% language=us runpath=texruns:manuals/metafun \startcomponent metafun-styles \environment metafun-environment \startchapter[title={Defining styles}] \index {layout} \index {styles} \startintro Since the integration of \METAPOST\ into \CONTEXT, a complete new range of layout fetaures became available. In this document we have introduced several ways to include graphics in your document definition. In this chapter we go one step further and make dynamic graphics part of a document style. \stopintro \startsection[title={Adaptive buttons}] So far we have seen a lot of graphic ingredients that you can use to make your documents more attractive. In this chapter we will define a simple document style. This style was written for the \PDFTEX\ presentations at the TUG 2000 conference in Oxford (UK). This style exploits a few tricks, like graphics calculated using positional information. It also demonstrates how you can make menu buttons that dynamically adapt their shapes to the rest of the page layout. \startbuffer[screens] \startlinecorrection[blank] \setupcombinations[distance=.0125\textwidth] \startcombination[5*1] {\typesetfile[mfun-77\ScrNum.tex][page=1,width=.19\textwidth]} {page 1} {\typesetfile[mfun-77\ScrNum.tex][page=2,width=.19\textwidth]} {page 2} {\typesetfile[mfun-77\ScrNum.tex][page=3,width=.19\textwidth]} {page 3} {\typesetfile[mfun-77\ScrNum.tex][page=4,width=.19\textwidth]} {page 4} {\typesetfile[mfun-77\ScrNum.tex][page=5,width=.19\textwidth]} {page 5} \stopcombination \stoplinecorrection \stopbuffer \def\ScrNum{1} \getbuffer[screens] Later we will see an instance with some more randomness in the graphics. While writing this style, the random alternative made me think of those organic buildings with non equal windows |<|we have a few of those in The Netherlands|>|, so I decided to label this style as \type {pre-organic}. If you use \CONTEXT, you can load this style with: \starttyping \usemodule[pre-organic] \stoptyping At the end of this file, there is a small test file, so when you process the file \type {s-pre-19.tex} \footnote {This style is the 19\high{th} presentation style. Those numbered styles are internally mapped onto more meaningful names like in this case \type {pre-organic}.} with the options \type {--mode=demo} and \type {--pdf}, you will get a demo document. We use one of the standard screen \quote {paper} sizes, and map it onto the same size, so that we get a nicely cropped page. Other screen sizes are \type {S4} and \type {S5}. \starttyping \setuppapersize[S6][S6] \stoptyping Like in this \METAFUN\ manual, we use the Palatino as main bodyfont. This font is quite readable on even low resolution screens, although I admit that this style is developed using an $1400\times1050$ pixel \kap {lcd} screen, so the author may be a little biased. \starttyping \setupbodyfont[ppl] \stoptyping The layout specification sets up a text area and a right edge area where the menus will go (see \in {chapter} [sec:page] for a more in depth discussion on the layout areas). Watch how we use a rather large edge distance. By setting the header and footer dimensions to zero, we automatically get rid of page body ornaments, like the page number. \starttyping \setuplayout [topspace=48pt, backspace=48pt, cutspace=12pt, width=400pt, margin=0cm, rightedge=88pt, rightedgedistance=48pt, header=0cm, footer=0cm, height=middle] \stoptyping We use a moderate, about a line height, inter||paragraph white space. \starttyping \setupwhitespace[big] \stoptyping Of course we use colors, since on computer displays they come for free. \starttyping \setupcolors[state=start] \definecolor [red] [r=.75] \definecolor [yellow] [r=.75,g=.75] \definecolor [gray] [s=.50] \definecolor [white] [s=.85] \stoptyping Because it is an interactive document, we have to enable hyperlinks and alike. However, in this style, we disable the viewer's \quote {highlight a hyperlink when it's clicked on} feature. We will use a menu, so we enable menus. Later we will see the contrast color |<|hyperlinks gets that color when we are already on the location|>| in action. \starttyping \setupinteraction [state=start, click=off, color=red, contrastcolor=gray, menu=on] \stoptyping The menu itself is set up as follows. Because we will calculate menu buttons based on their position on the page, we have to keep track of the positions. Therefore, we set the \type {position} variable to \type {yes}. \starttyping \setupinteractionmenu [right] [frame=off, position=yes, align=middle, topoffset=-.75cm, bottomoffset=-.75cm, color=gray, contrastcolor=gray, style=bold, before=, after=] \stoptyping The menu content is rather sober: just a list of topics and a close button. Later we will define the command that generates topic entries. The alternative \type {right} lets the topic list inherit its characteristics from the menu. \starttyping \startinteractionmenu[right] \placelist[Topic][alternative=right] \vfill \but [CloseDocument] close \\ \stopinteractionmenu \stoptyping We have now arrived at the more interesting part of the style definition: the graphic that goes in the page background. Because this graphic will change, we define a useable \METAPOST\ graphic. Page backgrounds are recalculated each page, opposite to the other backgrounds that are calculated when a new background is defined, or when repetitive calculation is turned on. \starttyping \setupbackgrounds [page] [background=page] \defineoverlay [page] [\useMPgraphic{page}] \setupMPvariables [page] [alternative=3] \stoptyping We will implement three alternative backgrounds. First we demonstrate the relatively simple super ellipsed one. The main complication is that we want the button shapes to follow the right edge of the curve that surrounds the text. We don't know in advance how many lines of text there will be in a button, and we also don't know at what height it will end up. Therefore, we need to calculate each button shape independently and for that purpose we need to know its position (see \in {chapter} [sec:positioning]). In \in {figure} [fig:style] you can see what lines we need in order to be calculate the button shapes. \startpostponing \startmode[screen] \placefigure [here][fig:style] {The lines used to calculate the button shapes.} {\typesetfile[mfun-774.tex][page=1,height=.85\textheight]} \stopmode \startnotmode[screen] \placefigure [here][fig:style] {The auxiliary lines used to calculate the button shapes.} {\rotate{\typesetfile[mfun-774.tex][page=1,height=\textwidth]}} \stopnotmode \page \stoppostponing We separate the calculation of the button shape from the rest by embedding it in its own usable graphic container. The \type {StartPage}||\type {StopPage} pair takes care of proper placement of the whole graphic. \starttyping \startuseMPgraphic{page} \includeMPgraphic{rightsuperbutton} StartPage ; path p, q ; pickup pencircle scaled 3pt ; p := Field[Text][Text] enlarged 36pt superellipsed .90 ; fill Page withcolor \MPcolor{yellow} ; fill p withcolor \MPcolor{white} ; draw p withcolor \MPcolor{red} ; p := Field[Text][Text] enlarged 48pt superellipsed .90 ; def right_menu_button (expr nn, rr, pp, xx, yy, ww, hh, dd) = if (pp>0) and (rr>0) : q := rightsuperbutton(p,xx,yy,RightEdgeWidth,hh) ; fill q withcolor \MPcolor{white} ; draw q withcolor if rr=2 : \MPcolor{gray} else : \MPcolor{red} fi ; fi ; enddef ; \MPmenubuttons{right} StopPage ; \stopuseMPgraphic \stoptyping The \TEX\ macro \type {\MPmenubuttons} expands into a list of (in this case four) calls to the \METAPOST\ macro \type {right_menu_button}. This list is generated by \CONTEXT\ when it generates the menu. Because the page background is applied last, this list is available at that moment. \starttyping ... (expr nn, rr, pp, xx, yy, ww, hh, dd) ... \stoptyping This rather long list of arguments represents the following variables: number, referred page, current page, x coordinate, y coordinate, width, height and depth. The last six variables originate from the positioning mechanism. Because the variables are only available after a second \TEX\ pass, we only draw a button shape when the test for the page numbers succeeds. \starttyping \startuseMPgraphic{rightsuperbutton} vardef rightsuperbutton (expr pat, xpos, ypos, wid, hei) = save p, ptop, pbot, t, b, edge, shift, width, height ; path p, ptop, pbot ; pair t, b ; numeric edge, shift, width, height ; edge := xpos + wid ; shift := ypos + hei ; p := rightpath pat ; ptop := ((-infinity,shift)--(edge,shift)) ; pbot := ((-infinity,shift-hei)--(edge,shift-hei)) ; t := p intersectionpoint ptop ; b := p intersectionpoint pbot ; p := subpath(0,xpart (p intersectiontimes ptop)) of p ; p := subpath(xpart (p intersectiontimes pbot),length(p)) of p ; (p -- t -- point 1 of ptop & point 1 of ptop -- point 1 of pbot & point 1 of pbot -- b -- cycle) enddef ; \stopuseMPgraphic \stoptyping The calculation of the button itself comes down to combining segments of the main shape and auxiliary lines. The \type {rightpath} macro returns the right half of the path provided. This half is shown as a non dashed line. Topics are identified with \type {\Topic}, which is an instance of chapter headings. The number is made invisible. Since it still is a numbered section header, \CONTEXT\ will write the header to the table of contents. \starttyping \definehead [Topic] [chapter] \setuphead [Topic] [number=no] \stoptyping We will use a bold font in the table of contents. We also force a complete list. \starttyping \setuplist [Topic] [criterium=all, style=bold, before=, after=] \stoptyping The \type {\TitlePage} macro looks horrible, because we want to keep the interface simple: a list of small sentences, separated by \type {\\}. \starttyping \def\TitlePage#1% {\startstandardmakeup \switchtobodyfont[big] \def\\{\vfill\bfb\let\\=\par} \bfd\setupinterlinespace\gray \vskip.5cm#1\\\vskip.5cm % \\ is really needed -) \stopstandardmakeup} \stoptyping A presentation that uses this style, may look like the one below. You can choose among three alternatives. \starttyping \useenvironment[pre-organic] \setupoutput[pdftex] \setupMPvariables[page][alternative=1] \starttext \TitlePage {A Few Nice Quotes\\ A Simple Style Demo\\ Hans Hagen, August 2000} \Topic {Douglas R. Hofstadter} \input douglas \page \Topic {Donald E. Knuth} \input knuth \page \Topic {Edward R. Tufte} \input tufte \page \Topic {Hermann Zapf} \input zapf \page \stoptext \stoptyping We will not implement the two other alternative shapes: squeezed and randomized. \def\ScrNum{2} \getbuffer[screens] \def\ScrNum{3} \getbuffer[screens] We combine all alternatives into one page graphic. The alternative is chosen by setting the \type {alternative} variable, as we demonstrated in the example. \starttyping \startuseMPgraphic{page} \includeMPgraphic{rightsuperbutton} StartPage ; numeric alternative, seed, superness, squeezeness, randomness ; path p, q ; transform t ; \stoptyping This is one of those cases where a transform variable is useful. We need to store the random seed value because we want the larger path that is used in the calculations to have the same shape. \starttyping alternative := \MPvar{alternative} ; seed := uniformdeviate 100 ; if alternative > 10 : superness := .85 + ((\realfolio-1)/max(\lastpage,1)) * .25 ; squeezeness := 12pt - ((\realfolio-1)/max(\lastpage,1)) * 10pt ; else : superness := .90 ; squeezeness := 12pt ; fi ; randomness := squeezeness ; alternative := alternative mod 10 ; \stoptyping If you read closely, you will notice that when we add 10 to the alternative, we get a page dependant graphic. So, in fact we have five alternatives. We use \CONTEXT\ macros to fetch the (real) page number and the number of the last page. In further calculations we use the lower alternative numbers, which is why we apply a \type {mod}. The rest of the code is not so much different from the previous definition. The hard coded point sizes match the page dimensions (600pt by 450pt) quite well. \starttyping t := identity if alternative=3: shifted (9pt,-9pt) fi ; randomseed := seed ; p := Field[Text][Text] enlarged if alternative = 1 : 36pt superellipsed superness elseif alternative = 2 : 36pt squeezed squeezeness elseif alternative = 3 : 36pt randomized randomness else : 36pt fi ; pickup pencircle scaled 3pt ; fill Page withcolor \MPcolor{yellow} ; fill p withcolor \MPcolor{white} ; draw p withcolor \MPcolor{red} ; randomseed := seed ; p := ( Field[Text][Text] enlarged if alternative = 1 : 48pt superellipsed superness elseif alternative = 2 : 48pt squeezed squeezeness elseif alternative = 3 : 36pt randomized randomness else : 48pt fi ) transformed t ; def right_menu_button (expr nn, rr, pp, xx, yy, ww, hh, dd) = if (pp>0) and (rr>0) : q := rightsuperbutton(p,xx,yy,RightEdgeWidth,hh) ; fill q withcolor \MPcolor{white} ; draw q withcolor if rr=2 : \MPcolor{gray} else : \MPcolor{red} fi ; fi ; enddef ; \MPmenubuttons{right} StopPage ; \stopuseMPgraphic \stoptyping When we choose the alternatives~21 and~22 we get this result: \def\ScrNum{5} \getbuffer[screens] \def\ScrNum{6} \getbuffer[screens] \stopsection \stopchapter \stopcomponent