Can I use the calligraphy tool as a brush to create lineart?

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Gonzalj1992
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Joined: Sat Oct 08, 2016 6:46 pm

Can I use the calligraphy tool as a brush to create lineart?

Postby Gonzalj1992 » Sat Oct 08, 2016 6:56 pm

More specifically, is it possible to use the calligraphy brush :tool_calligraphic: in the way it's used in the Illustrator video below, and if so how do you create fillable shapes afterwards? If not possible, what is the most similar feature?

https://www.youtube.com/shared?ci=TuWLmr_2u-s

Moini
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Joined: Mon Oct 05, 2015 10:44 am

Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Moini » Mon Oct 10, 2016 4:43 am

I'd suggest taking a look at the power stroke path effect to get editable lines with variable width. The fill is being done by using another path effect, 'Clone original path'. These new features in 0.91 aren't documented, but you can find some info in the release notes: http://wiki.inkscape.org/wiki/index.php ... notes/0.91 (let us know if you need help). If you speak German, then there's a tutorial here: http://vektorrascheln.de/posts/2016/Apr ... fade3.html

Another option would be to use a simple 'Shape along path' path effect.

If you need pressure sensitivity, though, there's no other way than the calligraphy tool currently. You can fill the areas in between by using the bucket fill tool.
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Gonzalj1992
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Joined: Sat Oct 08, 2016 6:46 pm

Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Gonzalj1992 » Mon Oct 10, 2016 5:06 am

Thanks! I've managed to use the pencil tool :tool_pencil: with some custom ellipses to get a decent effect, but obviously this lacks pressure sensitivity. Also you can only change the color after the fact. It's tedious but I managed this little doodle.

IMG_20161008_154844.jpg
IMG_20161008_154844.jpg (112.76 KiB) Viewed 1951 times

Moini
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Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Moini » Mon Oct 10, 2016 8:29 am

There's a small blank margin around the areas that were filled with the bucket tool - when using it, take a look at the 'grow/shrink' options. What you could do to mitigate this for an existing object is to outset the brown path a little (or maybe give it or the black border a tiny black stroke?)
Something doesn't work? - Keeping an eye on the status bar can save you a lot of time!

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Gonzalj1992
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Joined: Sat Oct 08, 2016 6:46 pm

Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Gonzalj1992 » Mon Oct 10, 2016 8:44 am

I didn't use the :tool_paintbucket: tool. If I remember right I made a rectangle over the line art I made with the :tool_pencil: , used the division tool or some other boolean operation and then broke it apart to get a bunch of shapes whos fill and stroke I could edit. I scaled my work up quite a bit and noticed that when I exported as a png the gaps in fill would suddenly appear.
Last edited by Gonzalj1992 on Mon Oct 10, 2016 1:14 pm, edited 1 time in total.

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Maestral
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Joined: Sat Aug 27, 2011 7:10 am

Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Maestral » Mon Oct 10, 2016 8:44 am

Would you find this acceptable?

Image

I`ve managed to tame :tool_calligraphic: but it does depend on tablet, how much time you`ve spent in setting the tool and skill, of course.
Try different settings till you find the desired output and then it`s all up to you ,)
:tool_zoom: <<< click! - but, those with a cheaper tickets should go this way >>> :!:

Moini
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Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Moini » Mon Oct 10, 2016 12:41 pm

@Gonzalj1992 : Ah, okay. So then this is due to antialiasing and a tiny bit of computing inaccuracy.
Many threads in this forum to explain that in detail, and show different workarounds to make it look fine. The easiest way I know of is to just duplicate/clone the contents of the drawing. Overlapping and other techniques are explained somewhere here, too.
Something doesn't work? - Keeping an eye on the status bar can save you a lot of time!

Inkscape FAQ - Learning Resources - Website with tutorials (German and English)

Gonzalj1992
Posts: 4
Joined: Sat Oct 08, 2016 6:46 pm

Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Gonzalj1992 » Mon Oct 10, 2016 1:20 pm

Thanks! I appreciate the responses. The powerstroke tool seems like it'd be great for achieving the look I'm seeking. I will definitely spend some time messing around with it.

Lazur
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Joined: Tue Jun 14, 2016 10:38 am

Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Lazur » Mon Oct 10, 2016 7:01 pm

The "antialising gap" is not really caused by anti-aliasing itself.

When the object is anti-aliased, the edges of the filled area get a linear transition from fully opaque to transparent in the subpixels (considering the opacity of the object is at 100%).
These subpixels above eachother don't add up to an opaque fill.
For example, in between, at the middle the two antialiased edges next to eachother are producing subpixels with 50% opacity both, and one of them above the other in the z-ordering.
It is how the objects are composited. Two objects with 50% transparency above eachother won't add up to an opaque area.

The duplicating method results in more of the same coloured subpixels above eachother with more of the opacity
-so in the end it won't produce a perfect result, some of the background will always show through theoretically.
Switching off anti-aliasing produces fully opaque sub-pixels, therefore it is a workaround.
It can also be achieved by adding the pixellize filter, if you don't want switching it off globally in the document.
Or by having a copy of the object with the pixellize filter below the originals for smoother edges? Theoretically.

But the best results are always the overlapped ones because they are not relying that much on the renderer.


Here is a collection of cliparts drawn with special care on the overlapping.

This example shows how the renderer can be "brute-forced" to produce the right look on anti-aliased objects.
It is using the arithmetic compositing mode where you can set the parametres, and the sub-pixels alpha's are adding up to full opacity.
Very tedious pulling in all the objects with the image filter primitive and compositing them manually but it shows both the nature of the problem and that it could be solved automatically.
Either by a script that would do the same thing with every separate objects in a drawing or by a new rendering mode.

Moini
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Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Moini » Wed Oct 12, 2016 12:27 am

@Lazur: thanks for that great explanation :D (I suspected it worked like that, but never knew)
Something doesn't work? - Keeping an eye on the status bar can save you a lot of time!

Inkscape FAQ - Learning Resources - Website with tutorials (German and English)

Lazur
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Joined: Tue Jun 14, 2016 10:38 am

Re: Can I use the calligraphy tool as a brush to create lineart?

Postby Lazur » Wed Oct 12, 2016 12:52 am

To be fair though I didn't dig into the svg specs corresponding part or have any coder background for the explanation, it's just based on my observation.


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