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Bug 651

Summary:	Fastline DrawAllPointsSyle.MinMax did not work (second request)
Product:	.NET TeeChart	Reporter:	loeffler
Component:	Chart	Assignee:	Steema Issue Manager <issuemanager>
Status:	RESOLVED DUPLICATE
Severity:	blocker	CC:	chris
Priority:	---
Version:	TeeChart.NET 2014 4.1.2014.02060
Target Milestone:	---
Hardware:	PC
OS:	Windows
Chart Series:	---	Delphi / C++ Builder RAD IDE Version:
Attachments:	Three plots in zip file to illustrate problem.

Description loeffler 2014-03-19 11:23:14 EDT

Created attachment 123 [details]
Three plots in zip file to illustrate problem.

Hello Support

I found no possibility to reopen my Bug 635, therefore I have to create a new.
To visualize the problem I have streamed a sinus with increasing frequency to the TeeChart (see FastLine-1-10-100Hz-Sinus.png). As you can see the 1Hz is shown correctly, when switching to 10Hz the maximum is still shown correctly, but the minimum shows different amplitudes (and not the correct minimum). This effect is getting worse when switching to 100Hz.
Furthermore, when resizing the plot horizontally the shape of the trace is changing dramatically (see FastLine-1-10-100Hz-Sinus-ResizedHorizontal.png). This is definitely the wrong way to handle MinMax values when the plot down samples the trace values to the x-axes pixels. Moreover, the shape of the trace changes dramatically. When I zoom in the 100Hz segment I can see that the trace is a perfect sinus (FastLine-1-10-100Hz-Sinus-ZoomedIn100Hz.png).

Please notice, that the plot behaves differently for the minimum and maximum. The maximum shows the correct value, whereas the minimum varies depending on the difference between trace values and x-axis pixel.

As I wrote before, we can not use Version 2014 with this strange behavior.

Best wishes
hans Löffler

Comment 1 christopher ireland 2014-03-19 12:48:32 EDT

Hello Hans,

Did you read the reasons for closing the bug http://bugs.teechart.net/show_bug.cgi?id=635? Is there anything you disagree with there?

Of course there is nothing stopping us finding code that fixes http://bugs.teechart.net/show_bug.cgi?id=650 and also fixes the problem that you perceive. Presumably you would like this calculation to be identical to the TeeChart 2012 - clearly this cannot be, as this would leave the problem of http://bugs.teechart.net/show_bug.cgi?id=650 in tact. 

In order to try and make the traces you post in your images identical in both 2012 and 2014, would you be so kind as to post the code you used to create them? We can then try to modify the existing code to recreate the kind of trace that we believe you are expecting.

Comment 2 christopher ireland 2014-03-20 10:20:33 EDT


*** This bug has been marked as a duplicate of bug 653 ***