Legacy ImageMagick Discussions Archive

The XPM coder is miss-handling the realing of XPM images contains actual color names rather than hex values.


For example using a "colortable" image..
http://www.imagemagick.org/Usage/images/colortable.gif

This was converted a long time ago (correctly using NetPBMPlus)

While here is the source XPM image (and a IM converted GIF version)
http://www.cit.griffith.edu.au/~anthony ... rtable.xpm


As you can see in the IM converted XPM the colors "Green" and "Purple" come out wrong.

XPM images are ONLY supposed to use X11 color definitions, but IM is using its complete color database for color name conversion which uses SVG definition for "Green" and "Purple", and as such getting the resulting final image wrong. here is its internal color database definition for these two colors. green rgb(0,128,0) SVG
green rgb(0,255,0) X11 XPM purple rgb(128,0,128) SVG
purple rgb(160,32,240) X11 XPM

XPM coder MUST only use X11 colors for colornames when parsing the XPM image file format.

Bump... Still not fixed.

We can reproduce the problem you posted and have a patch in ImageMagick 6.6.3-2 Beta available by sometime tomorrow. Thanks.

I now get a Corrupt image Error for the XPM image!!!

display: unrecognized color `DarkSlateGrey' @ warning/color.c/GetColorCompliance/946.
display: corrupt image `icons/local/colortable.xpm' @ error/xpm.c/ReadXPMImage/393.


I have no idea why it does not know what DarkSlateGrey is.

The X11 rgb.txt color table lists it as
47 79 79 DarkSlateGrey

And IM lists is as being a X11 color (as well as a SVG color)
DarkSlateGrey rgb(47,79,79) SVG X11

XPM supports a subset of the X11 colors. For example, your colortable.xpm includes the Khaki4 color which is not an XPM compliant color. However, we can't find the original format specification that lists the color names supported by XPM so we now permit any colorname when reading an XPM.

However, we can't find the original format specification that lists the color names

I don't know if this will help or is the original list of color names. But see

ftp://ftp.x.org/contrib/libraries/xpm-README.html
http://www.fileformat.info/format/xpm/egff.htm
http://en.wikipedia.org/wiki/X_PixMap
http://www.bolthole.com/java/Xpm.java

The X11 color list has no changed in more than 10 years. It is normally extracted from Xlib functions, whcih in turn reads them from a file installed with the X server.

They are listed in the file named "rgb.txt" somewhere on any X window system.
originally it was located at /usr/lib/X11/rgb.txt
however the newer Xorg Xwindow servers moved it to /usr/share/X11/rgb.txt

NetPBM also installs a copy in /usr/share/netpbm/rgb.txt

IM never had problems with either DarkSlateGrey or Khaki4

And I am not adding the complication of having spaces in color names in the XPM color table.

Example XPM color table entry....

" s None c None",
". c dark slate grey",
"X c lemon chiffon",
"o c black",

teh first characters are the 'index' for the pixel data. after that single letters are 'keys' followed by the key value
'c' is for color and the color can be multiple words as you can see by the example above.
's' is a symbol name used for program modification of that color.

Also like GIF you can have multiple indexes with the same color, though typically different program 'symbols', however use of symbols is extremely rare, and can be ignored by IM. Multiple indexes in a palette should not be ignored!

see http://en.wikipedia.org/wiki/X11_color_names

it has a link to x11 rgb.txt at http://cvsweb.xfree86.org/cvsweb/*check ... xt?rev=1.1