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Diffstat (limited to 'include/lengths')
| -rw-r--r-- | include/lengths | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/include/lengths b/include/lengths new file mode 100644 index 0000000..2c1d447 --- /dev/null +++ b/include/lengths @@ -0,0 +1,150 @@ + +########################################################################### +# # +# lengths # +# # +# Jeffrey H. Kingston # +# 30 October 2002 # +# # +# This file offers two symbols for converting between PostScript # +# lengths and Lout lengths. This has been a messy area and the two # +# symbols in this file, @LoutLengths and @PSLengths, are my attempt # +# to put a final end to the mess. # +# # +# A Lout length is, and has always been, a number followed by # +# a one-letter unit of measurement: i c p m s v f d. # +# # +# A PostScript length is, and has always been, a number followed # +# by a space followed by a two-letter unit of measurement, one of # +# in cm pt em sp vs ft dg. # +# # +# To the ordinary user who reads the User's Guide, all lengths # +# now look like Lout lengths. However, internally some of these # +# lengths are used by Lout and others are passed to PostScript. # +# Based on the two symbols @PSLengths and @LoutLengths defined # +# below, an option x which could contain a length of either kind # +# can be classified as one of three types: # +# # +# Type of option How to handle it # +# ------------------------------------------------------------------- # +# Option was never advertised named x { ... } # +# as taking a PostScript length # +# # +# Option was advertised as import @LoutLengths named x { ... } # +# possibly taking a PostScript # +# length, but its value is used # +# by Lout # +# # +# Option whose value has to be import @PSLengths named x { ... } # +# passed to PostScript # +# ------------------------------------------------------------------- # +# # +# Either kind of import allows either kind of length to be given; # +# @LoutLengths makes sure the final result is suitable for passing # +# to Lout, while @PSLengths makes sure the final result is suitable # +# for passing to PostScript. If things had been done right from the # +# start, there would be no need for @LoutLengths, but for backward # +# compatibility we will continue to use it basically forever. # +# # +########################################################################### + + +########################################################################### +# # +# @LoutLengths # +# # +# Convert PostScript lengths into Lout lengths. # +# # +########################################################################### + +export in cm pt em sp vs ft dg +def @LoutLengths +{ + def in left x { x"i" } + def cm left x { x"c" } + def pt left x { x"p" } + def em left x { x"m" } + def sp left x { x"s" } + def vs left x { x"b" } + def ft left x { x"f" } + def dg left x { x"d" } +} + + +########################################################################### +# # +# @PSLengths # +# # +# Convert Lout lengths into PostScript (also PDF) lengths. # +# PDF is no longer supported but this code was there already so # +# it's been carried over. # +# # +########################################################################### + +export i c p m s v f d +def @PSLengths +{ + def i left x { + @BackEnd @Case { + PostScript @Yield { x" in" } + PDF @Yield { "__mul(__in, "x")" } + PlainText @Yield "" + } + } + + def c left x { + @BackEnd @Case { + PostScript @Yield { x" cm" } + PDF @Yield { "__mul(__cm, "x")" } + PlainText @Yield "" + } + } + + def p left x { + @BackEnd @Case { + PostScript @Yield { x" pt" } + PDF @Yield { "__mul(__pt, "x")" } + PlainText @Yield "" + } + } + + def m left x { + @BackEnd @Case { + PostScript @Yield { x" em" } + PDF @Yield { "__mul(__em, "x")" } + PlainText @Yield "" + } + } + + def s left x { + @BackEnd @Case { + PostScript @Yield { x" sp" } + PDF @Yield { "__mul(__louts, "x")" } + PlainText @Yield "" + } + } + + def v left x { + @BackEnd @Case { + PostScript @Yield { x" vs" } + PDF @Yield { "__mul(__loutv, "x")" } + PlainText @Yield "" + } + } + + def f left x { + @BackEnd @Case { + PostScript @Yield { x" ft" } + PDF @Yield { "__mul(__loutf, "x")" } + PlainText @Yield "" + } + } + + def d left x { + @BackEnd @Case { + PostScript @Yield { x" dg" } + PDF @Yield { "__mul(__loutd, "x")" } + PlainText @Yield "" + } + } +} |