Re: Transparent background with pdfcairo

[Christoph B. <us...@be...>]

On 24.05.2011 05:35, sfeam (Ethan Merritt) wrote:
> Christoph Bersch<us...@be...>  wrote>
>>
>> is there a specific reason why the 'transparent' terminal option applies
>> only to the pngcairo and not to the pdfcairo terminal?
>>
>
> So far as I know, pdf and PostScript files have no "background" to be
> set transparent or opaque.

Correct, but in cairo.trm the background of the pdf is explicitely set 
to white. This can be avoided with the 'transparent' option which is 
used only by the pngcairo terminal

> Do you actually see a difference in the output file after your patch?

Yes.
I came to this problem when I tried to combine the epslatex and the 
pdfcairo terminal. I could not use the pdf file unless all text was set 
to front.

> Using what tool to view it?

To show the problem, consider the following code:


set terminal pdfcairo transparent
set output 'test-inc.pdf'
set tics lc rgbcolor 'white'
plot sin(x) lw 4


\documentclass{minimal}
\usepackage{graphicx}
\begin{document}
\rule{3cm}{3cm}\hspace*{-3cm}\includegraphics{test-inc}
\end{document}


Without my patch, the file test-inc.pdf completely covers the black 
square. Only with my patch the background of the pdf file is transparent 
to show the black square behind.

Christoph