fix: use a separate shadow view for the cards

packages/stack/src/TransitionConfigs/CardStyleInterpolators.tsx

@@ -21,7 +21,7 @@ export function forHorizontalIOS({
       })
     : 0;
 
-  const opacity = interpolate(current, {
+  const overlayOpacity = interpolate(current, {
     inputRange: [0, 1],
     outputRange: [0, 0.07],
   });
@@ -33,16 +33,15 @@ export function forHorizontalIOS({
 
   return {
     cardStyle: {
-      backgroundColor: '#eee',
       transform: [
         // Translation for the animation of the current card
         { translateX: translateFocused },
         // Translation for the animation of the card on top of this
         { translateX: translateUnfocused },
       ],
-      shadowOpacity,
     },
-    overlayStyle: { opacity },
+    overlayStyle: { opacity: overlayOpacity },
+    shadowStyle: { shadowOpacity },
   };
 }
 
@@ -60,7 +59,6 @@ export function forVerticalIOS({
 
   return {
     cardStyle: {
-      backgroundColor: '#eee',
       transform: [
         // Translation for the animation of the current card
         { translateY },

packages/stack/src/types.tsx

@@ -105,6 +105,8 @@ export type NavigationConfig = TransitionPreset & {
   mode: 'card' | 'modal';
   headerMode: HeaderMode;
   headerBackTitleVisible?: boolean;
+  cardShadowEnabled?: boolean;
+  cardOverlayEnabled?: boolean;
   transparentCard?: boolean;
 };
 
@@ -170,6 +172,7 @@ export type CardInterpolatedStyle = {
   containerStyle?: any;
   cardStyle?: any;
   overlayStyle?: any;
+  shadowStyle?: any;
 };
 
 export type CardStyleInterpolator = (

packages/stack/src/views/Stack/Card.tsx

@@ -23,6 +23,8 @@ type Props = ViewProps & {
   onGestureCanceled?: () => void;
   onGestureEnd?: () => void;
   children: React.ReactNode;
+  overlayEnabled: boolean;
+  shadowEnabled: boolean;
   gesturesEnabled: boolean;
   gestureResponseDistance?: {
     vertical?: number;
@@ -85,6 +87,8 @@ const {
 
 export default class Card extends React.Component<Props> {
   static defaultProps = {
+    overlayEnabled: true,
+    shadowEnabled: true,
     gesturesEnabled: true,
   };
 
@@ -414,6 +418,8 @@ export default class Card extends React.Component<Props> {
       current,
       next,
       direction,
+      overlayEnabled,
+      shadowEnabled,
       gesturesEnabled,
       children,
       styleInterpolator,
@@ -424,6 +430,7 @@ export default class Card extends React.Component<Props> {
       containerStyle,
       cardStyle,
       overlayStyle,
+      shadowStyle,
     } = this.getInterpolatedStyle(styleInterpolator, current, next, layout);
 
     const handleGestureEvent =
@@ -435,7 +442,7 @@ export default class Card extends React.Component<Props> {
       <StackGestureContext.Provider value={this.gestureRef}>
         <View pointerEvents="box-none" {...rest}>
           <Animated.Code exec={this.exec} />
-          {overlayStyle ? (
+          {overlayEnabled && overlayStyle ? (
             <Animated.View
               pointerEvents="none"
               style={[styles.overlay, overlayStyle]}
@@ -452,14 +459,21 @@ export default class Card extends React.Component<Props> {
               onHandlerStateChange={handleGestureEvent}
               {...this.gestureActivationCriteria()}
             >
-              <Animated.View
-                style={[
-                  styles.card,
-                  cardStyle,
-                  transparent ? styles.transparent : null,
-                ]}
-              >
-                {children}
+              <Animated.View style={[StyleSheet.absoluteFill, cardStyle]}>
+                {shadowEnabled && !transparent ? (
+                  <Animated.View
+                    style={[styles.shadow, shadowStyle]}
+                    pointerEvents="none"
+                  />
+                ) : null}
+                <View
+                  style={[
+                    StyleSheet.absoluteFill,
+                    transparent ? styles.transparent : styles.opaque,
+                  ]}
+                >
+                  {children}
+                </View>
               </Animated.View>
             </PanGestureHandler>
           </Animated.View>
@@ -474,20 +488,26 @@ const styles = StyleSheet.create({
     flex: 1,
     overflow: 'hidden',
   },
-  card: {
-    ...StyleSheet.absoluteFillObject,
-    shadowOffset: { width: -1, height: 1 },
-    shadowRadius: 5,
-    shadowColor: '#000',
-    backgroundColor: 'white',
-    elevation: 2,
-  },
   overlay: {
     ...StyleSheet.absoluteFillObject,
     backgroundColor: '#000',
   },
+  shadow: {
+    top: 0,
+    left: 0,
+    bottom: 0,
+    width: 3,
+    position: 'absolute',
+    backgroundColor: '#fff',
+    shadowOffset: { width: -1, height: 1 },
+    shadowRadius: 5,
+    shadowColor: '#000',
+    shadowOpacity: 1,
+  },
   transparent: {
     backgroundColor: 'transparent',
-    shadowOpacity: 0,
+  },
+  opaque: {
+    backgroundColor: '#eee',
   },
 });

packages/stack/src/views/Stack/Stack.tsx

@@ -35,6 +35,8 @@ type Props = {
   transparentCard?: boolean;
   headerMode: HeaderMode;
   direction: GestureDirection;
+  cardOverlayEnabled?: boolean;
+  cardShadowEnabled?: boolean;
   onTransitionStart?: (
     curr: { index: number },
     prev: { index: number }
@@ -159,6 +161,8 @@ export default class Stack extends React.Component<Props, State> {
     const {
       descriptors,
       navigation,
+      cardOverlayEnabled,
+      cardShadowEnabled,
       routes,
       closingRoutes,
       onOpenRoute,
@@ -205,6 +209,8 @@ export default class Stack extends React.Component<Props, State> {
                 closing={closingRoutes.includes(route.key)}
                 onOpen={() => onOpenRoute({ route })}
                 onClose={() => onCloseRoute({ route })}
+                overlayEnabled={cardOverlayEnabled}
+                shadowEnabled={cardShadowEnabled}
                 gesturesEnabled={getGesturesEnabled({ route })}
                 onTransitionStart={({ closing }) => {
                   onTransitionStart &&
@@ -244,6 +250,7 @@ export default class Stack extends React.Component<Props, State> {
                     scenes={[scenes[index - 1], scenes[index]]}
                     navigation={navigation}
                     styleInterpolator={headerStyleInterpolator}
+                    style={styles.header}
                   />
                 ) : null}
                 {renderScene({ route })}
@@ -259,7 +266,7 @@ export default class Stack extends React.Component<Props, State> {
             navigation={navigation}
             onLayout={this.handleFloatingHeaderLayout}
             styleInterpolator={headerStyleInterpolator}
-            style={styles.header}
+            style={[styles.header, styles.floating]}
           />
         ) : null}
       </React.Fragment>
@@ -273,6 +280,10 @@ const styles = StyleSheet.create({
     overflow: 'hidden',
   },
   header: {
+    // This is needed to show elevation shadow
+    zIndex: 1,
+  },
+  floating: {
     position: 'absolute',
     top: 0,
     left: 0,