BUG - "Canvas does not allow drawing"

rbuser

Delphi 6 / RB 7.04

Hi there

I know that Im running an older version of Delphi/RB, but all is still
working well.

However, every so often (randomly) users receive the error message "Canvas
does not allow drawing" when trying to print a document. On screen the page
display fine. It is only when they click the print button from within the
Screen Preview.

We have a number of printers, and it only seems to be a Kyocera FS4020
causing the problem, which is a new printer.

Could I maybe insert some code into the ScreenPreview Print button.onclick
event, that checks for a default printer before the button is clicked. I
mention this, because I have read that sometimes this is a bug in RB trying
to print to a printer, when no printers exists etc? I could put code in the
onclick event to check for a Default printer.

Not sure if this helps, (or makes a difference) but the environment is Win
XP SP 3 clients and a SBS 2003 Server. The Kyocera printer is a shared
printer from the server. Using GPO, when a user logs onto the client PC,
printers are deleted and then re-added depending on which PC has been logged
on.


Any thoughts

Lee Parvin

nardmoseley

ReportBuilder caches the list of available printers, if you printers being
add/removed, then you try calling.

uses
ppPrintr;

ppPrinters.Refresh;

If you get this error on a specific printer, then I recommend updating the
printer driver.

You can also try checking to make your application does not have
memory/resource leaks. A tool such as FastMM configured in debug mode can be
used to do this.



-
Nard Moseley
Digital Metaphors
www.digital-metaphors.com

rbuser

Hi Nard

I have updated the printer drivers, and ran the Delphi code in Eurakalog,
which does not report any problems.

However, today some of our users reported :-

"Screen printer does not support printing" and
"Canvas does not allow drawing"

These errors occur as the Delphi code tries to display the screen preview ie

Report1.DeviceType := 'Screen';
Report1.PrinterSetup.PrinterName := 'Default'
Report1.Print;

The printer is question is a Kyocera FS4020DN.

Before calling the Report.Print code, could i use some error checking code?
eg if (Report1.PrinterExits) then Report1.Print;

Do you have any thoughts?

Many thanks

Lee

nardmoseley

RB 12.-05 was the last produced release for Delphi 6. I recommend
downloading a trial of RB 12.05 and then perform the same test. The
ReportBuilder architecture has evolved quite a long way since RB 7.x.

I also recommend trying to recreate the error on your machine. Download and
install the printer driver to your machine and configure it to be the
default printer (you can do this without having the printer hardware). Ask
the user for specific steps to recreate the issue, and then perform those
steps.

Both of those errors indicate ReportBuilder could not get valid printer
device context (i..e. printer canvas handle). You can try checking
Report.Printer.DC = 0, that would indicate an issue, the value should be
non-zero.

-
Nard Moseley
Digital Metaphors
www.digital-metaphors.com

rbuser

Hi there

Im going to buy an upgrade. Im currently on 7.04 Pro.

Wich one of the selections in the Order Product list do I use???? Is it
Upgrade Professional $399. Will this give me 12.05???

Cheers

Lee

nardmoseley

Yes, purchasing an upgrade to ReportBuilder 14 also includes the ability to
download the last produced release for Delphi 6, which is ReportBuilder
12.05. I recommend contacting sales@ if you have additional questions about
ordering or downloading.


-
Nard Moseley
Digital Metaphors
www.digital-metaphors.com