feat: add experimental image orientation fix

packages/core/package.json

@@ -32,6 +32,7 @@
     "dev": "rollup -cw",
     "build": "rollup -c",
     "test": "vitest run",
+    "test:watch": "vitest watch",
     "coverage": "vitest run --coverage"
   },
   "devDependencies": {

packages/core/src/lib/apply-transforms.ts

@@ -1,11 +1,43 @@
 import type { Sharp } from 'sharp'
 import type { ApplyTransformsOptions, ImageTransformation, TransformResult } from '../types.js'
 import { METADATA } from './metadata.js'
+import sharp from 'sharp'
 
 const defaultOptions: ApplyTransformsOptions = {
   removeMetadata: true
 }
 
+async function applyPreTransformOrientation(
+  transforms: ImageTransformation[],
+  image: Sharp,
+  opts: ApplyTransformsOptions
+) {
+  if (!opts.experimental?.preserveInitialOrientation) return image
+
+  const initialOrientation = image[METADATA].orientation
+  if (!initialOrientation || initialOrientation === 1) return image
+
+  let tempImage = image.clone()
+  tempImage[METADATA] = { ...image[METADATA] }
+
+  for (const transform of transforms) {
+    tempImage = await transform(tempImage)
+  }
+
+  const willFlip = !!tempImage[METADATA].flip
+  const willFlop = !!tempImage[METADATA].flop
+  const willRotate = !!tempImage[METADATA].rotate
+
+  image.rotate() // no args -> do the exif orientation
+
+  if (willFlip || willFlop || willRotate) {
+    image = sharp(await image.toBuffer())
+    image[METADATA] = { ...image[METADATA] }
+  }
+
+  return image
+}
+
 export async function applyTransforms(
   transforms: ImageTransformation[],
   image: Sharp,
@@ -41,6 +73,8 @@ export async function applyTransforms(
     image.withMetadata()
   }
 
+  image = await applyPreTransformOrientation(transforms, image, opts)
+
   for (const transform of transforms) {
     image = await transform(image)
   }