hi, Wolfgang Schuster and Sietse Brouwer
   Thank you for your patience!
   I got it !

BEST REGARDS
PengCZ


2013/1/7 Wolfgang Schuster <wolfgang.schuster@gmail.com>

>
> Am 06.01.2013 um 15:10 schrieb Sietse Brouwer <sbbrouwer@gmail.com>:
>
> >>> but the rightmarginwidth = 3.7569cm, not 0.1cm, I do not know why?
> >>> what should I do to widen the texwidth?
> >>
> >> http://www.ntg.nl/pipermail/ntg-context/2012/064650.html
> >
> > In which Wolfgang wrote:
> >> The horizontal dimensions are determined by the three values
> >>
> >> - backspace (distance from the left/inner margin)
> >> - cutspace (distance from the right/outer margin)
> >> - width (width of the textblock)
> >>
> >> Normally you need only two values because when you set
> >> backspace + width the cutspace is > calculated and when
> >> you set backspace + cutspace you can write width=middle
> >> and the width of the text block will be calculated.
> >
> > Which is a good explanation, and he explains how vertical dimensions
> > work, too. Allow me to add this e-mail to answer another question you
> > will probably have: "What about the marginwidth, margindistance,
> > edgewidth, and edgedistance? Those are also horizontal values!"
> >
> > A good question. The answer is that ‘margin’ means two things:
> > 1. the space between the edge of the textblock and the boundary of the
> paper
> > 2. a typesetting area inside that space, in which marginal material is
> typeset.
> >
> > Inside \setuplayout, margin has the second meaning: marginwidth is the
> > width of the margin, and margindistance the distance between the text
> > area and the margin area.
> >
> > There are also the ‘edges’: these are typesetting areas outside the
> > margin areas. Some uses I can think of: colouring the edge of the page
> > in a guidebook with sections; placing informative marks in general;
> > printing a sort of vertical header/footer; etc.
> >
> > This is not a bad reference:
> > http://wiki.contextgarden.net/Layout
>
>
> I wrote a short seven page example where you can see both margins
> don’t influence the layout because they’re just put on the sides like
> attachments.
>
> \setuppapersize[A4][A3]
>
> \setuplayout
>   [location=middle,
>    header=0pt,
>    footer=0pt]
>
> \setuppagenumbering[location=]
>
> \definefont[BigFont][Mono*none sa 4]
>
> \starttext
>
> \showframe[page]
> \centerbox{\BigFont PAGE}\page
>
> \setuplayout
>   [backspace=2cm,
>    cutspace=2cm,
>    width=middle,
>    topspace=2cm,
>    bottomspace=2cm,
>    height=middle]
>
> \showframe[text]
> \centerbox{\BigFont TEXTBLOCK}\page
>
> \setuplayout
>   [header=2cm,
>    headerdistance=1cm,
>    footer=2cm,
>    footerdistance=1cm]
>
> \showframe[header,footer]
> \centerbox{\BigFont HEADER/FOOTER}\page
>
> \setuplayout
>   [leftmargin=2cm,
>    leftmargindistance=1cm]
>
> \showframe[leftmargin]
> \centerbox{\BigFont LEFTMARGIN}\page
>
> \setuplayout
>   [leftedge=2cm,
>    leftedgedistance=1cm]
>
> \showframe[leftedge]
> \centerbox{\BigFont LEFTEDGE}\page
>
> \setuplayout
>   [rightmargin=2cm,
>    rightmargindistance=1cm]
>
> \showframe[rightmargin]
> \centerbox{\BigFont RIGHTMARGIN}\page
>
> \setuplayout
>   [rightedge=2cm,
>    rightedgedistance=1cm]
>
> \showframe[rightedge]
> \centerbox{\BigFont RIGHTEDGE}\page
>
> \stoptext
>
> Wolfgang
>
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