How to do a gradient in Postscript Re: [Open-graphics] Linux Tag 2007 [Poster-Preview]

[James Richard Tyrer]

Dieter wrote:
>> But does postscript support the same types of gradients that SVG does?=20
>> SVG lets you make pretty complex gradients, and while the PS version of=20
>> the poster does have some kind of gradient, it's not the same as the=20
>> SVG version. So either there's a bug in the conversion, or PS just=20
>> doesn't support complex gradients.
> 
> I don't know what you mean by "complex gradients".  My copy of the red book
> has wandered off, but PS is a full blown programming language, so I imagine
> it can do what you want.
> 
> Taking a quick glance at the wikipedia SVG page, looks like someone decided
> to create yet another graphics language, a couple of browsers have partial
> support, Adobe will drop support in less than a year, yadda yadda yadda...
> 
> The final output is supposed to be a large piece of paper, right?  What
> language(s) does the printer speak?  Probably not SVG.

It appears that a ShadingType 2 has built in support for extending 
beyond the end points like InkScape does.

It appears (page 266 & 267 PLRM) that a ShadingType 2 dictionary can 
include a function definition.  If none is defined, then a linear 
shading is used, however, you should be able to define a f(t) do do 
whatever you want.

-- 
JRT