Re: Fetch and store color value in a variable

On Wed, 11 Nov 2009 02:32:37 -0800 (PST)
mini prashanth <[email protected]> wrote:

| Hi,
| Iam basically trying to fetch the color value of the pixel at position 0,0 and store it in the hex format "#cccccc" in a variable . 
| 
| FOR /F %%i IN ('identify -format "%%[fx:p{0,0}]" "img.jpg"') DO SET x=%%i (here iam getting some decimal value like x=0.298110)
| 
| I tried to change it into Hex value by using this..
| 
| For /F %%s IN ('EVAL "rgb(%x%)"') Do SET hexColor=%%s
| 
| This is not working ..Please Help
| 
fx only works with single values. That number if just the red color value
as a normalized 0 to 1 value.

color  will return a color value which IM can use. Often it will be
a rgb(...) color, but sometimes it will return the corresponding color
name  'black' 'white' 'red' puce' etc.  It is not in hexadecimal format.

   convert rose: -format "%[pixel:u]" info:-
   rgb(48,47,45)


As Fred pointed out, you can extract the value from a TXT: output

  convert rose:[1x1+0+0] txt:
  # ImageMagick pixel enumeration: 1,1,255,rgb
  0,0: ( 48, 47, 45)  #302F2D  rgb(48,47,45)

But as you are windows  'sed' is not really available, and windows
command line string handling abilities is pretty non-existant.

You can use -fx to extract each of the three color values (red, green,
blue), but you will get them as a floating point numbers, or intergers.

  convert rose: -crop 1x1+0+0 \
          -format "%[fx:int(255*r)],%[fx:int(255*g)],%[fx:int(255*b)]" \
          info:-
  48,47,45

If %[fx:..] had a awy to format its output we could ask it to output
the values as 2 digit hexadecimal values ( printf format "%02X" )
but that feature is not available at this time, and you again do not
have access to the UNIX 'printf' command to convert them.


I am sorry their is no simple way to extract the color, as a hexadecimal
directly from the command line ImageMagick.  The values are there just
not in the right format.


  Anthony Thyssen ( System Programmer )    <[email protected]>
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