[Lightbox] Set 2 as minimal allowed zoom level (#6132)

* [Lightbox] Set 2 as minimal allowed zoom level on iOS

* Fix both Android and iOS

src/view/com/lightbox/ImageViewing/components/ImageItem/ImageItem.android.tsx

@@ -26,7 +26,7 @@ import {
   TransformMatrix,
 } from '../../transforms'
 
-const MIN_DOUBLE_TAP_SCALE = 2
+const MIN_SCREEN_ZOOM = 2
 const MAX_ORIGINAL_IMAGE_ZOOM = 2
 
 const initialTransform = createTransform()
@@ -166,8 +166,10 @@ const ImageItem = ({
       // Don't let the picture zoom in so close that it gets blurry.
       // Also, like in stock Android apps, don't let the user zoom out further than 1:1.
       const [, , committedScale] = readTransform(committedTransform.value)
-      const maxCommittedScale =
-        (imageDimensions.width / screenSize.width) * MAX_ORIGINAL_IMAGE_ZOOM
+      const maxCommittedScale = Math.max(
+        MIN_SCREEN_ZOOM,
+        (imageDimensions.width / screenSize.width) * MAX_ORIGINAL_IMAGE_ZOOM,
+      )
       const minPinchScale = 1 / committedScale
       const maxPinchScale = maxCommittedScale / committedScale
       const nextPinchScale = Math.min(
@@ -277,11 +279,13 @@ const ImageItem = ({
       const candidateScale = Math.max(
         imageAspect / screenAspect,
         screenAspect / imageAspect,
-        MIN_DOUBLE_TAP_SCALE,
+        MIN_SCREEN_ZOOM,
       )
       // But don't zoom in so close that the picture gets blurry.
-      const maxScale =
-        (imageDimensions.width / screenSize.width) * MAX_ORIGINAL_IMAGE_ZOOM
+      const maxScale = Math.max(
+        MIN_SCREEN_ZOOM,
+        (imageDimensions.width / screenSize.width) * MAX_ORIGINAL_IMAGE_ZOOM,
+      )
       const scale = Math.min(candidateScale, maxScale)
 
       // Calculate where we would be if the user pinched into the double tapped point.

src/view/com/lightbox/ImageViewing/components/ImageItem/ImageItem.ios.tsx

@@ -28,7 +28,7 @@ import {ImageSource} from '../../@types'
 const SWIPE_CLOSE_OFFSET = 75
 const SWIPE_CLOSE_VELOCITY = 1
 const MAX_ORIGINAL_IMAGE_ZOOM = 2
-const MIN_DOUBLE_TAP_SCALE = 2
+const MIN_SCREEN_ZOOM = 2
 
 type Props = {
   imageSrc: ImageSource
@@ -56,10 +56,13 @@ const ImageItem = ({
     src: imageSrc.uri,
     knownDimensions: imageSrc.dimensions,
   })
-  const maxZoomScale = imageDimensions
-    ? (imageDimensions.width / screenSizeDelayedForJSThreadOnly.width) *
-      MAX_ORIGINAL_IMAGE_ZOOM
-    : 1
+  const maxZoomScale = Math.max(
+    MIN_SCREEN_ZOOM,
+    imageDimensions
+      ? (imageDimensions.width / screenSizeDelayedForJSThreadOnly.width) *
+          MAX_ORIGINAL_IMAGE_ZOOM
+      : 1,
+  )
 
   const animatedStyle = useAnimatedStyle(() => {
     return {
@@ -218,7 +221,7 @@ const getZoomRectAfterDoubleTap = (
   const zoom = Math.max(
     imageAspect / screenAspect,
     screenAspect / imageAspect,
-    MIN_DOUBLE_TAP_SCALE,
+    MIN_SCREEN_ZOOM,
   )
   // Unlike in the Android version, we don't constrain the *max* zoom level here.
   // Instead, this is done in the ScrollView props so that it constraints pinch too.