diff_image

A Dart Package to get the % difference between two images of the same width and height.

diff_image is a Dart version of this with changes on visualization and , you guessed it, the language.

Example

A simple usage example:

import 'package:diff_image/diff_image.dart';
import 'package:image/image.dart';

final FIRST_IMAGE = 'https://raw.githubusercontent.com/nicolashahn/diffimg/master/images/mario-circle-cs.png';
final SECOND_IMAGE = 'https://raw.githubusercontent.com/nicolashahn/diffimg/master/images/mario-circle-node.png';

void foo() async {
  try {
      var diff = await DiffImage.compareFromUrl(
        FIRST_IMAGE,
        SECOND_IMAGE,
      );
      print('The difference between images is: ${diff.value} %');
  } catch(e) {
      print(e);
  }
}

void goo(Image first, Image second) {
  try {
    var diff = DiffImage.compareFromMemory(
      first,
      second,
    );
    print('The difference between images is: ${diff.diffValue} %');
  } catch(e) {
    print(e);
  }
}

main() {
  foo();
  /*These can be obtained with any method*/
  Image first;
  Image second;
  // Here is posible to manipulate both images before passing them
  // to the function.
  goo(first, second);
}

A more detailed example can be found here

Features

1. Currently there is support for comparing images fetched from urls and from memory or storage.
2. The compareFromUrl definition is:

  static Future<DiffImgResult> compareFromUrl(
    dynamic firstImgSrc,
    dynamic secondImgSrc, {
    bool asPercentage = true,
    bool ignoreAlpha = true,
  }) async{...}

3. And the compareFromMemory definition is:

  static DiffImgResult compareFromMemory(
    Image firstImg,
    Image secondImg, {
    bool asPercentage = true,
    bool ignoreAlpha = true,
  }) {...}

where:

• ignoreAlpha allows to decide whether to take alpha from RGBA into account for the calculation
• asPercentage set the format of the output (as percentage or between 0-1)

Both methods return an DiffImgResult, a model which contains two elements: An image showing the differences between both images and the numeric value representing the difference (as percentage or not).

4. A function called saveDiffImg which saves a png showing the differences between firstImg and secondImg (currently not available on Dart Web).

Sample Results

First Image

Second Image

Difference Percentage

With Alpha : 35.67169421487167 %

Without Alpha : 34.83905183744361 %

Difference Image

Suggestions and bugs

Please file feature requests, suggestions and bugs at the issue tracker.