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diff --git a/doc/context/sources/general/manuals/details/details-finetuningfloats.tex b/doc/context/sources/general/manuals/details/details-finetuningfloats.tex new file mode 100644 index 000000000..71e0772d1 --- /dev/null +++ b/doc/context/sources/general/manuals/details/details-finetuningfloats.tex @@ -0,0 +1,657 @@ +% language=uk + +% todo: \setlayeranchored[text-1]{HELLO WORLD} + +\environment details-environment + +\startcomponent details-finetuningfloats + +\startchapter[title={Finetuning graphics}] + +In this chapter we will discuss a few more tricks to control float placement. +This control is needed if you want to typeset documents in a semi desk top +publishing way. + +When you combine technical graphics, you may wish to align the content optically. +This can be done with the \type {offset} command. We will demonstrate this with a +couple of \METAPOST\ graphics: + +\startbuffer +\startreusableMPgraphic{alpha} + fill fullsquare xyscaled( 2cm, 2cm) withcolor \MPcolor{red} ; + fill unitsquare xyscaled(+.5cm,+.5cm) withcolor \MPcolor{gray} ; +\stopreusableMPgraphic + +\startreusableMPgraphic{beta} + fill fullsquare xyscaled( 2cm, 2cm) withcolor \MPcolor{red} ; + fill unitsquare xyscaled(+.5cm,-.5cm) withcolor \MPcolor{gray} ; +\stopreusableMPgraphic + +\startreusableMPgraphic{gamma} + fill fullsquare xyscaled( 2cm, 2cm) withcolor \MPcolor{red} ; + fill unitsquare xyscaled(-.5cm,-.5cm) withcolor \MPcolor{gray} ; +\stopreusableMPgraphic + +\startuseMPgraphic{delta} + fill fullsquare xyscaled( 2cm, 2cm) withcolor \MPcolor{red} ; + fill unitsquare xyscaled(-.5cm,+.5cm) withcolor \MPcolor{gray} ; +\stopuseMPgraphic +\stopbuffer + +\typebuffer \getbuffer + +\startbuffer +\startcombination[2*2] + {\reuseMPgraphic{alpha}} {alpha} + {\reuseMPgraphic {beta}} {beta} + {\reuseMPgraphic{gamma}} {gamma} + {\reuseMPgraphic{delta}} {delta} +\stopcombination +\stopbuffer + +\typebuffer + +In \in {figure} [fig:offset-1] we place these graphics in a \type {2*2} grid. As +you can see, the centers don't align well. + +\placefigure[here][fig:offset-1]{}{\getbuffer} + +In \in {figure} [fig:offset-2] the centers of the graphic align well. This is +accomplished by adding some space around the graphics. + +\startbuffer +\startcombination[2*2] + {\ruledhbox{\offset[rightoffset=1cm] {\reuseMPgraphic{alpha}}}} {alpha} + {\ruledhbox{\offset[bottomoffset=.5cm]{\reuseMPgraphic {beta}}}} {beta} + {\ruledhbox{\offset[bottomoffset=.5cm]{\reuseMPgraphic{gamma}}}} {gamma} + {\ruledhbox{\offset[leftoffset=1cm] {\reuseMPgraphic{delta}}}} {delta} +\stopcombination +\stopbuffer + +\placefigure[here][fig:offset-2]{}{\getbuffer} + +\starttyping +\startcombination[2*2] + {\offset[rightoffset=1cm] {\reuseMPgraphic{alpha}}} {alpha} + {\offset[bottomoffset=.5cm]{\reuseMPgraphic {beta}}} {beta} + {\offset[bottomoffset=.5cm]{\reuseMPgraphic{gamma}}} {gamma} + {\offset[leftoffset=1cm] {\reuseMPgraphic{delta}}} {delta} +\stopcombination +\stoptyping + +If we align the centers vertically, as demonstrated in \in {figure} +[fig:offset-2] we can stick to a few bottom offsets. + +\starttyping +\startcombination[4*1] + {\reuseMPgraphic{alpha}} {alpha} + {\offset[bottomoffset=.5cm]{\reuseMPgraphic {beta}}} {beta} + {\offset[bottomoffset=.5cm]{\reuseMPgraphic{gamma}}} {gamma} + {\reuseMPgraphic{delta}} {delta} +\stopcombination +\stoptyping + +\startbuffer +\startcombination[4*1] + {\ruledhbox {\reuseMPgraphic{alpha}}} {alpha} + {\ruledhbox{\offset[bottomoffset=.5cm]{\reuseMPgraphic {beta}}}} {beta} + {\ruledhbox{\offset[bottomoffset=.5cm]{\reuseMPgraphic{gamma}}}} {gamma} + {\ruledhbox {\reuseMPgraphic{delta}}} {delta} +\stopcombination +\stopbuffer + +\placefigure[here][fig:offset-3]{}{\getbuffer} + +These examples demonstrate that the dimensions change with the offset. You can +retain the dimensions but still align them by using the \type {x} and \type {y} +parameter. This kind of manipulations will often result in a ugly spacing because +the placement macros handle on the original dimensions. \in {Figure} +[fig:offset-4] demonstrates this. + +\starttyping +\startcombination[4*1] + {\reuseMPgraphic{alpha}} {alpha} + {\offset[y=-.5cm]{\reuseMPgraphic {beta}}} {beta} + {\offset[y=-.5cm]{\reuseMPgraphic{gamma}}} {gamma} + {\reuseMPgraphic{delta}} {delta} +\stopcombination +\stoptyping + +\startbuffer +\startcombination[4*1] + {\ruledhbox {\reuseMPgraphic{alpha}}} {alpha} + {\ruledhbox{\offset[y=-.5cm]{\reuseMPgraphic {beta}}}} {beta} + {\ruledhbox{\offset[y=-.5cm]{\reuseMPgraphic{gamma}}}} {gamma} + {\ruledhbox {\reuseMPgraphic{delta}}} {delta} +\stopcombination +\stopbuffer + +\placefigure[here][fig:offset-4]{}{\getbuffer} + +In the previous chapter we demonstrated how a side float can be moved up or down +by providing a placement directive or by preceding the placement with \type +{\movesidefloat}. Such a move can be used to align a graphic with particular line +of text. This command can also be used for alignment purposes similar to the +\type {\offset} command. We will demonstrate this with the following graphics. + +\startbuffer +\startreusableMPgraphic{gnu} + fill fullsquare xyscaled( 4cm, 1cm) withcolor \MPcolor{red} ; + fill unitsquare xyscaled(-1cm,.5cm) + shifted (0,-.25cm) withcolor \MPcolor{gray} ; +\stopreusableMPgraphic + +\startreusableMPgraphic{gnat} + fill fullsquare xyscaled( 4cm, 1cm) withcolor \MPcolor{red} ; + fill unitsquare xyscaled(+1cm,.5cm) + shifted (0,-.25cm) withcolor \MPcolor{gray} ; +\stopreusableMPgraphic +\stopbuffer + +\typebuffer \getbuffer + +In the next two examples we shift the \type {gnu} and \type {gnat} graphics +horizontally in order to get them aligned. The move does not change the +dimensions of the float, but they do influence the paragraph shape. + +\startbuffer[a] +\movesidefloat [x=.5cm] +\placefigure [left,none] {} {\reuseMPgraphic{gnu}} +\stopbuffer + +\startbuffer[b] +\movesidefloat [x=-.5cm] +\placefigure [left,none] {} {\reuseMPgraphic{gnat}} +\stopbuffer + +\typebuffer[a,b] + +\getbuffer[a] \fakewords{50}{100} +\getbuffer[b] \fakewords{50}{100} + +\blank + +It is possible to shift vertically by setting \type {y}, but this is often a bad +idea and definitely may spoil alignment of graphics to the grid. If you have to +revert to this trick, you are probably working in document screw||up mode. This +is why in grid mode, we automatically round to an equal number of lines. + +If you know what text you're dealing with and also can be sure about the height +of a graphic, you can trick \CONTEXT\ to ignore the dimensions of a graphic. Here +we use the graphic: + +\startbuffer +\startreusableMPgraphic{gnome} + fill fullsquare xyscaled(2cm, 1cm) withcolor \MPcolor{red} ; + fill fullsquare xyscaled(1cm,.5cm) withcolor \MPcolor{gray} ; +\stopreusableMPgraphic +\stopbuffer + +\typebuffer \getbuffer + +\startbuffer +\placefigure[leftmargin,none,reset]{}{\reuseMPgraphic{gnome}} +\stopbuffer + +\typebuffer \getbuffer + +The graphic is moved into the margin (\type {leftmargin}), has no caption (\type +{none}), and all kind of tricky housekeeping is reset (\type {reset}). + +\startbuffer +\placefigure[left,none,high,low]{}{\reuseMPgraphic{gnome}} +\stopbuffer + +\getbuffer + +Now the next graphic is not influenced by the previous one, so we can place them +close to each other. Use these tricks with care, especially if your document +source is reused and the typeset products are not carefully checked. + +\typebuffer + +When \CONTEXT\ tries to determine if a float fits, it makes a couple of +assumptions, for instance that the available room equals the text height minus +the height of the text so far. You can slightly influence the way these values +are interpreted by setting the calculation method. You can set the methods as +follows: + +\starttyping +\setupfloats[textmethod=0,sidemethod=1] +\stoptyping + +Method~0 just looks at the raw dimensions, while method~1 lessens the maximum +text height by one percent, thereby playing safe. Method~2 takes a window of +1~point. This may lead to better decisions since we may run into rounding errors +of several scaled points (which is small but troublesome). Method~2 is well +suited when typesetting on a grid, because there everything has to fit in a +rounded number of lines, which leaves no room for rounding errors. + +\starttabulate[||c|c|] +\NC \bf grid mode \NC \bf yes \NC \bf no \NC \NR +\NC \type{sidemethod} \NC \type{2} \NC \type{1} \NC \NR +\NC \type{textmethod} \NC \type{2} \NC \type{0} \NC \NR +\stoptabulate + +\startusableMPgraphic{demo-1}{color} + path p ; + p := fullsquare xyscaled (3cm,2LineHeight) ; + fill p withcolor \MPvar{color} ; +\stopusableMPgraphic + +\startusableMPgraphic{demo-2}{color,morecolor} + path p ; p := fullsquare xyscaled (6cm,4LineHeight) ; + path q ; q := fullsquare xyscaled (3cm,2LineHeight) ; + fill p withcolor \MPvar{color} ; + setbounds currentpicture to q ; + fill q withcolor \MPcolor{morecolor} ; +\stopusableMPgraphic + +As you may know by now, we can use the directives \type {high}, \type {low}, +\type {height}, \type {depth} and \type {line} to influence the spacing around a +side float. A real tight spacing can be achieved with \type {fit}. + +\starttyping +\placefigure[left,fit,none]{}{some graphic} +\stoptyping + +\placefigure[left,fit,none]{}{\useMPgraphic{demo-1}{color=red}} + +This kind of placements only make sense in special situations, because normally +you don't want the graphic to touch the text. + +If you think that this is all a user may want, you're wrong. It is not imaginary +that graphics have small pieces sticking out and|/|or lots of white space as part +of their design. In that case, the bounding box can be set to a smaller size. + +\placefigure + [left,fit,none] + {} + {\setlayer + [graphics] + {\useMPgraphic{demo-2}{color=red,morecolor=tgreen}}} + +Now, when handling a side float, \CONTEXT\ first places the float, and then +starts with typesetting the paragraph, cleverly avoiding the graphic. However, +when the graphic is virtually larger than its known size, it may cover part of +the preceding paragraph. + +How come that the graphic starting this paragraph does not do that? It is because +we explicitly moved it to the background. This involves some preparation. At the +document level, we define a layer called \type {graphic}. + +\starttyping +\definelayer[graphics][position=yes] +\stoptyping + +The position directive tells \CONTEXT\ that it should honour the position of the +graphic. Next we must make sure that this layer is placed. + +\starttyping +\setupbackgounds[page][background=graphics] +\stoptyping + +Now we're ready to move graphics to this layer: + +\starttyping +\placefigure + [left,fit,none] + {}{\setlayer[graphics]{graphic}} +\stoptyping + +It's now a small step to more advanced movements. Say that you want to move the +graphic a little bit to the left. In that case you can tell the layer placement +to do so. + +\starttyping +\placefigure + [left,fit,none]{}{\setlayer[graphics][hoffset=-12pt]{graphic}} +\stoptyping + +From this you can deduce that there is also a movement in the vertical direction +using \type {voffset}. In addition you can anchor the graphic using the \type +{location} parameter and provide offsets. + +\placefigure + [left,fit,none] + {} + {\setlayer + [graphics][hoffset=-12pt] + {\useMPgraphic{demo-2}{color=red,morecolor=tgreen}}} + +As soon as you run into situations where float placement is to be consistently +enforced, you will feel the need for dedicate placement macros. For example: + +\startbuffer +\definefloat + [somefloat] + [figure] + +\setupfloat + [somefloat] + [sidespaceafter=, + sidespacebefore=, + default={left,none}] +\stopbuffer + +\typebuffer \getbuffer + +Instead of resetting the side spacing, we could have default to \type {high,low}, +but this way we can overload the default placement and still get zero spacing. + +Throughout this manual we discuss features related to overlays and layers. These +permit you to move content around in ways that either or not depend on the text +flow. We have now come to another trick based on these mechanisms: bleeding. + +When printing a document, you need to take into account that when graphics go +beyond the page boundary, you need to compensate for inaccuracies in cutting the +pages. Such graphics are called bleeding graphics and the amount of bleed is +often a few millimeters. + +The best way to handle such graphics is to use the correct dimensions and play +with the edge widths and distances in combination with backspace and cut space. In +a properly set up layout and by using a well designed set of predefined graphic +placements, you can handle this quite well. A bleeding figure can be defined as +follows: + +\startbuffer +\definefloat + [edgefigure] + [figure] + +\setupfloat + [edgefigure] + [default={inner,height,high,low,none}, + maxwidth=4cm] + +\defineexternalfigure + [edgefigure] + [width=\dimexpr\backspace+4cm-1mm\relax, + lines=4] +\stopbuffer + +\typebuffer \getbuffer + +The default placement is pre|-|configured to have no additional vertical space and +align on the height of a line (this is default behaviour so the \type {height} +key is redundant here. The 1mm in the previous definition simulates what happens +when a page is cut off slightly wrong: we get an annoying gap. + +\startbuffer[a] +\placeedgefigure + {} + {\externalfigure[hacker][edgefigure]} +\stopbuffer + +\typebuffer[a] \getbuffer[a] \fakewords{50}{100} + +One of the nice things about \TEX\ is that you can fine tune dimensions pretty +well. So, instead of the previous placement, which turns out rather ugly, we can +come up with a better one: + +\startbuffer +\setupfloat + [edgefigure] + [default={inner,height,high,low,none}, + maxwidth=4cm, + margin=\strutdepth] + +\defineexternalfigure + [edgefigure] + [width=\dimexpr\backspace+4cm+2mm\relax, + height=\dimexpr3\lineheight+\strutheight\relax] +\stopbuffer + +\typebuffer \getbuffer + +This time we take no risk and add 2mm to the dimensions so that we can be sure +that the edge of the graphic falls outside the page boundary. + +\getbuffer[a] \fakewords{50}{100} + +The \CONTEXT\ resourse library modules provide means to report back the +dimensions of graphics used in a document, so that you can develop (tune) them +with the proper dimensions. In practice a slightly wider than normal graphic +(scaling it horizontally a few millimeters more) does not harm the visual +appearance that much, so adapting a graphic to this kind of bleeding is not +really needed. + +In addition to this (rather natural) way of adding bleed to a graphic, you can +apply the \type {\bleed} macro. In the previously discussed method the figure +placement mechanisms work with the real dimensions. The \type {bleed} macro is +using scaling in a different way: from the perspective of \CONTEXT\ the graphic +remains its original dimensions and the figure placement mechanisms will act +accordingly. We will give a couple of examples of using this macro. + +Permitted bleeding locations are \type {l}, \type {r}, \type {t}, \type {b}, +\type {lr}, \type {bl}, \type {br}, \type {tl} and \type {tr}. + +\startbuffer +\placesomefloat + [left,none,fit] + {} + {\setupbleeding[offset=5mm]% + \bleed[width=5cm,height=1cm,location=l] + {\externalfigure[mill][bleed]}} +\stopbuffer + +\typebuffer \getbuffer \fakewords{50}{100} + +\startbuffer +\placesomefloat + [left,none,fit] + {} + {\setupbleeding[offset=2mm]% + \bleed[width=5cm,height=1cm,location=l] + {\externalfigure[mill][bleed]}} +\stopbuffer + +\typebuffer \getbuffer \fakewords{50}{100} + +The amount of bleeding depends on the postprocessing. In the previous paragraph +we used a bleed offset of 5mm, and here we used 2mm. Because the graphic is +scaled in order to match the bleed, it will be slightly distorted. With small +values this will go unnoticed. You can set the offset with: + +\starttyping +\setupbleeding[offset=5mm] +\stoptyping + +Bleeding itself is accomplished by the \type {\bleed} macro as in: + +\starttyping +\bleed + [width=5cm,height=1cm,location=l] + {\externalfigure[mill][width=\bleedwidth,height=\bleedheight]} +\stoptyping + +It is kind of awkward to pass those two dimensions so here is a shorter way of +doing the same: + +\starttyping +\bleed + [width=5cm,height=1cm,location=l] + {\externalfigure[mill][bleed]} +\stoptyping + +In fact, this uses the following definition: + +\starttyping +\defineexternalfigure[bleed][width=\bleedwidth,height=\bleedheight] +\stoptyping + +You can influence the scaling of a graphic by setting the \type {stretch} +parameters. The location parameter determines the direction of the stretch: \type +{l}~(left), \type {r}~(right), \type {t}~(top), \type {b}~(bottom) or a +combination of these. We will now combine the previous example code with this +knowledge. + +\startbuffer +\placefigure + [left] + {} + {\bleed + [stretch=no,voffset=0pt,hoffset=1cm] + {\externalfigure[detcow][bleed]}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +\startbuffer +\placefigure + [left] + {} + {\bleed + [width=5cm,height=3cm,location=l] + {\externalfigure[detcow][bleed]}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +\startbuffer +\placefigure + [right] + {} + {\bleed + [width=5cm,height=3cm,location=r] + {\externalfigure[detcow][bleed]}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +You can combine this feature with layers. We will now show a few applications +which may look like magic at first glance, but will become natural to your +repertoire once you have played with them. + +The next example moves the graphic to a layer associated with the (current) page. + +\startbuffer +\placefigure + [right,none] + {} + {\setlayer + [graphics] + {\bleed + [width=5cm,height=3cm,location=rb] + {\externalfigure[detcow][bleed]}}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +You can also predefine locations where graphics (or other content) needs to be +anchored. A direct call to anchor looks as follows: + +\starttyping +\placefigure + [left,none] + {} + {\anchor + [text-1] + [location=lt,hoffset=max,voffset=max] + [width=3cm,height=3cm,frame=on]% + {\externalfigure[detcow][width=5cm,frame=on]}} +\stoptyping + +This will anchor a graphic in one of the text layers, but at the cost of +specifying this in the document source. One way around this is to predefine +anchors. + +\startbuffer +\defineanchor[rightbottom][text-1][location=lt,hoffset=max,voffset=max] +\defineanchor[righttop] [text-1][location=lb,hoffset=max] +\defineanchor[leftbottom] [text-1][location=rt,voffset=max] +\defineanchor[lefttop] [text-1][location=rb] +\stopbuffer + +\startbuffer +\defineanchor[rightbottom][text-1][preset=rightbottom] +\defineanchor[righttop] [text-1][preset=righttop] +\defineanchor[leftbottom] [text-1][preset=leftbottom] +\defineanchor[lefttop] [text-1][preset=lefttop] +\stopbuffer + +\typebuffer \getbuffer + +We will apply this to a predefined float type. + +\startbuffer +\definefloat[myfigure][figure] +\setupfloat[myfigure][sidespaceafter=,sidespacebefore=] +\stopbuffer + +\typebuffer \getbuffer + +Our previous example can now be reduced to: + +\startbuffer +\placemyfigure + [left,none] + {} + {\anchor[rightbottom] + {\externalfigure[detcow][width=5cm,frame=on]}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +You can still specify dimensions and anchors can be combined with bleeding. Of +course this kind of mixed usage means that you need to have some feeling for what +these mechanisms do. + +\startbuffer +\placemyfigure + [left,none] + {} + {\anchor + [rightbottom] + [width=5cm,height=3cm,frame=on] + {\bleed + [width=5cm,height=3cm,location=l] + {\externalfigure[detcow][bleed]}}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +\startbuffer +\placemyfigure + [right,none] + {} + {\anchor + [rightbottom] + [width=5cm,height=3cm,frame=on] + {\bleed + [width=5cm,height=3cm,location=r] + {\externalfigure[detcow][bleed]}}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +\startbuffer +\placemyfigure + [left,none] + {} + {\anchor + [lefttop] + [width=3cm,height=3cm,frame=on] + {\externalfigure[detcow][width=5cm,frame=on]}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +\startbuffer +\placemyfigure + [left,none] + {} + {\anchor + [lefttop] + [width=3cm,height=3cm,frame=on] + [offset=.5cm] + {\externalfigure[detcow][width=5cm,frame=on]}} +\stopbuffer + +\typebuffer \getbuffer \fakewords {100} {150} + +\blank {\em Todo: parameter specifications of all those macros.} + +\stopchapter + +\stopcomponent |