[Award Winner] Tapered Rivers in GIMP

[RobA]

There have been many questions in the past on tapering rivers in Gimp... I stated in this tutorial on making rivers with a mouse in photoshop that Gimp didn't have tapered strokes

SO I wrote a little script-fu to do it!

This isn't so much a tutorial, as a posting of a new script. It ain't too fast, but it works

Just unzip the attachment at the end, and save the script into your normal spot.

Draw a path using the pen tool, then switch back to the paintbrush tool (the script strokes with the active tool, so you could even, for example, erase tapered strokes). The script registers under the Edit menu as "Tapered Stroke Path..."
menu.png

The dialog allows you to select the start width, end width, spacing (20 percent is a good default, but by setting it to 100 you get a string of pearls effect), and a parameter called "Taper Exponent". This control the rate of taper. At 1, the taper is linear from the start to the end. At values less than 1 the taper changes faster, and greater than 1 the taper changes slower (nearer the end). I set the default at 5, which seems good for rivers.
dialog.png

Here is the result after stoking in black with the defaults. I have turned on the path visibility to show how it lines up:
taper.png

And since I have one more attachment, here is the image:
result.png

Couple of things... It will only stroke the first segment of a multi (broken) segmented path. If there are no paths, the script will run but error out.

Hope people find this one useful!

-Rob A>

[Patrakis]

Now i feel a new award for RobA will be coming soon Though i don't use gimp, this is no doubt worthy of a little rep from me sir.

Thanks.

Pat

[ravells]

RobA you totally rock.

[Sagenlicht]

Would rep you if I could, but at least I can rate the threat

[lisze]

Thank you. I will definitely try this out.

[RobA]

Lizse - Since 2.6 gimp supports some basic tapering when stroking along paths, but this script still gives a bit more flexibility.

-Rob A>

[Torq]

I've only just seen this script now. Thanks Rob, it will save me a fortune of time. Actually it would have saved me a whole lot more time if I had looked at it before doing the rivers on my challenge entry this month. Served me right for going to sleep.

Torq

[heathan666]

Ya I'm using the script and I've used some others from you RobA but I seem to keep getting an error message saying invalid path.
Now I looked and I noticed that in the Path to Stroke entry mine always says empty....what am i doing wrong?

[RobA]

Have you drawn a path using the path tool first?

Once that is done you need to select it with the drop-down of the field.

-Rob A>

[heathan666]

yay that's awesome, no I didn't do that because I didn't know that was a tool, that's pretty kewl, guess you do learn something new every day.