RobA Grayscale Dither

dinasset · **Posted:** Thu Nov 02, 2017 9:15 am **(#41)**

dinasset wrote:

Because -during my trials- I've seen that the most critical part in the use of the filter is choosing the most appropriate pattern size, I've prepared a slightly amended version which allows the user to enter the value "0", in which case the filter calculates the size according to the image width.
Still you may enter the value you like, if not "0" the filter doesn't apply any calculation.
Here the amended version (if you like the idea -which as usual comes from a lazy user-, you may download this one):

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The attachment DIEGO_DISTORTS_Greyscale Dither.zip is no longer available

Someone noted that there is some "dirty" code at the end of the filter (commented out).
Cleaned, but no change in active code.

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DIEGO_DISTORTS_Greyscale Dither.zip [3.06 KiB]
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Pat625 · **Joined:** May 12, 2015 **Posts:** 4693

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Pat625 · **Joined:** May 12, 2015 **Posts:** 4693

I have been experimenting with the size of the pattern and types of patterns. If some look weird to you it is because they were not made for "dithering". Just plain fabric swatch images like the ones used in patchwork.

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dinasset · **Posted:** Sat Nov 04, 2017 12:30 am **(#44)**

Thanks Pat, first set is very "romantic".
Experimenting is good, a way to obtain surprises on the outcome.
For this one I used a knitting pattern with a size of 99.

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The pattern used:

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Creative-Knitting-7.jpg [ 644 KiB | Viewed 1549 times ]

Pat625 · **Joined:** May 12, 2015 **Posts:** 4693

I like the knitting pattern, Dinasset. It is nice. I used many different cloth patterns. Some worked out well and a few did not work at all. It is worth the trial and error.

dinasset · **Posted:** Mon Nov 06, 2017 9:40 am **(#46)**

I took the suggestion of Lyle (in another thread) to distort the image when applying hedcutting techniques.
So I did this one:
- whirled-pinched
- used RobA Dither
- whirled-pinched back
Interesting effect!

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laura_by_vejitatoja-d4ozyia-100dpi dithered, using pattern (generated) with a size of 9(plus whirlpinch as per Lyle idea).jpg [ 274 KiB | Viewed 1515 times ]

dinasset · **Posted:** Mon Nov 06, 2017 11:50 am **(#47)**

If someone else likes the "whirled" effect, here is an updated version of the filter which allows that.
Default does not ask for this effect, modifying the new parameter you may request it with an angle of 45 or 90 or 135 degrees.

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DIEGO_DISTORTS_Greyscale Dither.zip [3.21 KiB]
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dinasset · **Posted:** Mon Nov 06, 2017 11:52 am **(#48)**

Using 45 degrees:

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katerina_by_xeneras-d7viy8j dithered, using pattern (generated) with a size of 9, whirled.jpg [ 190.67 KiB | Viewed 1510 times ]

Issabella · **Posted:** Mon Nov 06, 2017 3:22 pm **(#49)**

Wow! I like that effect, too I'll test it tomorrow. Thank you Dinasset.

Issabella · **Posted:** Tue Nov 07, 2017 2:58 am **(#50)**

A few tries.

Issabella · **Posted:** Tue Nov 07, 2017 2:59 am **(#51)**

Issabella · **Posted:** Tue Nov 07, 2017 2:59 am **(#52)**

dinasset · **Posted:** Tue Nov 07, 2017 3:19 am **(#53)**

Interesting, isn'it?
Good finding by Lyle.

dinasset · **Posted:** Tue Nov 07, 2017 3:20 am **(#54)**

(results look better when face is at centre...)

lylejk · **Joined:** Sep 24, 2010 **Posts:** 12838

Looks good, Diego. As you have noticed, the problem with Whirl is it's center specific. That is why I've been using two distort method. Either use G'MIC's Polar/Rect preset then whirl (either order) and then reverse it, or use G'MIC's Square to Circle then Whirl and reverse it. Now the edges to get the dynamics.

dinasset · **Posted:** Tue Nov 07, 2017 2:54 pm **(#56)**

I made a little step forward, to deal with centres of interest not at the centre of the image.
I added a parameter in the filter where the user can indicate a non-central point of interest:
- north half
- north east quadrant
- east half
- south east quadrant
- south half
- south west quadrant
- west half
- north west quadrant
Something like this (visually):

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CentreOfInterest.png [ 4.7 KiB | Viewed 1526 times ]

The filter will then perform the whirl on the chosen area.
Here the enhanced version, for whom interested.

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DIEGO_DISTORTS_Greyscale Dither.zip [3.56 KiB]
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lylejk · **Joined:** Sep 24, 2010 **Posts:** 12838

You can also try to use Horizontal and Vertical Ripple (reversable by applying mirror and leaving Ripple setting the same). I recently used that technique for the Tesla render.

viewtopic.php?f=18&t=11108&p=222088#p222088

dinasset · **Posted:** Tue Nov 07, 2017 3:01 pm **(#58)**

Just one example, with an image having the face (centre of interest) in the "East Side":

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thought_by_sulevlange-dbo8rn3B_DITHERED-LeftWhirl.jpg [ 188.82 KiB | Viewed 1524 times ]

dinasset · **Posted:** Tue Nov 07, 2017 3:02 pm **(#59)**

Lyle,
tomorrow I will consider also your indication.

Issabella · **Posted:** Tue Nov 07, 2017 3:21 pm **(#60)**

I think that your idea works great, Dinasset. I did these results.