I need help - I can help - Reduce PDF file size

Reduce PDF file size

Printed From: Debenu Quick PDF Library - PDF SDK Community Forum
Category: For Users of the Library
Forum Name: I need help - I can help
Forum Description: Problems and solutions while programming with the Debenu Quick PDF Library and Debenu PDF Viewer SDK
URL: http://www.quickpdf.org/forum/forum_posts.asp?TID=2846
Printed Date: 22 Nov 24 at 5:39PM
Software Version: Web Wiz Forums 11.01 - http://www.webwizforums.com

Topic: Reduce PDF file size

Posted By: kk aw
Subject: Reduce PDF file size
Date Posted: 12 Mar 14 at 10:14AM

I have a large pdf document, and I want to reduce the document size.

Can I use replaceimage and clearimage to reduce the document size?

In my test with both version 9.16 and 10.13, it does not seem to work.

The replaceimage function always returned 0. Does this mean that it failed?

Using the clearimage function by itself works and the image is no longer visible in the document. Unfortunately, the filesize is not reduced.

Replies:

Posted By: AndyD
Date Posted: 12 Mar 14 at 10:30AM

I expect you've already tried this but just in case, have you used the compress page function so that QP reduces your PDF as much as possible?

For a = 1 To QP.PageCount
Call QP.SelectPage(a)
Call QP.CompressPage
Next a

QP.SaveToFile (SaveString)

Worth mentioning just in case.

Posted By: AndrewC
Date Posted: 12 Mar 14 at 11:50PM

In versions of Debenu Quick PDF Library since version 8 or so the CompressImages flag has been set to true.

This flag does not resize images. All it does is turn on image compression so that when a PDF file is saved then the image data is compressed and stored much like a Zip file compresses a file. If the image data in the PDF is not compressed (quite rare these days) then compressing it will save some space. Most files will not be affected.

Currently if you would like to resample and downscale images then you would need to extract the image, load the image into an image processing library such as ImageEn, ImageMagick - process it and then call QP.ReplaceImage to replace the image with smaller compressed, lower quality image data.

Andrew.

Posted By: kk aw
Date Posted: 13 Mar 14 at 7:04PM

I use the following codes to convert the bmp image format to jpg image format:

procedure TMainform.ConvertImage1Click(Sender: TObject);

var

i,j,n: Integer;

ImgID, nImgID: Integer;

ImgCount: Integer;

ImgName1, ImgName2: widestring;

ImgType: Integer;

ImgConverted: Integer;

FPrivdir: string;

FileExt: string;

FFileName: string;

retval: Integer;

Fsize1, FSize2: Integer;

begin

Screen.Cursor := crHourGlass;

FPrivdir:= sm.slashAdd(LmdSysInfo1.TempPath);

FileExt:= sm.locase(ElcomboBox1.Text);

FSize1:= Qp.GetDocumentFileSize;

ImgConverted:= 0;

try

ImgCount := Qp.FindImages;

j:= 1;

imgId := QP.GetImageID(j);

while j <= ImgCount do

begin

qp.SelectImage(ImgID);

ImgType := Qp.ImageType;

if ImgType = 2 then

begin

ImgName1 := FPrivdir + Format('PdfImage%d.bmp',[j]);

ImgName2 := FPrivdir + Format('PdfImage%d.%s',[j,FileExt]);

QP.SaveImageToFile(Imgname1);

If sm.EqualIC(FileExt,'jpg') then

Bmp2Jpeg(ImgName1, ImgName2)

else if sm.EqualIC(FileExt,'gif') then

continue

else if sm.EqualIC(FileExt,'png') then

continue;

If FileExists(imgname2) then

begin

nImgID:= qp.AddImageFromFile(ImgName2,0);

if nImgID = 0 then

begin

ShowMessage('Cannot addimagefromfile '+ImgName2);

exit;

end;

end

else

begin

ShowMessage(ImgName2 + ' not found');

exit;

end;

retval:= qp.ReplaceImage(ImgID, nImgID);

If retval = 0 then

begin

ShowStatusBar('Image not replaced');

Sleep(500);

end

else

begin

retval:= qp.ClearImage(ImgID);

If retval = 0 then

ShowMessage('Image not cleared');

end;

FSize2:= Qp.GetDocumentFileSize;

Inc(ImgConverted);

end;

Inc(j);

imgId := QP.GetImageID(j);

end;

Screen.Cursor := crDefault;

If ImgConverted > 0 then

begin

ShowMessage(Format('%d Embedded images successfully converted.'+crlf+

'Originalsize: %d New size: %d',[ImgConverted, FSize1, FSize2]));

FFileName:= FSelectedFile;

n:= sm.posIC('.pdf', FFileName);

System.Insert('[IR]',FFileName, n);

Qp.SaveToFile(FFileName);

end

else

ShowStatusBar('No image to convert or converted');

finally

Screen.Cursor := crDefault;

end;

procedure TMainform.Bmp2Jpeg(const BmpFileName, JpgFileName: string);

var

Bmp: TBitmap;

Jpg: TJPEGImage;

begin

Bmp := TBitmap.Create;

Jpg := TJPEGImage.Create;

try

Bmp.LoadFromFile(BmpFileName);

Jpg.Assign(Bmp);

Jpg.SaveToFile(JpgFileName);

finally

Jpg.Free;

Bmp.Free;

end;

The image files in bmp and jpg as exported.

The retval in the line: retval:= qp.ReplaceImage(ImgID, nImgID) is always 0.

If I carry one regardless, qp.clearimage(imgid) returns 1.....

The image-replaced file size is slightly bigger than the original.

Any ideas what is happening?