Le 09/07/2014 15:32, PDG-USER a crit :

Very new to this program with elementary uses for Gimp. Main task is erasing extraneous graphics from pdf. maps and drawings. Currently, the setting for the eraser tool is not removing graphics, but painting on the checkerboard pattern.

I'm sure this is a simple fix (or understanding of the program) but I would appreciate your advice.

have you tried, in the layers pane, to select the layer, click right, and remove the alpha channel ?
JL

On 09/07/14 16:00, PDG-USER wrote:

Yes that worked. Thanks so much.

Another simple question: Can the eraser tool shape be changed from circular to square?

The eraser will use any brush, so you just have to select a square brush...

On 9.7.2014 at 3:38 PM Jluc wrote:

Le 09/07/2014 15:32, PDG-USER a crit :

Very new to this program with elementary uses for Gimp. Main task is erasing
extraneous graphics from pdf. maps and drawings. Currently, the setting for the
eraser tool is not removing graphics, but painting on the checkerboard pattern.

have you tried, in the layers pane, to select the layer, click right, and remove the alpha channel ?

Hi,

the default setting for the Eraser Tool is to not erase from the background layer. As the example above shows this is not what users expect and therefore (new) users have problems with it. Is there a reason to have chosen this default?

Kind regards,

Sven

On Thu, 2014-07-10 at 05:02 +0200, scl wrote:

On 9.7.2014 at 3:38 PM Jluc wrote:

Le 09/07/2014 15:32, PDG-USER a écrit :

Very new to this program with elementary uses for Gimp. Main task is erasing
extraneous graphics from pdf. maps and drawings. Currently, the setting for the
eraser tool is not removing graphics, but painting on the checkerboard pattern.

have you tried, in the layers pane, to select the layer, click right, and remove the alpha channel ?

Hi,

the default setting for the Eraser Tool is to not erase from the background layer. As the example above shows this is not what users expect and therefore (new) users have problems with it. Is there a reason to have chosen this default?

I don't know what you mean, the eraser erases to "transparent background", which results in transparency if there is an alpha channel, and in the background color if there is no alpha channel.

I can't see anything unexpected here, I don't even see a "default" because that's how it always behaves.

--Mitch

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.

2014-07-10 11:06 GMT+02:00 Michael Natterer :

On Thu, 2014-07-10 at 05:02 +0200, scl wrote:

On 9.7.2014 at 3:38 PM Jluc wrote:

Le 09/07/2014 15:32, PDG-USER a écrit :

Very new to this program with elementary uses for Gimp. Main task is erasing
extraneous graphics from pdf. maps and drawings. Currently, the setting for the
eraser tool is not removing graphics, but painting on the checkerboard pattern.

have you tried, in the layers pane, to select the layer, click right, and remove the alpha channel ?

Hi,

the default setting for the Eraser Tool is to not erase from the background layer. As the example above shows this is not what users expect and therefore (new) users have problems with it. Is there a reason to have chosen this default?

I don't know what you mean, the eraser erases to "transparent background", which results in transparency if there is an alpha channel, and in the background color if there is no alpha channel.

I can't see anything unexpected here, I don't even see a "default" because that's how it always behaves.

--Mitch

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Date: Wed, 9 Jul 2014 15:32:32 +0200 From: forums@gimpusers.com
To: gimp-user-list@gnome.org
CC: notifications@gimpusers.com
Subject: [Gimp-user] ERASER TOOL

Very new to this program with elementary uses for Gimp. Main task is erasing extraneous graphics from pdf. maps and drawings. Currently, the setting for the eraser tool is not removing graphics, but painting on the checkerboard pattern.

I'm sure this is a simple fix (or understanding of the program) but I would appreciate your advice.

Thanks

-- PDG-USER (via www.gimpusers.com/forums) _______________________________________________ gimp-user-list mailing list

The "checkerboard pattern" is not part of the actual image data, but instead GIMP's way of informing you that that region of the image is transparent and there's nothing below it (note that the size of the checkerboard doesn't change as you zoom in and out).

-- Stratadrake strata_ranger@hotmail.com
--------------------
Numbers may not lie, but neither do they tell the whole truth.

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