Delphi 12.3 DataSnap Server - Best HTML TO PDF converter ?

[Mauro Botta 2]

Hi

I have a Delphi 12.3 DataSnap Server application (Win64),
i have a problem with  HTML text To PDF converter. 

I'm using this codice: work fine but have a problem , if the application is Showed in Windows, Don't work (  "canvas does not allow drawing" error  )

if  i minimize my App server then work fine.

Are there any TWebView2 example for make it ?

 

Mauro

 

My code:

TgtPDFEngine : Last Version

THtmlViewer: Last Version

 

begin
gtPDFEngine1 := TgtPDFEngine.Create(nil);
gtPDFEngine1.Name := 'gtPDFEngine_Temp_' + IntToStr(Random(100000));
gtPDFEngine1.FileExtension := 'pdf';
gtPDFEngine1.FileDescription := 'Adobe PDF Files';
gtPDFEngine1.Preferences.ShowSetupDialog := False;
gtPDFEngine1.Preferences.OpenAfterCreate := False;

gtHtmlViewInterface1 := TgtHtmlViewInterface.Create(nil);
gtHtmlViewInterface1.Name := 'gtHtmlViewInterface_Temp_' + IntToStr(Random(100000));
gtHtmlViewInterface1.Engine := gtPDFEngine1;
gtHtmlViewInterface1.DoBeginDoc := True;
gtHtmlViewInterface1.DoEndDoc := True;
gtHtmlViewInterface1.AutoSizePage := True;

Randomize();

HtmlViewer1 := THtmlViewer.Create(nil);
HTMLViewer1.Name := 'HTMLViewer_Temp_' + IntToStr(Random(100000));
HTMLViewer1.Visible := False;
HTMLViewer1.Parent := Application.MainForm;  
HTMLViewer1.LoadFromString(sHTML);

gtPDFEngine1.FileName := sPDF_File_Dest;

if slPDF_ExtraInfo <> nil then
   begin
   gtPDFEngine1.DocInfo.Keywords := slPDF_ExtraInfo.Text;
   end;

 

try
gtHtmlViewInterface1.RenderDocument(HTMLViewer1);   //<------  "canvas does not allow drawing"
finally
HtmlViewer1.Free;
gtHtmlViewInterface1.Free;
gtPDFEngine1.Free;
end;

end;

[ertank 30]

Hi,

I believe Gnostice uses a modified version of HTMLViewer and first you should check if you version is actually the one coming with the Gnostice installation.

If your HTML does not contain any JavaScript then I would suggest you consider https://delphihtmlcomponents.com

If you have JavaScript in your HTML then you might need to shell execute Chromium based browser as "headless" and relevant other parameters to generate a pdf for you. This is CPU intensive and might take 0.5-2.0 seconds per pdf file.

[havrlisan 46]

You can always use an external tool. I run a Docker instance and have a running container of html2pdf image, which has API endpoints for passing HTML in the body, along with useful query parameters for manipulation. The obvious benefit is that it uses puppeteer.