Blank bitmaps from RenderDocumentToFile

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   Hello,
The following C# program works good for some PDF documents, but for the iSED manual it doesn't work at all.
Every resulting bitmap page I check appears to be blank. When I view such a page with a HEX-Editor, I see a header followed bei 0xff for the rest of the file. With some different PDF files I tried the program, some pages have been rendered correctly, while some pages have appeared blank also.
using System;
using System.IO;
using System.Text;
using System.Drawing;
using iSED = SEDTech.iSED;
class Test
{
    public static void Main() 
    {
        iSED.QuickPDF qp = new iSED.QuickPDF();
        qp.UnlockKey( "your key" );
        string file = "iSEDQuickPDF 5.11 Reference Guide.pdf";

        Console.Write( "Loading PDF file " + file );
        int result = qp.LoadFromFile( file );
        int pages = qp.PageCount();

        if ( result == 1 )
        {
            Console.WriteLine( "Rendering " + file + " (" + pages.ToString() + " pages)" );
            qp.RenderDocumentToFile(72, 1, pages, 0, "Page_%p_of_file.bmp" );
        }
        Console.WriteLine( "Finished!" );
    }
}
Could please somebody try this program, ported to Delpi, ActiveX or something else?
Thanks in advance.
Best regards,
Pirmin

Edited by Pirmin

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Pirmin Members Profile Find Members Posts Team Player Joined: 28 Nov 05 Status: Offline Points: 28	Post Options Post Reply Quote Pirmin Report Post Thanks(0) Quote Reply Topic: Blank bitmaps from RenderDocumentToFile Posted: 04 Jan 06 at 3:12AM
	Hello, The following C# program works good for some PDF documents, but for the iSED manual it doesn't work at all. Every resulting bitmap page I check appears to be blank. When I view such a page with a HEX-Editor, I see a header followed bei 0xff for the rest of the file. With some different PDF files I tried the program, some pages have been rendered correctly, while some pages have appeared blank also. using System; using System.IO; using System.Text; using System.Drawing; using iSED = SEDTech.iSED; class Test { public static void Main() { iSED.QuickPDF qp = new iSED.QuickPDF(); qp.UnlockKey( "your key" ); string file = "iSEDQuickPDF 5.11 Reference Guide.pdf"; Console.Write( "Loading PDF file " + file ); int result = qp.LoadFromFile( file ); int pages = qp.PageCount(); if ( result == 1 ) { Console.WriteLine( "Rendering " + file + " (" + pages.ToString() + " pages)" ); qp.RenderDocumentToFile(72, 1, pages, 0, "Page_%p_of_file.bmp" ); } Console.WriteLine( "Finished!" ); } } Could please somebody try this program, ported to Delpi, ActiveX or something else? Thanks in advance. Best regards, Pirmin Edited by Pirmin

swb1 Members Profile Find Members Posts Debenu Quick PDF Library Expert Joined: 05 Dec 05 Location: United States Status: Offline Points: 100	Post Options Post Reply Quote swb1 Report Post Thanks(0) Quote Reply Posted: 04 Jan 06 at 10:31AM
	I tried the following in Delphi. I got the same results that you did , Pirmin. procedure TForm1.Button3Click(Sender: TObject); var qp : TiSEDQuickPDF; begin if OpenDialog1.Execute then begin qp := TiSEDQuickPDF.Create; try qp.UnlockKey(MY_QDPF_KEY); qp.LoadFromFile(OpenDialog1.FileName ); Screen.Cursor := crHourGlass; qp.RenderDocumentToFile( 72, 1, qp.PageCount, 0, 'ISedDoc.bmp' ); finally Screen.Cursor := crDefault; qp.Free; end; end; end; I then changed my code to this : procedure TForm1.Button3Click(Sender: TObject); var qp : TiSEDQuickPDF; i : integer; stream : TMemoryStream; bmp : TBitmap; begin if OpenDialog1.Execute then begin stream := TMemoryStream.Create; bmp := TBitmap.Create; qp := TiSEDQuickPDF.Create; try qp.UnlockKey(MY_QDPF_KEY); qp.LoadFromFile(OpenDialog1.FileName ); Screen.Cursor := crHourGlass; for i := 1 to qp.PageCount do begin stream.Clear; qp.RenderPageToStream(72,i,0,stream ); stream.Position := 0 ; bmp.LoadFromStream( stream ); bmp.SaveToFile(ExtractFilePath(OpenDialog1.FileName) + Format('ISedDoc%d.bmp',[ i ])); end; finally Screen.Cursor := crDefault; stream.Free; bmp.Free; qp.Free; end; end; end; This took longer to run however the resulting bitmap files appeared to be correct. I don��t know the equivalent structures for TMemoryStream and TBitmap in C# however this is the method I have used in the past (with Delphi) and it has work reliably for me. Perhaps when I find myself with some time on my hands I will step through the RenderDocumentToFile function and see if I can tell why it is yielding null Bitmaps. Steve Edited by swb1

Pirmin Members Profile Find Members Posts Team Player Joined: 28 Nov 05 Status: Offline Points: 28	Post Options Post Reply Quote Pirmin Report Post Thanks(0) Quote Reply Posted: 04 Jan 06 at 10:34PM
	Hi Steve Thank you! When I was reading the code in your post, it looked a kind of familiar to me. The equivalent function RenderPageToString gives good results! In my topic Convert string from RenderPageToString I have described how I used this function and what workarounds are necessary to make it work properly. When I saw, that RenderPageToString needed about 6 times more time then RenderDocumentToFile (as you noted also), I thought it would be better, using RenderDocumentToFile. After having to solve other problems and because sometimes I have to pause my work for a long time, I forgot about the rendering problems I have found myself. Now my conclusion is, to be slow is better than to be faulty. So I will definitely use the function RenderPageToString instead of RenderDocumentToFile. Best regards, Pirmin Edited by Pirmin