Feature/rtl support

README.md

@@ -89,33 +89,43 @@ const topics = [
     }
 ]
 
-export default function TopicsScreen() {
-    const { topicContainer, topicText, title } = styles
+export default function App() {
+    const {
+        topicContainer,
+        topicText,
+        title,
+        container,
+        steveContainer
+    } = styles
 
     const renderTopic = ({ item }) => {
         const { emoji, text } = item
         return (
-            <View style={topicContainer} >
-                <Text >
+            <View style={topicContainer}>
+                <Text>
                     {emoji}
-                </Text >
-                <Text style={topicText} >
+                </Text>
+                <Text style={topicText}>
                     {text}
-                </Text >
-            </View >
+                </Text>
+            </View>
         )
     }
 
     return (
-        <View style={styles.container} >
-            <Text style={title} >
+        <View style={container}>
+            <Text style={title}>
                 {'TOPICS TO EXPLORE'}
-            </Text >
+            </Text>
             <Steve
+                isRTL={false}
                 data={topics}
+                itemSpacing={10}
                 renderItem={renderTopic}
-                keyExtractor={item => item.text} />
-        </View >
+                itemStyle={{ margin: 5 }}
+                containerStyle={steveContainer}
+                keyExtractor={item => item.text}/>
+        </View>
     )
 }
 
@@ -137,7 +147,6 @@ const styles = StyleSheet.create({
         justifyContent: 'center',
         alignItems: 'center',
         flexDirection: 'row',
-        margin: 5,
         backgroundColor: '#FFF'
     },
     topicText: {
@@ -151,7 +160,8 @@ const styles = StyleSheet.create({
         marginBottom: 5,
         marginLeft: 15,
         fontWeight: '600'
-    }
+    },
+    steveContainer: { marginHorizontal: 5 }
 })
 ```
 
@@ -162,7 +172,9 @@ const styles = StyleSheet.create({
 | data                | yes      |   Array      |  | An array of items to render
 | renderItem | yes | Function | | Function that returns a component with given item and index. It is similar to FlatList's renderItem prop  |
 |keyExtractor| yes | Function| | Function that returns an unique key for each item in the array. Notice that it is a must to provide a unique key since it's used to make calculations||
-|containerStyle|no|Style Object| | Style to use for root component | 
+|containerStyle|no|Style Object| | Style object for root component |
+|isRTL|no|boolean|false|Whether the component is RTL layout|
+|itemStyle|no|Style Object| |Style object for parent component of each child|
 
 ## Contributing
 

example/src/App.js

@@ -62,7 +62,13 @@ const topics = [
 ]
 
 export default function App() {
-    const { topicContainer, topicText, title } = styles
+    const {
+        topicContainer,
+        topicText,
+        title,
+        container,
+        steveContainer
+    } = styles
 
     const renderTopic = ({ item }) => {
         const { emoji, text } = item
@@ -79,13 +85,17 @@ export default function App() {
     }
 
     return (
-        <View style={styles.container}>
+        <View style={container}>
             <Text style={title}>
                 {'TOPICS TO EXPLORE'}
             </Text>
             <Steve
+                isRTL={false}
                 data={topics}
+                itemSpacing={10}
                 renderItem={renderTopic}
+                itemStyle={{ margin: 5 }}
+                containerStyle={steveContainer}
                 keyExtractor={item => item.text}/>
         </View>
     )
@@ -109,7 +119,6 @@ const styles = StyleSheet.create({
         justifyContent: 'center',
         alignItems: 'center',
         flexDirection: 'row',
-        margin: 5,
         backgroundColor: '#FFF'
     },
     topicText: {
@@ -123,5 +132,6 @@ const styles = StyleSheet.create({
         marginBottom: 5,
         marginLeft: 15,
         fontWeight: '600'
-    }
+    },
+    steveContainer: { marginHorizontal: 5 }
 })

index.d.ts

@@ -4,8 +4,10 @@ declare module 'react-native-steve' {
 	export interface SteveProps<T> {
 		data: T[],
 		renderItem: ({item, index}: {item: T, index: number}) => JSX.Element,
-		keyExtractor: (item: T) => string,
+		keyExtractor: (item: T, index: number) => string,
 		containerStyle?: ViewStyle,
+		isRTL?: boolean,
+		itemStyle?: ViewStyle
 	}
 	const Steve: <T extends {}>(props: SteveProps<T>) => JSX.Element;
 

src/Steve.js

@@ -2,22 +2,37 @@ import React, { useRef, useState } from 'react'
 import Animated, {
     useAnimatedGestureHandler,
     useSharedValue,
-    withDecay,
     withSpring,
     cancelAnimation,
-    useAnimatedStyle
+    useAnimatedStyle,
+    withDecay
 } from 'react-native-reanimated'
 import { Dimensions } from 'react-native'
 import { PanGestureHandler } from 'react-native-gesture-handler'
 
 const { width: screenWidth } = Dimensions.get('window')
-const containerPaddingHorizontal = 10
 
-export const Steve = ({ data, renderItem, keyExtractor, containerStyle }) => {
+const getContainerHorizontalSpacing = style => {
+    const {
+        margin = 0,
+        marginHorizontal = 0,
+        marginLeft = 0,
+        marginRight = 0,
+        padding = 0,
+        paddingHorizontal = 0,
+        paddingLeft = 0,
+        paddingRight = 0
+    } = style
+    return 2 * (margin + marginHorizontal + padding + paddingHorizontal)
+           + (marginLeft + marginRight + paddingLeft + paddingRight)
+}
+
+export const Steve = ({ data, renderItem, keyExtractor, containerStyle, isRTL, itemStyle }) => {
     const itemLayoutsCache = useRef({})
     const [itemLayouts, setItemLayouts] = useState({})
+    const containerHorizontalSpacing = getContainerHorizontalSpacing(containerStyle)
     const translateX = useSharedValue(0)
-    const paddingHorizontal = containerStyle?.paddingHorizontal || containerPaddingHorizontal
+    const rtlStyle = isRTL ? { flexDirection: 'row-reverse' } : {}
     const onGestureEvent = useAnimatedGestureHandler({
         onStart: (event, context) => {
             if (context.isDecayAnimationRunning) {
@@ -32,18 +47,21 @@ export const Steve = ({ data, renderItem, keyExtractor, containerStyle }) => {
             context.offset = translateX.value
             const { offset } = context
             const { velocityX } = event
-            const maxLevelDifference = screenWidth - Math.max(...Object.values(itemLayouts.sumWidthOfLayer))
+            const maximumLayerWidth = Math.max(...Object.values(itemLayouts.sumWidthOfLayer))
+            const levelDifference = screenWidth - maximumLayerWidth - containerHorizontalSpacing
             const leftBound = 0
-            const rightBound = maxLevelDifference - paddingHorizontal
+            const rightBound = isRTL ? -levelDifference : levelDifference
+            const firstCondition = isRTL ? (offset < leftBound) : (offset > leftBound)
+            const secondCondition = isRTL ? (offset > rightBound) : (offset < rightBound)
 
-            if (offset > leftBound) {
+            if (firstCondition) {
                 context.offset = leftBound
                 translateX.value = withSpring(leftBound, {
                     velocity: velocityX,
                     mass: 0.6,
                     stiffness: 90
                 })
-            } else if (offset < rightBound) {
+            } else if (secondCondition) {
                 context.offset = rightBound
                 translateX.value = withSpring(rightBound, {
                     velocity: velocityX,
@@ -52,10 +70,26 @@ export const Steve = ({ data, renderItem, keyExtractor, containerStyle }) => {
                 })
             } else {
                 context.isDecayAnimationRunning = true
+                let clamp
+
+                if (isRTL) {
+                    if (velocityX < 0) {
+                        clamp = [0, translateX.value]
+                    } else {
+                        clamp = [translateX.value, rightBound]
+                    }
+                } else {
+                    if (velocityX < 0) {
+                        clamp = [rightBound, translateX.value]
+                    } else {
+                        clamp = [translateX.value, 0]
+                    }
+                }
+
                 translateX.value = withDecay(
                     {
                         velocity: velocityX,
-                        clamp: velocityX < 0 ? [rightBound, translateX.value] : [translateX.value, 0]
+                        clamp
                     },
                     () => {
                         context.isDecayAnimationRunning = false
@@ -103,7 +137,7 @@ export const Steve = ({ data, renderItem, keyExtractor, containerStyle }) => {
 
         return (
             <Animated.View
-                {...{ style }}
+                style={[style, itemStyle]}
                 onLayout={event => handleItemLayout(event, itemKey)}>
                 {renderItem({ item, index })}
             </Animated.View>
@@ -121,9 +155,20 @@ export const Steve = ({ data, renderItem, keyExtractor, containerStyle }) => {
     }
 
     const finalizeLayoutSetUp = () => {
+        let spacingBetweenItems = 0
         itemLayoutsCache.current = Object
             .values(itemLayoutsCache.current)
-            .reduce((accumulator, current) => {
+            .reduce((accumulator, current, index) => {
+                if (index === 0) {
+                    const firstIndex = isRTL ? 1 : 0
+                    const secondIndex = isRTL ? 0 : 1
+                    const firstKey = keyExtractor(data[firstIndex], firstIndex)
+                    const secondKey = keyExtractor(data[secondIndex], secondIndex)
+                    const firstItem = itemLayoutsCache.current[firstKey]
+                    const secondItem = itemLayoutsCache.current[secondKey]
+                    spacingBetweenItems = secondItem.layout.x - firstItem.layout.width - firstItem.layout.x
+                }
+
                 if (!accumulator.sumWidthOfLayer) {
                     accumulator.sumWidthOfLayer = {}
                 }
@@ -132,13 +177,7 @@ export const Steve = ({ data, renderItem, keyExtractor, containerStyle }) => {
                     accumulator.sumWidthOfLayer[current.layout.y] = 0
                 }
 
-                const tempMax = accumulator.sumWidthOfLayer[current.layout.y]
-                const maybeMax = current.layout.x + current.layout.width
-
-                if (maybeMax > tempMax) {
-                    accumulator.sumWidthOfLayer[current.layout.y] = maybeMax
-                }
-
+                accumulator.sumWidthOfLayer[current.layout.y] += current.layout.width + spacingBetweenItems
                 return accumulator
             }, itemLayoutsCache.current)
         setItemLayouts(itemLayoutsCache.current)
@@ -159,9 +198,12 @@ const styles = {
     container: {
         flexWrap: 'wrap',
         flexDirection: 'row',
-        width: screenWidth * 1.8,
-        paddingHorizontal: containerPaddingHorizontal
+        width: screenWidth * 1.8
     }
 }
 
-Steve.displayName = 'Steve'
+Steve.displayName = 'Steve'
+Steve.defaultProps = {
+    containerStyle: {},
+    isRTL: false
+}