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 SaveToFilePDF creating huge PDFs		  New Topic  Reply to Topic
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EricNat

USA
37 Posts
Posted - Sep 26 2011 :  14:12:41  Show Profile  Reply
I am using TImageEnMView to acquire a scan using TWAIN and then save the acquired image as a PDF using SaveToFilePDF. The issue is that it is creating huge PDF files. A 4 page B&W scan at 200dpi is about 45MB. When I open it in Acrobat and "optimize" it, the file shrinks to 600kb. Here is what I am doing:

ScanView->MIO->SelectAcquireSource(ieaTWain);
if (ScanView->MIO->Acquire(ieaTWain)) {
ScanView->MIO->SaveToFilePDF("testscan.pdf");
}

I have tried adjusting the PDF_Compression value for each page, but that doesn't seem to affect anything.

Any thoughts?

Thanks,
Eric

fab

1310 Posts
Posted - Sep 26 2011 :  22:23:32  Show Profile  Reply
Hello,
you have to specify a compression method.
For example, for B&W images, the best is G4FAX, so you should write:

ScanView->MIO->Params[0]->PDF_Compression  = ioPDF_G4FAX;
ScanView->MIO->Params[0]->SamplesPerPixel = 1;
ScanView->MIO->Params[0]->BitsPerSample = 1;
ScanView->MIO->DuplicateCompressionInfo();
ScanView->MIO->SaveToFilePDF("testscan.pdf");

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EricNat

USA
37 Posts
Posted - Sep 26 2011 :  23:11:52  Show Profile  Reply
I have tried adding that code, but I still get large PDF files. Setting the compression doesn't seem to affect anything. Each page results in about 10MB in the PDF. Do you have any other thoughts?

Thank you.
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fab

1310 Posts
Posted - Sep 27 2011 :  04:57:25  Show Profile  Reply
It must work. I just re-tested it.
Make sure that:
1) BitsPerSample and SamplesPerPixel are both "1"
2) the input/output parameters are assigned at index "0"
3) you call DuplicateCompressionInfo()
4) you always reference the embedded "MIO" object, instead of a possible external TImageEnMIO object

Four common US Letter (at 200 dpi) pages should require about 15KB (while uncompressed is about 45MB).
This is the code I used for the test:

ImageEnMView1->MIO->SelectAcquireSource();
ImageEnMView1->MIO->Acquire();
ImageEnMView1->MIO->Params[0]->PDF_Compression = ioPDF_G4FAX;
ImageEnMView1->MIO->Params[0]->BitsPerSample = 1;
ImageEnMView1->MIO->Params[0]->SamplesPerPixel = 1;
ImageEnMView1->MIO->DuplicateCompressionInfo();
ImageEnMView1->MIO->SaveToFilePDF("test.pdf");
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EricNat

USA
37 Posts
Posted - Sep 28 2011 :  23:41:30  Show Profile  Reply
Thank you Fabrizio. I ended up getting it to work by doing two things -- I updated the component to the latest version (I was using an older version) and I had to also either scan in B&W or run ConvertToBW_FloydSteinberg() on each page before compressing and saving. That did the trick. Thank you.
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rogmartins

Brazil
2 Posts
Posted - Oct 11 2011 :  05:20:48  Show Profile  Reply
Hi !
Iīm having the same related trouble with both tif and pdf formats using the version 3.1.2
I canīt compile the code you suggested because it doesnīt have the DuplicateCompresseionInfo method.

How can i correct this anyway ?

My clients are so annoyed.

Thanks
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fab

1310 Posts
Posted - Oct 11 2011 :  08:56:09  Show Profile  Reply
Hello,
please re-check your code, because version 3.1.2 has DuplicateCompressionInfo method.
Otherwise please post your code.
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