What is pollexor?

Pollexor is a Java library by Square that helps you generate URLs for resizing, cropping, and applying effects to images. It works with Thumbor, an open-source image service that processes images on the fly. Instead of manually writing out long, complex URL strings, you use a clean, readable style where each operation chains together naturally. At a high level, you tell the library where your Thumbor server lives and optionally provide an encryption key. Then you specify the source image URL and chain together whatever transformations you need, resize to 48 by 48 pixels, crop a specific region, align to a corner, add a watermark, round the corners, or adjust quality. The library handles assembling all of those instructions into the correct URL format that Thumbor understands. When you are done chaining commands, you call a method that produces the final URL string to drop into your app. This is useful for teams running mobile apps or websites who need to serve many image sizes and variations without pre-generating each one. For example, if you have user-uploaded profile photos and need to display them as small thumbnails in a list view and large avatars on a detail page, you can generate both URLs on the fly from the same source image. The image service does the actual processing when the URL is requested, so your app just builds and requests the URLs. The library is fully compatible with Android, which makes sense given Square's mobile-focused background. The fluent, chaining style is a deliberate design choice, it keeps image transformation code readable and less error-prone compared to hand-crafting URL strings with the right syntax and parameter order.