Growing/Shrinking Brush on Path Plug-in

[tim]

Asked by Wallace (in discord chat).
To draw a path with increasing/decreasing size.
so here it is:

growing-brush-on-path.py

(4.37 KiB) Downloaded 47 times

Menu Location: Python-Fu/Growing Brush On Path...

Instructions:
1. Open image with an active path.
2. Choose your brush.
3. Run plug-in. You can set starting brush percentage (small number) and ending brush percentage (large number). Designed to be growing in size but because of nature of Math, you can go from larger size to smaller size as well.
Percentage will act on current brush-size.
And you can choose how many brushes on average (per 100 pixels to draw).
It'll brush the path keeping angle relative to context's brush's angle.


That's it.
Sample result:

growing-brush-on-path-plugin.png (199.01 KiB) Viewed 1287 times

[tim]

Another play with this plug-in
Here I just hand-drawn a hash (#) symbol and use plug-in to repeat it so it looks like train tracks.

sample-hand-drawn-train-tracks.png (122.43 KiB) Viewed 1281 times

[Wallace]

Thanks Tim!

[Wallace]

It worked out well.

dash_test.png (20.58 KiB) Viewed 1256 times

[tim]

man that's a good looking dash!

[Krikor]

It is a pity that it does not work with all brushes and that it does not enable the dynamic functionality of the brushes.

But still a useful plugin.
Thx Tin.

[tim]

dynamics doesn't work because I resize the brush then call the brush at each location like dotting them
instead of moving brush stroke that dynamics apply to.
Not sure how i would do dynamics there are so many options with dynamics but one of which isn't size based on length
or anything based on length.
I guess that's a GIMP feature that can be built hopefully by GIMP developers.

UPDATE: Which brushes doesn't it work for?
And which dynamics do you want to control...probably can't do the whole dynamics options like GIMP offers but I am sure I can add some more options (other than size changing and rotate to path angle).
It's all a matter of doing calculations for each brush (location).

It works with "Acrylic 01" Brush which is animated brush, as GIMP automatically switches to a different frame of brush after each brush (location).

Let me know what dynamics you want and I can try to make it less pitiful

[Krikor]

Hi Tim,

I am not sure which brushes do not work with the plugin. I thought of attaching some three that I found but they are very large; above 10 MB. But I found a little one that I leave attached.

I just thought about the possibility that a brush I created had this behavior; growing while following a path.

In the image below, on the right the normal brush stroke and on the left the brush after running the plugin.

Krikor - Brush Growing Path

BrushGrowPath.jpg (57.38 KiB) Viewed 1194 times

I thought that with the plugin I would have both effects, the brush twisting simultaneously (concomitantly) to its growth.

Thx Tim.

[tim]

The foot prints brush you attached is hardcoded to use angular frames so it doesn't work with the plug-in.
However with these brushes we can just open them up as a regular image and edit the frames and save it as our own brush to work with plug-in.
Here I have attached is the foot-print brush that would work with plug-in.

TT-foot.zip

(4.53 KiB) Downloaded 24 times

(note: I did have to set angle 90 as active brush angle since the two frames I used for the brush the feet are pointing upward and not to the right which is default 0 angle.)

foot-prints.png (20.2 KiB) Viewed 1192 times

[tim]

with your multi color brush from looking at your result, looks like you just have to increase number of average brushes per 100px setting in plug-in and they should draw more brushes to create the twisting effect because the twist is already happening just too far apart.