Gimp-Forum.net
Delete works different with different tools - Printable Version

+- Gimp-Forum.net (https://www.gimp-forum.net)
+-- Forum: GIMP (https://www.gimp-forum.net/Forum-GIMP)
+--- Forum: General questions (https://www.gimp-forum.net/Forum-General-questions)
+--- Thread: Delete works different with different tools (/Thread-Delete-works-different-with-different-tools)



Delete works different with different tools - biuro74 - 02-27-2022

Hi,

1. I've noticed something annoying - or maybe it's a special feature and it works as supposed ?

When I select some shape using a lasso tool, and use "Delete" key on that area, which is "edit-clear" function as I think, it erases an area with very nice edge antialiasing.
But when I select the same shape using a Magic Wand tool, and erase that area with "Delete" ley as well, edges are harsh, like in an old graphic editor which simply clears selected pixels.

This makes me very sick, as I do two-stage editing in majority of pictures: first stage is a shape select, reverse and background removal, then layer is being moved into another file... and I repeat that for few pictures. Second stage is detailing of all layers in new file, and here my problems begin - because what I have selected previously wasting many minutes, is not repeat-able as I don't want to double the time spent already for selecting area with lasso -> so I simply click MagicWand at background & select inverse. So easy, but erasing details give me sharp edges this time.

Do you know, how to make antialiased edges again ? I don't even think about feather, blur or similar options. How to clear selected area the same way, no matter with tool I use ? In both tools properties I've got "antialiasing" ticked on, I've got transparency (alpha channel).

2. Sometimes when I select some shape with lasso tool (usually when selecting comes over physical picture size - but Gimp shrinks selection automatically to picture size), click Layers->Transpareny->colour to alpha and use "Delete" key, some part of picture disappears. I've found a workaround to insert an alpha channel first, and then it all works fine. It's a bug for sure, where can I report it ?

Any clues appreciated.
Cheers


RE: Delete works different with different tools - Ofnuts - 02-27-2022

The lasso/freehand defines a shape. When a pixel straddles the shape boundary, It is possible to determine how much of that pixel lies in the shape , and this is used to set a selection level and this partial selection translates into partial color blends which translate into smooth edges.

The Fuzzy selection (and the color selection) check if a pixel is selected or not depending on likeness (threshold slider) with the initial pixel. There is no notion of partial selection, so you get full color painting or no paint at all, and jagged edges. Very often what you want to do instead is working with color layers, replacing a color by transparency (Colors > Colors to alpha). See this for more details.


RE: Delete works different with different tools - biuro74 - 02-28-2022

Thank you for reply.

I was reading that link, reading and still had no clue how to bind that technique to my case.
Tried google some YT solutions and accidentally found something really quick, easy and working: alpha to selection, shrink, invert, delete.
https://www.youtube.com/watch?v=wchU1_skBwU
Maybe someone will find this helpful as well.