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Shared Element Transition
with React Native
@narendra_shetty
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Narendra Shetty
Front-End Engineer @ Booking.com
Amsterdam
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What is Shared Element Transition?
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What is Transition?
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What is Transition?
Transition is an animation which
guides users to focus on what you want
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What is Transition?
Transition is an animation which
guides users to focus on what you want
Keep Users from getting lost
Transitions between different screens
involves enter and exit transitions
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What is Shared Element Transition?
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What is Shared Element Transition?
As the name suggest, there is a single element
being shared and moved from one screen to
another during transition
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What is Shared Element Transition?
As the name suggest, there is a single element
being shared and moved from one screen to
another during transition
This emphasizes continuity between
transitions and breaks screen boundaries as
the user navigates the app.
This forces the human eye to focus on
the content and its representation
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Few good examples
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Few good examples
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Does React Native support
shared elements?
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Does React Native support
shared elements?
NO! :(
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App
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App
Grid Detail
Text Image Text Image
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App
Grid Detail
Text Image Text Image
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App
Grid Detail
Text Image Text Image
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Goal
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Goal
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Goal
Pure JavaScript
Reasonably smooth animation
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Dissecting the animation
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Dissecting the animation
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Dissecting the animation
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Do you really believe that there is a single
image being shared between the grid and
detail screens?
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Do you really believe that there is a single
image being shared between the grid and
detail screens?
NO! :)
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Dissecting the animation
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Things to know
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Things to know
import { Animated } from 'react-native';
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Things to know
import { Animated } from 'react-native';
let AnimatedValue = new Animated.Value(0);
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Things to know
import { Animated } from 'react-native';
Animated.timing(AnimatedValue, {
toValue: 1,
duration: 3000
}).start();
let AnimatedValue = new Animated.Value(0);
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Things to know
import { Animated } from 'react-native';
let AnimatedValue = new Animated.Value(0);
Animated.timing(AnimatedValue, {
toValue: 1,
duration: 3000
}).start();
AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [1, 0]
});
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Implementation
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Grid Screen Detail Screen
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Without
Transition
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Adding Exit Transition
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Adding Exit Transition
{
opacity: 1
}
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Adding Exit Transition
{
opacity: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [1, 0]
})
}
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Adding Exit Transition
Animated.timing(AnimatedValue, {
toValue: 1,
duration: 3000,
}).start();
Trigger
{
opacity: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [1, 0]
})
}
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With exit transition
on Grid screen
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Adding Entry Transition
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{
transform: [{
translateY: 0
}]
}
Adding Entry Transition
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{
transform: [{
translateY: AnimatedValue.interpolate({
inputRange: [0, 0.5, 1],
outputRange: [100, 100, 0]
})
}]
}
Adding Entry Transition
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Adding Entry Transition
{
transform: [{
translateY: AnimatedValue.interpolate({
inputRange: [0, 0.5, 1],
outputRange: [100, 100, 0]
})
}]
}
Animated.timing(AnimatedValue, {
toValue: 1,
duration: 3000,
}).start();
Trigger
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With exit and entry transition
on grid and detail screen
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Adding Transition Layer
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Grid Screen Detail Screen
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Grid Screen Detail Screen
Transition Layer
x: 0
y: 600
width: 200
height: 112
x: 0
y: 0
width: 360
height: 300
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Grid Screen Detail Screen
Transition Layer
x: 0
y: 600
width: 200
height: 112
x: 0
y: 0
width: 360
height: 300
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Grid Screen Detail Screen
Transition Layer
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Animation in Transition Layer
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Animation in Transition Layer
By interpolating on
width, height, top and left
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{
position: 'absolute',
width: source.width,
height: source.height,
left: source.pageX,
top: source.pageY
}
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{
position: 'absolute',
width: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.width, destination.width]
})
}
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{
position: 'absolute',
width: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.width, destination.width]
}),
height: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.height, destination.height]
})
}
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{
position: 'absolute',
width: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.width, destination.width]
}),
height: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.height, destination.height]
}),
left: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.pageX, destination.pageX]
})
}
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{
position: 'absolute',
width: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.width, destination.width]
}),
height: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.height, destination.height]
}),
left: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.pageX, destination.pageX]
}),
top: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [source.pageY, destination.pageY]
})
}
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By interpolating on
width, height, top and left
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Performance Analysis
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Performance Analysis
Simulating a busy app
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Performance Analysis
Simulating a busy app
setInterval(() => {
for (let i = 0; i < 5e8; i++) {}
}, 1000);
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Simulating a busy app
setInterval(() => {
for (let i = 0; i < 5e8; i++) {}
}, 1000);
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JS thread Native thread
Click
Uses requestAnimationFrame
Generates new input value
Generates new output value
Passed as props to the View
View is updated using
setNativeProps
Passed to Native
over the bridge
Native View is updated
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useNativeDriver
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useNativeDriver
Animated.timing(AnimatedValue, {
toValue: 1,
duration: 3000
}).start();
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Animated.timing(AnimatedValue, {
toValue: 1,
duration: 3000,
useNativeDriver: true
}).start();
useNativeDriver
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JS thread Native thread
Uses Native Driver
Generates new input value
Generates new output value
Serializes animated
nodes
Native View is updated
Click
Passed to Native
over the bridge
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useNativeDriver
can only animate non-layout properties, things
like transform and opacity will work but flexbox
and position properties won't.
Disadvantage
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Animation in Transition Layer
By interpolating on
Transform and using useNativeDriver
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By interpolating on
Transform and using useNativeDriver
translateX
translateY
scale
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Grid Screen Detail Screen
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const sourceAspectRatio = source.width / source.height;
const destAspectRatio = dest.width / dest.height;
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const sourceAspectRatio = source.width / source.height;
const destAspectRatio = dest.width / dest.height;
if (sourceAspectRatio - destAspectRatio > 0) {
// Landscape image
} else {
// Portrait image
}
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if (sourceAspectRatio - destAspectRatio > 0) {
// Landscape image
const newWidth = sourceAspectRatio * dest.height;
} else {
// Portrait image
const newHeight = dest.width / sourceAspectRatio;
}
const sourceAspectRatio = source.width / source.height;
const destAspectRatio = dest.width / dest.height;
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No content
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const sourceAspectRatio = source.width / source.height;
const destAspectRatio = dest.width / dest.height;
if (sourceAspectRatio - destAspectRatio > 0) {
// Landscape image
} else {
// Portrait image
}
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if (sourceAspectRatio - destAspectRatio > 0) {
// Landscape image
dest.posX -= (newWidth - dest.width) / 2;
} else {
// Portrait image
dest.posY -= (newHeight - dest.height) / 2;
}
const sourceAspectRatio = source.width / source.height;
const destAspectRatio = dest.width / dest.height;
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No content
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No content
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const openingInitScale = source.width / newWidth;
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No content
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No content
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No content
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const translateInitX = source.posX + source.width / 2;
const translateInitY = source.posY + source.height / 2;
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const translateInitX = source.posX + source.width / 2;
const translateInitY = source.posY + source.height / 2;
const translateDestX = dest.posX + dest.width / 2;
const translateDestY = dest.posY + dest.height / 2;
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const translateInitX = source.posX + source.width / 2;
const translateInitY = source.posY + source.height / 2;
const translateDestX = dest.posX + dest.width / 2;
const translateDestY = dest.posY + dest.height / 2;
openingInitTranslateX = translateInitX - translateDestX;
openingInitTranslateY = translateInitY - translateDestY;
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{
position: 'absolute',
width: destination.width,
height: destination.height,
left: destination.posX,
top: destination.posY
}
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{
position: 'absolute',
width: destination.width,
height: destination.height,
left: destination.posX,
top: destination.posY,
transform: [
{
translateX: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [openingInitTranslateX, 0]
})
},
{
translateY: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [openingInitTranslateY, 0]
})
},
{
scale: AnimatedValue.interpolate({
inputRange: [0, 1],
outputRange: [openingInitScale, 1]
})
}
]
}
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By interpolating on
transform and using
useNativeDriver
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Performance Analysis
Simulating a busy app
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Performance Analysis
Simulating a busy app
setInterval(() => {
for (let i = 0; i < 5e8; i++) {}
}, 1000);
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Simulating a busy app
setInterval(() => {
for (let i = 0; i < 5e8; i++) {}
}, 1000);
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No content
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Hiding the source and destination image
during transition
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Hiding the source and destination image
during transition
{
opacity: AnimatedValue.interpolate({
inputRange: [0.005, 0.01],
outputRange: [1, 0]
})
}
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Hiding the source and destination image
during transition
{
opacity: AnimatedValue.interpolate({
inputRange: [0, 0.99, 0.995],
outputRange: [0, 0, 1]
})
}
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After hiding source and
destination image during
transition
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Handling back button
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Handling
Back button
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@narendrashetty
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@narendrashetty
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https://expo.io/@narendrashetty/
photo-gallery
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Narendra Shetty
@narendra_shetty
https://expo.io/@narendrashetty/photo-gallery