how to use drawJpeg

Dave Novo

Hello,

the instructions for how to use pdfPrinter.drawJpeg are very unclear. What do I put in the buffer and bufLen parameters.

Here is a sample

bmp:=tbitmap.create
//draw something onbitmap
jpg:=tjpegImage.create;
jpg.assign(bmp)
pdfPrinter.drawJpeg(x,y,w,h,bmp.width,bmp.height,?,?)

what do I put in place of the question marks?

support

DrawJPEG is useful to draw JPEG data which has not been decompressed yet. It is important that the physical size is known since the PDF engine cannot detect this itself.

The function is internally used by the DrawTGraphic procedure:

Code

function TWPCustomPDFExport.DrawTGraphic(x, y, w, h: Integer; Graphic: TGraphic): Integer;
var temp: TMemoryStream; 
  inch : Integer;
begin
  Result := -1;
  if Graphic <> nil then
  begin
     if Graphic is TBitmap then
   ...
   else if Graphic is TJPEGImage then
    begin
      if not TJPEGImage(Graphic).Empty then
      begin
        temp := TMemoryStream.Create;
        try
          TJPEGImage(Graphic).SaveToStream(temp);
          Result := DrawJPEG(x, y, w, h, TJPEGImage(Graphic).Width, TJPEGImage(Graphic).Height, temp.Memory, temp.Size);
        finally
          temp.Free;
        end;
      end;
    end
    else
      raise PDFException.Create('Cannot convert ' + Graphic.ClassName);
  end;
end;

Alles anzeigen

I hope this makes it clear.

Julian