Re: pdfcairo terminal; seams between bars in the colorbox

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

On Thursday, 15 June 2023 15:39:22 PDT Dima Kogan wrote:
> 
>   dima@shorty:~/projects/gnuplot$ git show-branch HEAD origin/master
>   ! [HEAD] smooth colorbox: render as a bitmap if the terminal supports it
>    ! [origin/master] Do not report terminal type to user until after initialization is complete
>   --
>   +  [HEAD] smooth colorbox: render as a bitmap if the terminal supports it
>   +  [HEAD^] no-op cleanup: consolidated next-colorbox-slice logic
>   +  [HEAD~2] no-op cleanup: consolidated draw-colorbox-slice logic
>   +  [HEAD~3] no-op cleanup: consolidated colorbox bounds logic
>   +  [HEAD~4] no-op cleanup: consolidated steps-in-colorbox logic
>    + [origin/master] Do not report terminal type to user until after initialization is complete
>    + [origin/master^] VMS cleanup
>   ++ [HEAD~5] qt:  qt4 was apparently weak at int->double promotion
> 
> I'm attaching the patches to this email.

I like it so far.
I will try to think of more tests to run.

> > OK. The other alternative is to make this specific to cairopdf. Unless
> > you know of other terminals that suffer from the same problem?

[snip descroption of svg problems with small number of image pixels]
> So if we
> can fix this, I'd say we should do the colorbox-image thing whenever
> available. But if we can't, maybe limiting it to only cairopdf (or NOT
> svg) is the answer.
> 
> Let me ask a web-dev friend about how to make svg work right in all
> browsers. There's probably a way.
> 
> The current set of attached patches does NOT limit itself to cairopdf

I think it benefits all the cairo terminals, or at least doesn't hurt.
Beyond that, well - that's what I am trying to test.
I will add a FIXME comment.
 
> Ah yes. This is exactly what I mentioned above. I don't remember any
> terminal other than svg having this problem. But I certainly haven't
> touched all of them.

The HTML5 canvas terminal has the same problem: browsers apply
inter-pixel interpolation, details of which are poorly documented.

   cheers
   Ethan