Author Topic: Problem with transparency - and a workaround...  (Read 5408 times)

samps

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Problem with transparency - and a workaround...
« on: December 09, 2013, 04:30:17 am »
Having spent ten hours creating an end-of-year colour magazine for my daughter's primary school, I finally got to the point where I wanted to see a hard copy of it all. Exporting to PDF, choosing PDF 1.4 because of heavy use of transparency, only to see that all pages containing a JPG which had had its transparency changed with the Scribus F2,Transparency tool refused to export any content other than a coloured background.

The diagnosis of the problem was fairly quick, the workaround took an hour longer:

1. Change the F2, Transparency setting back to 100%,
2. right-click the image in question and choose 'Edit Image'.
3. Gimp fires up with the image loaded.
4. On Gimp's Layers Tool Menu is an Opacity Slider. Use that to set the desired transparency.
5. Export the transparent image as PNG by choosing File, Export from Gimp's main menu.
6. Back in Scribus, right-click your picture and choose 'Get Image' (or CTRL+I) and choose the PNG version you just saved from Gimp.

The transparency is now an inherent part of the file format and will print neatly to PDF 1.4

utnik

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Re: Problem with transparency - and a workaround...
« Reply #1 on: December 09, 2013, 09:44:37 am »
hi samps

what's your operating system and scribus version?
i never used scribus' transparency function for pictures – just tried it and it works well on macos10.6.8/scribus1.4.3 – exports a perfect .pdf file…

utnik

samps

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Re: Problem with transparency - and a workaround...
« Reply #2 on: December 09, 2013, 11:40:36 am »
OS is Ubuntu 13.10 and Scribus is 1.5.0svn from PPA

The document that won't print to PDF has three layers of transparent polygons with a single transparent (made transparent using the F2, Transparency tool in Scribus) JPG, scaled to cover the whole A3 page.

The error is reliably reproducible on my computer.

1. Place a rectangle on a page
2. Colour it and change transparency to 20%
3. Place an Image Frame on top of the rectangle from 1.
4. Use Get Image to fill the Image Frame with some JPG
5. Set the Transparency of the JPG to 20%
6. Export to PDF 1.4
7. View the produced PDF in Adobe Reader or Evince Document Viewer. It is blank

utnik

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Re: Problem with transparency - and a workaround...
« Reply #3 on: December 09, 2013, 02:15:00 pm »
hi samps

looks like a bug. you should file a report on bugs.scribus.net.
the best 'workaround' for problems in development versions of every program should be to try first with the stable version…

utnik

GarryP

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Re: Problem with transparency - and a workaround...
« Reply #4 on: December 09, 2013, 03:13:32 pm »
samps, just for a bit of extra info I tried your workflow and got the following results:

On OS X 10.9, Scribus 1.4.3:

Adobe Reader 9.5.5 - PDF looks as expected, rectangle and image (OKAY).
Preview - OKAY.
Skim 1.4.2 - OKAY.
Firefox 25.0.1 - OKAY.
Safari 7.0 - OKAY.
Chrome 31.0 - OKAY.
Chrome Canary 33.0 - OKAY.

On Ubuntu 13.10, Scribus 1.4.2:

Evince - Image is missing.
ImageMagick (display) - OKAY.
GNOME Document Previewer - Image is missing.
MuPDF 1.2 - OKAY.
Firefox 25.0.1 - OKAY.
Chrome 31.0 - OKAY.

It looks like there are some differences between viewers but most show the document just fine when generated from stable Scribus versions.

If you can find a reader that displays the document without issue then I’d say it might not be a bug with Scribus but, in this case, there is a chance that Scribus isn’t quite creating the PDF correctly, which would be a bug, if it wasn’t properly following the rules.

So, I’d say that utnik’s suggestions are both perfectly valid. Try using a stable version first - if at all possible - then, if you still get the problem, file a report - if you can - and let the developers see if it’s a bug or not (they are best placed to decide).

samps

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Re: Problem with transparency - and a workaround...
« Reply #5 on: December 10, 2013, 02:03:44 am »
Utnik, GarryP,


Thanks for doing the testing on other configurations.

I will stick with my workaround for this publication, too late to change horses now...

Once done, I will take it through the wringer with a stable Scribus version and file a bug report for the 1.5.0svn version, but for now, I gotta a year book to finish,

:-)
Samps