Issue #142 resolved

Block corners are distorted when using pdflatex and flash-based pdf viewer

linjaaho
created an issue

Slides made with beamer+pdlatex and viewed with any flash-based pdf-reader (in Slideshare, Scribd etc.) will show some clutter in the corners of the blocks (alertblock, exampleblock etc.).

If you look the slide number two here: http://www.slideshare.net/linjaaho/latex-and-slidesharefinnishfinal-7275984

you see the problem. By downloading the pdf and opening it with Adobe Reader you see no distorted elements.

There is a detour: if you use latex+dvips+ps2pdf, the problem disappears. The problem is probably related to embedding fonts in the pdf file, but I have not been able to investigate it deeper.

Finally, I'm not sure if the real bug is in Adobe Flash or in Beamer.

Comments (4)

  1. linjaaho reporter

    I found a work-around: by compiling the slides using pdflatex --output-format dvi filename.tex dvips filename.dvi ps2pdf filename.ps

    There are no problems with the output viewed with flash player. This work-around is better than using latex+dvips+ps2pdf, especially if you have all your images in png/jpg format (latex requires eps images, pdflatex requires png/pjg).

  2. linjaaho reporter

    Someone has been having a slightly similar problem: http://www.latex-community.org/forum/viewtopic.php?f=5&t=7427

    I believe the solution is simply tweaking the commands related to forming that shadow, but I don't have enough expertise to do it. The shadow element is the thing which causes the actual problem, because if I specify: \setbeamertemplate{blocks}[rounded][shadow=false] or use a theme with sharp (not rounded) corners, there are no crappy output.

    Some people have written a version for different shades: http://old.nabble.com/Transparent-shadows-under-boxes.-td11357827.html http://old.nabble.com/-Patch--Real-transparency-for-shadows-td25529391.html

    I don't know if they fix this problem (I did not have guts to copy-paste their modifications to my working MikTeX-system :).

  3. linjaaho reporter

    I located the problem: Slideshare does not render correctly a shaded ball made with pgf. The ball is rendered as a square, as you can see in this example document I made: http://www.slideshare.net/linjaaho/beamerbug-8578652

    I also re-tested with Scribd and noticed that now both their Flash viewer and HTML5 viewer show the document correctly (last year, when I tried, this was not the case). My employer's intranet still shows the ball as a square.

    (The thing that all three pdf viewers I have used showed the document incorrectly, made me think that the bug is in Beamer, not in the viewers. Sorry.)

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