 1.00,
+                width: 400,
+            },
+            inputOptions: {
+                scaleImageBy: 0.5,
+            } as Options,
+            name: 'scale dimensions by',
+            scale: 0.5,
+        },
+        {
+            image: {
+                height: 1000,
+                width: 500,
+            },
+            inputOptions: {
+                maxHeight: 1200,
+                scaleImageBy: 2.00,
+            } as Options,
+            name: 'scale dimensions by, limit to maxHeight',
+            scale: 1.2,
+        },
+        {
+            image: {
+                height: 500,
+                width: 1000,
+            },
+            inputOptions: {
+                maxWidth: 1200,
+                scaleImageBy: 2.00,
+            } as Options,
+            name: 'scale dimensions by, limit to maxWidth',
+            scale: 1.2,
+        },
+        {
+            image: {
+                height: 400,
+                width: 400,
+            },
+            inputOptions: {
+                maxHeight: 900,
+                scaleImageBy: 0.5,
+            } as Options,
+            name: 'scale dimensions by, do not limit to maxHeight',
+            scale: 0.5,
+        },
+        {
+            image: {
+                height: 400,
+                width: 400,
+            },
+            inputOptions: {
+                maxWidth: 900,
+                scaleImageBy: 0.5,
+            } as Options,
+            name: 'scale dimensions by, do not limit to maxWidth',
+            scale: 0.5,
+        },
     ];
 
     scenarios.forEach((scenario: {
         image: {
             height: number,
             width: number,
         },
-        inputOptions: {},
+        inputOptions: Options,
         name: string,
         scale: number,
     }) => {