Fwd: Re: colorizing

Fwd: Re: colorizing

[Hans Hagen]

>
>On Mon, 28 Jan 2002 18:17:26 +0100
>Henning Hraban Ramm <angerweit@gmx.net> wrote:
>
> > e.g. I use a bitmap logo that should show exactly the same color as 
> defined
> > for backgrounds. If I define the "same" color with PhotoShop it looks
> > slightly different. Further I'd like to place it white on color.
>
>I have tried this using a RGB-PNG-image above a Metapost-image
>including only a rectangle filled with the background-color
>of the PNG-image. I can see no difference between both backgrounds.
>Is your image in cmyk or in rgb?
>
>
>On Tue, 29 Jan 2002 21:01:16 +0100
>Hans Hagen <pragma@wxs.nl> wrote:
>
> > At 06:17 PM 1/28/2002 +0100, Henning Hraban Ramm wrote:
>
> > >It should as easy as in other functions to assign foreground and 
> background
> > >color, maybe even transparency?
> >
> > when i browsed the specs some time ago i got the impression that this is
> > doable, but so far i didn't need it (although i will probably need it
> > soon). Building ther sources is trivial (once i understand it) and we can
> > probably hook things into the resource dict of graphics, but cooking up a
> > proper interface will take me some time. We can look into the specs at the
> > coming dante meeting to see what can be done.
>
>i think not all can be done on TeX-level. For example the alpha-channel
>in png or tiff-images, it would be nice when pdftex could support this
>directly.
>
>Best,
>   Jens

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                                   Hans Hagen | PRAGMA ADE | pragma@wxs.nl
                       Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
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Re: Fwd: Re: colorizing

[Henning Hraban Ramm]

> >I have tried this using a RGB-PNG-image above a Metapost-image
> >including only a rectangle filled with the background-color
> >of the PNG-image. I can see no difference between both backgrounds.
> >Is your image in cmyk or in rgb?

RGB. But it may be a matter of color management, as Hans assumed.

> >i think not all can be done on TeX-level. For example the alpha-channel
> >in png or tiff-images, it would be nice when pdftex could support this
> >directly.

Try PDF! At least clipping paths are working.

Grüßlis vom Hraban!

Re: Fwd: Re: colorizing

[Jens-Uwe Morawski]

On Sat, 2 Feb 2002 19:49:09 +0100
Henning Hraban Ramm <angerweit@gmx.net> wrote:

> > >I have tried this using a RGB-PNG-image above a Metapost-image
> > >including only a rectangle filled with the background-color
> > >of the PNG-image. I can see no difference between both backgrounds.
> > >Is your image in cmyk or in rgb?
> 
> RGB. But it may be a matter of color management, as Hans assumed.
> 
> > >i think not all can be done on TeX-level. For example the alpha-channel
> > >in png or tiff-images, it would be nice when pdftex could support this
> > >directly.
> 
> Try PDF! At least clipping paths are working.

I know, but the thing i'm looking for is to put an image above a text
and see the text shine through, since the image is semi-transparent,
for instance a alpha-gradient from left to right which makes the
text "fade-in".

Best,
  Jens

Re: Fwd: Re: colorizing

[Hans Hagen]

At 07:49 PM 2/2/2002 +0100, Henning Hraban Ramm wrote:
> > >I have tried this using a RGB-PNG-image above a Metapost-image
> > >including only a rectangle filled with the background-color
> > >of the PNG-image. I can see no difference between both backgrounds.
> > >Is your image in cmyk or in rgb?
>
>RGB. But it may be a matter of color management, as Hans assumed.
>
> > >i think not all can be done on TeX-level. For example the alpha-channel
> > >in png or tiff-images, it would be nice when pdftex could support this
> > >directly.
>
>Try PDF! At least clipping paths are working.

if you can find out the right snippets of pdf code needed .. or make stand 
alone pdf graphics illustrating the principle ... this is how i could 
figure out transparency: make a file in AI and look at the pdf code.

Hans
-------------------------------------------------------------------------
                                   Hans Hagen | PRAGMA ADE | pragma@wxs.nl
                       Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
  tel: +31 (0)38 477 53 69 | fax: +31 (0)38 477 53 74 | www.pragma-ade.com
-------------------------------------------------------------------------
                                   fall-back web server: 
www.pragma-pod.nl
-------------------------------------------------------------------------