react-native/RNTester/js/ImageEditingExample.js

314 lines
8.0 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @format
* @flow
*/
'use strict';
var React = require('react');
var ReactNative = require('react-native');
var {
CameraRoll,
Image,
ImageEditor,
Platform,
ScrollView,
StyleSheet,
Text,
TouchableHighlight,
View,
} = ReactNative;
var PAGE_SIZE = 20;
type ImageOffset = {|
x: number,
y: number,
|};
type ImageSize = {|
width: number,
height: number,
|};
type ImageCropData = {|
offset: ImageOffset,
size: ImageSize,
displaySize?: ?ImageSize,
resizeMode?: ?any,
|};
class SquareImageCropper extends React.Component<
$FlowFixMeProps,
$FlowFixMeState,
> {
state: any;
_isMounted: boolean;
_transformData: ImageCropData;
constructor(props) {
super(props);
this._isMounted = true;
this.state = {
randomPhoto: null,
measuredSize: null,
croppedImageURI: null,
cropError: null,
};
this._fetchRandomPhoto();
}
async _fetchRandomPhoto() {
try {
const data = await CameraRoll.getPhotos({first: PAGE_SIZE});
if (!this._isMounted) {
return;
}
var edges = data.edges;
var edge = edges[Math.floor(Math.random() * edges.length)];
var randomPhoto = edge && edge.node && edge.node.image;
if (randomPhoto) {
this.setState({randomPhoto});
}
} catch (error) {
console.warn("Can't get a photo from camera roll", error);
}
}
componentWillUnmount() {
this._isMounted = false;
}
render() {
if (!this.state.measuredSize) {
return (
<View
style={styles.container}
onLayout={event => {
var measuredWidth = event.nativeEvent.layout.width;
if (!measuredWidth) {
return;
}
this.setState({
measuredSize: {width: measuredWidth, height: measuredWidth},
});
}}
/>
);
}
if (!this.state.croppedImageURI) {
return this._renderImageCropper();
}
return this._renderCroppedImage();
}
_renderImageCropper() {
if (!this.state.randomPhoto) {
return <View style={styles.container} />;
}
var error = null;
if (this.state.cropError) {
error = <Text>{this.state.cropError.message}</Text>;
}
return (
<View style={styles.container}>
<Text>Drag the image within the square to crop:</Text>
<ImageCropper
image={this.state.randomPhoto}
size={this.state.measuredSize}
style={[styles.imageCropper, this.state.measuredSize]}
onTransformDataChange={data => (this._transformData = data)}
/>
<TouchableHighlight
style={styles.cropButtonTouchable}
onPress={this._crop.bind(this)}>
<View style={styles.cropButton}>
<Text style={styles.cropButtonLabel}>Crop</Text>
</View>
</TouchableHighlight>
{error}
</View>
);
}
_renderCroppedImage() {
return (
<View style={styles.container}>
<Text>Here is the cropped image:</Text>
<Image
source={{uri: this.state.croppedImageURI}}
style={[styles.imageCropper, this.state.measuredSize]}
/>
<TouchableHighlight
style={styles.cropButtonTouchable}
onPress={this._reset.bind(this)}>
<View style={styles.cropButton}>
<Text style={styles.cropButtonLabel}>Try again</Text>
</View>
</TouchableHighlight>
</View>
);
}
_crop() {
ImageEditor.cropImage(
this.state.randomPhoto.uri,
this._transformData,
croppedImageURI => this.setState({croppedImageURI}),
cropError => this.setState({cropError}),
);
}
_reset() {
this.setState({
randomPhoto: null,
croppedImageURI: null,
cropError: null,
});
this._fetchRandomPhoto();
}
}
class ImageCropper extends React.Component<$FlowFixMeProps, $FlowFixMeState> {
_contentOffset: ImageOffset;
_maximumZoomScale: number;
_minimumZoomScale: number;
_scaledImageSize: ImageSize;
_horizontal: boolean;
componentWillMount() {
// Scale an image to the minimum size that is large enough to completely
// fill the crop box.
var widthRatio = this.props.image.width / this.props.size.width;
var heightRatio = this.props.image.height / this.props.size.height;
this._horizontal = widthRatio > heightRatio;
if (this._horizontal) {
this._scaledImageSize = {
width: this.props.image.width / heightRatio,
height: this.props.size.height,
};
} else {
this._scaledImageSize = {
width: this.props.size.width,
height: this.props.image.height / widthRatio,
};
if (Platform.OS === 'android') {
// hack to work around Android ScrollView a) not supporting zoom, and
// b) not supporting vertical scrolling when nested inside another
// vertical ScrollView (which it is, when displayed inside UIExplorer)
this._scaledImageSize.width *= 2;
this._scaledImageSize.height *= 2;
this._horizontal = true;
}
}
this._contentOffset = {
x: (this._scaledImageSize.width - this.props.size.width) / 2,
y: (this._scaledImageSize.height - this.props.size.height) / 2,
};
this._maximumZoomScale = Math.min(
this.props.image.width / this._scaledImageSize.width,
this.props.image.height / this._scaledImageSize.height,
);
this._minimumZoomScale = Math.max(
this.props.size.width / this._scaledImageSize.width,
this.props.size.height / this._scaledImageSize.height,
);
this._updateTransformData(
this._contentOffset,
this._scaledImageSize,
this.props.size,
);
}
_onScroll(event) {
this._updateTransformData(
event.nativeEvent.contentOffset,
event.nativeEvent.contentSize,
event.nativeEvent.layoutMeasurement,
);
}
_updateTransformData(offset, scaledImageSize, croppedImageSize) {
var offsetRatioX = offset.x / scaledImageSize.width;
var offsetRatioY = offset.y / scaledImageSize.height;
var sizeRatioX = croppedImageSize.width / scaledImageSize.width;
var sizeRatioY = croppedImageSize.height / scaledImageSize.height;
var cropData: ImageCropData = {
offset: {
x: this.props.image.width * offsetRatioX,
y: this.props.image.height * offsetRatioY,
},
size: {
width: this.props.image.width * sizeRatioX,
height: this.props.image.height * sizeRatioY,
},
};
this.props.onTransformDataChange &&
this.props.onTransformDataChange(cropData);
}
render() {
return (
<ScrollView
alwaysBounceVertical={true}
automaticallyAdjustContentInsets={false}
contentOffset={this._contentOffset}
decelerationRate="fast"
horizontal={this._horizontal}
maximumZoomScale={this._maximumZoomScale}
minimumZoomScale={this._minimumZoomScale}
onMomentumScrollEnd={this._onScroll.bind(this)}
onScrollEndDrag={this._onScroll.bind(this)}
showsHorizontalScrollIndicator={false}
showsVerticalScrollIndicator={false}
style={this.props.style}
scrollEventThrottle={16}>
<Image source={this.props.image} style={this._scaledImageSize} />
</ScrollView>
);
}
}
exports.framework = 'React';
exports.title = 'ImageEditor';
exports.description = 'Cropping and scaling with ImageEditor';
exports.examples = [
{
title: 'Image Cropping',
render() {
return <SquareImageCropper />;
},
},
];
var styles = StyleSheet.create({
container: {
flex: 1,
alignSelf: 'stretch',
},
imageCropper: {
alignSelf: 'center',
marginTop: 12,
},
cropButtonTouchable: {
alignSelf: 'center',
marginTop: 12,
},
cropButton: {
padding: 12,
backgroundColor: 'blue',
borderRadius: 4,
},
cropButtonLabel: {
color: 'white',
fontSize: 16,
fontWeight: '500',
},
});