Feathering won't turn off

[Ferdrimmler]

I posted a problem in the 2.8 forum here:
https://www.gimp-forum.net/Thread-Feathe...t-turn-off

Then I uninstalled 2.8 and installed 2.10.16.
The same bug exists in GIMP 2.10: I can't add or subtract regions from a selection without a cut doing feathering, regardless of whether I have feathering turned on or off.  It's worse in GIMP 2.10; the effect is even more clearly visible.

But I have done this exact operation for years, and it only stopped working yesterday!

Can someone please look at the images in the 2.8 thread, and help figure out why even a fresh install of GIMP, working on a brand new image, won't let me add or subtract selections to the current selection anymore?  I can't use GIMP anymore unless I can fix this!

I'm running Windows 7 64-bit.

[Blighty]

The problem is not feathering. What you have is:
1. white background that is not pure white
2. a black hat that is not pure black
3. anti-aliasing pixels between the black and white (these are shades of gray)

General method is:
1. Select the white background with a suitable threshold and delete. This leaves a white halo (anti-aliasing pixels) around the hat.
2. Grow the selection by 1 or 2 pixels
3. Use Colour To Alpha with the default white to get rid of the halo

More info can be found here:
https://www.gimp-forum.net/Thread-Backgr...r-graphics

[rich2005]

My tuppenceworth.

From the other post, this says it all

Quote:...I used select-by-color with a very high threshold to select anything with white in it...

A different way to improve your selections. Use the Quick-Mask and paint out the 'extra' selection.

Not the best documentation https://docs.gimp.org/2.10/en/gimp-image...utton.html There is a hot-key, shift-Q a menu entry bottom of Select and an icon bottom-left corner of the image window.

The default colour is red, for your image it can be changed, right click on the icon to bring up a little menu.

screenshots: https://i.imgur.com/zyBV1om.jpg

Then paint black to subtract, white to add. The X key toggles between FG and FG colours.

A better way is use the initial selection in a (white) layer mask. Fill with black, turn the selection off. With some images the Gimp checker transparency pattern gets in the way and a light coloured background layer helps (although you can change the default checker in Preferences)

screenshots: https://i.imgur.com/jk5b0Dy.jpg

Then paint in black or white to improve the background removal. Still need some anti-aliasing (not feathering) to give a decent edge.

screenshot: https://i.imgur.com/fVhRJ9H.jpg

Depends on the rest of your image but for a simple shape like a hat, a path around the perimeter, then path to selection, is often faster.

[Ferdrimmler]

(06-27-2019, 06:59 AM)Blighty Wrote: The problem is not feathering. What you have is:
1. white background that is not pure white
2. a black hat that is not pure black
3. anti-aliasing pixels between the black and white (these are shades of gray)

I don't think that can be the problem.  I'm talking about "cut" making all black pixels more transparent for a distance of hundreds of pixels outside the selection area.  And the area that is affected is defined not by the current selection, but by the selection areas made in earlier editing operations.

Here's another example:  I'm trying to make the end of a line oval-shaped by selection an oval outline and clearing outside it, but everything inside the square region (which I intersected with the oval) gets made more transparent.  This isn't a feathering or aliasing effect, because it ends precisely at the border of the square that I intersected with the oval, even where that is not part of the border of the selected region.  Plus, this line is about 80 pixels across, and I have feathering set at 2 pixels.  This must be a bug.

I can't, BTW, turn antialiasing off for rectangle select, though I can for other select operations.  I think that's because there is no antialiasing for square regions, as they never cross rows or columns of pixels.

[Blighty]

(07-13-2019, 04:48 PM)Ferdrimmler Wrote: [I'm trying to make the end of a line oval-shaped by selection an oval outline and clearing outside it, but everything inside the square region (which I intersected with the oval) gets made more transparent.

I have been trying to understand what you are actually doing. But I'm afraid that from your description I just can't figure it out.