Can anyone recommned a program (preferably small compact and specialize to this
purpse) to use to obtain the color index/register or a particular color?

The question is in regards to the 'image_map' pigment and the 'filter' and
'transmit' properties (see http://www.povray.org/documentation/view/3.6.1/337/)

I usually use 'irfanview' (http://www.irfanview.com/) for such tasks, but it is
limited in that you can only get the register from a list of displayed colors.
You cannot use a dropper tool on the image itself to obtain the color register
for a particular pixel.

As some of the imaes i'm working with my have colors not normally distinguisable
by the human eye, does anyone know of such an app (preferably with 'color
dropper' functionality?

-Woody

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Le 29/08/2012 14:27, Woody a écrit :
> Can anyone recommned a program (preferably small compact and specialize to this
> purpse) to use to obtain the color index/register or a particular color?
> 
> The question is in regards to the 'image_map' pigment and the 'filter' and
> 'transmit' properties (see http://www.povray.org/documentation/view/3.6.1/337/)
> 
> I usually use 'irfanview' (http://www.irfanview.com/) for such tasks, but it is
> limited in that you can only get the register from a list of displayed colors.
> You cannot use a dropper tool on the image itself to obtain the color register
> for a particular pixel.
> 
> As some of the imaes i'm working with my have colors not normally distinguisable
> by the human eye, does anyone know of such an app (preferably with 'color
> dropper' functionality?


Gimp.

With an indexed image of course,

To see the map: Colors->Map->Rearrange ColorMap
(right click for sorting...)

To actually play with the palette: "on toolbox, click on the left
pointing arrow/triangle in a box, (top right of bottom panel, under the
ink/paper colour rectangle)"->Add tab->colormap

Enjoy!

Post a reply to this message

> I usually use 'irfanview' (http://www.irfanview.com/) for such tasks, but it is
> limited in that you can only get the register from a list of displayed colors.
> You cannot use a dropper tool on the image itself to obtain the color register
> for a particular pixel.

You could just use irfanview to crop the image down to the single pixel that you
are interested in and then extract the color register. How do you get the
register information from Irfanview anyway? I didn't find the fuction. Are you
using Irfanview from the command line? ... Gimp is definately a good suggestion.
But if you need to script this you could also have a look at "Imagemagick".

Post a reply to this message

Woody wrote:

> I usually use 'irfanview' (http://www.irfanview.com/) for such tasks, but it is
> limited in that you can only get the register from a list of displayed colors.
> You cannot use a dropper tool on the image itself to obtain the color register
> for a particular pixel.

Not sure I understood what you need, but if you click on a pixel in
the image in irfanview, the rgb (and index for images with palette)
appear in the title bar.

Post a reply to this message

>
> You could just use irfanview to crop the image down to the single pixel that you
> are interested in and then extract the color register. How do you get the
> register information from Irfanview anyway? I didn't find the fuction. Are you
> using Irfanview from the command line? ... Gimp is definately a good suggestion.
> But if you need to script this you could also have a look at "Imagemagick".

Perhaps register was the wrong word (I used it since that was the description in
the 'image_map' definition.

It's more of an index that points to individual colors in the image, with each
color having a distinct index. Starting at 0 or 1 (I forget which) then
increasing by 1 until each color has index.

The only problem is that shrinking it down to a single pixel, one of two things
could happen:

a) due to the reduced image, only 1 color remains and that color now has an
index of 1. the problem with this being you can't find the index of that color
with respect to the original picture

or

b) the image retains all the colors of the original image, even though only a
single color in a single pixel is being displayed. The palette thereby keeps the
same color index scheme, and you are back where you started (trying to find the
correct index for a color that has similar colors that are so close the human
eye can't distinguish between them.)

-Jeff

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> Can anyone recommned a program (preferably small compact and specialize to this
> purpse) to use to obtain the color index/register or a particular color?
>
> The question is in regards to the 'image_map' pigment and the 'filter' and
> 'transmit' properties (see http://www.povray.org/documentation/view/3.6.1/337/)
>
> I usually use 'irfanview' (http://www.irfanview.com/) for such tasks, but it is
> limited in that you can only get the register from a list of displayed colors.
> You cannot use a dropper tool on the image itself to obtain the color register
> for a particular pixel.
>
> As some of the imaes i'm working with my have colors not normally distinguisable
> by the human eye, does anyone know of such an app (preferably with 'color
> dropper' functionality?
>
> -Woody
>
>

In IrfanView, you can edit the palete itself.
In the menu, sellect Image|Palette|Edit

You now have a new window containing all the colours from the palette in 
order: 0 to 15 for the top row.

When you double-click a given colour block, you get the colour editing 
dialog from where you can change the actual colour values.
You can change the red, green and blue values by entering the values. 
You can do the same using hue, saturation and brightness.

If you click somewhere on the image, the index position for that pixel 
will be sellected and highlighted in a red frame.


Alain

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