The direction of the annotation leader is unintentionally reversed

kyosukeSakurai commented 3 years ago

Load & Save the sample data (SampleX.dxf). SAMPLE_X.zip

In the previous netDxf version, Leader group code '211' becomes '1'. When opened with a viewer such as AutoCAD, the correct display is as shown below.

In the new netDxf version, Leader group code '211' becomes '-1'. When opened with a viewer such as AutoCAD, the display is incorrect as shown below.

I think it is a bug in the new version, so please check it.

Ref. ) Leader group code https://help.autodesk.com/view/ACD/2020/ENU/?guid=GUID-396B2369-F89F-47D7-8223-8B7FB794F9F3

See 'WriteLeader' on DxfWriter.cs. 211 is set at the line below: 　this.chunk.Write (211, xDir.X)；

There is a possible way to fix it, but how about it?

Determine xDir from the attachment point.
Determine xDir from the X coordinate of the second and third points when there are 3 points.

I'm trying to fix the #294 and #293 failure at the same time. Please check the attached file. I would like to cooperate with early improvement. If you are unsure of the intent of the correction, please let me know. SampleCode.zip

haplokuon commented 3 years ago

I will continue the discussion in the older issue since the origin of those problems seems to be the same.

kyosukeSakurai commented 3 years ago

If issues #293 and #294 are solved, we can see the following issues.

If the annotation leader line has an acute angle, Load and save will make it impossible to reproduce the acute angle.

Sample code:

var dxfDoc = DxfDocument.Load( filename );
dxfDoc.Save( filename );

SAMPLE_C.zip

I think the following processing is needed to be fixed. Line 4511 on DXFReader.cs

            if (hasHookline && wcsVertexes.Count >= 3)
            {
        // When 1st, 2nd and 3rd points make up an acute angle, not to delete the 2nd point 
               //  because it need to be restored. See 'WriteLeader' on 'DxfWriter.cs'.
                var x1 = wcsVertexes[2].X - wcsVertexes[1].X;
                var x2 = wcsVertexes[1].X - wcsVertexes[0].X;
                if ((x1 * x2) > 0)
                {
                    wcsVertexes.RemoveAt(wcsVertexes.Count - 2);
                }
            }

Line 364 on Leader.cs

              // Recalculate and add Hookline only if there are two vertices.
              if (this.vertexes.Count == 2)
              {
                      this.vertexes.Insert(this.vertexes.Count - 1, this.CalculateHookLine());
              }

FixedCode.zip

haplokuon / netDxf

The direction of the annotation leader is unintentionally reversed #294