#440 Supports character entity reference

[Tatsuro MATSUOKA]

On gd based terminals (png, jpeg, gif), one can use the character entity reference,

set term png
set output 'test.png'
plot sin(x) title '{/:Italic \θ}'

This is very useful but one cannot use tha above syntax except the gd based terminals.
If the syntax like the above is supported, it will be very grateful.

[Tatsuro MATSUOKA]

The above was discussed in the one of the gnuolot comminity in Japan.
In the original post, the character entity reference feature can be used also in svg terminal.
But I could not reproduce his results.