Multi-pages : how to keep the changes (draw, ...) ?

[louis]

Hi Loic,

I have a little doubt ... ! Or I'm half asleep ...

When we make some modifications in a page (draw text, lines, ...), then we change the page, and we go back to the previous page, the modifications seem to be lost.
How to do to keep them ? Is it necessary to save the image handle before changing the page ?
To do that, is there an event to be used before PageChange ? Or must we save the image handle each time we make a modification in order to prevent the change of page ?

Louis

[Loïc]

Hi Louis,

Which kind of document are you edition and which method are you using ?

Kind regards,

Loïc

[louis]

I'm using a pdf document with 6 pages and I change some rectangular zones on the 1st page with SetROI and SwapColor (white to yellow). I go to the 2nd page then to the 1st. The rectangular zones are white like when I open the document.

[louis]

More information may be useful :
I use this code to initialize the viewer (GDV_File) and the imaging (GDI_File) after the display of the file with GDV_File.DisplayFromPdfFile :

GDI_File.SetNativeImage (GDV_File.GetNativeImage)
GDV_File.SetNativeImage (GDI_File.GetNativeImage)

After GDI_File.SwapColor, I use GDV_File.Redraw

[Loïc]

Hi,

You can edit a PDF document like with this method.

What you have to do is:

- Extract all PDF page to bitmap
- Edit desired bitmap
- Compose a new document from extracted bitmaps.

You can find a lot of sample into the code request section. Please have a look on it.

With best regards,

Loïc Carrère

[louis]

Hi Loic,

Ok, your suggestion may be convenient, ... but what do you think about mine ? That is to say, save the image, reload it when there is a page change.
Because I need to edit one page, move to another page, edit it, back to the previous, edit it, ... Is it possible with your solution ?
"My" solution could be easier if there was an event "BeforePageChange".
Both are a little bit complex indeed.

Louis

[Tom Moran]

Hi Louis:

The easiest way I've found to edit a multipage document is to convert/copy it to a multipage TIFF. I added a multi undo/redo feature that allows you to make changes on the page that is being displayed. When you navigate to a new page, however, those changes become a permanent part of the multipage tiff you're editing. Using this method you can navigate through your document like a viewer and edit, insert, swap, delete, add pages, etc. Once you're finished you then may save the Tiff to a new file name or convert it to a PDF or PDF/A file.

Tom

[Loïc]

Hi There,

Tom, as always: thank you very much for your answer.

I have nothing else to add. Converting to editable multipage TIFF seems the best alternative to keep modifications easily. Then, you will be able to convert multipage tiff to multipage PDF.

With best regards,

Loïc

[louis]

Tom and Loic, thanks a lot !

I have found the following code to convert pdf to tif.

Code: Select all

For nPage = 1 To oGdViewer.PageCount
    oGdViewer.DisplayFrame (nPage)

    If nPage = 1 Then
       oImaging.SetNativeImage (oImaging.CreateClonedImage(oGdViewer.GetNativeImage))
       Call oImaging.TiffSaveAsNativeMultiPage("c:\output.tif")
    Else
       Call oImaging.TiffAddToNativeMultipage(oGdViewer.GetNativeImage)
    End If
Next nPage

So, I'll choose between this solution and mine, depending on the performances and the modifications to do in the file. Because converting a file may be long if there are many pages (more than 100 for example). On the other hand, the conversion to tif is necessary if we need to add, swap or delete pages.

Louis

[Tom Moran]

Hi Louis:

Yes that's basically correct. A couple of things...

1. Be sure to lock the viewer right before your For/Next Loop:

Code: Select all

oGdViewer.LockControl = True

2. Remember to Close the new multipage Tiff and unlock the viewer right after your For/Next Loop:

Code: Select all

        oImaging.TiffCloseNativeMultiPage
                 oGdViewer.LockControl = False

And then... converting back to PDF is a piece of cake:

Code: Select all

nStat = oImaging.SaveAsPDFEx(TiffFileName, Title, Author, "", "", Creator, 0, 0, "", "")

All in all, execution is pretty fast.

Best regards,

Tom

Tom





nStat = oImaging.SaveAsPDFEx(TiffFileName)

[louis]

I spoke about performances because, with big pdf files (reports with several hundred pages), I get a long time if we consider the time to draw each page (loop on DisplayFrame) and, above all, the time to create each pdf page. Until now, I made PdfNewPdf then a loop with PdfNewpage, PdfDrawImage, PdfEndPage, ... !

So, your idea seems very attractive !
I'll keep you informed when I'll make the change (with time comparison).

Louis