Can anyone tell me if there is a straightforward way to make a circular path?

You could use the "Elliptical Select" Tool (hold Shift down to get a perfect circle).
Then convert your selection to a path (Rightclick on Image - Select - To Path)

Andreas

Hi,

Eric Seppanen writes:

Can anyone tell me if there is a straightforward way to make a circular path? Or alternatively, how can I can come as close as possible to a circular arc with the bezier path tool? Positioning the handles by eye doesn't seem very accurate or reliable.

There are lots of webpages with pages of math on how to approximate circular arcs using bezier curves, but nothing practical.

Either use the elliptical selection tool and convert the selection to a path or import a simple SVG that says something like:

Sven

Hi,

Eric Seppanen writes:

Yes, but at smaller sizes this results in a bad lumpy circle. Presumably elliptical-select is drawing a pixellated circle, and then selection-to-path is approximating that pixellated shape with the path.

It's a known problem of the selection to path conversion that the source is a mask, and thus bound to pixels. You can get better results by tuning the selection to path conversion (Shift-Click the button in the Paths dialog).

To me this demonstrates a need for one of two things: 1. A way to add elliptic arcs to paths 2. A simple way to constrain the bezier curves to very precise approximations of circular arcs (and/or elliptic arcs).

Basically what's needed is a tool to create basic shapes. Internally most of the infrastructure needed for this is already available, including functions to generate perfect circular paths (as you may probably already have found out from the SVG example).

Sven

Yes, but at smaller sizes this results in a bad lumpy circle.
Presumably elliptical-select is drawing a pixellated circle, and then
selection-to-path is approximating that pixellated shape with the path.

Another solution (maybe easyer) could be : 1. Create a big circular selection
2. Selection -> path
3. Resize this path to get it as small as you want (using the usual layer/selection/path resize tool).

PA.

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On Wednesday 02 March 2005 14:39, Eric Seppanen wrote:

Hello,

Can anyone tell me if there is a straightforward way to make a circular path? Or alternatively, how can I can come as close as possible to a circular arc with the bezier path tool? Positioning the handles by eye doesn't seem very accurate or reliable.

There are lots of webpages with pages of math on how to approximate circular arcs using bezier curves, but nothing practical.

Hmm....make a circular selection, and selection->path ?

That creates a few more points than are needed, but it is fine for what I do.

If you will be needing two or three bezier points only, tell me, and point me to such a page, I can work a python script for doing that.

Regards, JS
->

Thanks,
Eric

Hi,

"Joao S. O. Bueno Calligaris" writes:

If you will be needing two or three bezier points only, tell me, and point me to such a page, I can work a python script for doing that.

I just added a new PDB function to CVS that will simplify this a lot. Basically you can now say

gimp_path_import_string ("", -1, FALSE, FALSE);

and don't have to fiddle with the details of getting the bezier points right. We still need a better PDB API for vectors though. Someone needs to motivate Simon...

Sven

Sven Neumann gimp.org> writes:

Hi,

"Joao S. O. Bueno Calligaris" mpc.com.br> writes:

If you will be needing two or three bezier points only, tell me, and point me to such a page, I can work a python script for doing that.

I just added a new PDB function to CVS that will simplify this a lot. Basically you can now say

gimp_path_import_string ("", -1, FALSE, FALSE);

and don't have to fiddle with the details of getting the bezier points right. We still need a better PDB API for vectors though. Someone needs to motivate Simon...

*motivates*

Functionality like this would be really neat. When it happens, it shouldn't stop at circles. You could have a whole slew of basic shapes and things.

Also, wouldn't be a bad idea to have tools to, say, rotate a path? Resize it?

-- - nornagon

On Wednesday 09 March 2005 08:10, Nornagon wrote:

Sven Neumann gimp.org> writes:

Hi,

"Joao S. O. Bueno Calligaris" mpc.com.br> writes:

If you will be needing two or three bezier points only, tell me, and point me to such a page, I can work a python script for doing that.

I just added a new PDB function to CVS that will simplify this a lot. Basically you can now say

gimp_path_import_string ("", -1, FALSE, FALSE);

and don't have to fiddle with the details of getting the bezier points right. We still need a better PDB API for vectors though. Someone needs to motivate Simon...

*motivates*

Functionality like this would be really neat. When it happens, it shouldn't stop at circles. You could have a whole slew of basic shapes and things.

This doesn't stop at circles,a s it will work for any SVG statement, including other shapes. JUst check the SVG specification.

Also, wouldn't be a bad idea to have tools to, say, rotate a path? Resize it?

Now, these tools are in place. Just use the normal transformation tools, and set then to operate on Paths (first row of icons on the transformation tool options, first -> operates in drawables, second -> operates in selections, third -> operates in paths)

--
- nornagon

Regards,

JS
->