Re: libgd update in the works

[Mojca M. <moj...@gm...>]

On 1/9/07, Ethan Merritt wrote:
> On Monday 08 January 2007 00:10, Mojca Miklavec wrote:
> > 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.

http://partners.adobe.com/public/developer/en/ps/sdk/TN5600.SmoothShading.pdf
(Type 4)

I went exploring and have written a much longer email. And then I
figured out an extremely weird fact. Not only the libraries have a
missing functionality ... not even my PDF viewer (Preview.app, the
main PDF viewer under Mac) is capable of displaying/rendering such
triangles. (Free-Form Gouraud-Shaded Triangle Meshes)

See
      http://www.math.ubc.ca/~cass/graphics/manual/pdf/ch13.ps
      http://www.math.ubc.ca/~cass/graphics/manual/pdf/ch14.pdf
(examples which inspired me to start learning PostScript, and in
particular this sphere)

I only see one sphere on the first page, but there should be two :(

Mojca