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SOLVED Limit/constrain size, etc. to a range in paint dynamics

Thu May 21, 2020 10:54 am

GIMP Version: 2.10.14
Operating System: Windows
GIMP Experience: Experienced User



In the last few days, I remember reading a question somewhere asking if there is any way to limit the variables in Brush Dynamics to be within a range (smaller than the one including the extremes).

A search in GimpChat for:
+dynamics +limit +size
didn't turn up anything so I'm bound to ask if there's way to do it.

For the sake of an example, when painting with a brush with Basic Dynamics on, I'd like for the brush size to be say only 50%-100% of the size specified.
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GraMP

Re: Way to limit/constrain size, etc. in dynamics to lie within a Rang

Thu May 21, 2020 12:41 pm

You just make the curve not reach the lower corners. For instance, the curve below means that the brush starts at full size (60px) and then decreases to half-size (30px) over the fade length (about 150px) and then of course remains at that size for the rest of the stroke.

Screenshot_20200521_193646.png
Screenshot_20200521_193646.png (35.89 KiB) Viewed 1652 times

Re: Way to limit/constrain size, etc. in dynamics to lie within a Rang

Thu May 21, 2020 8:45 pm

Thanks, Ofnuts. Your reply has all the signs of the one I thought I saw. It also triggered the same, huh?, response about how to get to the plot/curve because my Paint Dynamics Editor shows a "matrix". But your attachment prompted me to take some initiative and make a little visit to The GIMP's documentation (where I learned about the little down arrow I'd been ignoring all along) and filled in for myself.

1. "Make a custom dynamics." (Prob. a different topic, but select a painting tool like pencil or paintbrush and then the, large, Dynamics button about midway down in the Tool Options tab, and then the same smaller icon in the lower-righthand corner. In the window that pops up, click the second icon [sheet of paper with a + sign] from bottom left, to create a new "Untitled" Dynamics. Name it. Fill it in as you wish. )
2. Notice the little down arrow to the right of "Mapping Matrix" and click it. (You can return to this later by selecting your custom dynamics in the Tool Options and then the Edit this Dynamics icon to its right when selected.)
3. See a list of properties below "Mapping Matrix" (which you may want to return to later).
4. Clicking any of the properties will bring up a curve, allowing the property to be derived from one of a number of inputs.
5. You can decide, say, to have "Jitter" be dependent on "Direction" and also drag endpoints to change the slope of the curve, or click on the curve to add new intermediate points to make the line into a curve (and the behavior even less intuitive).

And I said start making your own custom dynamics because I tried to do the steps above on "Basic Dynamics" just for the sake of laying out the steps and found I could not make any changes to it.
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