howto overlayers on section head

howto overlayers on section head

[Eros Albertazzi]

I would like to start to experiment some metafun "decoration 
around(over)" section head and/or page number.
Something similar, just for example but I do not want to copy the style,
to the one used to produce the metafun manual.

 From the (small "scale") drawing primitives to the (large "scale")
\setuphead I miss an howto that combine the two
(specifically I was thinking at a (non-existent) background keyword in 
\setup to pass an overlay...but likely I am far off)

I don't want to be lazy, maybe it is already written in the manuals, but
I still miss a certain kick.... so to say...
Regards.

Re: howto overlayers on section head

[Patrick Gundlach]

Hello,

[...]

> I don't want to be lazy, maybe it is already written in the manuals, but
> I still miss a certain kick.... so to say...

go to

http://levana.de/context/

and down to the last item and take a look at 

http://levana.de/emacs/refcard/emacs.pdf

The sources are avialable there.


I have made some MP graphic around the section heading. 

I will add this to the wiki soon. 

Patrick

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Re: Re: howto overlayers on section head

[Eros Albertazzi]

Patrick Gundlach wrote:
> and down to the last item and take a look at 
> 
> http://levana.de/emacs/refcard/emacs.pdf
> 
> The sources are avialable there.
> 
> 
> I have made some MP graphic around the section heading. 


Thanks a lot. I think I start to grasp.

I have experimented with some other graphics but if I use "chapter"
instead of "subject" as section heading the result is different.
I believe it depends on your

\def\HeadTitle#1#2{\hbox to \hsize%
         {\hfil%
         \framed[frame=off,
                 background=myhead,
                 offset=overlay,
                 align=middle]{#1#2}\hfil}}

tighted to the latter heading and not to the former .
Am I right?
Deeply down to low level TeX at this point?
Is just a question to redefine a command adding 
background=something-of-mine ?
Then where these command are discribed?
regards

Re: howto overlayers on section head

[Patrick Gundlach]

Hello,

[...]

> I have experimented with some other graphics but if I use "chapter"
> instead of "subject" as section heading the result is different.
> I believe it depends on your

Here is the important stuff:

> \def\HeadTitle#1#2{% ....
>          \framed[background=myhead]{#1#2}}

(which is the command without spacing)

> tighted to the latter heading and not to the former .
> Am I right?


you should use something like

\setuphead[chpater][command=\HeadTitle]

> Deeply down to low level TeX at this point?

This is partly high level ConTeXt (\framed, background) and low level
TeX (hfill,...).

> Is just a question to redefine a command adding
> background=something-of-mine ?

background has to be a color or an overlay or ...

> Then where these command are discribed?

They should be described in the main manual or the metafun manual.


Summary: define a metapost graphic, use \defineoverlay to access
the mp graphic and use \framed{} to access the overlay
(background=...) and use \setuphead (command=somecommand) to define
your own command that acesses the \framed[background=...].

Patrick
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Re: Re: howto overlayers on section head

[Eros Albertazzi]

thanks again for the summary.
hope this back and forth will not be just a waste, but something out of 
which we can both/all learned to improuve.


Patrick Gundlach wrote:
> This is partly high level ConTeXt (\framed, background) and low level
> TeX (hfill,...).

"partially high and low"... Here laid  my question not easy to untungle 
for a beginner (and believe me I have read the docs, although I do not 
claim to remember or understand all)

> 
> Summary: define a metapost graphic, use \defineoverlay to access
> the mp graphic and use \framed{} to access the overlay
> (background=...) and use \setuphead (command=somecommand) to define
> your own command that acesses the \framed[background=...].

"define your own command" , but you have to know THE (default) command 
fist, otherwise it is hard to obtain a result (.pdf) from something that 
is not just a copy of someonelse .tex

let me start basic, ex-1

\starttext
\chapter{ciao}
\stoptext

let me remove \framed from your command, ex-2

\def\HeadTitle#1#2{\hbox to \hsize%
         {\hfil%
	{#1#2}\hfil}}

\setuphead [chapter]
   [command=\HeadTitle]

\starttext
\chapter{ciao}
\stoptext

the two ex-s  are not the same , because spacing between the number and 
the title and allignment, why?
Moving your howto overlay example, indeed very useful, from subject to 
chapter seems to me more subtle than just changing  section names

Re: howto overlayers on section head

[Patrick Gundlach]

Hello,

[...]

> hope this back and forth will not be just a waste, but something out
> of which we can both/all learned to improuve.

I think so, too. It has been a long time since I used ConTeXt. So I
have to refresh my rusty knowledge :-)

> "define your own command" , but you have to know THE (default) command
> fist, otherwise it is hard to obtain a result (.pdf) from something
> that is not just a copy of someonelse .tex

Right, but I'd guess that the default command is quite tricky. All
ConTeXt commands are quite tricky.

> \def\HeadTitle#1#2{\hbox to \hsize%
>          {\hfil%
> 	{#1#2}\hfil}}
>
> \setuphead [chapter]
>    [command=\HeadTitle]
>
> \starttext
> \chapter{ciao}
> \stoptext
>
> the two ex-s  are not the same , because spacing between the number
> and the title and allignment, why?

There is no horizontal "space" command between #1 (number) and #2
(title). But "space" is not just a simple " ". It can be many things.
I don't know if there is any good reading about these kind of spaces,
but let me show you a few:

( )        regular space is pretty small, but can be stretched
\enspace   fixed space 0.5em  
\enskip    space .5em      (so called "skip")
\quad      space 1em          "
\qquad     space 2em          "
\kern xx   space xx 
\hfil, \hfill  "very long" and "very very long" space

> Moving your howto overlay example, indeed very useful, from subject to
> chapter seems to me more subtle than just changing  section names

It is more a matter of section numbers/no section numbers. 

Patrick

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Re: howto overlayers on section head

[Patrick Gundlach]

Hello,

one addition,

you can always use the great debugging commands like

\showframe 

and 

\showmakeup

The latter is pretty complex to read, but in many cases you get a
grasp of what is going on without understanding every detail.

Patrick
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