Superfluous lines

[laof]

Version

• fabric.js version: 2.0.0-rc.3
• Chrome version:61.0.3163.79

Test Case

http://fabricjs.com/

Steps to reproduce

Ask one thing, when the object is rotated, there are two lines appearing. As shown in the picture，
How to solve it, help ，thank you！

Expected Behavior

Actual Behavior

[asturur]

I do not see those lines.
Do you see on other browsers or simply other computer too?

what OS are you on?

[JSteunou]

never seen those glitch too, but I know that sometimes weird things can happen with Windows and bad graphic drivers.

[asturur]

Also please replicate turning off the hw accell from chrome, if they disappear is a driver issue

[laof]

I'm sorry, I forgot to say, I'm using Windows 7. There's the same problem on desktop and laptop computers. I can make sure that the phone is normal

[asturur]

please try with hw acceleration turned off

[laof]

OK, I will give it a try

[laof]

Version

2.0.0-rc.3

Test Case

http://fabricjs.com/

describe

I tested it with two computers and got some data. It's easy to find it related to hardware acceleration. It's not a good way to configure the switch. What should we do now? Thanks

Actual Behavior

Browser	Hw acceleration	Finally	OS
Chrome 55.0.2883.87	OFF	√	Windows 7
	ON	×
Chrome 61.0.3163.79	OFF	√
	ON	×
Firefox 48.0.2	OFF/ON	√
Firefox Quantum 57.0.2
Chrome 63.0.3239.84	OFF	√
	ON	×
	OFF/ON	√	OS X Yosemite 10.10

[laof]

Find out the problem, look at the merge request

[asturur]

so that closePath is effectively extra. and can be removed being a straight line.
outo f curiosity what hardware you tested? what videocard?

[laof]

The mistake I found in the project. The third point of the triangle is the central coordinates of the canvas, not random . videocard is Intel (R) HD Graphics

[asturur]

there is no real mistake. happy to have removed that useless line if it helps.

The point is that if do

beginPath, moveTo(p1), lineTo(p2) i do not need to closePath at all, but if i do the closing is in p1 again, the first point i moved to.

Intel HD graphics has some other bugs around, definitely a driver issue.