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Stippling /dotting / halftone plugin?
October 23, 2008 - 16:44 — johanmark
Hello,
I'm trying to create a single line drawing from pictures. This can be done with with a mathematical procedure that connects x,y points on a grid, so that no line intersects another, this is a result of choosing the shortest possible pathway . This has been done before and is called TSP (Traveling Salesman Problem) art.
What I need is a method of producing the discrete points from a picture. Possibilities are some sort of stippling or halftone plugin. After making the dotted picture I will program a method of converting these points to a coordinate file, then the TSP problem will be solved and the solution will be converted to a SVG file that draws the solution ( the single line drawing)
Does anyone know a plugin that produces dots or points from a picture, or something similar?
with kind regards,
John
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Filters/Distortion/Newspaper
You should prepare the image to limit the dots and the levels of gray at your needs...
1) Image/gray tones
2) Colors/Posterize (number of colors in gray to have) lowest: 3 white,gray,black
3) Filters/Distortion/Newspaper
Is similar to the old technique of achieving a number of gray tones by using only black ink. The tiny dots can be reduced by diminishing the value of the size of each cell. And increased in number by using a higher value in anti aliasing.
Hope it helps!
Good luck & happy new year!
alberto
Even Easier
Here is an even easier method...
Starting with an image like the one on this page.
- Scale it to 50%
- Change the levels so the "black" output level is about 220. You will have a really washed out image.
- Change the mode to Indexed, 1-bit, using floyd-steinberg dithering.
- Change the mode back to greyscale.
- Scale the image back up 200%, using Linear Interpolation.
- Threshold the image.
Here is a result:
Playing with both the scale and levels will adjust the dither density.
-Rob A>
Density map plugin
I wrote a plugin posted at Gimp Talk that might do what you want.
It will paint dots (the current brush) based on the intensity of another image. It is based on a grid pattern but has a randomization parameter.
Try it out.
-Rob A>
Density map pluging
Wow this is a nice plugin, it produces a result very close to what I want. I need single pixel black dots. This script uses the current brush, thus no single pixels and not pure black. I've tried to alter the script a little bit by replacing the gimp-brush part with gimp-pencil. Sadly this doesn't work.
If anyone knows how to do this I would really like to hear about it.
Still this script is useful to some extent.
small change?
Should it just require a change from:
(gimp-paintbrush-default inLayer 2 *randompoint*)
to
(gimp-pencil inLayer 2 *randompoint*)
Also - I have changed this script so it paints a (optionally jittered) grid, rather than a fixed number of points:
http://ffaat.pointclark.net/incoming/scripts/random_density_map.scm
(file name and function are the same, so you will have to change one if you want both)
I quickly threw in an option to choose paintbrush or pencil, and it seems to work fine.
-Rob A>
dottingscript works like a dream
Cool changing from paintbrush to pencil works like a dream. Your site is down for now but I'll check out the jittered grid as soon as its up again.
I've noticed that using the pencil dots uses a lot!! less memory, which is also nice.
Thanks for helping me out.
John.
Over limit
Yeah - I ran over my ISP limit this month. I'll be back up in a couple of days (Sept.)
-Rob A>