Logarithmic scale bug

[neurosoft]

In the attachment there are two TChart with logarithmic scale and the same data. First is WPF TChart (ver. 4.0.2010.13053), second WinForms TChart (ver. 2.0.2987.19069).

wpf.png (8.51 KiB) Viewed 10921 times

wf.png (4.56 KiB) Viewed 10923 times

You can see: pictures are quite different! Why??

[neurosoft]

You can easy check correctness of WPF TChart with logarithmic scale: make TChart with logarithmic Y axis, set MinValue to 100, MaxValue to 1000 and add one point with Y = 316.2 ( it is sqrt (100*1000)). This point must be in the middle of TChart between bottom and top. And it will not be in the middle!

[neurosoft]

Steema people, please!

Did you check this issue? It's critical because of wrong data presentation! Can you fix it?

[Yeray]

Hi neurosoft,

It seems that the axes' logarithmic property has been broken for some reason with the latest build (v4.0.2010.13052), with WinForms. In WPF it still seems to work fine.
I've added it to the defect list to be fixed asap (TF02014882). Thanks for reporting it.

[Yeray]

Hi neurosoft,

We will close the (TF02014882) because both in WinForms and WPF the following code describes a straight line, which we think would be the expected:

Code: Select all

            tChart1.Aspect.View3D = false;
            tChart1.Legend.Visible = false;

            tChart1.Axes.Left.Logarithmic = true;
            tChart1.Axes.Left.SetMinMax(100, 1000);
            tChart1.Axes.Bottom.SetMinMax(0, 20);

            Steema.TeeChart.Styles.Points points1 = new Steema.TeeChart.Styles.Points(tChart1.Chart);
            //Steema.TeeChart.WPF.Styles.Points points1 = new Steema.TeeChart.WPF.Styles.Points(tChart1.Chart);

            for (int i = 0; i < 20; i++)
            {
                points1.Add(i * (1000 - 100) / 20 + 100);
            }

[neurosoft]

Hi Yeray!

Logarithmic scale bug is very serious!

I have changed your sample a little to see points from 10 to 1000.

Please see attached pictures

Picture N 1 (WPF TChart Version=4.0.2010.27963, logarithmic scale) is wrong! It's look like Picture N 2 (WPF TChart Version=4.0.2010.27963, linear scale).
Picture N 1 must be look like as Picture 3 (Windows Forms TChart Version=2.0.2987.19069, logarithmic scale)! Picture 4 (Windows Forms TChart Version=2.0.2987.19069, linear scale) is here only to compare with others.

Please fix this bug, it's very serious, because of it we have to use old TChart versions and can't go to using WPF TChart!!

Log.png (38.94 KiB) Viewed 10733 times

[neurosoft]

Hi, Steema people!

Why didn't you response to my cry from the heart? Can you fix this bug with logarithmic axes? Because of this bug it's impossible to use latest TChart!

[Yeray]

Hi neurosoft,

We haven't forgotten this. We are investigating it and we'll be back here asap.

[Yeray]

Hi neurosoft,

We've found the problem and solved it. The fix will be available with the next maintenance release.
In the meanwhile here it is an ugly workaround:
After: tChart1.Axes.Left.Logarithmic = true;
Run: tChart1.Axes.Left.Horizontal = tChart1.Axes.Left.Horizontal;

[neurosoft]

Hi Yeray!

It works! Thank you!!