Imgix Dart Client

imgix logo

A Dart client library for generating URLs with imgix.

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Install

dependencies:
  imgix_client: ^1.0.0

Basic Usage

A simple usage example:

import 'package:imgix_client/imgix_client.dart';

void main() {
  var urlBuilder = UrlBuilder('demos.imgix.net');
  var params = { 'w': '100', 'h': '100' };
  print('awesome: ${urlBuilder.createURL('bridge.png', params)}');
}

// Prints out:
// https://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 'package:imgix_client/imgix_client.dart';

void main() {
  var builder = UrlBuilder('demos.imgix.net');
  builder.useHttps = false; // use http

  var params = { 'w': '100', 'h': '100' };
  print(builder.createURL("bridge.png", params));
}


// Prints out
// http://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 'package:imgix_client/imgix_client.dart';

void main() {
  var builder = UrlBuilder('demos.imgix.net');
  builder.useHttps = false; // use http
  builder.signKey = 'test1234'; // set sign key

  var params = { 'w': '100', 'h': '100' };
  print(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.

import 'package:imgix_client/imgix_client.dart';

void main() {
  var ub = UrlBuilder('demos.imgix.net', true, 'my-token', false);
  var srcset = ub.createSrcSet("bridge.png");

  print(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.

import 'package:imgix_client/imgix_client.dart';

void main() {
  var ub = UrlBuilder('demos.imgix.net', true, 'my-token', false);
  var params = { 'h': '200', 'ar': '3:2', 'fit': 'crop' };
  var srcset = ub.createSrcSet("bridge.png", params);

  print(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.

Features and bugs

Please file feature requests and bugs at the issue tracker.

Running Tests

To run tests clone this project and run:

pub run test

Libraries

imgix_client