- Inkscape Devel - Inkscape Mailman

dealing with broken external functions
by Paul Beard 06 Jun '13

06 Jun '13

After being told that the changes to a bug report aren't valid*, I decided to look into how hard it is to simply take broken functions off the menu, from the user perspective. > To remove the plt conversion as an option, I found that simply moving the Contents/Resources/extensions/plt* files to a subdirectory took them off the menu in the save dialog. For whatever reason, the HPGL and SK1 conversions work and I assume they draw on the same libraries. > > That seems to be the simplest solution to the frustration of seeing features you can't use. No changes to executables or removal of dependencies, just making a broken option invisible. If it gets fixed at a later date, an update script or a new point release could be made available. > I'm sure this seems like a trivial issue for most, but if broken dependencies/features illuminate why the OS X releases are out of sync with Windows and linux, it seems relevant. I don't see why an external function should add to any delay in getting a release out the door, if references to it can be easily removed and restored. I thank the developer(s) who persevered and built these Inkscape RCs, not only as updates but making it into a full OS X app, getting away from X-Windows. * https://bugs.launchpad.net/inkscape/+bug/1187197 -- Paul Beard Are you trying to win an argument or solve a problem?

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Re: [Inkscape-devel] [cairo] Tentative patch for downscaling in Cairo
by Krzysztof Kosiński 06 Jun '13

06 Jun '13

2013/6/4 Chris Wilson <chris@...2923...>: > On Sun, Mar 31, 2013 at 05:03:36AM +0200, Krzysztof Kosiński wrote: >> Hello >> >> I had a look at how complex would it be to add correct downscaling to >> Cairo now that Pixman supports convolution filters. It turns out it >> this is rather easy. Here is an initial, minimal attempt. It uses >> convolution filters only if the image is being downscaled by more than >> half a pixel in at least one dimension. > > Looks very nice. My plan at the moment is to finish a bugfix 1.12 > release, then start on 1.14 to add some new API. This improvement would > be better in a major release, so I'll add it then. Great! Having proper downscaling in Cairo would really make our life easier :) >> Some discussion: >> >> 1. The sampling and reconstruction kernels are picked in a way that >> gives comparable quality when upscaling and downscaling. I paired box >> sampling with bilinear reconstruction and impulse (point) sampling >> with box reconstruction. This gives the expected result for NEAREST >> filter. BEST filter uses Lanczos3 for both kernels. > > Do we need to use a reconstruction filter for NEAREST at all? Or maybe > differentiate between NEAREST and FAST in that case? If impulse (point) sampling is used, there must be some reconstruction filter, otherwise no image is produced. That's because the sampling grid does not match the data grid, and since there is no reconstruction filter, values between data points are undefined. The alternative is to use box sampling + no reconstruction. Regards, Krzysztof

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[Units] Unit Refactor
by Matthew Petroff 05 Jun '13

05 Jun '13

I am going to working on refactoring and then improving Inkscape's unit handling this summer for Google Summer of Code. I plan on posting regular progress updates on my blog [1] and summaries of the updates here. I have branched the repository for the first phase of my project [2] and will merge the changes back into the trunk once it is done and create a new branch for the second phase. I look forward to working with the Inkscape community this summer. -Matthew [1] http://www.mpetroff.net/archives/category/programming/gsoc/ [2] https://code.launchpad.net/~matthewpetroff/inkscape/gsoc-2013-unit-refactor

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SVG vs. EMF+
by mathog 05 Jun '13

05 Jun '13

Hi all, I'm having a look through EMF+, which is the metafile type corresponding to GDI+, to see what is in it that would add SVG features not currently representable in EMF (vanilla GDI). So far... These would be worth having: 1. Objects with colors that are RGB + Alpha. GDI uses only RGB and mixing operators to emulate opacity, the mixing operators are complex and I did not implement 99% of that in the present EMF input/output code. 2. Gradients. EMF has gradients, but the rectangular gradient record is apparently toxic - I have yet to find an application, including from Microsoft that can accept one. The majority of programs that write EMF files work around this by writing scads of tiny rectangles to emulate the gradient. (By majority I mean no programs, other than the ones I wrote, generate EMF gradient records.) Possibly the EMF+ gradients are not toxic so input/output of SVG gradients can stay as gradients and not have to be emulated. 3. Expanded hatch patterns (up from 7 in GDI [essentially] to 52). 4. Custom line caps. It is not clear to me how many of the other features in GDI+ have SVG equivalents. For instance: 5. Compound lines. GDI+ can draw a line with what is essentially a row of pens of various widths. Define a pen with a narrow stroke, space, wide stroke, space, narrow stroke, and draw a rectangle, and the result is a set of 3 nested rectangles, with a fat central stroke and thinner strokes inside and outside of it. Can SVG do this? I'm thinking one would have to import this in a loop, and create the rectangles one by one with the appropriate "sub" pen. 6. Clipping regions can be combined with XOR, UNION, INTERSECT and so forth. However, I do not recall in the present EMF output that clipping information is passed into the driver. Rather I vaguely recall that it was applied many levels above and the clipped shape is what is sent to the output driver. Other than for clipping there does not seem to be a way to create compound regions using these operators. I don't think SVG has these operators for general shapes either. Inkscape performs these operations on paths, but just puts the combined path in the SVG. 7. Graphics containers. Apparently the point of these is to provide a way to segregate high cost operations (like antialiasing) from low cost ones (a normal draw). So on one screen set up different containers and the quality sensitive ones are sent into the high cost container, while everything else goes into the lost container. For a Metafile this makes no sense, we are not interested in real time performance, and all objects should remain high quality. 8. Gradient curves. GDI+ does this by specifying an array of points (the curve) and a corresponding array of colors, and then some rules about how to interpolate colors. (Fill is another story, that uses a brush with a defined gradient.) I could not find an example of SVG stroking a gradient curve like this, other than by breaking it down into a series of separate line segments of slowly varying color. One thing that is definitely not a step in the right direction EMF to EMF+, at least in terms of dealing with the resulting metafile: 9. Remarkably few EMF+ objects and records have a fixed size. There are so many "optional" and "variable" fields that most objects and records cannot be represented with a struct. There were some complex EMF records, as for image storage, that were like this, but most EMF records had a fixed memory layout, so one could map a pointer in memory to a struct, and then just reference the values in that record by field names. That rarely works for EMF+ records. Regards, David Mathog mathog@...1176... Manager, Sequence Analysis Facility, Biology Division, Caltech

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[ReColor] GSoc 2013
by Arshdeep Singh 04 Jun '13

04 Jun '13

Hello all, I am very excited to be on board. Sorry for the late reply, I had some formalities to complete at my University post my end semester exams. I shall begin my requisite research for the project in one-two days. -- Arshdeep Singh (demicoder) Third Year, Computer Engineering Delhi Technological University Ph: +91-9654115614 https://sites.google.com/site/adsingh1729/home

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Additional pdf type for export.
by john Culleton 03 Jun '13

03 Jun '13

It would help if Inkscape could produce a pdf file in the PDF X-3 format. That gets around the CMYK problem insofar as many printers have new printer and prepress software (e.g., LSI, Brandt-Doubleday) that will handle the conversion automatically from RGB to CMYK. I can always import into Scribus and then export in PDF X-3 but that is an extra step. -- John Culleton Wexford Press Free list of books for self-publishers: http://wexfordpress.net/shortlist.html PDF e-book: "Create Book Covers with Scribus" available at http://www.booklocker.com/books/4055.html

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Re: [Inkscape-devel] GSoC 2013: Implement a new raster-to-vector algorithm...
by Vinícius dos Santos Oliveira 31 May '13

31 May '13

2013/5/31 Martin Sucha <martin.sucha-inkscape@...2313...> > What about something like libdepixelize? Although the name does not > exactly mention pixel art, it seems it does not yield any hits in google > yet. My concern was about the name of the symbols/variables/classes/..., not the library per se. The library could implement (as you stated) other algorithms in future and should use a generic name. The potrace tool ( http://potrace.sourceforge.net/ ) uses the name tracing to refer to this technique. I like both names (libtracer, libdepixelize) and other names also (libvectorizer) and whatever you guys choose is fine to me. -- Vinícius dos Santos Oliveira https://about.me/vinipsmaker

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Re: [Inkscape-devel] New Inkscape Website (Staging)
by Martin Owens 31 May '13

31 May '13

Nicolas, Thanks for getting back to me with some fantastic questions. I've pushed the conversation to the inkscape developer mailing list so others can stay up to date and offer their ideas. ... On Fri, 2013-05-31 at 14:34 +0100, Nicolas Dufour wrote: > I've started to work on translating pages and parts of the UI. > Django-CMS is a bit complex and its website documentation somewhat > cryptic, but it looks very interesting, and quite convenient for a > translator. It can take one like that. The template formula for including blocks of CMSable widgets is something that may require refinement as we go forwards. Especially for the front page. For now, we're using the most basic formulations. > I've just added a bug report about translated menus that are split in > two lines and cause some issues > (https://bugs.launchpad.net/inkscape-web/+bug/1186235). It's a very > annoying problem, but I'm sure it won't be too difficult to solve. I > also have some questions: I saw the problem with the french menu and have already contacted the designer and some other people to help solve the issue. There has been no response as of yet, partly because of classes/exams. If anyone else wishes to help solve the bug, please see the developers link below. > * Regarding static content, we currently have some pages (tutorials > and keys and mouse references) that are generated externally (see > https://launchpad.net/inkscape-docs). How should we handle them? Note > that the keys and mouse references are linked directly in the > application and thus should be accessible from exactly the same > localized URL (for French: http://inkscape.org/doc/keys048.fr.html). I didn't know about the generative content, that's quite interesting. We could either insert the generated content into the right cms widget items, or do something else. It depends if we want the content committed to bzr or just in the database with other content. > * How will the news be managed? I see nothing about it on the website, > but I guess that's something that won't be abandoned. The news module is operational, but it has two big caveats: 1. English only, 2. No on-site editing. Thus as the technical lead, I intend to replace the news module with a newly written one which has both multi-language and onsite editing. > * The French menu is exactly as defined in > http://staging.inkscape.org/fr/admin/cms/page/, but it's not the case > with the other languages. Is the menu order language-dependent? The CMS seems to order the menu according to how much has been translated and which menu was edited last. It is not idea, but a fix would require patching upstream. > * Apparently, the website is synchronized to the LP code manually > (I've ported images for the books page, but they are not on-line yet). > Do you plan to give update access to someone else, or do you prefer > that we ask you every time we something is committed. The cron jobs are not complete, there is a bug report assigned to me. Images should actually be uploaded via the CMS unless they are non-content images for use in the style/theme of the website. I may have to reverse your commit for now. If you get stuck adding images, let me know and we'll figure it out together. > Apart from it, I'd like to run a local version of the website for > testing purposes. SQLite, Django, Django CMS and the dependencies are > installed on my computer, but I still have difficulties with the CMS > modules (Error: No module named cmsplugin_news, or Error: No module > named cms.plugins.twitter if I comment the cmsplugin_news line). Do > you have some documentation on how to run it (the README file didn't > help)? I'm new to Django CMS, and not very experienced with Django and > I've probably missed something obvious... If not, I'll try to search > the web, there should be some tips somewhere. Absolutely, at the bottom of the website there's a link "Website development guide:" to this wiki page: http://wiki.inkscape.org/wiki/index.php/WebSite and by following this guide we hope, the website should work locally for development. This also includes bringing in the data from the staging website, since the cms would be empty otherwise. Please continue to report bugs and press the website further :-) Best Regards, Martin Owens

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I have a faster, SIMD IIR filter implementation, but have accuracy problems
by Yale Zhang 29 May '13

29 May '13

All, I have ported the IIR filter implementation to use SSE intrinsics and have achieved a 2.5x speedup so far. But I'm having accuracy problems for large blurs due to using single precision instead of double. I've attached examples outputs that blurs a box with several sizes. For sigma=120, the annoying mach bands start getting noticeable. At sigma=200, it looks very bad, and at 350, you might as well use it as a sharpen filter :) This is the first graphics application I've seen where single precision isn't enough. Is the reason due to the recursive behavior of IIR (more accumulation of error) ? Basically, for large blurs (stdev > 100), 24 bits of precision isn't sufficient and you end up getting very annoying mach bands. For sigma = 100, the filter coefficients are: b[0] = 0.00000387430191040 b[1] = 2.96391582489013672 b[2] = -2.92843437194824219 b[3] = 0.96451467275619507 If I add b[0] to the other terms last (b[1] + b[2] + b[3]) + b[0], (earlier, when I added the b[0] term to b[1], the accuracy was even worse as expected), the alignment of the operands in binary is approximately: 1.00000000000000000000000 0.00000000000000000100000 meaning the addition loses a lot of the b[0] term's precision. Can anyone suggest how to proceed next and how useful you think this speedup is? (for me it's a moderate improvement because in my comic, I use marble and brick textures for the walls and floors - I also vectorized the turbulence generator). I would like to avoid using double precision since SSE supports only 2 doubles per operation instead of 4 floats. The things I thought about of trying next are: 1. Use int32 arithmetic (that would add 9 extra bits of precision) 2. Use 4 taps instead of 3. Would this really help? I don't know much about IIR filter design. Can someone give me the coefficient formula for 4 taps? Thanks for helping, Yale

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[CAD] Connectors and Symbols
by Martin Owens 29 May '13

29 May '13

Dear Sebastian Götte and Tavmjong Bah, I'm working on these two items most keenly too, I would like to participate in code review as well as design review for the blueprints etc. The codebases for both items are not super big so I'd like to make sure we don't start committing over each other since the GSoC projects are nominally forked. I have a UI change for symbols which is waiting merge. I'm also interested in the design of the connectors since I know we all have different ideas about how it should be done (elements vs attributes, children vs groups). I'm not sure of the scope yet of the CAD work for 2013, can someone link me to the blueprint? Best Regards, Martin Owens

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