Re: unified FLTK & Gnuplot printing

[Ben Abbott]

On Aug 30, 2010, at 1:16 AM, Jordi Gutiérrez Hermoso wrote:

> On 23 August 2010 20:13, Ben Abbott <address@hidden> wrote:
>> I've prepared a changeset to unify the printing for both the FLTK
>> and Gnuplot backends.
>> 
>> For both backends, ghostscript is relied upon more heavily than
>> before.
> 
> I've been meaning to comment on this.
> 
> It's nice that you've found a unified method for all formats. I still
> think, however, that we could profitably use a bitmap method for
> bitmap output formats. Vector graphics aren't good for getting a
> picture of a colourful surface with shading at an interesting angle.
> It would also be nice to generate an exact screenshot of what's shown
> on the screen in a bitmap format, which at least Søren has wished for.
> 
> I have no idea how much work this will be, but I want to get started
> on it, as an option or alternative to gl2ps at least for some output
> formats. Maybe not for the 3.4 release, but soonish.
> 
> - Jordi G. H.

I've occasionally noticed the on screen rendering looks better than the printed 
version. However, I don't have a deep enough understanding the technical 
details to conclude why.

The two cases for the FLTK backend

(1) OpenGL -> bitmap (on screen may have anti-aliasing, or may not).

(2) OpenGL -> Postscript -> bitmap (usign gs with anti-aliasing)

I assumed any visible difference would depend upon which anti-aliasing method 
is superior (assuming each image is the same size and resolution).

For the earlier Gnuplot backend, antialiasing only accompanied the cairo and 
wxt terminals. In this case, the wxt image is expected to render a superior 
result as compared to any bitmap, except for pngcairo.

Ben