Steema Central

Hi all,

In my company's software, there's one (TeeChart related) bug that has been bothering us for a long time now. Our software generates HTML management reports, and for this, large batches of graphs have to be generated. It does this by building the charts using TeeChart, and then exporting them with the TeeSaveToPNG() method.

The problem is that many of the images come out completely black, with a band of randomly colored pixels at the bottom (see attachment). These colored pixels are different in each image. This, however, doesn't always occur. It happens with about half of our clients, and with those clients, about 30-50% of the images come out black.

Our software:
- C++ Builder 2007
- TeeChart 7.12
- Windows XP Professional


I can't figure out how to reproduce this on my own machine, nor can I see any common factor with our clients that might be causing this issue. Any ideas, anyone? Maybe there's a certain library/DLL that TeeChart relies on that is different or faulty at some of our clients' servers?

Kind regards,

Hugo de Jong

Hi Hugo,

For IDE versions prior to RAD Studio 2009, the LPNG.dll is required in \Windows\System or \Windows\System32 folder. Could you please check if you have it?

Hi Yeray,

The LPNG.dll file is present in the application directory instead of in the %windir%/System32 or %windir%/system folders. Is this a problem? I will try to find out whether the issue is caused by different versions of LPNG.dll.

Kind regards,

Hugo de Jong

Hi Hugo,

You could try copying it to the system and system32 folders to see if it solves the problem.
If this doesn't solve the problem, if you have access to one of these "problematic" machines, please, try to arrange a simple example project we can run as-is here; a project that reproduces the problem in that machine consistently, if possible.