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diff --git a/doc/context/sources/general/manuals/luametafun/luametafun-fonts.tex b/doc/context/sources/general/manuals/luametafun/luametafun-fonts.tex new file mode 100644 index 000000000..27ea2fd00 --- /dev/null +++ b/doc/context/sources/general/manuals/luametafun/luametafun-fonts.tex @@ -0,0 +1,328 @@ +% language=us + +\environment luametafun-style + +\startcomponent luametafun-fonts + +\startchapter[title={Fonts}] + +Fonts are interesting phenomena but can also be quite hairy. Shapes can be +missing or not to your liking. There can be bugs too. Control over fonts has +always been on the agenda of \TEX\ macro packages, and \CONTEXT\ provides a lot +of control, especially in \MKIV. In \LMTX\ we add some more to that: we bring +back \METAFONT's but now in the \METAPOST\ way. A simple example shows how this +is (maybe I should say: will be) done. + +We define three simple shapes and do that (for now) in the \type {simplefun} +instance because that's what is used when generating the glyphs. + +\startbuffer +\startMPcalculation{simplefun} + vardef TestGlyphLB = + image ( + fill (unitsquare xscaled 10 yscaled 16 shifted (0,-3)) + withcolor "darkred" withtransparency (1,.5) + ; + ) + enddef ; + + vardef TestGlyphRB = + image ( + fill (unitcircle xscaled 15 yscaled 12 shifted (0,-2)) + withcolor "darkblue" withtransparency (1,.5) + ; + ) + enddef ; + + vardef TestGlyphFS = + image ( + fill (unittriangle xscaled 15 yscaled 12 shifted (0,-2)) + withcolor "darkgreen" withtransparency (1,.5) + ; + ) + enddef ; +\stopMPcalculation +\stopbuffer + +\typebuffer[option=TEX] \getbuffer + +This is not that spectacular, not is the following: + +\startbuffer +\startMPcalculation{simplefun} + lmt_registerglyphs [ + name = "test", + units = 10, % 1000 + ] ; + + lmt_registerglyph [ + category = "test", + unicode = 123, + code = "draw TestGlyphLB ;", + width = 10, % 1000 + height = 13, % 1300 + depth = 3 % 300 + ] ; + + lmt_registerglyph [ + category = "test", + unicode = 125, + code = "draw TestGlyphRB ;", + width = 15, + height = 10, + depth = 2 + ] ; + + lmt_registerglyph [ + category = "test", + unicode = "/", + code = "draw TestGlyphFS ;", + width = 15, + height = 10, + depth = 2 + ] ; + +\stopMPcalculation +\stopbuffer + +\typebuffer[option=TEX] \getbuffer + +We now define a font. We always use a font as starting point which has the +advantage that we always get something reasonable when we test. Of course you can +use this \type {mps} font feature with other fonts too. + +\startbuffer +\definefontfeature[metapost][metapost=test] % or: mps={category=test} + +\definefont[MyFontA][Serif*metapost @ 10bp] +\definefont[MyFontB][Serif*metapost @ 12bp] +\stopbuffer + +\typebuffer[option=TEX] \getbuffer + +These fonts can now be used: + +\startbuffer +\MyFontA \dorecurse{20}{\{ /#1/ \} }\par +\MyFontB \dorecurse{20}{\{ /#1/ \} }\par +\stopbuffer + +\typebuffer[option=TEX] + +We get some useless text but it demonstrates the idea: + +{\getbuffer} + +If you know a bit more about \CONTEXT\ you could think: so what, wasn't this +already possible? Sure, there are various ways to achieve similar effects, but +the method described here has a few advantages: it's relatively easy and we're +talking about real fonts here. This means that using the shapes for characters is +pretty efficient. + +A more realistic example is given next. It is a subset of what is available in +the \CONTEXT\ core. + +\startbuffer +\startMPcalculation{simplefun} + + pen SymbolPen ; SymbolPen := pencircle scaled 1/4 ; + + vardef SymbolBullet = + fill unitcircle scaled 3 shifted (1.5,1.5) withpen SymbolPen + enddef ; + vardef SymbolSquare = + draw unitsquare scaled (3-1/16) shifted (1.5,1.5) withpen SymbolPen + enddef ; + vardef SymbolBlackDiamond = + fillup unitdiamond scaled (3-1/16) shifted (1.5,1.5) withpen SymbolPen + enddef ; + vardef SymbolNotDef = + draw center unitcircle + scaled 3 + shifted (1.5,1.5) + withpen SymbolPen scaled 4 + enddef ; + + lmt_registerglyphs [ + name = "symbols", + units = 10, + usecolor = true, + width = 6, + height = 6, + depth = 0, + code = "SymbolNotDef ;", + ] ; + + lmt_registerglyph [ category = "symbols", unicode = "0x2022", + code = "SymbolBullet ;" + ] ; + lmt_registerglyph [ category = "symbols", unicode = "0x25A1", + code = "SymbolSquare ;" + ] ; + lmt_registerglyph [ category = "symbols", unicode = "0x25C6", + code = "SymbolBlackDiamond ;" + ] ; +\stopMPcalculation +\stopbuffer + +\typebuffer[option=TEX] \getbuffer + +We could use these symbols in for instance itemize symbols. You might notice the +potential difference in bullets: + +\startbuffer +\definefontfeature[metapost][metapost=symbols] + +\definefont[MyFont] [Serif*metapost sa 1] + +\startitemize[packed] + \startitem {\MyFont • □ ◆}\quad Regular rendering. \stopitem + \startitem {\MyFont\red • □ ◆}\quad Rendering with color. \stopitem + \startitem {\MyFont\blue\showglyphs • □ ◆}\quad Idem but with boundingboxes shown. \stopitem +\stopitemize +\stopbuffer + +\typebuffer[option=TEX] \getbuffer + +When blown up, these symbols look as follows: + +\startlinecorrection +\scale[width=\textwidth]{% + {\MyFont •□◆}% + {\MyFont\red •□◆}% + {\MyFont\blue\showglyphs •□◆}% +} +\stoplinecorrection + +You can use these tricks with basically any font, so also with math fonts. +However, at least for now, you need to define these before the font gets loaded. + +\startbuffer +\startMPcalculation{simplefun} + + pen KindergartenPen ; KindergartenPen := pencircle scaled 1 ; + + % 10 x 10 grid + + vardef KindergartenEqual = + draw image + ( + draw (2,6) -- (9,5) ; + draw (2,4) -- (8,3) ; + ) + shifted (0,-2) + withpen KindergartenPen + withcolor "KindergartenEqual" + enddef ; + vardef KindergartenPlus = + draw image + ( + draw (1,4) -- (9,5) ; + draw (4,1) -- (5,8) ; + ) + shifted (0,-2) + withpen KindergartenPen + withcolor "KindergartenPlus" + enddef ; + vardef KindergartenMinus = + draw image + ( + draw (1,5) -- (9,4) ; + ) + shifted (0,-2) + withpen KindergartenPen + withcolor "KindergartenMinus" + enddef ; + vardef KindergartenTimes = + draw image + ( + draw (2,1) -- (9,8) ; + draw (8,1) -- (2,8) ; + ) + shifted (0,-2) + withpen KindergartenPen + withcolor "KindergartenTimes" + enddef ; + vardef KindergartenDivided = + draw image + ( + draw (2,1) -- (8,9) ; + ) + shifted (0,-2) + withpen KindergartenPen + withcolor "KindergartenDivided" + enddef ; + + lmt_registerglyphs [ + name = "kindergarten", + units = 10, + % usecolor = true, + width = 10, + height = 8, + depth = 2, + ] ; + + lmt_registerglyph [ category = "kindergarten", unicode = "0x003D", + code = "KindergartenEqual" + ] ; + lmt_registerglyph [ category = "kindergarten", unicode = "0x002B", + code = "KindergartenPlus" + ] ; + lmt_registerglyph [ category = "kindergarten", unicode = "0x2212", + code = "KindergartenMinus" + ] ; + lmt_registerglyph [ category = "kindergarten", unicode = "0x00D7", + code = "KindergartenTimes" + ] ; + lmt_registerglyph [ category = "kindergarten", unicode = "0x002F", + code = "KindergartenDivided" + ] ; + +\stopMPcalculation +\stopbuffer + +\typebuffer[option=TEX] \getbuffer + +We also define the colors. If we leave \type {usecolor} to true, the text colors +will be taken. + +\startbuffer[definitions] +\definecolor[KindergartenEqual] [darkgreen] +\definecolor[KindergartenPlus] [darkred] +\definecolor[KindergartenMinus] [darkred] +\definecolor[KindergartenTimes] [darkblue] +\definecolor[KindergartenDivided][darkblue] + +\definefontfeature[mathextra][metapost=kindergarten] +\stopbuffer + +\typebuffer[definitions][option=TEX] \getbuffer[definitions] + +Here is an example: + +\starttyping +\switchtobodyfont[cambria] + +$ y = 2 \times x + a - b / 3 $ +\stoptyping + +Scaled up: + +\startlinecorrection + \switchtobodyfont[cambria] + \scale[width=\textwidth]{$ y = 2 \times x + a - b / 3 $} +\stoplinecorrection + +Of course this won't work out well (yet) with extensible yet, due to related +definitions for which we don't have an interface yet. There is one thing that you +need to keep in mind: the fonts are flushed when the document gets finalized so +you have to make sure that colors are defined at the level that they are still +valid at that time. So best put color definitions like the above in the document +style. + +This is an experimental interface anyway so we don't explain the parameters yet +as there might be more of them. + +\stopchapter + +\stopcomponent |