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Diffstat (limited to 'doc/context/sources/general/manuals/luametatex/luametatex-metapost.tex')
| -rw-r--r-- | doc/context/sources/general/manuals/luametatex/luametatex-metapost.tex | 102 |
1 files changed, 97 insertions, 5 deletions
diff --git a/doc/context/sources/general/manuals/luametatex/luametatex-metapost.tex b/doc/context/sources/general/manuals/luametatex/luametatex-metapost.tex index bd9189956..85dc30036 100644 --- a/doc/context/sources/general/manuals/luametatex/luametatex-metapost.tex +++ b/doc/context/sources/general/manuals/luametatex/luametatex-metapost.tex @@ -427,10 +427,6 @@ a bunch of vital characteristics of the used pen (all values are floats): \LL \stoptabulate -\stopsection - -\startsection[title=Acessors] - \subsection[title={Character size information}] \libindex{char_width} @@ -441,13 +437,109 @@ These functions find the size of a glyph in a defined font. The \type {fontname} is the same name as the argument to \type {infont}; the \type {char} is a glyph id in the range 0 to 255; the returned \type {w} is in AFM units. - \startfunctioncall <number> w = char_width(mp,<string> fontname, <number> char) <number> h = char_height(mp,<string> fontname, <number> char) <number> d = char_depth(mp,<string> fontname, <number> char) \stopfunctioncall +\stopsection + +\startsection[title=Scanners] + +After a relative long period of testing the scanners are now part of the +interface. That doesn't mean that there will be no changes: depending on the +needs and experiences details might evolve. The summary below is there +still preliminary and mostly provided as reminder. + +\starttabulate[|l|l|p|] +\DB scanner \BC argument \BC returns \NC \NR +\TB +\NC \type{scan_next} \NC instance, keep \NC token, mode, type \NC \NR +\NC \type{scan_expression} \NC instance, keep \NC type \NC \NR +\NC \type{scan_token} \NC instance, keep \NC token, mode, kind \NC \NR +\NC \type{scan_symbol} \NC instance, keep, expand \NC string \NC \NR +\NC \type{scan_numeric} \NC instance, type \NC number \NC \NR +\NC \type{scan_integer} \NC instance, type \NC integer \NC \NR +\NC \type{scan_boolean} \NC instance, type \NC boolean \NC \NR +\NC \type{scan_string} \NC instance, type \NC string \NC \NR +\NC \type{scan_pair} \NC instance, hashed, type \NC table or two numbers \NC \NR +\NC \type{scan_color} \NC instance, hashed, type \NC table or three numbers \NC \NR +\NC \type{scan_cmykcolor} \NC instance, hashed, type \NC table or four numbers \NC \NR +\NC \type{scan_transform} \NC instance, hashed, type \NC table or six numbers \NC \NR +\NC \type{scan_path} \NC instance, hashed, type \NC table with hashes or arrays \NC \NR +\NC \type{scan_pen} \NC instance, hashed, type \NC table with hashes or arrays \NC \NR +\LL +\stoptabulate + +The types and token codes are numbers but they actually depend on the +implementation (although changes are unlikely). The types of data structures can +be queried with \type {mplib.types()}: + +\dontleavehmode \startluacode + local t = mplib.types() + for i=0,#t do + if i > 0 then + context(", ") + end + context("%i: %s",i,t[i]) + end +\stopluacode . + +The command codes are available with \type {mplib.codes()}: + +\dontleavehmode \startluacode + local t = mplib.codes() + for i=0,#t do + if i > 0 then + context(", ") + end + context("%i: %s",i,t[i]) + end +\stopluacode . + +Now, if you really want to use these, keep in mind that the internals of +\METAPOST\ are not trivial, especially because expression scanning can be +complex. So you need to experiment a bit. In \CONTEXT\ all is (and will be) +hidden below an abstraction layer so users are not bothered by all these +look|-|ahead and push|-|back issues that originate in the way \METAPOST\ scans +its input. + +\stopsection + +\startsection[title=Injectors] + +It is important to know that piping code into the library is pretty fast and +efficient. Most processing time relates to memory management, calculations and +generation of output can not be neglected either. Out of curiousity I added some +functions that directly push data into the library but the gain is not that +large. \footnote {The main motivation was checking of huge paths could be +optimized. The other data structures were then added for completeness.} + +\starttabulate[|l|l|] +\DB scanner \BC argument \NC \NR +\TB +\NC \type{inject_numeric} \NC instance, number \NC \NR +\NC \type{inject_integer} \NC instance, number \NC \NR +\NC \type{inject_boolean} \NC instance, boolean \NC \NR +\NC \type{inject_string} \NC instance, string \NC \NR +\NC \type{inject_pair} \NC instance, (table with) two numbers \NC \NR +\NC \type{inject_color} \NC instance, (table with) three numbers \NC \NR +\NC \type{inject_cmykcolor} \NC instance, (table with) four numbers \NC \NR +\NC \type{inject_transform} \NC instance, (table with) six numbers \NC \NR +\NC \type{inject_path} \NC instance, table with hashes or arrays, cycle, variant \NC \NR +\LL +\stoptabulate + +The path injector takes a table with subtables that are either hashed (like the +path solver) or arrays with two, four or six entries. When the third argument has +the value \type {true} the path is closed. When the fourth argument is \type +{true} the path is constructed out of straight lines (as with \type {--}) by +setting the \type {curl} values to~1 automatically. \footnote {This is all +experimental so future versions might provide more control.} + +\stopsection + \stopchapter \stopcomponent |