RSS/Atom feed Twitter
Site is read-only, email is disabled
  1. Chat
  2. Useful links
  3. Polls

Featured content

How do I delete to transparency?

This discussion is connected to the gimp-user-list.gnome.org mailing list which is provided by the GIMP developers and not related to gimpusers.com.

This is a read-only list on gimpusers.com so this discussion thread is read-only, too.

5 of 5 messages available
Toggle history

Please log in to manage your subscriptions.
How do I delete to transparency? bobdobbs 30 Sep 05:39
  How do I delete to transparency? T?kés Ábel 30 Sep 08:38
  How do I delete to transparency? yahvuu 30 Sep 08:53
   How do I delete to transparency? bobdobbs 02 Oct 02:50
    How do I delete to transparency? yahvuu 05 Oct 14:11
bobdobbs
2010-09-30 05:39:41 UTC (over 14 years ago)
postings
31

How do I delete to transparency?

Hi all.

I'd like to delete in such a way that transparency remains.

I've found that this is the default when I'm working on images that I've created myself. But if I'm working on an image that I've downloaded or gotten from another source, I can't predict the behaviour of functions that remove pixels.

In my immediate case, I've got a icon with a white background. I want to remove the background. However, when I try to remove the white pixels, the result is black pixels.

How can I figure out what the result of deletion operations on pixels will be?

How can I consistantly remove colour, leaving transparency?

Thanks.

T?kés Ábel
2010-09-30 08:38:10 UTC (over 14 years ago)

How do I delete to transparency?

9/30/2010 5:39 AM keltezéssel, bobdobbs írta:

Hi all.

I'd like to delete in such a way that transparency remains.

I've found that this is the default when I'm working on images that I've created myself. But if I'm working on an image that I've downloaded or gotten from another source, I can't predict the behaviour of functions that remove pixels.

In my immediate case, I've got a icon with a white background. I want to remove the background. However, when I try to remove the white pixels, the result is black pixels.

How can I figure out what the result of deletion operations on pixels will be?

How can I consistantly remove colour, leaving transparency?

Thanks.

Hi,

You have to add alpha channel from the image menubar through Layer ? Transparency ? Add alpha Channel.
http://docs.gimp.org/2.6/en/gimp-layer-alpha-add.html

With an alpha channel, the default operation of eraser is deleting to transparency.
However, if you want to turn white to transparency, you'd better use Colors ? Color to alpha.

Abel

yahvuu
2010-09-30 08:53:05 UTC (over 14 years ago)

How do I delete to transparency?

On 30.09.2010 05:39, bobdobbs wrote:

Hi all.

I'd like to delete in such a way that transparency remains.

I've found that this is the default when I'm working on images that I've created myself. But if I'm working on an image that I've downloaded or gotten from another source, I can't predict the behaviour of functions that remove pixels.

In my immediate case, I've got a icon with a white background. I want to remove the background. However, when I try to remove the white pixels, the result is black pixels.

How can I figure out what the result of deletion operations on pixels will be?

How can I consistantly remove colour, leaving transparency?

short answer: always add an alpha channel to the layer, either using the layers dialog or via Layers->Transparency->Add Alpha Channel [1].

The alpha channel determines the transparency for each pixel. The absence of an alpha channel means that all pixels are fully opaque and hence they get deleted to background color [2].

regards, peter

[1] http://docs.gimp.org/2.6/en/gimp-layer-alpha-add.html [2] http://docs.gimp.org/2.6/en/gimp-image-combining.html#gimp-layer-properties

bobdobbs
2010-10-02 02:50:02 UTC (over 14 years ago)
postings
31

How do I delete to transparency?

I'm foolish.
I should have realised this.

Thank you.

On 30.09.2010 05:39, bobdobbs wrote:

Hi all.

I'd like to delete in such a way that transparency remains.

I've found that this is the default when I'm working on images that I've created myself. But if I'm working on an image that I've downloaded or gotten from another source, I can't predict the behaviour of functions that remove pixels.

In my immediate case, I've got a icon with a white background. I want to remove the background. However, when I try to remove the white pixels, the result is black pixels.

How can I figure out what the result of deletion operations on pixels will be?

How can I consistantly remove colour, leaving transparency?

short answer: always add an alpha channel to the layer, either using the layers dialog or via Layers->Transparency->Add Alpha Channel [1].

The alpha channel determines the transparency for each pixel. The absence of an alpha channel means that all pixels are fully opaque and hence they get deleted to background color [2].

regards,
peter

[1] http://docs.gimp.org/2.6/en/gimp-layer-alpha-add.html [2] http://docs.gimp.org/2.6/en/gimp-image-combining.html#gimp-layer-properties

yahvuu
2010-10-05 14:11:32 UTC (over 14 years ago)

How do I delete to transparency?

On 02.10.2010 02:50, bobdobbs wrote:

How can I figure out what the result of deletion operations on pixels will be?

for the record, i just learned that a bold layer name indicates a missing alpha channel (as displayed in the layers dialog): http://docs.gimp.org/2.6/en/gimp-dialogs-structure.html#gimp-layer-dialog

-peter