Use parâmetros de corte indexado para fatiar uma imagem source armazenada no Object Storage Service (OSS) com base em um tamanho específico e recuperar a parte desejada. Este tópico descreve os parâmetros do corte indexado e fornece exemplos.
Parâmetros
Ação: indexcrop
A tabela a seguir descreve os parâmetros configuráveis para fatiar uma imagem.
|
Parâmetro |
Descrição |
Valor válido |
|
x |
Comprimento de cada partição da imagem durante o corte horizontal. Especifique apenas um dos parâmetros: x ou y. |
[1, largura da imagem] |
|
y |
Comprimento de cada partição da imagem durante o corte vertical. Especifique apenas um dos parâmetros: x ou y. |
[1, altura da imagem] |
|
i |
Partição da imagem a selecionar após o corte. |
[0, número máximo de partições) O valor padrão é 0, que indica a primeira partição. Para retornar a última partição, execute o corte indexado com base no tamanho da imagem e na faixa de valores do parâmetro. |
Observações de uso
Se o índice especificado exceder o número de partições, o sistema retornará a imagem source.
Caso x e y sejam especificados simultaneamente com valores válidos, o valor de y prevalecerá.
Métodos
Fatiar uma imagem de leitura pública ou leitura/gravação pública
Esta seção apresenta exemplos de como fatiar a imagem example.jpg no bucket oss-console-img-demo-cn-hangzhou, na região China (Hangzhou). A imagem está hospedada na seguinte URL:
https://oss-console-img-demo-cn-hangzhou.oss-cn-hangzhou.aliyuncs.com/example.jpg
-
Fatiar a imagem ao longo do eixo horizontal
Configure os seguintes parâmetros para fatiar a imagem:
Fatie a imagem em 100 pixels ao longo do eixo horizontal:
indexcrop,x_100Recupere a primeira partição:
i_0
A URL usada para processar a imagem é https://oss-console-img-demo-cn-hangzhou.oss-cn-hangzhou.aliyuncs.com/example.jpg?x-oss-process=image/indexcrop,x_100,i_0
. -
Fatiar a imagem ao longo do eixo vertical
Configure os seguintes parâmetros para fatiar a imagem:
Fatie a imagem em 100 pixels ao longo do eixo vertical:
indexcrop,y_100Selecione a 11ª partição:
i_10
A URL usada para processar a imagem é https://oss-console-img-demo-cn-hangzhou.oss-cn-hangzhou.aliyuncs.com/example.jpg?x-oss-process=image/indexcrop,y_100,i_10.
O sistema retorna a imagem source porque o número de partições após o corte é inferior a 10.

Fatiar uma imagem privada
Use os SDKs do OSS e a API do OSS para fatiar uma imagem privada.
Usar SDKs do OSS
Os exemplos de código a seguir mostram como fatiar uma imagem privada usando o SDK do OSS para linguagens de programação comuns. Para obter mais informações sobre como fatiar uma imagem privada com outras linguagens, consulte Visão geral.
Java
É necessário o OSS SDK for Java 3.17.4 ou posterior.
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 private 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.
// Call the shutdown method to release resources when the OSSClient is no longer in use.
ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
OSS ossClient = OSSClientBuilder.create()
.endpoint(endpoint)
.credentialsProvider(credentialsProvider)
.clientConfiguration(clientBuilderConfiguration)
.region(region)
.build();
try {
// Slice the image by 100 pixels along the horizontal axis and select the first partition.
String image = "image/indexcrop,x_100,i_0";
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
É necessário o OSS SDK for PHP 2.7.0 ou posterior.
<?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);
// Slice the image by 100 pixels along the horizontal axis and select the first partition.
$image = "image/indexcrop,x_100,i_0";
$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
É necessário o OSS SDK for Python 2.18.4 ou posterior.
# -*- 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'
// Slice the image by 100 pixels along the horizontal axis and select the first partition.
image = 'image/indexcrop,x_100,i_0'
bucket.get_object_to_file(key, new_pic, process=image)
Go
É necessário o OSS SDK for Go 3.0.2 ou posterior.
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"
// Slice the image by 100 pixels along the horizontal axis and select the first partition.
image := "image/indexcrop,x_100,i_0"
err = bucket.GetObjectToFile(sourceImageName, targetImageName, oss.Process(image))
if err != nil {
HandleError(err)
}
}
Usar a API RESTful
Se o seu cenário exigir alto nível de personalização, chame diretamente as APIs RESTful. Para chamar uma API diretamente, inclua o cálculo da assinatura no código. Para mais informações, consulte (Recomendado) Incluir uma assinatura V4.
Especifique os parâmetros de corte indexado ao chamar a operação GetObject para fatiar uma imagem.
GET /oss.jpg?x-oss-process=image/indexcrop,x_100,i_0 HTTP/1.1
Host: oss-example.oss-cn-hangzhou.aliyuncs.com
Date: Fri, 28 Oct 2022 06:40:10 GMT
Authorization: OSS4-HMAC-SHA256 Credential=LTAI********************/20250417/cn-hangzhou/oss/aliyun_v4_request,Signature=a7c3554c729d71929e0b84489addee6b2e8d5cb48595adfc51868c299c0c218e