#303 Transparency

[Ethan Merritt]

This patchset adds support for transparent fill areas.
Two forms of transparent fill are included, solid fill
with an explicit alpha channel value and pattern fill
with a fully transparent background.

set style fill transparant solid <alpha-value>
set style fill transparent pattern <pattern #>

Please see examples on
http://gnuplot.sourceforge.net/demo_4.1/

Not all terminals can handle transparency; some can
handle one form but not the other. The initial version
of the patchset implements

gif pattern
jpeg solid
pdf solid + pattern
png solid (truecolor) + pattern (indexed)
post pattern
svg solid + pattern (viewer dependent)
wxt solid + pattern
x11 pattern

Please contribute support for additional terminal
types. Aquaterm should be easy, I am uncertain which
others are possible.

[Ethan Merritt]

Transparency

[Ethan Merritt]

Transparency (with new demo)

[Ethan Merritt]

Logged In: YES
user_id=235620

Added transparent_tori.dem to the patchset by popular demand

[Ethan Merritt]

Logged In: YES
user_id=235620

Added to CVS.
No known problems with current code.
It would be nice if someone were to add support for
aquaterm
windows
other terminals?