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Object Storage Service:画像輝度

最終更新日:Oct 08, 2024

brightパラメーターを指定すると、Object Storage Service (OSS) に保存されている画像の明るさを調整できます。 このトピックでは、画像の明るさを調整するために使用されるbrightパラメーターについて説明し、画像の明るさを調整する方法の例を示します。

パラメーター

アクション: 明るい

次の表に、brightパラメーターの有効な値を示します。

Format

説明

有効値

[値]

画像の明るさを調整する割合。

[-100, 100]

  • 0より小さい値は、画像の明るさを低下させる。

  • 0の値は、画像の明るさを変更しません。

  • 0より大きい値は、画像の明るさを増加させる。

方法

パブリック読み取りイメージまたはパブリック読み取り /書き込みイメージの明るさを調整する

このセクションでは、中国 (杭州) リージョンのoss-console-img-demo-cn-hangzhouバケットでexample.jpgという名前の画像の明るさを調整する方法の例を示します。 イメージは次のURLでホストされます。

プライベート画像の明るさを調整する

OSS SDKとOSS APIを使用して、プライベートイメージの明るさを調整できます。

OSS SDKの使用

次のサンプルコードは、一般的なプログラミング言語のOSS SDKを使用してプライベートイメージの明るさを調整する方法の例を示しています。 他のプログラミング言語を使用してプライベート画像の明るさを調整する方法の詳細については、「概要」をご参照ください。

Java

Java 3.17.4以降のOSS SDKが必要です。

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.GetObjectRequest;
import java.io.File;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Specify the region of the bucket in which the image is stored. Example: cn-hangzhou. 
        String region = "cn-hangzhou";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Do not include the bucket name in the full path. 
        String objectName = "example.jpg";
        // Specify the full path of the processed image. Example: D:\\dest.jpg. If an image that has the same name already exists in the path, the processed image overwrites the image. Otherwise, the processed image is saved in the path. 
        String pathName = "D:\\dest.jpg";

        // Create an OSSClient instance. 
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Increase the brightness of the image by 50 percent. 
            String image = "image/bright,50";
            GetObjectRequest request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(image);
            // Set the name of the processed image to dest.jpg and save it to your local computer. 
            // If you specify only the name of the processed image such as dest.jpg without specifying the local path, the processed image is saved to the local path of the project to which the sample program belongs. 
            ossClient.getObject(request, new File("D:\\dest.jpg"));
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

PHP

PHP 2.7.0以降のOSS SDKが必要です。

<?php
if (is_file(__DIR__ . '/../autoload.php')) {
    require_once __DIR__ . '/../autoload.php';
}
if (is_file(__DIR__ . '/../vendor/autoload.php')) {
    require_once __DIR__ . '/../vendor/autoload.php';
}
use OSS\Credentials\EnvironmentVariableCredentialsProvider;
use OSS\OssClient;

// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
$provider = new EnvironmentVariableCredentialsProvider();
// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
$endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Specify the name of the bucket. Example: examplebucket. 
$bucket= "examplebucket";
// Specify the full path of the object. Do not include the bucket name in the full path. 
$object = "example.jpg";
// Specify the full path of the processed image. Example: D:\\dest.jpg. If an image that has the same name already exists in the path, the processed image overwrites the image. Otherwise, the processed image is saved in the path. 
// If you specify only the name of the processed image such as dest.jpg without specifying the local path, the processed image is saved to the local path of the project to which the sample program belongs. 
$download_file = "D:\\dest.jpg";

$config = array(
        "provider" => $provider,
        "endpoint" => $endpoint,        
        "signatureVersion" => OssClient::OSS_SIGNATURE_VERSION_V4,
        // Specify the ID of the Alibaba Cloud region in which the bucket is located. 
        "region" => "cn-hangzhou"
    );
$ossClient = new OssClient($config);

// Increase the brightness of the image by 50 percent. 
$image = "image/bright,50";

$options = array(
    OssClient::OSS_FILE_DOWNLOAD => $download_file,
    OssClient::OSS_PROCESS => $image);

// Save the processed image to your local computer. 
$ossClient->getObject($bucket, $object, $options);                           

Python

Python 2.18.4以降のOSS SDKが必要です。

# -*- coding: utf-8 -*-
import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider

# Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
auth = oss2.ProviderAuthV4(EnvironmentVariableCredentialsProvider())
# Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
# Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
endpoint = 'https://oss-cn-hangzhou.aliyuncs.com'
# Specify the ID of the Alibaba Cloud region in which the bucket is located. 
region = 'cn-hangzhou'
bucket = oss2.Bucket(auth, endpoint, 'examplebucket', region=region)
# Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must include the full path of the image. Example: exampledir/src.gif. 
key = 'example.jpg'
# Specify the name of the processed image. 
new_pic = 'D:\\dest.jpg'

# Increase the brightness of the image by 50 percent. 
image = 'image/bright,50'
bucket.get_object_to_file(key, new_pic, process=image)

Go

Go 3.0.2以降のOSS SDKが必要です。

package main

import (
	"fmt"
	"os"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func HandleError(err error) {
	fmt.Println("Error:", err)
	os.Exit(-1)
}

func main() {
	// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}

	// Create an OSSClient instance. 
	// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint. 
	client, err := oss.New("https://oss-cn-hangzhou.aliyuncs.com", "", "", oss.SetCredentialsProvider(&provider), oss.AuthVersion(oss.AuthV4), oss.Region("cn-hangzhou"))
	if err != nil {
		HandleError(err)
	}

	// Specify the name of the bucket in which the source image is stored. Example: examplebucket. 
	bucketName := "examplebucket"
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		HandleError(err)
	}

	// Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must include the full path of the image. Example: exampledir/src.gif. 
	sourceImageName := "example.jpg"
	// Specify the name of the processed image. 
	targetImageName := "D://dest.jpg"
	// Increase the brightness of the image by 50 percent. 
	image := "image/bright,50"
	err = bucket.GetObjectToFile(sourceImageName, targetImageName, oss.Process(image))
	if err != nil {
		HandleError(err)
	}
}

OSS APIの使用

ビジネスで高度なカスタマイズが必要な場合は、RESTful APIを直接呼び出すことができます。 APIを直接呼び出すには、コードに署名計算を含める必要があります。 詳しくは、「GetObject」をご参照ください。

GetObject操作を呼び出して画像の明るさを調整するときに、brightパラメーターを指定できます。

GET /oss.jpg?x-oss-process=image/bright,50 HTTP/1.1
ホスト: oss-example.oss-cn-hangzhou.aliyuncs.com
日付: 10月28日金曜日2022 06:40:10 GMT
承認: OSS qn6q ****************: 77Dv **************************