Fix: CircleControls transparentCorners styling

[Kronoxis]

CircleControls didn't listen to the transparentCorners styling of the fabricObject.

Steps to reproduce

You can verify this issue in the controls customization demo: http://fabricjs.com/controls-customization

1. Set cornerStyle to option 2 (circular)
2. Toggle transparentCorners on

[asturur]

Hi, thanks for the PR.
One visual test around circle coners is indeed failing, and this is expected.

Could you please have a look at why is failing and fix it?

Do you know how to run the test suite locally?

[Kronoxis]

Could you please have a look at why is failing and fix it?

I'm assuming the test image controls4.png is wrong, as this has solid circle controls while transparent are used in the test code. How do I go about re-rendering this image so I can provide the repo with the correct test image?

Do you know how to run the test suite locally?

I'm not familiar with writing and running tests in JavaScript, could you guide me through how I can do this? So far I have cloned the repo on my machine and installed the npm dependencies.

[asturur]

if you are past npm install, you should be able to do the following:

npm run build:fast will build fabric.js with your fix
npm run test:visual will run the tests and give you a single failure
once you are sure that the old image was wrong and now with the new code needs an updated, you can search it and delete the image.
run again the tests with npm run test:visual and the test won't find the image and create it.
before committing the changes, you should remove the built dist file with git checkout master dist
then the usual git add . and git commit -am 'corrected the snapshot' and you should be done.

[Kronoxis]

I have uploaded the new controls4.png image and the visual unit test succeeds now.

[asturur]

Thanks!