Image Processing (IMG) is an efficient, cost-effective, and highly reliable image processing service that is provided by Object Storage Service (OSS) to help you process images. After you upload source images to OSS, you can call RESTful API operations to process the images on a device that is connected to the Internet anytime, anywhere.
Usage notes
In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS from other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about OSS regions and endpoints, see Regions, endpoints and open ports.
In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient by using custom domain names or Security Token Service (STS), see Create an OSSClient instance.
Use IMG parameters to process images
Use a single IMG parameter to process an image
#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;
int main(void)
{
/* Initialize information about the account that is used to access OSS. */
/* 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. */
std::string Endpoint = "yourEndpoint";
/* Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. */
std::string Region = "yourRegion";
/* Specify the name of the bucket in which the source image is stored. Example: examplebucket. */
std::string BucketName = "examplebucket";
/* Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg. */
std::string ObjectName = "exampledir/example.jpg";
/* Initialize resources such as network resources. */
InitializeSdk();
ClientConfiguration conf;
conf.signatureVersion = SignatureVersionType::V4;
/* 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. */
auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
OssClient client(Endpoint, credentialsProvider, conf);
client.SetRegion(Region);
/* Resize the image to a height and width of 100 pixels and save the image to your local computer. */
std::string Process = "image/resize,m_fixed,w_100,h_100";
GetObjectRequest request(BucketName, ObjectName);
request.setProcess(Process);
auto outcome = client.GetObject(request);
if (outcome.isSuccess()) {
std::cout << "Image processed successfully." << std::endl;
} else {
std::cout << "Failed to process image. Error code: " << outcome.error().Code()
<< ", Message: " << outcome.error().Message()
<< ", RequestId: " << outcome.error().RequestId() << std::endl;
}
/* Release resources such as network resources. */
ShutdownSdk();
return 0;
}Use multiple IMG parameters to process an image
The following code provides an example on how to use multiple IMG parameters to process an image. IMG parameters are separated by forward slashes (/).
#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;
int main(void)
{
/* Initialize information about the account that is used to access OSS. */
/* 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. */
std::string Endpoint = "yourEndpoint";
/* Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. */
std::string Region = "yourRegion";
/* Specify the name of the bucket in which the source image is stored. Example: examplebucket. */
std::string BucketName = "examplebucket";
/* Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg. */
std::string ObjectName = "exampledir/example.jpg";
/* Initialize resources such as network resources. */
InitializeSdk();
ClientConfiguration conf;
conf.signatureVersion = SignatureVersionType::V4;
/* 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. */
auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
OssClient client(Endpoint, credentialsProvider, conf);
client.SetRegion(Region);
/* Resize the image to a height and width of 100 pixels, rotate the image 90 degrees, and save the image to your local computer. */
std::string Process = "image/resize,m_fixed,w_100,h_100/rotate,90";
GetObjectRequest request(BucketName, ObjectName);
request.setProcess(Process);
auto outcome = client.GetObject(request);
if (outcome.isSuccess()) {
std::cout << "Image processed successfully." << std::endl;
} else {
std::cout << "Failed to process image. Error code: " << outcome.error().Code()
<< ", Message: " << outcome.error().Message()
<< ", RequestId: " << outcome.error().RequestId() << std::endl;
}
/* Release resources such as network resources. */
ShutdownSdk();
return 0;
}Use an image style to process images
Create an image style.
You can add multiple IMG parameters to an image style to perform complex operations on images that are stored in a bucket. For more information, see Image styles.
Use the image style to process the image.
#include <alibabacloud/oss/OssClient.h> using namespace AlibabaCloud::OSS; int main(void) { /* Initialize information about the account that is used to access OSS. */ /* 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. */ std::string Endpoint = "yourEndpoint"; /* Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. */ std::string Region = "yourRegion"; /* Specify the name of the bucket in which the source image is stored. Example: examplebucket. */ std::string BucketName = "examplebucket"; /* Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg. */ std::string ObjectName = "exampledir/example.jpg"; /* Initialize resources such as network resources. */ InitializeSdk(); ClientConfiguration conf; conf.signatureVersion = SignatureVersionType::V4; /* 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. */ auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>(); OssClient client(Endpoint, credentialsProvider, conf); client.SetRegion(Region); /* Use the image style to process the image. Replace yourCustomStyleName with the name of the image style that you created in Step 1. */ std::string Process = "style/yourCustomStyleName"; GetObjectRequest request(BucketName, ObjectName); request.setProcess(Process); auto outcome = client.GetObject(request); if (outcome.isSuccess()) { std::cout << "Image processed successfully." << std::endl; } else { std::cout << "Failed to process image. Error code: " << outcome.error().Code() << ", Message: " << outcome.error().Message() << ", RequestId: " << outcome.error().RequestId() << std::endl; } /* Release resources such as network resources. */ ShutdownSdk(); return 0; }
Save processed images
You can call the ImgSaveAs operation to save the processed images to the bucket in which the source images are stored. The following code provides an example on how to save a processed image:
#include <alibabacloud/oss/OssClient.h>
#include <sstream>
using namespace AlibabaCloud::OSS;
int main(void)
{
/* Initialize information about the account that is used to access OSS. */
/* 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. */
std::string Endpoint = "yourEndpoint";
/* Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. */
std::string Region = "yourRegion";
/* Specify the name of the bucket. Example: examplebucket. */
std::string BucketName = "examplebucket";
/* Specify the name of the source image. If the image is not stored in the root directory of the bucket, precede the image name with the path to the image. Example: example/example.jpg. */
std::string SourceObjectName = "example/example.jpg";
/* Specify the name of the processed image. If the image is not stored in the root directory of the bucket, precede the image name with the path to the image. Example: exampledir/example.jpg. */
std::string TargetObjectName = "exampledir/example.jpg";
/* Initialize resources such as network resources. */
InitializeSdk();
ClientConfiguration conf;
conf.signatureVersion = SignatureVersionType::V4;
/* 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. */
auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
OssClient client(Endpoint, credentialsProvider, conf);
client.SetRegion(Region);
/* Resize the image to a height and width of 100 pixels and save the image to the bucket in which the source image is stored. */
std::string Process = "image/resize,m_fixed,w_100,h_100";
std::stringstream ss;
ss << Process
<<"|sys/saveas"
<< ",o_" << Base64EncodeUrlSafe(TargetObjectName)
<< ",b_" << Base64EncodeUrlSafe(BucketName);
ProcessObjectRequest request(BucketName, SourceObjectName, ss.str());
auto outcome = client.ProcessObject(request);
if (outcome.isSuccess()) {
std::cout << "Image processed successfully." << std::endl;
} else {
std::cout << "Failed to process image. Error code: " << outcome.error().Code()
<< ", Message: " << outcome.error().Message()
<< ", RequestId: " << outcome.error().RequestId() << std::endl;
}
/* Release resources such as network resources. */
ShutdownSdk();
return 0;
}Generate a signed object URL that includes IMG parameters
URLs of private objects must be signed. IMG parameters cannot be added to the end of a signed URL. If you want to process a private object, add IMG parameters to the signature. Sample code:
#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;
int main(void)
{
/* Initialize information about the account that is used to access OSS. */
/* 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. */
std::string Endpoint = "yourEndpoint";
/* Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. */
std::string Region = "yourRegion";
/* Specify the name of the bucket in which the image is located. Example: examplebucket. */
std::string BucketName = "examplebucket";
/* Specify the name of the image. If the image is not stored in the root directory of the bucket, precede the image name with the path to the image. Example: exampledir/example.jpg. */
std::string ObjectName = "exampledir/example.jpg";
/* Initialize resources such as network resources. */
InitializeSdk();
ClientConfiguration conf;
conf.signatureVersion = SignatureVersionType::V4;
/* 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. */
auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
OssClient client(Endpoint, credentialsProvider, conf);
client.SetRegion(Region);
/* Generate a signed URL that includes IMG parameters for the object. */
std::string Process = "image/resize,m_fixed,w_100,h_100";
GeneratePresignedUrlRequest request(BucketName, ObjectName, Http::Get);
request.setProcess(Process);
/* The maximun validity period of the URL is 32400s. */
auto outcome = client.GeneratePresignedUrl(request);
if (outcome.isSuccess()) {
std::cout << "Generated presigned URL: " << outcome.result() << std::endl;
} else {
std::cout << "Failed to generate presigned URL. Error code: " << outcome.error().Code()
<< ", Message: " << outcome.error().Message()
<< ", RequestId: " << outcome.error().RequestId() << std::endl;
}
/* Release resources such as network resources. */
ShutdownSdk();
return 0;
}References
For more information about the supported IMG parameters, see Overview.
For more information about image styles, see Image styles.