February 2014 - Inkscape Devel

Swatch dialog has a serious bug
by Johan Engelen 03 Mar '14

03 Mar '14

Hi all, I just discovered a very serious bug in the swatches dialog (/src/ui/dialog/swatches.cpp). Using a vector of DocTrack*, it tracks all current documents, and using a timer callback updates itself. The problem is, no DocTrack* is ever removed from that list. A DocTrack* (that points to an SPDocument) is added whenever you open a new document. Then when closing a 2nd document, the DocTrack* should be removed from the list and ~DocTrack should be called. Because this is _not_ happen, the timerfunction will use an already deleted SPDoc and will eventually crash in SPDocument::getResourceList (priv is set to nullptr for deleted SPDoc). I added proper ref-counting of the SPDoc object in DocTrack's constructor and destructor, but still the SPDoc is deleted and the crash occurs. Some code in swatches.cpp looks unfinished, creating data structures that are never used... Thanks for any help in tracking down and fixing the issue, Johan

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Why is the position of this line of code so touchy?
by mathog 28 Feb '14

28 Feb '14

In the files in src/display there are many instances of this Inkscape::DrawingContext::Save save(dc); First thing, I don't understand the syntax. What does the lower case "save" in that line indicate? The only places "::Save save(" appear in the source code are instances of this line. Secondly, it acts strangely. Moving it around breaks graphics for some reason that escapes me. For instance this: Inkscape::DrawingContext::Save save(dc); //PROBLEM LINE dc.transform(aff); double thickness = decorateItem(dc, aff, phase_length); dc.setLineWidth(thickness); dc.strokePreserve(); dc.newPath(); results in mangled graphics (text decoration drawn as if with a very thick line, but in what appears to be the correct location), whereas moving the first two lines above into double DrawingText::decorateItem(DrawingContext &dc, Geom::Affine const &aff, double phase_length) as the first two lines of that method results in normal graphics (text decoration drawn with the expected line thickness). That is: line1 line2 call is broken but call (inside called function) line1 line2 works. Moving "dc.setlinewidth()" from the position shown above into decorateItem() as the line before its return does not make any difference in either of these cases. decorateItem() just defines a cairo path with moveto/lineto on _ct in dc, it doesn't touch anything else in the dc. Using the debugger and stepping through showed that execution of the problem line passes through this: DrawingContext::Save::Save(DrawingContext &dc) : _dc(&dc) { _dc->save(); } in drawing-context.cpp. _dc->save() just does cairo_save(_ct); I have never seen anything quite like this when using cairo directly, that is, calling cairo_save() and cairo_restore() has never resulted in mysteriousness of this level. And that seems to be mostly what the DrawingContext does - it keeps track of (private) cairo_t *_ct; I would have thought that passing dc by reference should have made the position of the problem line before the call, or just within the called function, a moot point, but apparently not. This is so even though when the address of _ct was checked with dc.raw(), before and after the problem line, it didn't change. Whether or not the problem line was before or inside decorateItem(). Can somebody please explain what is happening here? Thanks, David Mathog mathog@...1176... Manager, Sequence Analysis Facility, Biology Division, Caltech

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Href sub-document model
by Martin Owens 28 Feb '14

28 Feb '14

Hey developers, This is the model I'm going to implement for documents to reference other documents: SPDocument { GSList *child_documents; SPDocument *parent_document; // Parent of parents until parent == NULL; SPDocument *getRootDocument(); } Then in uri-reference, check paths of existing child_documents, load the referenced document and add to child_documents. Set parent_document. That should keep things consistant. The idea here is that we'll use this to track documents referenced in <use tags> as well as <image tags> and attributes like 'marker-*: url(...);' but not for non-vector graphics used in the image tag. Thoughts? Advice? Best Regards, Martin Owens

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Image Data URIs
by Martin Owens 28 Feb '14

28 Feb '14

He devs, I've been trying to read up on image tags special case, where a href will start with data: and then proceed to have data. Since I want to merge most of the sp-image logic into Inkscape::URI I need to know if data uris are something the svg spec says should only be available to image tags... or should be available to any href. The svg 1.1 spec says nothing about data uris that I could find. Any ideas? In the end, I want hrefs to be able to be loaded, processed into localised absolute references and even parsed for data if that's generic. From the same Inkscape::URI object. Does this seem sensible? I note the css url(...) handler isn't the same as the href handler; so should something be done to help those converge too? Any thoughts would be appreciated. Martin,

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Inkscape joins the Open Invention Network
by Bryce Harrington 28 Feb '14

28 Feb '14

Inkscape has been invited to join as a member of the Open Invention Network. On Tuesday, the Inkscape Board voted in favor. In so doing we pledge to never use patents aggressively against the Linux System. We would never do this of course so the step is merely symbolic, but an important symbol. We are joining almost 750 projects and companies from the software industry (see http://www.openinventionnetwork.com/licensees.php) in a pledge that covers over 2,100 Open Source packages. This helps to reduce risk on the core Linux System and other middleware technologies. Valer Mischenko of OIN sums it up: "This is the largest community to address software patent challenges in the world. The idea is: when everybody pledges freedom, there will be no wars." For more information, please read on, or go to openinventionnetwork.com Bryce ------------------------------------------------------------------------ Subject: Re: [Inkscape-board] [REFERENDUM] Should Inkscape Join the Open Invention Network? Resolved: The Inkscape Project agrees to join as a member of the Open Invention Network. In so doing we pledge to never use patents aggressively against the Linux System. Votes: Five votes in favor, none against. Motion passes. Josh Andler a Johan Engelen a Bryce Harrington a Jon Cruz a Tavmjong Bah a (Votes not received from Ted Gould and Mental Guy) http://sourceforge.net/mailarchive/forum.php?thread_name=20140225080118.GB2… On Sun, Feb 23, 2014 at 11:38:07PM -0800, Bryce Harrington wrote: > Proposal: > > [ ] a. Join the Open Invention Network (OIN). Pledge that the > Inkscape organization would never use patents aggressively > against the Linux System. > [ ] b. Remain independent from the Open Invention Network. > > > Background: > > Hi Bryce, > > My name is Valer and I am writing to you on behalf of the Open Invention > Network (OIN). Our mission is to support projects developing or using > Linux-related and open source technology by deterring patent aggression. > > We do this through a community that pledges not to assert patents > against each other over the Linux System technology. This pledge covers > over 2,100 Open Source packages. It is structured to reduce risk on core > operating system and middleware technologies. Almost 750 projects and > companies from all areas of technology creation, deployment and use have > joined our community so far (see not very up to date list: > http://www.openinventionnetwork.com/licensees.php) > > We want to invite Inkscape to our community. > > You may be interested in our community credentials and to get some more > context about our work. Here is an endorsement from Eben Moglen, > Chairman of the Software Freedom Law Center: > http://emoglen.law.columbia.edu/now/organizations/OIN > > Here is an endorsement from Jim Zemlin, Executive Director of the Linux > Foundation: > http://www.linux-foundation.org/weblogs/jzemlin/2009/09/09/protecting-linux… > > Our community is free to join. The only thing we want is a pledge that > Inkscape would never use patents aggressively against the Linux > System. Of course it never will, and that's a symbolic gesture, but it > remains very important for our work. When we also bind big companies > with this pledge we are sure they will not attack ç in this context for > example. But their participation in OIN is also very important in > various other aspects. > > And these companies are numerous. For example Valve Software and Dropbox > are on of the latest bigger companies joined in. UnitedStack from China > joined just a weeks hours before. Pretty much everyone else is in there > too, from Red Hat to GNOME, Fujitsu to CentOS, Google to KDE to > OpenStack Foundation. This is the largest community to address software > patent challenges in the world. The idea is: when everybody pledges > freedom, there will be no wars. > > We are passionate supporters of the Linux System and open innovation. I > hope we can work together by welcoming Inkscape to our non-aggression > community. Every single voice helps us face current market challenges > while investing in a more collaborative future. > > Attached is a very short overview of OIN + FAQs, but I am happy to > answer any questions and to explain in more detail why the pledge of > Linux System and open source patent non-aggression is so important for > open innovation. > > May you decide positively there is a possibility to sign online: > http://licenses.openinventionnetwork.com > > Please consult to Johan, Tavmjong, Ted and Josh and let me know what you > guys think. > > Regards, > Valer Mischenko, > Open Invention Network > > www.openinventionnetwork.com

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Potential GSoC 2014 project
by Krzysztof Kosiński 28 Feb '14

28 Feb '14

Hello As promised, here is a description of the project I could do as a student. The end goal of my MSc project is to write an OpenGL-based 2D scene graph library usable by Inkscape which is capable of displaying most of SVG. Unlike the Cairo OpenGL backend, this library would keep the data on the GPU as long as it's used, and only control points of the curves would be submitted to the GPU, which should give very good performance. However, this project has several prerequisites. The OpenGL drawing algorithm I'm thinking about (Loop-Blinn) handles only quadratic and cubic Bezier fills, so it would require substantial support from 2Geom to render SVG. http://http.developer.nvidia.com/GPUGems3/gpugems3_ch25.html For this GSoC, my proposal would be to implement boolean operations and the stroke-to-fill transformation in 2Geom (since I think the latter depends on the former). Some of the required code is already present, for example the code to compute the offset of a single curve, but it's not exposed in an usable form. The project would be both about implementing the missing parts and providing an easy to use API. Here are the potential work-items: 1. Convert Geom::PathVector to a real class. 2. Investigate whether it is possible to store curve data in a more efficient format that does not store every curve endpoint point twice (as a start point and as an end point). 3. Provide and document an API to the existing intersection code. 4. Provide and document an API to the existing curve offset code. 5. Implement path uncrossing and monotonization. 6. Implement boolean operations, based on the algorithm used in CGAL. If necessary, add CGAL as a dependency - this is now acceptable, because CGAL in Debian no longer depends on Qt. 7. Implement stroke-to-path. As a backup option, I'm considering changing my MSc project to implementing a Python scripting console for Inkscape. If I were to pick that instead, the GSoC project could involve a variety of refactoring tasks intended to simplify writing the Python bindings used by the console. In this case, I'm 100% sure that I could do it, whereas in the case of OpenGL I still have some doubts, mainly because I haven't programmed in OpenGL yet. Regards, Krzysztof

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Wiki down again
by John Cliff 28 Feb '14

28 Feb '14

Hi guys, The wiki seems to be down again, have checked with a couple of is it up type sites, and their all unable to see it. Have pinged an email to the osuosl support address about it. Thought I'd let you all know before anyone else did too. Cheers John

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Ellipses and other shapes may be modified on load
by Krzysztof Kosiński 28 Feb '14

28 Feb '14

Hello It looks like the recent changes to make ellipses use the correct SVG element cause incomplete undo events being left on the undo stack when a document containing old ellipses is loaded. To see for yourself, load the attached document and press Ctrl+Z. This is causing crashes in some scenarios, one of which is detailed here: https://bugs.launchpad.net/inkscape/+bug/1001756 The culprit is the update_patheffect() function of SPGenericEllipse, which writes to the XML tree and is called by document->ensureUpToDate(). This write happens even if the object in question does not have any path effect. Under the SP tree model, writing to the XML tree in response to view changes or update events is not permitted. For now, I have hacked around this by disabling undo tracking when ensureUpToDate() is called from SPDesktop::init(), but the proper solution would be to avoid rewriting the LPE result when loading, and prevent the update_patheffect() function from rewriting shapes which do not have any LPEs. Regards, Krzysztof

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Summer of Code 2014
by Josh Andler 27 Feb '14

27 Feb '14

Hey All, We've been accepted again as a mentoring organization for Google's Summer of Code. This is the 10th year they've held it and our 10th year participating! If you're a potential mentor or student, please sign up at melange (1). If you are interested in participating as a student please visit our page on Melange (2) to find links to our Ideas for summer projects on our wiki and our developer mailing list. As usual, please either introduce yourself on our developer mailing list or let us know what you're interested in working on this year. Cheers, Josh (1) http://google-melange.appspot.com/ (2) http://google-melange.appspot.com/gsoc/org2/google/gsoc2014/inkscape

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Re: [Inkscape-devel] URI
by Markus Engel 26 Feb '14

26 Feb '14

> auto initalising (c++ does this right?), C++ implicitly calls the default constructor for allmembers that are not initialized in the containing class's constructorinitializer list. Note that only *objects* are default initialized this way,atomic types are not (int, pointers, ...). They contain garbage until youassign them a value. class Member { public: Member(int i) {} }; class Container { public: Container() {} private: Member member; }; Thus, this will not compile. Instead you'll have to writethe constructor this way: Container() : member(42) {} I'm not sure whether you should add a parameterlessconstructor to Inkscape::URI. I mean, is an empty uri valid? Does it make senseto be able to create an uri this way, or is it's "path" necessary forthe object to have any sense at all? Regards, Markus -----Ursprüngliche Nachricht----- Von: Martin Owens [mailto:doctormo@...400...] Gesendet: Mittwoch, 26. Februar 2014 13:32 An: Krzysztof Kosiński Cc: Markus Engel; inkscape-devel Betreff: Re: [Inkscape-devel] URI Digging into the job, I've ripped away dom/* and most ofthe code works. I've ported color-profile.cpp which was using thedom::URI to Inkscape::URI and the same replacement can be done to odfextension. A missing piece was zipfile support. src/dom/util/ziptool.cpp/.h was a self-contained zipimplementation so I've moved that to src/util/ since it has no equivalentfunctionality. That worked well. I've hit a small problem with Inkscape::URInot having a constructor with no-arguments which I think can be solved byadding an OdfOutput constructor which initalises the URI instead of it autoinitalising (c++ does this right?), but this seems odd to me as if the Odfshouldn't initalise the URI until it needs it. Thoughts? Best Regards, Martin Owens

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