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

Featured content

value invert is for luminance only, or can be also other thing ?

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.

2 of 2 messages available
Toggle history

Please log in to manage your subscriptions.
value invert is for luminance only, or can be also other thing ? Cristian Secar? 10 Jun 17:46
  value invert is for luminance only, or can be also other thing ? Sven Neumann 10 Jun 23:57
Cristian Secar?
2008-06-10 17:46:38 UTC (over 16 years ago)

value invert is for luminance only, or can be also other thing ?

In Colors menu there are two invert positions, one is Invert and other in Value invert.

For the first invert, the floating help says "Invert the colors". For the second invert, the floatig help says "Invert the brightness of each pixel".

My first question is why are the menu names not self-explained. Why is the first only "Invert" and is not "Color invert" ? My second question is what other value things can be inverted other than the luminance pixels. Why is the second "Value invert" and not "Luminance invert" ? Whom else value ?

Cristi

Sven Neumann
2008-06-10 23:57:34 UTC (over 16 years ago)

value invert is for luminance only, or can be also other thing ?

Hi,

On Tue, 2008-06-10 at 18:46 +0300, Cristian Secar? wrote:

In Colors menu there are two invert positions, one is Invert and other in Value invert.

For the first invert, the floating help says "Invert the colors". For the second invert, the floatig help says "Invert the brightness of each pixel".

My first question is why are the menu names not self-explained. Why is the first only "Invert" and is not "Color invert" ?

Because "Invert" implements the classic definition of an Invert operation on RGB images. It's the term that people are looking for.

My second question is what other value things can be inverted other than the luminance pixels. Why is the second "Value invert" and not "Luminance invert" ? Whom else value ?

Value is a well-defined concept in image processing. The value of a pixel is defined as the maximum value of its RGB channels. It one way to define a measure for the intensity of a pixel. The Value Invert operation performs the color inversion in the HSV space (where V is Value), leaving Hue and Saturation untouched.

Sven