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  • Saturday, 12 November 2016
    LibreOffice session at DevTalks Jr. (Comments)

    (via DevTalksRo)

    Today I gave a Getting involved with LibreOffice Online and Android session at DevTalks Jr, Bucharest. The event had two tracks in parallel, with a total attendees of about 200 developers.

    Some photos I took after the event are available.

    Thanks the organizers and sponsors for the great event! :-)

  • Monday, 10 October 2016
    Insert PDF as image in LibreOffice 5.3 (Comments)


    LibreOffice 5.3 will add one more vector-based format that can be inserted as an image into documents: PDF. First, thanks to PMG who made this work possible. On the user interface you can now select PDF files when you choose e.g. Writer’s Insert → Image option:

    The first page of the PDF document will be shown, which is handy if the PDF file is basically used as a vector image format.

    Similarly to the SVG feature, the original vector image is stored in the document, but when saving to ODF, a replacement PNG file is also generated to be backwards compatible with older ODF readers. The image context menu → Save menu item allows to extract your original PDF data from the image, too:

    And that’s it, as long as you save your document in ODF, your PDF-as-an-image will be kept without loosing any data. As usual, you can try this right now with a 5.3 daily build. :-)

    However, if you’re interested in how this is implemented, keep reading…

    Document model

    The PDF image in the document model is really similar to how SVG is handled, next to Graphic::getSvgData(), there is now a Graphic::getPdfData(). This new member function exposes the original PDF data, otherwise the Graphic is just a metafile.


    The ReplacementGraphicURL property of the image at an UNO level now exposes the generated metafile for PDF images. This is implemented for both Draw and Writer images, and is used by the ODF export filter.


    When the Graphic instance is rendered, the layout knows nothing about the PDF data attached to the object, only parses the generated metafile. This way the display of the PDF image works out of the box.


    First I’ve implemented a PDF import-as-graphic filter, then the export equivalent of it. As you can see, the PDF import-as-graphic filter isn’t too complicated, it completely reuses the existing "import PDF into Draw" filter, it simply copies the first page of the resulting document model as a metafile.

    Second, once the graphic filters were working, I’ve also improved the ODF import to recognize PDF data — the export side needed no explicit work, once the ReplacementGraphicURL bits were in place.


    As mentioned above, the Draw and the Writer image implementation is separate, so first I’ve added tests for ODT files in the testEmbeddedPdf of CppunitTest_sw_odfexport, and then SdExportTest::testEmbeddedPdf() to cover ODP files (and other ODF formats). Second, the PDF part of the graphic swapout/in code has a dedicated test in GraphicObjectTest::testPdf(), and the UI’s "Save original PDF" feature has a new XOutdevTest::testPdfGraphicExport() test.

    Oh, and if you intent to test this manually in a self-created build, make sure to avoid --disable-pdfimport, otherwise this feature can’t work. ;-)

  • Monday, 03 October 2016
    Small capitals toolbar button in LibreOffice Writer (Comments)

    It was requested to be able to set the small capitals character property via a toolbar button in Writer, which was indeed not possible. Not only the toolbar button wasn’t there, but the underlying UNO command was also missing (which you can use e.g. from a macro to format the current selection).

    So my commit added a simple set of icons to the galaxy theme for the new toolbar button, defined the new UNO command for Writer text and added it to Writer’s text object bar, next to the upper case and lower case buttons (hidden by default). One difference from those buttons is that those buttons perform a transliteration, while this one really just sets a character property, you can easily undo the property later if needed.

    Wrt. other icon themes, see this mail, hopefully the design team can help there.

    As usual, you can try this right now with a 5.3 daily build. :-)

  • Tuesday, 13 September 2016
    Using clang-based tools beyond loplugin LOCon lightning talk (Comments)

    The last week I gave a Using clang-based tools beyond loplugin lightning talk at LibreOffice conference 2016, on the last day. Click on the image to see all the slides.

    If you’re a vim or emacs user and you work with C++11 code, you probably want to have a look at clang-rename, include-fixer and some editor plugin exposing the power of libclang (like YouCompleteMe or libclang-vim), sometimes these are really helpful.

  • Monday, 12 September 2016
    A year in LibreOffice's RTF support LOCon talk (Comments)

    Last week I gave a year in LibreOffice’s RTF support talk at LibreOffice conference 2016, in the development track. Click on the image to see all the slides.

    I’ve also published a number of (mostly) sightseeing pictures based on wondering around in Brno before and after the conference.

  • Friday, 09 September 2016
    Collaborative editing using LibreOfficeKit LOCon talk (Comments)

    Yesterday I gave a Collaborative editing using LibreOfficeKit talk at LibreOffice conference 2016, in the development track. There were many interested parties — not a surprise, as this is the power horse behind LibreOffice Online. :-)

  • Thursday, 08 September 2016
    Improved digital signature handling in LibreOffice LOCon talk (Comments)

    Earlier today I gave a Improved digital signature handling in LibreOffice talk at LibreOffice conference 2016, in the development track. The room was well-crowded — seems this year classification was a hot topic. ;-)

    Quite some pictures are now available on Twitter, don’t miss them.

  • Friday, 05 August 2016
    LibreOffice now bundles the latest libxmlsec version (Comments)

    I wrote about how LibreOffice uses the XMLSec Library in an earlier post from March. There are two long-term goals regarding xmlsec in LibreOffice:

    • bundle the latest xmlsec version, instead the one from 2009

    • upstream enough of the patches, so building & running against xmlsec as provided by a Linux distro also works

    I’m happy to say that the first goal is now reached:

    • libreoffice-5-1 bundled xmlsec 1.2.14 from 2009

    • libreoffice-5-2 bundles xmlsec 1.2.20 from 2014

    • master bundles the latest xmlsec 1.2.22, released earlier this year :-)

    This is good, as this way it’s easier to integrate xmlsec upstream improvements into LibreOffice in the future.

    Regarding the other goal, shrinking the patch list is still to be done. ;-)

  • Monday, 25 July 2016
    A LibreOffice / AddressSanitizer setup (Comments)

    sanitizers (ASAN, UBSAN, etc.) is a collection of tools to detect memory corruption bugs, undefined behavior and more by instrumenting the code generated by the compiler. (That’s the main difference from valgrind.) From LibreOffice’s perspective one more important difference is that there is a Jenkins_Linux_Ubsan tinderbox that makes sure that the master branch is kept clean from errors detected by a given configuration.

    So when the tinderbox failed after a commit of mine, I wanted to set up a similar environment locally, reproduce and fix the bug, and push the fix once I saw that the fix indeed solves the problem. You can set many options both at build and runtime, so while we have some documentation on the TDF wiki (and also Stephan was kind enough to share his config) on how to use these sanitizers, it wasn’t clear to me what to do step by step. So here is one possible setup that worked for me — in my case I wanted to reproduce a stack-use-after-return problem. If you haven’t ever built LibreOffice before, then go to the Development wiki page, first do a normal build, and if everything went fine, came back here.

    Build options

    My autogen.input looks like this:

    CC=clang -fsanitize=address
    CXX=clang++ -fsanitize=address

    Which is a normal clang debug build, except:

    • you need to add -fsanitize=... to CXX (not to CXXFLAGS), as explained on the wiki

    • you need to explicitly disable Firebird integration for now


    My first attempt failed at build time, as even the tools used only during the build are instrumented, and some memory leak was detected there, which means the build aborted before reaching the problem I was interested in. To disable leak detection during build, and disable parallelism (I needed this, as I did the build in the background while using the machine for something else):

    make build-nocheck ASAN_OPTIONS=detect_leaks=0 PARALLELISM=1

    This also means that I explicitly disabled running any tests, as I knew which is the single unit test I want to run for the purposes of reproducing and fixing the problem.


    Once the build completed, it turns out that the stack-use-after-return detection is disabled at runtime by default, which means I could not see any problem locally. Here is the commandline to run one specific CppunitTest with this detection on:

    cd sw; make -sr CppunitTest_sw_tiledrendering ASAN_OPTIONS=detect_leaks=0:detect_stack_use_after_return=1

    Again, this is just one possible setup, you can use other -fsanitize=... options, other environment variables during build and during testing — but hopefully it helps in the future to avoid pushing fixes for such problems detected by sanitizers just blindly.

  • Monday, 18 July 2016
    On LibreOffice's ViewContact/ViewObjectContact/ObjectContact (Comments)

    I’ve recently fixed a missing-repaint problem in LibreOffice’s headless backend, but the root cause wasn’t close to the symptom I saw first. Part of the debugging process was to understand what’s the relation between sdr::contact::ViewContact, sdr::contact::ViewObjectContact and sdr::contact::ObjectContact.

    See this old presentation and the review of my documentation update for the details, but the short version is that:

    • somewhat confusingly, sdr::contact::ViewContact is part of the model, and there is one sdr::contact::ViewContact object per shape

    • sdr::contact::ViewObjectContact is part of a view, and there is one sdr::contact::ViewObjectContact per shape, per view

    • finally sdr::contact::ObjectContact is part of a view, and there is one sdr::contact::ObjectContact per view

    So the answer to my original Is it normal that I have two object contacts and a single view contact for a shape and two views? question is: yes, that’s expected. ;-) Hopefully the updated documentation is now more clear, the incorrect 1:N relation in the original class diagram first confused me.

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