Re: transparent PNG on a coloured background

Re: transparent PNG on a coloured background

[siep.kroonenberg]

On  8 Jan, Tobias Burnus wrote:
> Hi Hans, hi all,
> 
> I now have a problem with a logo (PNG file) which is round and has a
> transparent background. I simply insert it using \externalfigure and the
> background of the transparent parts is white (not the colour of that
> page).
> 
> Tobias

I remember having this problem with [pdf]latex too.

-- 
Siep Kroonenberg
Kluwer Academic Publishers, Prepress Department
Achterom 119, 3311 KB Dordrecht, The Netherlands
siep.kroonenberg@wkap.nl

Re: transparent PNG on a coloured background

[Han The Thanh]

Hi,

> > I now have a problem with a logo (PNG file) which is round and has a
> > transparent background. I simply insert it using \externalfigure and the
> > background of the transparent parts is white (not the colour of that
> > page).
> > 
> > Tobias
> 
> I remember having this problem with [pdf]latex too.

transparency in pdf is not support in the current version of pdf yet (1.3,
acrobat 4.x), so the alpha channel of png figures will be ignored.

Thanh

Re: transparent PNG on a coloured background

[Tobias Burnus]

Hi Han The Thanh,

> transparency in pdf is not support in the current version of pdf yet (1.3,
> acrobat 4.x), so the alpha channel of png figures will be ignored.

Who bothers with PDF 1.3, why don't you use PDF 1.4?

As far as I know only Adobe Illustrator writes it so far, but since TeX
is always on the leading edge.

If you are concerned that one cannot view it -- have a look at
Ghostscript 6.50.

See for reference:
http://partners.adobe.com/asn/developer/technotes.html#acrobat-pdf
http://www.ghostscript.com/doc/AFPL/6.50/Language.htm

With warm regards (and looking forward),

Tobias

-- 
This above all: To thine own self be true / And it must follow as
the night the day / Thou canst not then be false to any man.

Re: transparent PNG on a coloured background

[Hans Hagen]

At 08:37 PM 1/9/01 +0100, Tobias Burnus wrote:
>Hi Han The Thanh,
>
>> transparency in pdf is not support in the current version of pdf yet (1.3,
>> acrobat 4.x), so the alpha channel of png figures will be ignored.

Do you mean, in the png inclusion? Does the png library support it? 

>Who bothers with PDF 1.3, why don't you use PDF 1.4?

Who knows what that is? Does adobe keep us informed then? 

>As far as I know only Adobe Illustrator writes it so far, but since TeX
>is always on the leading edge.
>
>If you are concerned that one cannot view it -- have a look at
>Ghostscript 6.50.

What happens in 1.3 viewers if it it used? 

Hans 
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transparent PNG on a coloured background

[Tobias Burnus]

Hi Hans, hi all,

I now have a problem with a logo (PNG file) which is round and has a
transparent background. I simply insert it using \externalfigure and the
background of the transparent parts is white (not the colour of that
page).

Tobias