Add back ImageEditingExample example (facebook#19972)

Summary:
add back missing file.
pass all current ci.
none
 [GENERAL] [INTERNAL] [RNTester] - Add back ImageEditingExample example.
Closes facebook#19972

Differential Revision: D8711888

Pulled By: TheSavior

fbshipit-source-id: 14070bfbf747f7f59c4039981a9bc83c1c10862b

Author: gengjiawen

RNTester/js/ImageEditingExample.js

@@ -5,5 +5,306 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @format
- * @flow strict
+ * @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',
+  },
+});