How to change the DPI of a photo in Java

Adjusting the dots per inch of a photo can have huge value when it comes time to print or web display an image. Being able to adjust this to a common value en mass is the focus of today’s tutorial. We will be using a Cloudmersive API to painlessly complete this chore, and we will do it in under 5 minutes. Let’s get started.

First we need to edit our Maven POM file and add two references.

Repository reference:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

Dependency reference:

<dependencies>
<dependency>
    <groupId>com.github.Cloudmersive</groupId>
    <artifactId>Cloudmersive.APIClient.Java</artifactId>
    <version>v2.75</version>
</dependency>
</dependencies>

All that’s left is to call convertImageImageSetDPI and provide it with a file and desired DPI value:

// Import classes:
//import com.cloudmersive.client.invoker.ApiClient;
//import com.cloudmersive.client.invoker.ApiException;
//import com.cloudmersive.client.invoker.Configuration;
//import com.cloudmersive.client.invoker.auth.*;
//import com.cloudmersive.client.ConvertImageApi;
ApiClient defaultClient = Configuration.getDefaultApiClient();
// Configure API key authorization: Apikey
ApiKeyAuth Apikey = (ApiKeyAuth) defaultClient.getAuthentication("Apikey");
Apikey.setApiKey("YOUR API KEY");
// Uncomment the following line to set a prefix for the API key, e.g. "Token" (defaults to null)
//Apikey.setApiKeyPrefix("Token");
ConvertImageApi apiInstance = new ConvertImageApi();
Integer dpi = 56; // Integer | New DPI in pixels-per-inch, for example 300 DPI or 600 DPI
File inputFile = new File("/path/to/file"); // File | Input file to perform the operation on.
try {
byte[] result = apiInstance.convertImageImageSetDPI(dpi, inputFile);
System.out.println(result);
} catch (ApiException e) {
System.err.println("Exception when calling ConvertImageApi#convertImageImageSetDPI");
e.printStackTrace();
}

That’s it! Our image will now have the desired DPI. Our APIs provide a plethora of other image-related functionality, including converting between image formats, resizing, and facial recognition, so be sure to check out our documentation section.