Re: [Gimp-developer] Eraser Tool default setting (Was [Gimp-user] ERASER TOOL)

[scl <scl gplus gmail com>]

On  10.7.2014 at 4:06 PM Przemyslaw Golab wrote:
> I think that the user didn't know that layers could be stripped of
> alpha channel,
> and by default Background layer is no-alpha layer.

Hi,

when I wrote this I actually asked myself: "Why can't the eraser
behave on the background layer behave like on the others?"
After some research in this list's archives I found that this
topic was already discussed thoroughly so I assume it's just so
for good reasons. (Handling the simplest use case "Editing a
one layered image with no alpha" most easily, comes to my mind).
So it's all fine about it. I didn't want to start a longish
painful discussion again.

While playing around with the Eraser tool I found out
another strange effect: The Anti-Erase option doesn't work
well:

On layers with no alpha channel:
In GIMP 2.8 it simply behaves like the Eraser, i.e. it
paints with the background color.
In GIMP master nothing happens at all.

On layers with alpha channel:
The erased pixels are properly restored.
However, if I paint on a transparent layer and anti-erase
formerly transparent pixels, they become painted in background color. 
There might be technical reasons for it, but from a user's point
of view this is unexpected.

After digging in the archives I found that this is an
ancient option that started out as quick hack and could
be replaced by an undo brush.
It seems with the GEGL port this problem could get solved easily and
the option be removed. Until then I think at least disabling the
Anti-Erase option on layers without alpha channel could be a way to
alleviate it.
Shall I file a bug for it?

Kind regards,

Sven