Problem with parsing/showing ARC entity

[mirh1]

Hi,

I posted this problem in dxf parser project before, but for I am not sure if this might rather be a viewer problem, I would like to open an issue here as well.

We have problems with showing some dxf files in dxf-viewer. A (simplified) example opend with three dxf sample viewer looks like this:

{ "type": "ARC", "handle": "26", "ownerHandle": "1C", "inPaperSpace": false, "layer": "Cutting", "colorIndex": 7, "color": 16777215, "lineType": "Continuous", "lineweight": 0, "lineTypeScale": 1, "visible": true, "center": { "x": 33.9061329504177, "y": -33.9061329504178, "z": 0 }, "radius": 1.5, "startAngle": 1.5707963267948966, "endAngle": 3.141592653589793, "angleLength": 1.5707963267948966 },
...
{ "type": "ARC", "handle": "28", "ownerHandle": "1C", "inPaperSpace": false, "layer": "Cutting", "colorIndex": 1, "color": 16711680, "lineType": "Continuous", "lineweight": 0, "lineTypeScale": 1, "visible": true, "center": { "x": -30.9061329504177, "y": -35.9061329504178, "z": 0 }, "radius": 1.5, "startAngle": 3.141592653589793, "endAngle": 4.71238898038469, "angleLength": 1.5707963267948966 },

You can see that in some cases an entity of Type ARC is not shown in its right position.
While other viewers that I used show the file correctly:

By debugging the parsing process until reaching parseEntity(scanner, curr) in arc.js we noticed that the extrusion vector of the specific ARC entity (Group 210-230) is like (0, 0, -1) and also the x value of the arc.center has a reversed sign.

For reproducing the problem see this example dxf below:
example.zip