AuthorTopic: Tool for single pixel width curves  (Read 4061 times)

Offline piffany

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Tool for single pixel width curves

on: May 30, 2011, 03:36:37 pm
Hi all,

I'm a noob at pixel art looking to learn some drawing techniques through this forum. All the tutorials say that pixel art edges should be drawn one-pixel width. My question, are there any tools that automatically convert splines (Bezier curves or other splines) into single pixel width curves? If not, do you follow some sort of algorithm when thinning curves or is it more by intuition?

Piff
--Piffany
Disclaimer: I am still fairly new at pixel art, so please don't be offended by my negative critiques :)

Offline alex pang

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Re: Tool for single pixel width curves

Reply #1 on: May 30, 2011, 09:04:47 pm
The whole point in pixel art is to NOT use automatic tools.
Or having full control over your actions. So no, I just follow the intuition.  :)

Offline HughSpectrum

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Re: Tool for single pixel width curves

Reply #2 on: May 30, 2011, 09:31:33 pm
I don't think there is a way to convert anti-alised lines into single pixel lines, but a lot of programs have a tool that makes single pixel width curved lines (even MS Paint).  Both Pro Motion 6 and Graphics Gale have intuitive curved line tools.

Offline piffany

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Re: Tool for single pixel width curves

Reply #3 on: May 31, 2011, 12:50:16 am
I just downloaded GraphicsGale to try out their curve tool, which produces single-pixel width curves but doesn't always avoid jaggies. So even though there are a lot of tools out there for creating pixel art, cleaning up outlines is still always done by hand?
--Piffany
Disclaimer: I am still fairly new at pixel art, so please don't be offended by my negative critiques :)

Offline Conzeit

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Re: Tool for single pixel width curves

Reply #4 on: May 31, 2011, 12:57:46 am
What I often do is use the straight line tool, instead. The difference is that every time you make the curve turn you have to start a new angle with the line tool, but it really allows all the control doing it with a pencil would and it is a bit faster

Offline piffany

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Re: Tool for single pixel width curves

Reply #5 on: May 31, 2011, 04:13:35 am
What I often do is use the straight line tool, instead. The difference is that every time you make the curve turn you have to start a new angle with the line tool, but it really allows all the control doing it with a pencil would and it is a bit faster

I was also wondering, what do you do when a line is at a *bad* angle? For example, it it has slope 2/5, do you draw it by alternating rows of three pixels followed by rows of two pixels?
« Last Edit: June 11, 2011, 09:43:54 am by EyeCraft »
--Piffany
Disclaimer: I am still fairly new at pixel art, so please don't be offended by my negative critiques :)

Offline EyeCraft

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Re: Tool for single pixel width curves

Reply #6 on: June 11, 2011, 09:45:27 am
I was also wondering, what do you do when a line is at a *bad* angle? For example, it it has slope 2/5, do you draw it by alternating rows of three pixels followed by rows of two pixels?

Pretty much. It depends what the situation is; if its an outline, an inner line, how many colours are available for anti-aliasing, that sort of thing.

The worse case is pure binary - you have only 2 colours, in which case alternating between 2/1 and 3/1 steps is the only option you have to make a line that matches the 5/2 gradient.

That looks pretty jagged though. Generally you try to avoid lines that lead to untidy alternating steps like that; 1/1, 2/1, 3/1, etc, or use a curve instead of a straight a line. In other words, be selective about how you render the subject such that you work only in pixel-friendly line gradients.

Hi all,

I'm a noob at pixel art looking to learn some drawing techniques through this forum. All the tutorials say that pixel art edges should be drawn one-pixel width. My question, are there any tools that automatically convert splines (Bezier curves or other splines) into single pixel width curves? If not, do you follow some sort of algorithm when thinning curves or is it more by intuition?

Piff

I don't know of any really reliable tools for that job. I would say the general method on non-jagged lines could probably be formalised into an algorithm. It depends on what exactly the line is supposed to be representing, though, in a way. If its just a spline for spline's sake, I'd say an algorithm could produce a nice smooth pixel-art-style line.

But if its a spline thats supposed to be representing the outer edge of a human arm in perspective at resolution XY, well there's subjective judgements the artist makes that might contradict the general pattern of a smooth line in order to accentuate or clarify a particular element of the form.

Ultimately lines become subordinant to pixel clusters; sometimes the smoothest outline interferes with the clarity of the pixel clusters that are defining the form via light and shadow, so you have to mess the line slightly to get the clusters behaving how you want.

I'm kind of rambling now. I guess I'm basically saying, yes you could have a tool that could import say, a spline representation of a human figure, and convert it into a smooth outline, but depending on the resolution chances are the artist is still going to have to noodle the resultant lines a bit for the betterment of the piece.

That's my guess.  :)
« Last Edit: June 11, 2011, 09:56:05 am by EyeCraft »

Offline piffany

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Re: Tool for single pixel width curves

Reply #7 on: June 12, 2011, 03:09:31 pm
EyeCraft, I really appreciate your detailed response. I guess I'm approaching the problem from a more theoretical standpoint, that is, instead of worrying about what I'm drawing, I just want to find a good way to render an arbitrary line/curve in a confined space using few pixels. It could be a useful tool for drawing some initial curves without jaggies, but ultimately, an artist would still have to tweak the results since the tool cannot fix artistic problems.

If you are interested, my project is described in greater detail in this post: http://www.wayofthepixel.net/pixelation/index.php?topic=6976.msg123574#msg123574
--Piffany
Disclaimer: I am still fairly new at pixel art, so please don't be offended by my negative critiques :)