[magick-users] GetFillColor and extract_info

[omicronpersei8 at imagemagick.org]

> provide an offset to the Draw functions when used with the tile
> option, which is exactly what I was hunting for. 

GetFillColor() is called by the object and text renderer.  If no fill
pattern is available it uses the fill color otherwise it uses the fill
pattern to paint the object or text with the pattern.  As you surmised
extract_info.{xy} sets the initial pattern offset which defaults
to 0,0.  You can set these fields when you read the pattern as in
readImage('image.gif[+13+20]').  However, we probably should include a
method in Magick++ to support this field but its possible we may want to
use some other way to set the pattern offset since the extract_info field
is already overloaded.  It would make the most sense to add a new member in
the draw_info structure to specify the pattern offset.  Given that why
not post a few lines of code of how you'd like to take advantage of a
pattern offset and we'll figure out a way to define new members to the
draw_info structure and a way to set the members in Magick++.