Outside the -draw MVG commands, you are limited to using the -fill setting option. This will only accept eitehr a previously defined color name, or a set of numbers. As the only non-opaque color pre-defined is "none" or "transparent" you are basically out of luck in that regard.
You will thus need to resourt to using numbers.
For examples See IM Examples, Channels, Semi-Transparent colors
http://www.cit.gu.edu.au/~anthony/graph ... els/#color
Sorry about the odd position of that, but it was and still is the most logical place in to put that information (EG alpha/matte channel info)
If you are using draw, you have more choice. As -draw uses MVG graphics lanuage, which is designed as a simplified SVG language, it can define the color and transparency seperatally.
See IM Examples, Drawing, MVG Specific Settings
Code: Select all
-draw 'fill red fill-opacity 0.6 .... '
http://www.cit.gu.edu.au/~anthony/graph ... g_settings
Unfortunatally, 'fill-opacity' is not availbale to the command line, though it would be a nice addition, as would 'stroke-opacity'.