Watermark posts in screenshots (#9637)

* watermark posts in screenshots

* disable when app is backgrounded

* fix alignment

* show watermark even when there isn't a button

src/screens/PostThread/components/GrowthHack.tsx

@@ -0,0 +1,65 @@
+import {useState} from 'react'
+import {View} from 'react-native'
+import {PrivacySensitive} from 'expo-privacy-sensitive'
+
+import {useAppState} from '#/lib/hooks/useAppState'
+import {isIOS} from '#/platform/detection'
+import {atoms as a, useTheme} from '#/alf'
+import {sizes as iconSizes} from '#/components/icons/common'
+import {Mark as Logo} from '#/components/icons/Logo'
+
+const ICON_SIZE = 'xl' as const
+
+export function GrowthHack({
+  children,
+  align = 'right',
+}: {
+  children: React.ReactNode
+  align?: 'left' | 'right'
+}) {
+  const t = useTheme()
+
+  // the button has a variable width and is absolutely positioned, so we need to manually
+  // set the minimum width of the underlying button
+  const [width, setWidth] = useState<number | undefined>(undefined)
+
+  const appState = useAppState()
+
+  if (!isIOS || appState !== 'active') return children
+
+  return (
+    <View
+      style={[
+        a.relative,
+        a.justify_center,
+        align === 'right' ? a.align_end : a.align_start,
+        width === undefined ? {opacity: 0} : {minWidth: width},
+      ]}>
+      <PrivacySensitive
+        style={[
+          a.absolute,
+          a.z_10,
+          a.flex_col,
+          align === 'right'
+            ? [a.right_0, a.align_end]
+            : [a.left_0, a.align_start],
+          // when finding the size of the button, we need the containing
+          // element to have a concrete size otherwise the text will
+          // collapse to 0 width. so set it to a really big number
+          // and hide the entire thing (see above)
+          width === undefined && {width: 10000},
+        ]}>
+        <View
+          onLayout={evt => setWidth(evt.nativeEvent.layout.width)}
+          style={[
+            t.atoms.bg,
+            // make sure it covers the icon! the won't always be a button
+            {minWidth: iconSizes[ICON_SIZE], minHeight: iconSizes[ICON_SIZE]},
+          ]}>
+          {children}
+        </View>
+      </PrivacySensitive>
+      <Logo size={ICON_SIZE} />
+    </View>
+  )
+}

src/screens/PostThread/components/ThreadItemAnchor.tsx

@@ -381,7 +381,7 @@ const ThreadItemAnchorInner = memo(function ThreadItemAnchorInner({
             </View>
           </Link>
           {showFollowButton && (
-            <View collapsable={false}>
+            <View collapsable={false} style={[a.self_center]}>
               <ThreadItemAnchorFollowButton did={post.author.did} />
             </View>
           )}

src/screens/PostThread/components/ThreadItemAnchorFollowButton.tsx

@@ -5,6 +5,7 @@ import {useLingui} from '@lingui/react'
 import {useNavigation} from '@react-navigation/native'
 
 import {logger} from '#/logger'
+import {isIOS} from '#/platform/detection'
 import {useProfileShadow} from '#/state/cache/profile-shadow'
 import {
   useProfileFollowMutationQueue,
@@ -14,10 +15,23 @@ import {useRequireAuth} from '#/state/session'
 import * as Toast from '#/view/com/util/Toast'
 import {atoms as a, useBreakpoints} from '#/alf'
 import {Button, ButtonIcon, ButtonText} from '#/components/Button'
-import {Check_Stroke2_Corner0_Rounded as Check} from '#/components/icons/Check'
-import {PlusLarge_Stroke2_Corner0_Rounded as Plus} from '#/components/icons/Plus'
+import {Check_Stroke2_Corner0_Rounded as CheckIcon} from '#/components/icons/Check'
+import {PlusLarge_Stroke2_Corner0_Rounded as PlusIcon} from '#/components/icons/Plus'
+import {GrowthHack} from './GrowthHack'
 
 export function ThreadItemAnchorFollowButton({did}: {did: string}) {
+  if (isIOS) {
+    return (
+      <GrowthHack>
+        <ThreadItemAnchorFollowButtonInner did={did} />
+      </GrowthHack>
+    )
+  }
+
+  return <ThreadItemAnchorFollowButtonInner did={did} />
+}
+
+export function ThreadItemAnchorFollowButtonInner({did}: {did: string}) {
   const {data: profile, isLoading} = useProfileQuery({did})
 
   // We will never hit this - the profile will always be cached or loaded above
@@ -113,15 +127,10 @@ function PostThreadFollowBtnLoaded({
       label={_(msg`Follow ${profile.handle}`)}
       onPress={onPress}
       size="small"
-      variant="solid"
       color={isFollowing ? 'secondary' : 'secondary_inverted'}
       style={[a.rounded_full]}>
       {gtMobile && (
-        <ButtonIcon
-          icon={isFollowing ? Check : Plus}
-          position="left"
-          size="sm"
-        />
+        <ButtonIcon icon={isFollowing ? CheckIcon : PlusIcon} size="sm" />
       )}
       <ButtonText>
         {!isFollowing ? (