How to control LibreOffice Draw PDF export file size?

[Parthenolide]

I am exporting LibreOffice Draw (odg) files into pdf. In older versions, LibreOffice Draw would create an 8M pdf file from a 52.8M odg file. This 52.8M odg file now converts into a pdf that is about 19M.

This odg file mostly contains jpg images. I suspect that the older version was compressing the jpg files more. I don’t see a setting for jpg compression or pdf compression on LibreOffice.

Any help would be appreciated.

[Parthenolide]

The issue appears to be due to an LibreOffice Draw upgrade. Version 5.0.6.3 produces smaller pdfs. The latest version 5.2.5.1 produces significantly larger pdf files. There doesn’t appear to be a setting to control the file size.

The work around is to import lower quality jpg files.

[john_hudson]

The issue is more to do with the fact that the PDF is having to cope with bit-mapped rather than vector images. LibreOffice uses a vector format by default. So, if you were able to convert the JPEGs to a vector format (perhaps using Inkscape), you would find that LibreOffice would naturally generate much smaller files.

[Akoellh]

@john_hudson

The issue is more to do with the fact that the PDF is having to cope with bit-mapped rather than vector images. LibreOffice uses a vector format by default. So, if you were able to convert the JPEGs to a vector format (perhaps using Inkscape), you would find that LibreOffice would naturally generate much smaller files.

This is not generally true.

Using a vector based format would only make sense if the original data for a picture actually is vector based, let’s say for some CAD image, a chemical structure drawing or a (more or less) simple logo.

If you would try to convert a photo of let’s say your grandma to a vector based format, this would -if it works at all- produce a much bigger file.

AK

[I_A]

from Draw if you select file=>export to pdf
the pdf export dialog appears there you can set the jpeg q factor
the default is q=90% you can try reducing it to 80 or 75
imo the biggest problem with jpeg in pdf is a lot of people embed extremely large images which are then downsized, downsampling images can reduce the output
https://help.libreoffice.org/Common/Export_as_PDF#Images

[john_hudson]

@Akoellh

This is not generally true.

Using a vector based format would only make sense if the original data for a picture actually is vector based, let’s say for some CAD image, a chemical structure drawing or a (more or less) simple logo.

If you would try to convert a photo of let’s say your grandma to a vector based format, this would -if it works at all- produce a much bigger file.

AK

Since the OP is using LibreOffice Draw, I would be surprised if the images are photos though perhaps they are. Almost any diagrammatic bitmap image with less than eight distinct colours can easily be converted into a vector using Inkscape - I have been doing it for years. It also makes them so easy to edit.