April 2012 - Inkscape Devel - Inkscape Mailman

Re: [Inkscape-devel] Powerstroke: adding/deleting width nodes
by Valerie 27 Apr '12

27 Apr '12

> Just fixed a big problem with thick paths, see if this fixes your > rendering issues. > (https://bugs.launchpad.net/inkscape/+bug/986394) Oh dear. It does fix my rendering issues, but unfortunately it seems to crash sometimes now: (Inkscape r11297) terminate called after throwing an instance of 'Geom::LogicalError' what(): lib2geom exception: rx2 < 0, while computing 'rx' coefficient (2geom/ellipse.cpp:87) Also, this showed up in the console several times as well: ** (inkscape:8834): WARNING **: Exception during LPE [Unstable!] Power stroke execution. lib2geom exception: Invariants violation (./2geom/piecewise.h:144) Thanks for your hard work by the way! :D

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Snapping
by Johan Engelen 27 Apr '12

27 Apr '12

Hi all, Am I the only one who finds it annoying that I have to specifically enable snapping *to* cusp nodes, in order for them to snap to the grid? In other words: I don't like the recent changes to the snapping UI. ;-) Suggestion: "snap nodes, paths, and handles" enables snapping OF all those things; and is completely unrelated for snapping TO those thingies. Then the buttons below that are decoupled from it, and mean snapping TO the things their tooltip says. Cheers, Johan

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Re: [Inkscape-devel] Powerstroke: adding/deleting width nodes
by Valerie 26 Apr '12

26 Apr '12

> The inside of joins should look better now. Thanks! And actually, I think I found the reason for my "hard to make points appear" issue. And I think it might have been resolved since. See the attachment. I made that example in a version of Inkscape on Windows. As you can see, if the control point was on one side, the pointy edges would not appear. But moving them to the other side somehow fixed the problem. So it had nothing to do with miter limit! However, I wanted to make sure, so I took that example home where I use Linux. By then the Linux version had been updated, and somehow the points render correctly now regardless of the position of the control point (did you fix something in the meantime?) Apart from that there's some rendering issues for large lines, but those are extreme cases. It's definitely quite nice to use now! Now my main wish-item involves quickly accessing settings. The most accessible way may be to have a drop-down option for "Last powerstroke settings" (shorter name needed...) Being able to save each settings and access them from the toolbar drop-downs would be even better, but that doesn't seem to be trivial to do right now. Amazing work by the way!

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Retinex color operation
by Michael Grosberg 24 Apr '12

24 Apr '12

I'd like to Discuss Retinex. I decided to do it here before submitting a bug report. In theory the retinex operation is very useful in fixing badly lit images. In practice, I've had little success with it. So I decided to fiddle around with it. My test picture was a chinese temple on a background of blue sky. usually you want to just brighten up some darker areas or bring detail in an area that's too brightly lit, without changing the rest of the image. In my test case, The sky's color was ruined when retinex was applied and most of the well-lit areas lost most of their color. I'll break down what happened: 1. The properties that can be changed by the sliders in the retinex dialog are not clear at all. The documentation doesn't explain the first two in terms understandable to a non-mathematician. Whatever it is they are doing, they are not helping in correcting images. 2. The result is too strong. I find I have to do a "fade" every time I use it. My suggestion: add a multiplier slider that would do an internal fade. The default should be about 0.5. 3. The algorithm is indiscriminate: it is used to fix bad lighting but it also works on well-lit areas. I believe it should have less effect on pixels (or areas) whose average luminosity value is 0.5, and more effect on pixels with values closer to 0 or 1. I managed to achieve a selective retinex using the following method: 1. copy the layer 2. paste into quick mask 3. blur the mask using gaussian blur (8.0 radius) 4. invert the colors (only if you want to affect just the darker areas) 5. use levels or contrast to mask out the mid values 6. Perform Retinex The above procedure can probably be turned into an integral part of retinex so that retinex only works on those parts. Perhaps adding another slider that controls the luminosity / strength ratio. Photoshop's "lighting/shadow" algorithm has two sliders. One for choosing the strength of the effect on lighter parts of the image, and one for choosing the strength of the effect on darker parts of the image. This seems like a desirable thing to have. Comments?

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Export without premultiplied alpha?
by Tobias Oelgarte 23 Apr '12

23 Apr '12

Hello, I used Inkscape in the recent years for great works and it keeps better and better. So at first big thanks to all developers that made it possible. But now to my question. ;-) Does Inkscape support image export (export to PNG) without premultiplied alpha? In a recent project I needed images with fairly high transparency, but with premultiplied alpha the colors inside this image regions are really suffering. As an example you could try to export a highly transparent rainbow open it with Gimp and remove the alpha channel. It should be clearly visible the the colors are strongly quantized. As long the image is just composited 1:1 over another image this is no problem, but in other scenarios it starts to give problems, since the color information is missing. Are there any plans to enable true RGBA (all seperated channels) for at least the export? Currently i have to export two images. RGB for the colors and a duplicate in graytones for alpha that i then combine to true RGBA to avoid the problem. Best Wishes Tobias Oelgarte

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Re: [Inkscape-devel] Powerstroke: adding/deleting width nodes
by Valerie 21 Apr '12

21 Apr '12

Strange, I seem to be having rendering problems now. See first attached file: sometimes (once every few renders) the render doesn't update after moving nodes or the width control. It takes moving things around a bit more before it renders again. I'm not sure if it's a Powerstroke problem or some other render problem, though I don't seem to have the same issue with normal paths or Pattern along Paths. The inside of strokes looks great for the most part now! It still renders "inside" for sharp angles. Also, it seems hard to make very sharp Extrapolated edges again. See second attachment. I've increased the miter limit to 400, and the edge does render under Miter mode, but not under Extrapolated mode. You're right about the UI, some discussion is needed. And then it needs to be coded (I can't code, unfortunately). It's a pity, because this is a feature that's bound to be very popular, and UI issues would slow down the workflow. Message: 6 Date: Fri, 20 Apr 2012 21:41:17 +0200 From: Johan Engelen <jbc.engelen@...2592...> Subject: Re: [Inkscape-devel] Powerstroke: adding/deleting width nodes To: inkscape-devel(a)lists.sourceforge.net Message-ID: <4F91BBDD.4080701@...2592...> Content-Type: text/plain; charset="iso-8859-1" On 16-4-2012 4:03, Valerie wrote: > > The inside of joins should look better now. > > Thanks! And actually, I think I found the reason for my "hard to > make points appear" issue. And I think it might have been > resolved since. See the attachment. > > I made that example in a version of Inkscape on Windows. As > you can see, if the control point was on one side, the pointy edges > would not appear. But moving them to the other side somehow > fixed the problem. So it had nothing to do with miter limit! > Yep you found the reason, and yep I had it already fixed :) > Apart from that there's some rendering issues for large lines, > but those are extreme cases. It's definitely quite nice to use > now! > Struggling with thick lines too... but I think it will be hard to fix as I think the 'bug' is actually 'correct' mathematical behavior. > Now my main wish-item involves quickly accessing settings. > The most accessible way may be to have a drop-down option > for "Last powerstroke settings" (shorter name needed...) > Being able to save each settings and access them from the > toolbar drop-downs would be even better, but that doesn't seem > to be trivial to do right now. All ideas are welcome. Help would be nice: UI stuff is generally not particularly difficult to code, but time consuming (and of course you need to decide what you want). I recently did quite a big "mathematical" change, so perhaps new bugs popped up... but it was supposed to fix the "instable" rendering stuff (where you see flickering joins for example). Cheers, Johan

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Parallel build on Windows
by Johan Engelen 18 Apr '12

18 Apr '12

Hi all, For parallel builds on Windows, update to >= rev11088, recompile buildtool: "g++ buildtool.cpp -o btool.exe -fopenmp" and run "btool -j" (or "btool -j x", x=number of threads to use) I fixed the bug, and with virusscanner disabled, I can build Inkscape clean in 5 mins and 2 seconds. (i7 2600) Cheers, Johan

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Re: [Inkscape-devel] Snapping
by gespertino＠...400... 17 Apr '12

17 Apr '12

2012/4/17 Vladimir Savic <vladimir.firefly.savic@...400...>: > Why not even setting it to zero? I do it almost immediately upon new > install. Although, I admit that even having an option for delay is great, > especially as drawing gets more complex. > > If you choose to change it (but not zero it) - half way down from default > will work, I guess. There was something witn zero delay, I can't remember what (and it probably was fixed already). I think it was something related with performance, but I'm not sure. I should check my bug reports and see what was the problem (and if it still exists), but I remember having to use a small delay to avoid it. Anyway, If snapping with zero delay doesn't conflict with other tools or something, I can agree that it's a much pleasing default, so +1. Gez

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Re: [Inkscape-devel] Powerstroke: adding/deleting width nodes
by Valerie 15 Apr '12

15 Apr '12

> By now, I have forgotten all feature requests and bugs. I think all big > issues are solved now, so it's ready for some proper beta testing (alert > me and the maillist if you think otherwise! :P) Yay! Looking great! In fact, I've noticed that the Windows Inkscape development version hasn't been updated in a while: http://www.oss-marketplace.com/index.php/downloads-mainmenu-63/Inkscape/Ent… So, I haven't been able to test it on Windows. Could those folks be prodded a bit? Right now the issues I've encountered are: - Adding a stroke to the rendered path will show extra bits of lines "inside" the stroke where at cusp corners. - Does "miter" limit only work with "miter" cusp nodes and not with "interpolate" cusp nodes? Because even when I increase that value a lot, the "pointy" edge still stubbornly remains beveled no matter what I do (more generally, I sometimes have a really hard time getting that edge to show up). - Rendering bugs sometimes. Yes, I'll try to make some proper example files over the weekend. Apart from that, extra features I hope for are: - Powerstroke for Ellipse shape (I know, non-trivial, but it's one of the most commonly used shapes) - More options in the toolbar drop-down corresponding to different cusp node settings (smooth nodes and either interpolate or miter nodes): "smooth" vs "sharp" lines. I favor "pointy" lines and it's awkward to have to open the LPE dialogue each time to switch things over. It'd be even better if Inkscape could just save settings automatically and add them to the shapes drop-down, but I'm not sure if that's easy to do right now. I've also looked at the "Apply LPE to clone" interface. It's one I can get used to, but I do admit it's a bit confusing: - It took me a while to understand what "clone original LPE" is supposed to be, and I don't think I'd have ever figured it out if it weren't for the mailing lists. How about "Clone LPE skeleton"? - How about just making this fill behavior a checkbox option for powerstroke? "Clone skeleton for fill." So, with just an extra checkbox, you can create both that complicated stroke and the fill in one go.

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Example for Inkscape extension in Java?
by Gerrit Karius 15 Apr '12

15 Apr '12

Dear Inkscape devs, Can anyone point me to a working example of an Inkscape effect extension written in Java, running on Windows? I've read the Script_extensions and INX_extension_descriptor_format wiki pages. I thought, theoretically I might just replace the command tag in the inx file with something like this: <command reldir="extensions" interpreter="java">Hello</command> And then I could call a Hello World program like this one: class Hello { public static void main(String[] args) { for( String arg : args) System.err.println("Hello error: "+arg); }} The program wouldn't return any document, but the error message would be displayed by Inkscape. However, when I test this, nothing gets displayed. When I change the program to write a file, that file doesn't appear either, so I guess the program isn't called. I can change the command text to any other value, but there is no notification that a script couldn't be found. I have written several Python extensions, but those hook up into the existing Inkscape Python extension framework, with inkex.py and everything. Maybe there's some hidden magic in there that I missed? Can someone point me to a working Java example, or tell me what I did wrong here? Many thanks in advance!Gerrit

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