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模板版本：v0.2.2

react-native-image-colors

Supported platforms License

[!TIP] Github 地址

安装与使用

请到三方库的 Releases 发布地址查看配套的版本信息：@react-native-oh-tpl/react-native-image-colors Releases 。对于未发布到npm的旧版本，请参考安装指南安装tgz包。

进入到工程目录并输入以下命令：

npm

npm install @react-native-oh-tpl/react-native-image-colors

yarn

yarn add @react-native-oh-tpl/react-native-image-colors

下面的代码展示了这个库的基本使用场景：

[!WARNING] 使用时 import 的库名不变。

import React, { useEffect, useState } from 'react'
import {
  Platform,
  StyleSheet,
  Text,
  View,
  Image,
  SafeAreaView,
  Button,
} from 'react-native'
import { getColors } from 'react-native-image-colors'

const imgCat = require('./assets/images/cat.jpg')
const yunaUrl = 'https://img0.baidu.com/it/u=1934875822,4119553331&fm=253&fmt=auto&app=138&f=JPEG?w=720&h=480'
const base = 'data:image/jpeg;base64...'

const initialState = {
  colorOne: { value: '', name: '' },
  colorTwo: { value: '', name: '' },
  colorThree: { value: '', name: '' },
  colorFour: { value: '', name: '' },
  rawResult: '',
}

export default function demo() {
  const [colors, setColors] = useState(initialState)
  const fetchColors = async () => {
    const result = await getColors(imgCat, {
      fallback: '#000000',
    })

    switch (result.platform) {
      case 'android':
      case 'web':
        setColors({
          colorOne: { value: result.lightVibrant, name: 'lightVibrant' },
          colorTwo: { value: result.dominant, name: 'dominant' },
          colorThree: { value: result.vibrant, name: 'vibrant' },
          colorFour: { value: result.darkVibrant, name: 'darkVibrant' },
          rawResult: JSON.stringify(result),
        })
        break
      case 'ios':
        setColors({
          colorOne: { value: result.background, name: 'background' },
          colorTwo: { value: result.detail, name: 'detail' },
          colorThree: { value: result.primary, name: 'primary' },
          colorFour: { value: result.secondary, name: 'secondary' },
          rawResult: JSON.stringify(result),
        })
        break
      case 'harmony':
        setColors({
          colorOne: { value: result.mainColor, name: 'mainColor' },
          colorTwo: { value: result.largestProportionColor, name: 'largestProportionColor' },
          colorThree: { value: result.highestSaturationColor, name: 'highestSaturationColor' },
          colorFour: { value: result.averageColor, name: 'averageColor' },
          rawResult: JSON.stringify(result),
        })
        break
      default:
        throw new Error('Unexpected platform')
    }
  }

  return (
    <View style={styles.container}>
      <SafeAreaView style={styles.resultContainer}>
        <Text style={styles.loading}>Result:</Text>
        <Button title='按钮' onPress={() => fetchColors() }></Button>
        <Text style={styles.result}>{colors.rawResult}</Text>
      </SafeAreaView>
      <Image
        resizeMode="contain"
        style={styles.image}
        source={ imgCat }
      />
      <View style={styles.row}>

        <Box name={colors.colorOne.name} value={colors.colorOne.value} />
        <Box name={colors.colorTwo.name} value={colors.colorTwo.value} />
      </View>
      <View style={styles.row}>
        <Box name={colors.colorThree.name} value={colors.colorThree.value} />
        <Box name={colors.colorFour.name} value={colors.colorFour.value} />
      </View>
    </View>
  )
}

interface BoxProps {
  value: string
  name: string
}

const Box = ({ value, name }: BoxProps) => {
  return (
    <View
      style={[
        styles.box,
        {
          backgroundColor: value,
        },
      ]}
    >
      <Text style={styles.colorName}>{name}</Text>
    </View>
  )
}

const styles = StyleSheet.create({
  image: {
    width: '100%',
    height: 250,
  },
  colorName: {
    backgroundColor: 'white',
    padding: 4,
    fontSize: 18,
  },
  box: {
    flex: 1,
    backgroundColor: 'red',
    justifyContent: 'center',
    alignItems: 'center',
  },
  row: {
    flex: 1,
    flexDirection: 'row',
    width: '100%',
  },
  resultContainer: {
    flex: 1,
    padding: 20,
    width: '100%'
  },
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  },
  loading: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  result: {
    textAlign: 'center',
    color: '#333333',
  },
})

使用 Codegen

本库已经适配了 Codegen ，在使用前需要主动执行生成三方库桥接代码，详细请参考 Codegen 使用文档。

Link

目前鸿蒙暂不支持 AutoLink，所以 Link 步骤需要手动配置。

首先需要使用 DevEco Studio 打开项目里的鸿蒙工程 harmony

1.在工程根目录的 oh-package.json5 添加 overrides 字段

{
  ...
  "overrides": {
    "@rnoh/react-native-openharmony" : "./react_native_openharmony"
  }
}

2.引入原生端代码

目前有两种方法：

  1. 通过 har 包引入（在 IDE 完善相关功能后该方法会被遗弃，目前首选此方法）；
  2. 直接链接源码。

方法一：通过 har 包引入（推荐）

[!TIP] har 包位于三方库安装路径的 harmony 文件夹下。

打开 entry/oh-package.json5，添加以下依赖

"dependencies": {
    "@rnoh/react-native-openharmony": "file:../react_native_openharmony",
    "@react-native-oh-tpl/react-native-image-colors": "file:../../node_modules/@react-native-oh-tpl/react-native-image-colors/harmony/image_colors.har"
  }

点击右上角的 sync 按钮

或者在终端执行：

cd entry
ohpm install

方法二：直接链接源码

[!TIP] 如需使用直接链接源码，请参考直接链接源码说明

3.在 ArkTs 侧引入 RNImageColorsPackage

打开 entry/src/main/ets/RNPackagesFactory.ts，添加：

  ...
+ import { RNImageColorsPackage } from "@react-native-oh-tpl/react-native-image-colors/ts";

export function createRNPackages(ctx: RNPackageContext): RNPackage[] {
  return [
    new SamplePackage(ctx),
+   new RNImageColorsPackage(ctx)
  ];
}

4.运行

点击右上角的 sync 按钮

或者在终端执行：

cd entry
ohpm install

然后编译、运行即可。

约束与限制

兼容性

要使用此库，需要使用正确的 React-Native 和 RNOH 版本。另外，还需要使用配套的 DevEco Studio 和 手机 ROM。

请到三方库相应的 Releases 发布地址查看 Release 配套的版本信息：@react-native-oh-tpl/react-native-image-colors Releases

API

ImageColors.getColors(uri: string, config?: Config): Promise

[!TIP] "Platform"列表示该属性在原三方库上支持的平台。

[!TIP] "HarmonyOS Support"列为 yes 表示 HarmonyOS 平台支持该属性；no 则表示不支持；partially 表示部分支持。使用方法跨平台一致，效果对标 iOS 或 Android 的效果。

Name Description Type Required Platform HarmonyOS Support
getColors Fetch prominent colors from an image. Function yes all yes

Uri

A string which can be:

Name Description Type Required Platform HarmonyOS Support
uri 1. URL: https://i.imgur.com/O3XSdU7.jpg;
2. Local file: const catImg = require('./images/cat.jpg');
3. Base64: const catImgBase64 = 'data:image/jpeg;base64,/9j/4Ri...'		 string yes all yes

The mime type prefix for base64 is required (e.g. data:image/png;base64).

Config

The config object is optional.

Name Description Type Required Default Supported HarmonyOS Support
fallback If a color property couldn't be retrieved, it will default to this hex color string string no "#000000" all yes
cache Enables in-memory caching of the result - skip downloading the same image next time. boolean no false all yes
key Unique key to use for the cache entry. The image URI is used as the unique key by default. You should explicitly pass a key if you enable caching and you're using a base64 string as the URI. string no undefined all yes
headers HTTP headers to be sent along with the GET request to download the image Record<string, string> no undefined iOS, Android yes
pixelSpacing How many pixels to skip when iterating over image pixels. Higher means better performance (note: value cannot be lower than 1). number no 5 Android no
quality Highest implies no downscaling and very good colors. 'lowest'
'low'
'high'
'highest'		 no 'low' iOS, Web no

ImageColorsResult

Every result object contains a respective platform key to help narrow down the type.

HarmonyImageColors

Name Description Type Required Platform HarmonyOS Support
mainColor The main colors of the image. string no harmonyOS yes
largestProportionColor The color with the highest proportion in the image. string no harmonyOS yes
highestSaturationColor The color with the highest saturation in the image. string no harmonyOS yes
averageColor The average color of the image. string no harmonyOS yes
platform The platform is HarmonyOS. string no all yes

ImageColors.cache

Name Description Type Required Params Platform HarmonyOS Support
getItem Read cache result. Function no key: string all yes
setItem Set a cached result. Function no key: string, value: ImageColorsResult all yes
removeItem Delete a cached result. Function no key: string all yes
clear Clearing the cache. Function no all yes

Notes

  • Since the implementation of each platform is different you can get different color results for each.
  • This module is a wrapper around the Palette class on Android, UIImageColors on iOS and node-vibrant for the web and @ohos.effectKit on harmonyOS.

遗留问题

  • harmonyOS获取颜色值暂时只能得到固定的一种颜色，暂不支持通过传入pixelSpacing或quality参数来计算获取不同精确度的颜色值。issue链接

其他

开源协议

本项目基于 The MIT License (MIT) ，请自由地享受和参与开源。