Repainting of charts

Michal Blazejczyk · Post by **Michal Blazejczyk** » Tue Jul 04, 2006 7:34 pm

Hi,

We're using TeeChart to display a lot of charts and some of them have lots of data associated with them and those are pretty slow to display (up to a few seconds). I can understand that the first time a chart is displayed it will take some time to calculate stuff. However, when only a simple refresh is necessary, TeeChart seems to be going over calculations for the entire chart all over again. This makes the application look unresponsive.

I've worked with other charting applications and they usually don't have this problem. They seem to be using some sort of a double-buffering technique to avoid unnecessary number crunching.

Do you guys (i.e. the TeeChart team) have a plan to improve this?

Narcís · Post by **Narcís** » Wed Jul 05, 2006 10:42 am

Hi Michal,

We are constantly working on TeeChart performance so you may expect improvements on that field with every TeeChart release.

However, you could try doing your own bit of data double buffering by not using the Series.DataSource property, by reading the database/dataset outside of TeeChart and then adding in the values using the Series.Add overloads. If you did this using classes you could even get events to fire when the Series.Count is different to the number of rows in the dataset to add in new ones.

Michal Blazejczyk · Post by **Michal Blazejczyk** » Wed Jul 05, 2006 6:00 pm

Hi Narcís,

I only use Series.Add in my code. What takes all this time is painting on the canvas.

Narcís · Post by **Narcís** » Thu Jul 06, 2006 10:30 am

Hi Michal,

As I already told you, we are always working on improving TeeChart's performance. Also, in TeeChart for .NET v3, on which we are currently working, substantial improvements have been made. In the meantime you could use DownSampling functions, shown at What's New?\Welcome !\New Functions\Reducing number of points in the features demo. It may also be helpful that you read this article on real-time charting with TeeChart. This article is written using TeeChart Pro VCL but most of it can be applied to TeeChart for .NET as well.

Michal Blazejczyk · Post by **Michal Blazejczyk** » Sat Jul 08, 2006 6:17 pm

Hi Narcís,

Yes, I understand that you do what you can. But there are always (i.e. in any software) lots of areas where efficiency can be improved. I'm just pointing you in a direction of one of them.