Re: Layer vs. overlay

[Wolfgang Schuster <wolfgang.schuster@gmail.com>]

Am 15.01.2013 um 09:04 schrieb Procházka Lukáš Ing. - Pontex s. r. o. <LPr@pontex.cz>:

> On Sat, 12 Jan 2013 19:11:47 +0100, Wolfgang Schuster <wolfgang.schuster@gmail.com> wrote:
> 
>> Move \definelayer and \setupbackgrounds *before* \startTEXpage because the environment creates a local group and you background setup is lost.
> 
> ... Thanks for the hint - here's my next trial.
> 
> It should write "BEFORE" to tho top right corner of the page.
> 
> ----
> \setupbodyfont[30pt]
> 
> \starttext
>  A
> 
>  \bgroup
>    \definelayer[beforetext][width=\paperwidth,preset=righttop]
> 
>    \setupbackgrounds
>      [page]
>      [background={foreground,beforetext}]
> 
>    \startTEXpage
>      \setlayer[beforetext]{\framed[width=2in]{BEFORE}}
>      \externalfigure[cow][width=30cm]
>    \stopTEXpage
>  \egroup
> 
>  Z
> \stoptext
> ----
> 
> The problem now is the layer "beforetext" has width of the page in the moment is is defined - 21 cm.
> 
> But the layer is supposed to be used later inside \start/stop-TEXpage whose page size may be arbitrary, or better, the size will result from the content it will contain.
> 
> In my example - an image of 30 cm width is to define the page size.
> 
> And the text "BEFORE" is not put to the top right corner of the (30 cm) page (what I'd like to achieve) but to cca 2 thirds of these 30 cm (given by \pagewidth which was 21 cm at the moment of definition).
> 
> I would probably need a way to alter the layer size to the current content...
> 
> Or any other way to place something to the top right corner of the page from within \start/stop-TEXpage, where page size is not known in advance?

\setupbodyfont[30pt]

\starttext

A

\definelayer  [beforetext][width=\overlaywidth,height=\overlayheight]
\defineoverlay[beforetext][{\setups[beforetext]\tightlayer[beforetext]}]

\startsetups[beforetext]
  \setlayer[beforetext][preset=righttop]{\framed[width=2in]{BEFORE}}
\stopsetups

\startTEXpage[background={foreground,beforetext}]
  \externalfigure[cow][width=30cm]
\stopTEXpage

Z

\stoptext

A similar example is also on the wiki: http://wiki.contextgarden.net/Layers#Place_labels_on_pictures

Wolfgang
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