Add resolution downsizing to image compression

src/state/gallery.ts

@@ -204,20 +204,17 @@ export async function compressImage(
   img: ComposerImage,
   options?: {
     highResolution?: boolean
+    attempts?: number
+    maxDimension?: number
   },
 ): Promise<PickerImage> {
   const source = img.transformed || img.source
+  const highResolution = options?.highResolution ?? false
+  const attempts = options?.attempts || 0
+  const maxDimension =
+    options?.maxDimension || (highResolution ? 4000 : POST_IMG_MAX.width)
 
-  const [w, h] = containImageRes(
-    source.width,
-    source.height,
-    options?.highResolution
-      ? {
-          width: 4000,
-          height: 4000,
-        }
-      : POST_IMG_MAX,
-  )
+  const [w, h] = containImageRes(source.width, source.height, maxDimension)
 
   let minQualityPercentage = 0
   let maxQualityPercentage = 101 // exclusive
@@ -228,6 +225,15 @@ export async function compressImage(
       (maxQualityPercentage + minQualityPercentage) / 2,
     )
 
+    /*
+     * In the event the image doesn't compress well, we want to avoid
+     * unecessary iterations. In this case, binary search will check 51, 26,
+     * 13(rounded). We don't want to go below 25, hence the break here at 13,
+     * which will result in a subsequent attempt with a smaller maxDimension
+     * and reset qualityPercentage to 100.
+     */
+    if (qualityPercentage <= 13) break
+
     const res = await manipulateAsync(
       source.path,
       [{resize: {width: w, height: h}}],
@@ -258,6 +264,14 @@ export async function compressImage(
     return newDataUri
   }
 
+  if (attempts < 4) {
+    return compressImage(img, {
+      highResolution,
+      attempts: attempts + 1,
+      maxDimension: maxDimension * 0.8,
+    })
+  }
+
   throw new Error(`Unable to compress image`)
 }
 
@@ -366,12 +380,12 @@ function joinPath(a: string, b: string) {
 function containImageRes(
   w: number,
   h: number,
-  {width: maxW, height: maxH}: {width: number; height: number},
+  max: number,
 ): [width: number, height: number] {
   let scale = 1
 
-  if (w > maxW || h > maxH) {
-    scale = w > h ? maxW / w : maxH / h
+  if (w > max || h > max) {
+    scale = w > h ? max / w : max / h
     w = Math.floor(w * scale)
     h = Math.floor(h * scale)
   }