react-native/Libraries/Image/Image.ios.js

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule Image
 * @flow
 */
'use strict';

const EdgeInsetsPropType = require('EdgeInsetsPropType');
const ImageResizeMode = require('ImageResizeMode');
const ImageSourcePropType = require('ImageSourcePropType');
const ImageStylePropTypes = require('ImageStylePropTypes');
const NativeMethodsMixin = require('NativeMethodsMixin');
const NativeModules = require('NativeModules');
const React = require('React');
const PropTypes = require('prop-types');
const ReactNativeViewAttributes = require('ReactNativeViewAttributes');
const StyleSheet = require('StyleSheet');
const StyleSheetPropType = require('StyleSheetPropType');

const createReactClass = require('create-react-class');
const flattenStyle = require('flattenStyle');
const requireNativeComponent = require('requireNativeComponent');
const resolveAssetSource = require('resolveAssetSource');

const ImageViewManager = NativeModules.ImageViewManager;

/**
 * A React component for displaying different types of images,
 * including network images, static resources, temporary local images, and
 * images from local disk, such as the camera roll.
 *
 * This example shows fetching and displaying an image from local storage
 * as well as one from network and even from data provided in the `'data:'` uri scheme.
 *
 * > Note that for network and data images, you will need to manually specify the dimensions of your image!
 *
 * ```ReactNativeWebPlayer
 * import React, { Component } from 'react';
 * import { AppRegistry, View, Image } from 'react-native';
 *
 * export default class DisplayAnImage extends Component {
 *   render() {
 *     return (
 *       <View>
 *         <Image
 *           source={require('./img/favicon.png')}
 *         />
 *         <Image
 *           style={{width: 50, height: 50}}
 *           source={{uri: 'https://facebook.github.io/react/logo-og.png'}}
 *         />
 *         <Image
 *           style={{width: 66, height: 58}}
 *           source={{uri: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADMAAAAzCAYAAAA6oTAqAAAAEXRFWHRTb2Z0d2FyZQBwbmdjcnVzaEB1SfMAAABQSURBVGje7dSxCQBACARB+2/ab8BEeQNhFi6WSYzYLYudDQYGBgYGBgYGBgYGBgYGBgZmcvDqYGBgmhivGQYGBgYGBgYGBgYGBgYGBgbmQw+P/eMrC5UTVAAAAABJRU5ErkJggg=='}}
 *         />
 *       </View>
 *     );
 *   }
 * }
 *
 * // skip this line if using Create React Native App
 * AppRegistry.registerComponent('DisplayAnImage', () => DisplayAnImage);
 * ```
 *
 * You can also add `style` to an image:
 *
 * ```ReactNativeWebPlayer
 * import React, { Component } from 'react';
 * import { AppRegistry, View, Image, StyleSheet } from 'react-native';
 *
 * const styles = StyleSheet.create({
 *   stretch: {
 *     width: 50,
 *     height: 200
 *   }
 * });
 *
 * export default class DisplayAnImageWithStyle extends Component {
 *   render() {
 *     return (
 *       <View>
 *         <Image
 *           style={styles.stretch}
 *           source={require('./img/favicon.png')}
 *         />
 *       </View>
 *     );
 *   }
 * }
 *
 * // skip these lines if using Create React Native App
 * AppRegistry.registerComponent(
 *   'DisplayAnImageWithStyle',
 *   () => DisplayAnImageWithStyle
 * );
 * ```
 *
 * ### GIF and WebP support on Android
 *
 * When building your own native code, GIF and WebP are not supported by default on Android.
 *
 * You will need to add some optional modules in `android/app/build.gradle`, depending on the needs of your app.
 *
 * ```
 * dependencies {
 *   // If your app supports Android versions before Ice Cream Sandwich (API level 14)
 *   compile 'com.facebook.fresco:animated-base-support:1.3.0'
 *
 *   // For animated GIF support
 *   compile 'com.facebook.fresco:animated-gif:1.3.0'
 *
 *   // For WebP support, including animated WebP
 *   compile 'com.facebook.fresco:animated-webp:1.3.0'
 *   compile 'com.facebook.fresco:webpsupport:1.3.0'
 *
 *   // For WebP support, without animations
 *   compile 'com.facebook.fresco:webpsupport:1.3.0'
 * }
 * ```
 *
 * Also, if you use GIF with ProGuard, you will need to add this rule in `proguard-rules.pro` :
 * ```
 * -keep class com.facebook.imagepipeline.animated.factory.AnimatedFactoryImpl {
 *   public AnimatedFactoryImpl(com.facebook.imagepipeline.bitmaps.PlatformBitmapFactory, com.facebook.imagepipeline.core.ExecutorSupplier);
 * }
 * ```
 *
 */
const Image = createReactClass({
  displayName: 'Image',
  propTypes: {
    /**
     * > `ImageResizeMode` is an `Enum` for different image resizing modes, set via the
     * > `resizeMode` style property on `Image` components. The values are `contain`, `cover`,
     * > `stretch`, `center`, `repeat`.
     */
    style: StyleSheetPropType(ImageStylePropTypes),
    /**
     * The image source (either a remote URL or a local file resource).
     *
     * This prop can also contain several remote URLs, specified together with
     * their width and height and potentially with scale/other URI arguments.
     * The native side will then choose the best `uri` to display based on the
     * measured size of the image container. A `cache` property can be added to
     * control how networked request interacts with the local cache.
     *
     * The currently supported formats are `png`, `jpg`, `jpeg`, `bmp`, `gif`,
     * `webp` (Android only), `psd` (iOS only).
     */
    source: ImageSourcePropType,
    /**
     * A static image to display while loading the image source.
     *
     * - `uri` - a string representing the resource identifier for the image, which
     * should be either a local file path or the name of a static image resource
     * (which should be wrapped in the `require('./path/to/image.png')` function).
     * - `width`, `height` - can be specified if known at build time, in which case
     * these will be used to set the default `<Image/>` component dimensions.
     * - `scale` - used to indicate the scale factor of the image. Defaults to 1.0 if
     * unspecified, meaning that one image pixel equates to one display point / DIP.
     * - `number` - Opaque type returned by something like `require('./image.jpg')`.
     *
     * @platform ios
     */
    defaultSource: PropTypes.oneOfType([
      // TODO: Tooling to support documenting these directly and having them display in the docs.
      PropTypes.shape({
        uri: PropTypes.string,
        width: PropTypes.number,
        height: PropTypes.number,
        scale: PropTypes.number,
      }),
      PropTypes.number,
    ]),
    /**
     * When true, indicates the image is an accessibility element.
     * @platform ios
     */
    accessible: PropTypes.bool,
    /**
     * The text that's read by the screen reader when the user interacts with
     * the image.
     * @platform ios
     */
    accessibilityLabel: PropTypes.node,
    /**
    * blurRadius: the blur radius of the blur filter added to the image
    */
    blurRadius: PropTypes.number,
    /**
     * When the image is resized, the corners of the size specified
     * by `capInsets` will stay a fixed size, but the center content and borders
     * of the image will be stretched.  This is useful for creating resizable
     * rounded buttons, shadows, and other resizable assets.  More info in the
     * [official Apple documentation](https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIImage_Class/index.html#//apple_ref/occ/instm/UIImage/resizableImageWithCapInsets).
     *
     * @platform ios
     */
    capInsets: EdgeInsetsPropType,
    /**
     * The mechanism that should be used to resize the image when the image's dimensions
     * differ from the image view's dimensions. Defaults to `auto`.
     *
     * - `auto`: Use heuristics to pick between `resize` and `scale`.
     *
     * - `resize`: A software operation which changes the encoded image in memory before it
     * gets decoded. This should be used instead of `scale` when the image is much larger
     * than the view.
     *
     * - `scale`: The image gets drawn downscaled or upscaled. Compared to `resize`, `scale` is
     * faster (usually hardware accelerated) and produces higher quality images. This
     * should be used if the image is smaller than the view. It should also be used if the
     * image is slightly bigger than the view.
     *
     * More details about `resize` and `scale` can be found at http://frescolib.org/docs/resizing-rotating.html.
     *
     * @platform android
     */
    resizeMethod: PropTypes.oneOf(['auto', 'resize', 'scale']),
    /**
     * Determines how to resize the image when the frame doesn't match the raw
     * image dimensions.
     *
     * - `cover`: Scale the image uniformly (maintain the image's aspect ratio)
     * so that both dimensions (width and height) of the image will be equal
     * to or larger than the corresponding dimension of the view (minus padding).
     *
     * - `contain`: Scale the image uniformly (maintain the image's aspect ratio)
     * so that both dimensions (width and height) of the image will be equal to
     * or less than the corresponding dimension of the view (minus padding).
     *
     * - `stretch`: Scale width and height independently, This may change the
     * aspect ratio of the src.
     *
     * - `repeat`: Repeat the image to cover the frame of the view. The
     * image will keep it's size and aspect ratio. (iOS only)
     */
    resizeMode: PropTypes.oneOf(['cover', 'contain', 'stretch', 'repeat', 'center']),
    /**
     * A unique identifier for this element to be used in UI Automation
     * testing scripts.
     */
    testID: PropTypes.string,
    /**
     * Invoked on mount and layout changes with
     * `{nativeEvent: {layout: {x, y, width, height}}}`.
     */
    onLayout: PropTypes.func,
    /**
     * Invoked on load start.
     *
     * e.g., `onLoadStart={(e) => this.setState({loading: true})}`
     */
    onLoadStart: PropTypes.func,
    /**
     * Invoked on download progress with `{nativeEvent: {loaded, total}}`.
     * @platform ios
     */
    onProgress: PropTypes.func,
    /**
     * Invoked on load error with `{nativeEvent: {error}}`.
     */
    onError: PropTypes.func,
    /**
     * Invoked when a partial load of the image is complete. The definition of
     * what constitutes a "partial load" is loader specific though this is meant
     * for progressive JPEG loads.
     * @platform ios
     */
    onPartialLoad: PropTypes.func,
    /**
     * Invoked when load completes successfully.
     */
    onLoad: PropTypes.func,
    /**
     * Invoked when load either succeeds or fails.
     */
    onLoadEnd: PropTypes.func,
  },

  statics: {
    resizeMode: ImageResizeMode,
    /**
     * Retrieve the width and height (in pixels) of an image prior to displaying it.
     * This method can fail if the image cannot be found, or fails to download.
     *
     * In order to retrieve the image dimensions, the image may first need to be
     * loaded or downloaded, after which it will be cached. This means that in
     * principle you could use this method to preload images, however it is not
     * optimized for that purpose, and may in future be implemented in a way that
     * does not fully load/download the image data. A proper, supported way to
     * preload images will be provided as a separate API.
     *
     * Does not work for static image resources.
     *
     * @param uri The location of the image.
     * @param success The function that will be called if the image was successfully found and width
     * and height retrieved.
     * @param failure The function that will be called if there was an error, such as failing to
     * to retrieve the image.
     *
     * @returns void
     *
     * @platform ios
     */
    getSize: function(
      uri: string,
      success: (width: number, height: number) => void,
      failure?: (error: any) => void,
    ) {
      ImageViewManager.getSize(uri, success, failure || function() {
        console.warn('Failed to get size for image: ' + uri);
      });
    },
    /**
     * Prefetches a remote image for later use by downloading it to the disk
     * cache
     *
     * @param url The remote location of the image.
     *
     * @return The prefetched image.
     */
    prefetch(url: string) {
      return ImageViewManager.prefetchImage(url);
    },
    /**
     * Resolves an asset reference into an object which has the properties `uri`, `width`,
     * and `height`. The input may either be a number (opaque type returned by
     * require('./foo.png')) or an `ImageSource` like { uri: '<http location || file path>' }
     */
    resolveAssetSource: resolveAssetSource,
  },

  mixins: [NativeMethodsMixin],

  /**
   * `NativeMethodsMixin` will look for this when invoking `setNativeProps`. We
   * make `this` look like an actual native component class.
   */
  viewConfig: {
    uiViewClassName: 'UIView',
    validAttributes: ReactNativeViewAttributes.UIView
  },

  render: function() {
    const source = resolveAssetSource(this.props.source) || { uri: undefined, width: undefined, height: undefined };

    let sources;
    let style = flattenStyle([styles.base, this.props.style]) || {};
    if (Array.isArray(source)) {
      sources = source;
    } else {
      const {uri} = source;
      sources = [source];

      if (uri === '') {
        console.warn('source.uri should not be an empty string');
      }
    }

    const resizeMode = this.props.resizeMode || (style || {}).resizeMode || 'cover'; // Workaround for flow bug t7737108
    const tintColor = (style || {}).tintColor; // Workaround for flow bug t7737108

    if (this.props.src) {
      console.warn('The <Image> component requires a `source` property rather than `src`.');
    }

    if (this.props.children) {
      throw new Error('The <Image> component cannot contain children. If you want to render content on top of the image, consider using aboslute positioning.');
    }

    return (
      <RCTImageView
        {...this.props}
        style={style}
        resizeMode={resizeMode}
        tintColor={tintColor}
        source={sources}
      />
    );
  },
});

const styles = StyleSheet.create({
  base: {
    overflow: 'hidden',
  },
});

const RCTImageView = requireNativeComponent('RCTImageView', Image);

module.exports = Image;