Re: pdfcairo terminal; seams between bars in the colorbox

[Ethan A M. <me...@uw...>]

On Sunday, 11 June 2023 14:14:27 PDT Dima Kogan wrote:
> >> What if we change the code from
> >>   calling term->filled_polygon() for each colorbox slice
> >> to
> >>   calling term->image() once for the whole colorbox
> >
> > In the case of pdf output it would mean going through the cairo
> > library either way. I wouldn't necessarily expect a difference.
> 
> I would expect it to fix things because gnuplot images look good with
> all pdf readers. Can you think of reasons such a patch wouldn't be a
> good idea? The fact that it wasn't done this way to begin with makes me
> think there's some reason.

I may not understand what you are suggesting.

Right now in order to create pdf output the code is calling 
cairotrm_filled_polygon() to render pixels into a cairo surface which
is eventually output as a pdf file.

I understood your suggestion to be that the program would instead
create a separate cairo png surface, use cairotrm_filled_polygon() to render
the pixels, then copy the pixels from the png surface to the pdf surface.

It is not obvious to me that the extra step would change the final output.
The same calls to cairotrm_filled_polygon() would be rendered
either way.  Copying the block of rendered pixels from one cairo surface to
another should not, I would think, change anything.

Anyhow, such a change would be specific to the cairo terminals.
We would not want to introduce a dependence on cairo image creation
when drawing the color box from other terminal types.

	Ethan