Hi,

this is my first GIMP related post on this forum.

As far as i understand, a path is superior to a selection, because its more detailed.
Especially if you have rounded corners or circles in general.

For example, if you make a circle selection with the ellipse tool and start growing or shrinking that selection, you seem to get more and more "jaggies". Especially if you do it several times.

A solution to this is converting a selection into a path (i read).
So whenever i want a perfect looking circle, i try to do that.

Yesterday i tried to replicate this label from a record, which consists of several rings, filled with a gradient.


And when finished it looked like this, which is pretty horrible, i think (the colors dont matter, please ignore that detail).
Its not exactly a perfect circle, really, isnt it ? *lol*


So any comments ?
Is this a problem with GIMP ?

I guess a solution would be to make every ring a circle on its own. But that would need a different procedure:
i would have to plan my piece, so i would know before, what size each circle is going to be and convert the selection into a path, which is different to working with one circle and shrinking the selection.

But i have the vague feeling, this is a basic problem in GIMP with anti-aliasing and maybe this kind of stuff needs to be done with Inkscape, because scaling works better with vectors ??

Awesome you chose Metalheadz record. You might be right about using Inkscape depending on what you want to use it for. However, if you want to do it with Gimp, here's a few ideas. Grids and guides may or may not be helpful. You can start with your outer circle, Select>To Path, name your paths appropriately to avoid confusion later, shrink your selection, Select>to Path, repeating this process. Then, go to your paths, right click>Path To Selection and you can go to work coloring or whatever. It sounds like you've been around. So, I won't go into using Add or Subtract with selections if you need them. I don't know if that's any help. I'm better at showing things than I am putting them into words.

thats exactly how i did it
i had thought, if i change every selection into a path, that would make the circle look better, but as you see, they are all jagged

its probably extra obvious because of the contrast between the green and the white

EDIT:

okay, i tried something else

1. i decided about a basic width of the label
2. create guides, so i know where the exact middle of the canvas is
3. create a selection with the measurements and turn into a path
4. give path a name (pixelsize)
5. repeat process for every ring (=another circle) which is a bit bigger
6. create layer(s) and fill with gradient

that turned out better (will post a picture later, must sleep first )

so it seemed the problem is the shrinking/growing, that process makes a circle jaggie,
turning the grown/shrinked selection into a path or not, doesnt matter in that case

Are you going back to your paths and right clicking>Path To Selection? I have the same understanding about paths making selections less jagged. So, if the knowledge is incorrect or could be improved upon, I'd love to hear some input. Anyway, here's something I did real quick and I wasn't precise with it. Therefore, it does look a little jagged.

Yes, please have a look at my edited last post.

It seems growing/shrinking the selection makes it jaggy.

Thanks for the inspiration !!!

There is a discussion in this thread about the difference between stroking a selection and stroking a path. You are correct about the advantage of stroking a path, however, there are distortions to your circular selection that were introduced when you grew your selection. These distortions were then incorporated into the path when you did "Select->To Path".

The distortion such as exhibited in your examples is created whenever you grow a selection. This is somewhat related to the discussion in the aforementioned thread because growing a selection works by painting with a round brush around the outline (marching ants) of the selection. This can be seen by growing a rectangular selection and noting that the corners of the resulting selection are rounded. When an elliptical selection is grown, the top, bottom, and sides become "flattened" (as seen in your images).

A good way to correct for this is to, in the case of growing an elliptical selection, clicking within the grown selection with the Elliptical Select Tool. This will cause the resizing handles to appear. Move the mouse to the top resizing bar and then press the cursor left key on your keyboard*. This will result in a "new" elliptical selection that is the same size as the original, but with the distortions caused by growing eliminated. Click in the center of the selection (or press ENTER) to accept this corrected selection. (A similar operation can be used for rectangular selections, only with the Rectangle Select Tool.)


* Alternately, you can place the mouse pointer over either of the side resizing bars and use the up or down cursor key -- the idea is to not actually resize the selection, but to "trick" GIMP into thinking you have.

I can see the difference. Thanks a lot Saulgoode.

If you want really circular paths, don't obtain them from circular selections. Use the excellent shape-paths script to produce circular paths (it will also produce other geometric shapes).

excellent advice and explanation, thank you so much saulgoode !




@ofnuts, thanks for the link, i downloaded that script and will have it a go with it later when i come back home

I agree with Ofnuts. You can do some really cool stuff with the shape paths script.
You don't have to stroke the path either you can just create the path and work with that.

Here is something i whipped together with one of the scripts named Flowers and Spikes.
Then i stroked the path with a rope brush.
The image below gives you an idea on how to use the values in the scripts.
My image is 512x512 pixels.The center for x and y is set to half that.That places the path in the center.

Yeah, thanks for the link Ofnuts. Up until Saulgoode posted and I actually zoomed and saw what was happening, I had no idea.