Re: libgd update in the works

[Ethan M. <merritt@u.washington.edu>]

On Monday 08 January 2007 00:10, Mojca Miklavec wrote:
> On 1/7/07, Ethan A Merrit wrote:
> 
> > Since both gnuplot and libgd are heading towards a significant new
> > release, this is a good time to revisit any long-standing problems
> > with functionality of the gnuplot gif/png/jpeg terminal drivers.
> >
> > It wouldn't hurt to add some wish-list items as well, perhaps taken
> > from our backlog of feature requests.  Support for color gradients
> > comes to mind
> 
> If that is meant by color gradients: I would really like to see if 3D
> plots could be drawn with (triangles) with a different color in each
> edge and smooth color transition between them, so that the plot
> wouldn't need a 100x100 grid to look realistic.
> 
> I've been just playing with smooth shading in PS and PDF (and a
> metapost interface for drawing it). It's a bit complicated to do, but
> doable (with quite some effort).

I am led to believe that we could define gradient-fill operations
directly in PDF, using the PDF_shading_pattern() routine in pdflib.
However, the documentation seems to say that you are limited
to a one-axis gradient (e.g. changes only along x) or a radial
gradient.  I am not sure how one would best adapt either of these
to the task of filling a triangle/rectangle with target colors specified
at the vertices.  The same is true for SVG.