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Canvas does not allow drawing error

edited March 2011 in General
Hello All:

When I run my application - i am getting "Canvas Does Not Allow Drawing"
errors when trying to run reportbuilder reports - everything is run from the
primary application thread (not a multi threaded app)

1) It ONLY happens when running under Remote Desktop
2) Rebooting the Remote Server seems to clear up the problem
3) It has NEVER happened running from the desktop

We would like to start hosting our app remotely - but need to solve this

We are currently running RB 6.01 on Delphi 5

We are converting the app to Delphi7 / RB 12

A) What is causing the "Canvas Does Not Allow Drawing Errors" ???

B) Will the upgrade solve the problem ???

C) Is the problem a bug in Delphi itself ???

Can anybody offer any guidance ??? Thank you.

Neil Huhta


  • edited March 2011
    Hi Neil,

    The "Canvas Does Not Allow Drawing" error can be caused by a number of
    items however it is usually related to a memory or resource leak. First
    be sure you are using the latest video and printer driver available for
    your hardware.

    I can tell you that ReportBuilder 6 for Delphi 5 was not designed to be
    thread safe. Upgrading to a later version should solve the issue
    however it may also be useful to run your application through at
    profiler such as FastMM or AutomatedQA to see how resources are
    allocated and freed.


    Nico Cizik
    Digital Metaphors

    Best Regards,

    Nico Cizik
    Digital Metaphors
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