From e5ac256dc25e2afa7729fffb21162f300c3b7fca Mon Sep 17 00:00:00 2001
From: Brent Vatne <brentvatne@gmail.com>
Date: Wed, 31 Oct 2018 13:38:21 -0700
Subject: [PATCH] Add headerBackgroundTransitionPreset with 'toggle'
 'translate' and 'fade' options

---
 example/src/HeaderBackgrounds.js       | 14 ++------
 src/views/StackView/StackViewLayout.js | 44 ++++++++++++++++++++++++--
 2 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/example/src/HeaderBackgrounds.js b/example/src/HeaderBackgrounds.js
index 0d4ae22..5910d47 100644
--- a/example/src/HeaderBackgrounds.js
+++ b/example/src/HeaderBackgrounds.js
@@ -1,9 +1,6 @@
 import React, { Component } from 'react';
 import { StyleSheet, View, Text } from 'react-native';
-import {
-  createStackNavigator,
-  HeaderStyleInterpolator,
-} from 'react-navigation-stack';
+import { createStackNavigator } from 'react-navigation-stack';
 
 function createHeaderBackgroundExample(options = {}) {
   return createStackNavigator(
@@ -94,15 +91,10 @@ function createHeaderBackgroundExample(options = {}) {
 }
 export const HeaderBackgroundDefault = createHeaderBackgroundExample();
 export const HeaderBackgroundTranslate = createHeaderBackgroundExample({
-  transitionConfig: () => ({
-    headerBackgroundInterpolator:
-      HeaderStyleInterpolator.forBackgroundWithTranslation,
-  }),
+  headerBackgroundTransitionPreset: 'translate',
 });
 export const HeaderBackgroundFade = createHeaderBackgroundExample({
-  transitionConfig: () => ({
-    headerBackgroundInterpolator: HeaderStyleInterpolator.forBackgroundWithFade,
-  }),
+  headerBackgroundTransitionPreset: 'fade',
 });
 
 const styles = StyleSheet.create({
diff --git a/src/views/StackView/StackViewLayout.js b/src/views/StackView/StackViewLayout.js
index 63ce67e..b1f774f 100644
--- a/src/views/StackView/StackViewLayout.js
+++ b/src/views/StackView/StackViewLayout.js
@@ -21,6 +21,7 @@ import { PanGestureHandler, State } from 'react-native-gesture-handler';
 import Card from './StackViewCard';
 import Header from '../Header/Header';
 import TransitionConfigs from './StackViewTransitionConfigs';
+import HeaderStyleInterpolator from '../Header/HeaderStyleInterpolator';
 import StackGestureContext from '../../utils/StackGestureContext';
 import clamp from '../../utils/clamp';
 import { supportsImprovedSpringAnimation } from '../../utils/ReactNativeFeatures';
@@ -43,7 +44,12 @@ const EaseInOut = Easing.inOut(Easing.ease);
  * Enumerate possible values for validation
  */
 const HEADER_LAYOUT_PRESET_VALUES = ['center', 'left'];
-const HEADER_TRANSITION_PRESET_VALUES = ['uikit', 'fade-in-place'];
+const HEADER_TRANSITION_PRESET_VALUES = ['fade-in-place', 'uikit'];
+const HEADER_BACKGROUND_TRANSITION_PRESET_VALUES = [
+  'toggle',
+  'fade',
+  'translate',
+];
 
 /**
  * The max duration of the card animation in milliseconds after released gesture.
@@ -138,13 +144,18 @@ class StackViewLayout extends React.Component {
     // Handle the case where the header option is a function, and provide the default
     const renderHeader = header || (props => <Header {...props} />);
 
-    const {
+    let {
       headerLeftInterpolator,
       headerTitleInterpolator,
       headerRightInterpolator,
       headerBackgroundInterpolator,
     } = this._getTransitionConfig();
 
+    let backgroundTransitionPresetInterpolator = this._getHeaderBackgroundTransitionPreset();
+    if (backgroundTransitionPresetInterpolator) {
+      headerBackgroundInterpolator = backgroundTransitionPresetInterpolator;
+    }
+
     const { transitionProps, ...passProps } = this.props;
 
     return (
@@ -640,6 +651,35 @@ class StackViewLayout extends React.Component {
     return 'float';
   }
 
+  _getHeaderBackgroundTransitionPreset() {
+    const { headerBackgroundTransitionPreset } = this.props;
+    if (headerBackgroundTransitionPreset) {
+      if (
+        HEADER_BACKGROUND_TRANSITION_PRESET_VALUES.includes(
+          headerBackgroundTransitionPreset
+        )
+      ) {
+        if (headerBackgroundTransitionPreset === 'fade') {
+          return HeaderStyleInterpolator.forBackgroundWithFade;
+        } else if (headerBackgroundTransitionPreset === 'translate') {
+          return HeaderStyleInterpolator.forBackgroundWithTranslation;
+        } else if (headerBackgroundTransitionPreset === 'toggle') {
+          return HeaderStyleInterpolator.forBackgroundWithInactiveHidden;
+        }
+      } else {
+        if (__DEV__) {
+          console.error(
+            `Invalid configuration applied for headerBackgroundTransitionPreset - expected one of ${HEADER_BACKGROUND_TRANSITION_PRESET.join(
+              ', '
+            )} but received ${JSON.stringify(headerBackgroundTransitionPreset)}`
+          );
+        }
+      }
+    }
+
+    return null;
+  }
+
   _getHeaderLayoutPreset() {
     const { headerLayoutPreset } = this.props;
     if (headerLayoutPreset) {