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Problem with PdfImage

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tom 88

Post subject: Problem with PdfImage

Posted: Tue May 24, 2011 9:57 am

Joined: Tue May 24, 2011 9:40 am
Posts: 5

A nullReference exception occured to me when adding an image to the pdf file.

Code:

graphicsObj.DrawImage(imageObj, 0, 0);

PdfSharp.Pdf.Advanced - PdfImage line 890

Code:

arrayColorSpace.Elements.Add(colorPalette.Reference);

Apparantly colorPalette wasn't initialized earlier because of the following combination of states:
isBitonal = -1
isGray = false
usesCcittEncoding = false

At the moment, I just use the "DeviceGray" setting when this happens, but when added to the pdf, the image's color is inverted.

Any ideas on how this situation could be dealt with better?

Last edited by tom 88 on Tue May 24, 2011 11:57 am, edited 1 time in total.

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Thomas Hoevel

Post subject: Re: Problem with PdfImage

Posted: Tue May 24, 2011 11:51 am

PDFsharp Guru

Joined: Mon Oct 16, 2006 8:16 am
Posts: 3101
Location: Cologne, Germany

I have this "if" at line 883 above line 890:

Code:

if ((usesCcittEncoding && isBitonal == 0) ||
  (!usesCcittEncoding && isBitonal <= 0  && !isGray))

So with "usesCcittEncoding = true" and "isBitonal = -1" line 890 should not be executed.

Can you provide a sample image that causes this exception?

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Thomas Hoevel
PDFsharp Team

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tom 88

Post subject: Re: Problem with PdfImage

Posted: Tue May 24, 2011 11:57 am

Joined: Tue May 24, 2011 9:40 am
Posts: 5

woops usesCcittEncoding = false
*was true on first page of the tif*
I'll edit my earlier post

Unfortunately I'm not allowed to provide any internal documents =/

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Thomas Hoevel

Post subject: Re: Problem with PdfImage

Posted: Tue May 24, 2011 12:03 pm

PDFsharp Guru

Joined: Mon Oct 16, 2006 8:16 am
Posts: 3101
Location: Cologne, Germany

In line 655 we have

Code:

if (isBitonal == 0 && !isGray)

Maybe that should be "<= 0" here to match line 883.

If would be nice to have a sample to test with.

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Thomas Hoevel
PDFsharp Team

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Thomas Hoevel

Post subject: Re: Problem with PdfImage

Posted: Tue May 24, 2011 12:07 pm

PDFsharp Guru

Joined: Mon Oct 16, 2006 8:16 am
Posts: 3101
Location: Cologne, Germany

tom 88 wrote:

Unfortunately I'm not allowed to provide any internal documents =/

I don't care what the image shows. It just has to be the format that leads to the problem.

Which format? Which tool?

OT: Recently we found that greyscale JPEGs created with IrfanView cause problems while other greyscale JPEGs work fine.

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Thomas Hoevel
PDFsharp Team

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tom 88

Post subject: Re: Problem with PdfImage

Posted: Tue May 24, 2011 12:28 pm

Joined: Tue May 24, 2011 9:40 am
Posts: 5

Transformed the tif (originally came from fax) to 2 png files using CxImage libraries.
Afterwards I tried to add these png's to a new pdf document.

The one that caused problems looked pretty gray on the left side while the right side was of better quality.
=> this probably caused "isBitonal = -1" on line 645.

also changed the following to make it work (line 655)

Code:

if (isBitonal == 0 && !isGray)

Code:

if (paletteData.Length > 0)

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Thomas Hoevel

Post subject: Re: Problem with PdfImage

Posted: Tue May 24, 2011 1:25 pm

PDFsharp Guru

Joined: Mon Oct 16, 2006 8:16 am
Posts: 3101
Location: Cologne, Germany

I cleaned up the code. Now I create the palette when it is needed.
That should solve the problem.

Please find attached the current version of the file.

Attachments:

PdfImage.zip [9.79 KiB]
Downloaded 280 times

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Thomas Hoevel
PDFsharp Team

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tom 88

Post subject: Re: Problem with PdfImage

Posted: Tue May 24, 2011 1:29 pm

Joined: Tue May 24, 2011 9:40 am
Posts: 5

Thank you VERY much

Tested and works great!

Keep up the great work, it's a brilliant piece of software.

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