Re: [Gimp-user] Strugglign with Smooth Edges

[Steve Kinney <admin pilobilus net>]

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On 09/07/2014 01:12 PM, NoWhizzKid wrote:

> OK, I'm losing the will to live with this now! I started out
> with the first attached image - a photograph of a blue paint
> footprint. I then used the path tool and once I had completed
> the path of the footprint and toes, I did CTRL+SHIFT+G then
> pressed ENTER. After this, I did right click - edit - fill with
> FG colour (pink). Then, I did add alpha channel. The edges are
> STILL jagged and there is a greyish outline around the image.
>
> I just don't know where I am going wrong! It's like I've
> mastered how to smooth out the lines using the path tool, but
> something I do afterwards is making the edges all jagged. I
> need the image to be .png with transparent background.
>
> Can you tell me where I am going wrong please? It's getting
> increasingly more urgent and I just don't seem to be getting it
> no matter how much I practice! Thank you x
>
> Attachments: *
> http://www.gimpusers.com/system/attachments/151/original/Eliza_and_Theo.jpg
*
http://www.gimpusers.com/system/attachments/152/original/ElizPrintFromPath.png

A pixel map a.k.a. raster image is ultimately a grid of squares,
and can not represent smooth curves accurately:  Aliasing, the
"jagged" or stair-step appearance, is inherent in the medium.
There are two ways to hide this and fool the eye into seeing
smooth edges on curved boundaries:  Blur the affected regions so
the eye can't tell exactly where one region ends and a contrasting
one begins, and/or, make the grid out of smaller squares that the
eye and brain will ignore when "seeing" the image.

- From the image provided, it looks like your jagged edges - that's
called aliasing, BTW - can be eliminated easily:  Start with a
larger image, which will give you more pixels per inch when the
finished product is displayed at the same size as the version that
is giving you problems:  The stair-steps will then be small
enough, relative to the whole image, for the eye to ignore.

In the case at hand you already have your vector path drawn, and
unlike colored-in pixels, it will scale smoothly to any size.  So,
you can just open the XCF file, save it with another name, and
scale it up.  I would probably try about 300%.

Then use the eyedropper to pick the fill color you want from the
footprint layer.  Delete that layer or turn off its visibility.
Make a new transparent layer, do Path To Selection in the Paths
dockable dialog, then just drag and drop your color straight from
the color tool in the main toolbox to the image canvas.

Hopefully this will restore your will to live for at least long
enough to finish the project you are working on.

:o)

Steve











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