re-printim

[Arlindo da Silva]

On Thu, Nov 19, 2009 at 5:15 PM, Daniel MAINEULT <daniel.maineult at neuf.fr>wrote:

> Dear Mike,
>
> me work under linux Fedora 11
> I have the problem with the two following versions:
>
> grads 2.0.a7 and opengrads 2.0.a5.oga.5
>
> Impossible to use a resolution 720*576 or 960*576 the transparency doesn't
> function
> but with 800*640 it is ok.
> I need to use formats broadcasts.
>
>
The command version of* gxyat* has a more flexible transparency capability
which allows each color you define to have its own transparency level (the
so-called alpha channel).  In particular, it can emulate the -t option of
printim and it does work with any resolution. Here is an example:

ga-> open model
ga-> set_rgba 60 125 125 125 0 1
ga-> set ccols 1 2 3 4 5 6 60          t.
ga-> set clevs 500 600 700 800 900 1000
ga-> d ps
ga-> gxyat -x 1600 -y 1200 img.png

As a bonus, you get anti-aliased fonts.  Here is the syntax of the
set_rgbacommand that Pablo Romero contributed:

NAME
     set_rgba - define color including alpha channel

SYNOPSIS
     set_rgba color red green blue alpha [mask]

DESCRIPTION
     This User Defined Command (UDC) defines *color* given its
     RGB triplet along with its *alpha* channel.

     color   integer in the range [16-255]
     red,
     green,
     blue    integers in the range [0-255]
     alpha   float, with alpha ranging from 0.0 (fully transparent)
             to 1.0 (fully opaque).

    The optional parameter *mask* determines whether the color below
    it is visible or not.

    mask=0  --- if alpha<1, *color* will be semi-transparent and the
                colors below it will be visible (default)
    mask=1  --- if alpha<1, *color* will be semi-transparent but the
                colors below it will *not* be visible

EXAMPLE
    In order to emulate the -t option in printim

       ga-> set rgb 60 125 125 125
       ga-> printim img.png -t 60

       Specify alpha=0 and mask=1

       ga-> set_rgba 60 125 125 125 0 1
       ga-> gxyat img.png

--
Arlindo da Silva
dasilva at alum.mit.edu
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