ericdeansanchez/imgix-java

A Java client library for generating URLs with imgix

imgix-java is a client library for generating image URLs with imgix.

---

• Dependencies
• Install Options
  • Gradle & JCenter
  • Creating a Jar
• Basic Usage
• Signed URLs
• Srcset Generation
• Running Tests

Dependencies

The library itself has no external dependencies. Although if you want to build from source (or run tests) then you need ant and the JDK 1.6+.

Install Options

Gradle & JCenter

To add Imgix-Java to your project, include the following in your project's build.gradle:

dependencies {
   compile "com.imgix:imgix-java:2.2.0"
}

And if this is your first external JCenter dependency you'll need to add, again to your project level build.gradle, the following:

buildscript {
   repositories {
      jcenter()
   }
}

Creating a Jar

To create a jar from source:

gradle build

This creates imgix-java-{VERSION_NUMBER}.jar under ./build/libs

Once a new version has been merged into master on GitHub (don't forget to update the version numbers in build.gradle first!), it can be deployed to Bintray with gradle build && gradle bintrayUpload. After that, the new version can be viewed via the Bintray web interface.

Basic Usage

To begin creating imgix URLs, add the jar to your project's classpath and import the imgix library. The URL builder can be reused to create URLs for any images on the domains it is provided.

import com.imgix.URLBuilder;
import java.util.Map;
import java.util.HashMap;

public class ImgixExample {
    public static void main(String[] args) {
        URLBuilder builder = new URLBuilder("demos.imgix.net");
        Map<String, String> params = new HashMap<String, String>();
        params.put("w", "100");
        params.put("h", "100");
        System.out.println(builder.createURL("bridge.png", params));
    }
}

// Prints out:
// http://demos.imgix.net/bridge.png?h=100&w=100

HTTPS support is available by default. However, if you need HTTP support, call setUseHttps on the builder:

import com.imgix.URLBuilder;
import java.util.Map;
import java.util.HashMap;

public class ImgixExample {
    public static void main(String[] args) {
        URLBuilder builder = new URLBuilder("demos.imgix.net");

        builder.setUseHttps(false); // use http

        Map<String, String> params = new HashMap<String, String>();
        params.put("w", "100");
        params.put("h", "100");
        System.out.println(builder.createURL("bridge.png", params));
    }
}

// Prints out
// https://demos.imgix.net/bridge.png?h=100&w=100

Signed URLs

To produce a signed URL, you must enable secure URLs on your source and then provide your signature key to the URL builder.

import com.imgix.URLBuilder;
import java.util.Map;
import java.util.HashMap;

public class ImgixExample {
    public static void main(String[] args) {
        URLBuilder builder = new URLBuilder("demos.imgix.net");
        builder.setSignKey("test1234"); // set sign key
        Map<String, String> params = new HashMap<String, String>();
        params.put("w", "100");
        params.put("h", "100");
        System.out.println(builder.createURL("bridge.png", params));
    }
}

// Prints out:
// http://demos.imgix.net/bridge.png?h=100&w=100&s=bb8f3a2ab832e35997456823272103a4

Srcset Generation

The imgix-java library allows for generation of custom srcset attributes, which can be invoked through createSrcSet(). By default, the srcset generated will allow for responsive size switching by building a list of image-width mappings.

URLBuilder ub = new URLBuilder("demos.imgix.net", true, "my-token", false);
String srcset = ub.createSrcSet("bridge.png");
System.out.println(srcset);

Will produce the following attribute value, which can then be served to the client:

https://demos.imgix.net/bridge.png?w=100&s=494158d968e94ac8e83772ada9a83ad1 100w,
https://demos.imgix.net/bridge.png?w=116&s=6a22236e189b6a9548b531330647ffa7 116w,
https://demos.imgix.net/bridge.png?w=134&s=cbf91f556dd67c0b9e26cb9784a83794 134w,
                                    ...
https://demos.imgix.net/bridge.png?w=7400&s=503e3ba04588f1c301863c9a5d84fe91 7400w,
https://demos.imgix.net/bridge.png?w=8192&s=152551ce4ec155f7a03f60f762a1ca33 8192w

In cases where enough information is provided about an image's dimensions, createSrcSet() will instead build a srcset that will allow for an image to be served at different resolutions. The parameters taken into consideration when determining if an image is fixed-width are w (width), h (height), and ar (aspect ratio). By invoking createSrcSet() with either a width or the height and aspect ratio (along with fit=crop, typically) provided, a different srcset will be generated for a fixed-size image instead.

URLBuilder ub = new URLBuilder("demos.imgix.net", true, "my-token", false);
HashMap<String,String> params = new HashMap<String,String> ();
params.put("h", "200");
params.put("ar", "3:2");
params.put("fit", "crop");
String srcset = ub.createSrcSet("bridge.png", params);
System.out.println(srcset);

Will produce the following attribute value:

https://demos.imgix.net/bridge.png?ar=3%3A2&dpr=1&fit=crop&h=200&s=4c79373f535df7e2594a8f6622ec6631 1x,
https://demos.imgix.net/bridge.png?ar=3%3A2&dpr=2&fit=crop&h=200&s=dc818ae4522494f2f750651304a4d825 2x,
https://demos.imgix.net/bridge.png?ar=3%3A2&dpr=3&fit=crop&h=200&s=ba1ec0cef6c77ff02330d40cc4dae932 3x,
https://demos.imgix.net/bridge.png?ar=3%3A2&dpr=4&fit=crop&h=200&s=b51e497d9461be62354c0ea12b6524fb 4x,
https://demos.imgix.net/bridge.png?ar=3%3A2&dpr=5&fit=crop&h=200&s=dc37c1fbee505d425ca8e3764b37f791 5x

For more information to better understand srcset, we recommend Eric Portis' "Srcset and sizes" article which goes into depth about the subject.

Running Tests

To run tests clone this project and run:

gradle test

Dependencies for running tests (junit, etc) are provided (in test/lib and referenced in the build config).