feat: alwaysKeepResolution - keep the resolution during compression and reduce the quality only

options.alwaysKeepResolution (default: false) - keep the resolution (width and height) during
compression and reduce the quality only (note that options.maxWidthOrHeight is still applied if set)

re #127

Author: Donaldcwl

lib/image-compression.js

@@ -22,6 +22,7 @@ import {
  * @param {Function} [options.onProgress] - a function takes one progress argument (progress from 0 to 100)
  * @param {string} [options.fileType] - default to be the original mime type from the image file
  * @param {number} [options.initialQuality=1.0]
+ * @param {boolean} [options.alwaysKeepResolution=false]
  * @param {number} previousProgress - for internal try catch rerunning start from previous progress
  * @returns {Promise<File | Blob>}
  */
@@ -88,15 +89,17 @@ export default async function compress(file, options, previousProgress = 0) {
   const renderedSize = tempFile.size;
   let currentSize = renderedSize;
   let compressedFile;
-  let newCanvas; let
-    ctx;
+  let newCanvas;
+  let ctx;
   let canvas = orientationFixedCanvas;
+  const shouldReduceResolution = !options.alwaysKeepResolution && origExceedMaxSize;
   while (remainingTrials-- && (currentSize > maxSizeByte || currentSize > sourceSize)) {
-    const newWidth = origExceedMaxSize ? canvas.width * 0.95 : canvas.width;
-    const newHeight = origExceedMaxSize ? canvas.height * 0.95 : canvas.height;
+    const newWidth = shouldReduceResolution ? canvas.width * 0.95 : canvas.width;
+    const newHeight = shouldReduceResolution ? canvas.height * 0.95 : canvas.height;
     if (process.env.BUILD === 'development') {
       console.log('current width', newWidth);
       console.log('current height', newHeight);
+      console.log('current quality', quality);
     }
     [newCanvas, ctx] = getNewCanvasAndCtx(newWidth, newHeight);
 

lib/index.d.ts

@@ -19,6 +19,8 @@ interface Options {
     fileType?: string;
     /** @default 1.0 */
     initialQuality?: number;
+    /** @default false */
+    alwaysKeepResolution?: boolean;
 }
 
 declare function imageCompression(image: File, options: Options): Promise<File>;

lib/index.js

@@ -30,6 +30,8 @@ import compressOnWebWorker from './web-worker';
  * @param {number} [options.exifOrientation] - default to be the exif orientation from the image file
  * @param {Function} [options.onProgress] - a function takes one progress argument (progress from 0 to 100)
  * @param {string} [options.fileType] - default to be the original mime type from the image file
+ * @param {number} [options.initialQuality=1.0]
+ * @param {boolean} [options.alwaysKeepResolution=false]
  * @returns {Promise<File | Blob>}
  */
 async function imageCompression(file, options) {