[Feature Request] Enable tolerance threshold settings for screenshots

[muhammadkhan0009]

Hello everyone, First of all, thank you very much for doing such a great work on this library. We are the early adopter of this library and really excited about its future because of its help to make sure that our app UI works as expected.

Problem :

We have recently noticed that our test cases are failing due to minor change in the screen pixels which leads us to further explore the codebase of your library. The more details are given in the screenshot.

Proposed solution :

While exploring the codebase we have found out that toMatchBaseline function only accepts the latestPath param to compare baseline image with latest images by using pixelmatch lib under the hood. Upon further investigation we have found that the pixelmatch also accepts threshold parameter as an argument to expose some tolerance.

pixelmatch(img1.data, img2.data, diff.data, width, height, {threshold: 0.1});

I think it would be nice to enable toMatchBaseline function to accommodate additional parameter as options where users can add the tolerance threshold so that tests don't get failed unnecessary i.e.

toMatchBaseline(latestPath:string, options?:{threshold?:number} )

Screenshot :

Zoomed in Screenshot :

@manosim As you can in the above screenshots that test is failing due to very minor pixel difference (i.e. red colour in the screenshot) . I think library should be tolerant enough to deal with these type of issues.