185 lines
6.8 KiB
Julia
185 lines
6.8 KiB
Julia
# Following work by @jiahao, we compute character widths using a combination of
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# * advance widths from GNU Unifont (advance width 512 = 1 en)
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# * UAX 11: East Asian Width
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# * a few exceptions as needed
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# Adapted from http://nbviewer.ipython.org/gist/jiahao/07e8b08bf6d8671e9734
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#
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# Requires Julia (obviously) and FontForge.
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#############################################################################
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CharWidths = Dict{Int,Int}()
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#############################################################################
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# Use ../libutf8proc for category codes, rather than the one in Julia,
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# to minimize bootstrapping complexity when a new version of Unicode comes out.
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catcode(c) = ccall((:utf8proc_category,"../libutf8proc"), Cint, (Int32,), c)
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# use Base.UTF8proc module to get category codes constants, since
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# we won't change these in utf8proc.
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import Base.UTF8proc
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#############################################################################
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# Use a default width of 1 for all character categories that are
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# letter/symbol/number-like, as well as for unassigned/private-use chars.
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# This can be overriden by Unifont or UAX 11
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# below, but provides a useful nonzero fallback for new codepoints when
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# a new Unicode version has been released but Unifont hasn't been updated yet.
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zerowidth = Set{Int}() # categories that may contain zero-width chars
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_MN)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_MC)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_ME)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_SK)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_ZS)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_ZL)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_ZP)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_CC)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_CF)
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push!(zerowidth, UTF8proc.UTF8PROC_CATEGORY_CS)
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for c in 0x0000:0x110000
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if catcode(c) ∉ zerowidth
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CharWidths[c] = 1
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end
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end
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#############################################################################
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# Widths from GNU Unifont
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#Read sfdfile for character widths
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function parsesfd(filename::AbstractString, CharWidths::Dict{Int,Int}=Dict{Int,Int}())
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state=:seekchar
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lineno = 0
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codepoint = width = nothing
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for line in readlines(open(filename))
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lineno += 1
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if state==:seekchar #StartChar: nonmarkingreturn
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if contains(line, "StartChar: ")
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codepoint = nothing
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width = nothing
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state = :readdata
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end
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elseif state==:readdata #Encoding: 65538 -1 2, Width: 1024
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contains(line, "Encoding:") && (codepoint = parse(Int, split(line)[3]))
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contains(line, "Width:") && (width = parse(Int, split(line)[2]))
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if codepoint!=nothing && width!=nothing && codepoint >= 0
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w=div(width, 512) # 512 units to the en
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if w > 0
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# only add nonzero widths, since (1) the default is zero
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# and (2) this circumvents some apparent bugs in Unifont
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# (https://savannah.gnu.org/bugs/index.php?45395)
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CharWidths[codepoint] = w
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end
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state = :seekchar
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end
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end
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end
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CharWidths
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end
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CharWidths=parsesfd("unifont.sfd", CharWidths)
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CharWidths=parsesfd("unifont_upper.sfd", CharWidths)
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#############################################################################
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# Widths from UAX #11: East Asian Width
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# .. these take precedence over the Unifont width for all codepoints
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# listed explicitly as wide/full/narrow/half-width
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for line in readlines(open("EastAsianWidth.txt"))
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#Strip comments
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(isempty(line) || line[1] == '#') && continue
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precomment = split(line, '#')[1]
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#Parse code point range and width code
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tokens = split(precomment, ';')
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length(tokens) >= 2 || continue
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charrange = tokens[1]
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width = strip(tokens[2])
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#Parse code point range into Julia UnitRange
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rangetokens = split(charrange, "..")
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charstart = parse(UInt32, "0x"*rangetokens[1])
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charend = parse(UInt32, "0x"*rangetokens[length(rangetokens)>1 ? 2 : 1])
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#Assign widths
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for c in charstart:charend
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if width=="W" || width=="F" # wide or full
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CharWidths[c]=2
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elseif width=="Na"|| width=="H"
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CharWidths[c]=1
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end
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end
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end
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#############################################################################
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# A few exceptions to the above cases, found by manual comparison
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# to other wcwidth functions and similar checks.
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for c in keys(CharWidths)
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cat = catcode(c)
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# make sure format control character (category Cf) have width 0
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# (some of these, like U+0601, can have a width in some cases
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# but normally act like prepended combining marks. U+fff9 etc
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# are also odd, but have zero width in typical terminal contexts)
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if cat==UTF8proc.UTF8PROC_CATEGORY_CF
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CharWidths[c]=0
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end
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# Unifont has nonzero width for a number of non-spacing combining
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# characters, e.g. (in 7.0.06): f84,17b4,17b5,180b,180d,2d7f, and
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# the variation selectors
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if cat==UTF8proc.UTF8PROC_CATEGORY_MN
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CharWidths[c]=0
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end
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# We also assign width of one to unassigned and private-use
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# codepoints (Unifont includes ConScript Unicode Registry PUA fonts,
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# but since these are nonstandard it seems questionable to use Unifont metrics;
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# if they are printed as the replacement character U+FFFD they will have width 1).
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if cat==UTF8proc.UTF8PROC_CATEGORY_CO || cat==UTF8proc.UTF8PROC_CATEGORY_CN
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CharWidths[c]=1
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end
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# for some reason, Unifont has width-2 glyphs for ASCII control chars
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if cat==UTF8proc.UTF8PROC_CATEGORY_CC
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CharWidths[c]=0
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end
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end
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#Soft hyphen is typically printed as a hyphen (-) in terminals.
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CharWidths[0x00ad]=1
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#By definition, should have zero width (on the same line)
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#0x002028 '
' category: Zl name: LINE SEPARATOR/
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#0x002029 '
' category: Zp name: PARAGRAPH SEPARATOR/
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CharWidths[0x2028]=0
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CharWidths[0x2029]=0
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#By definition, should be narrow = width of 1 en space
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#0x00202f ' ' category: Zs name: NARROW NO-BREAK SPACE/
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CharWidths[0x202f]=1
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#By definition, should be wide = width of 1 em space
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#0x002001 ' ' category: Zs name: EM QUAD/
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#0x002003 ' ' category: Zs name: EM SPACE/
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CharWidths[0x2001]=2
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CharWidths[0x2003]=2
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#############################################################################
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# Output (to a file or pipe) for processing by data_generator.rb,
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# encoded as a sequence of intervals.
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firstc = 0x000000
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lastv = 0
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uhex(c) = uppercase(hex(c,4))
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for c in 0x0000:0x110000
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v = get(CharWidths, c, 0)
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if v != lastv || c == 0x110000
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v < 4 || error("invalid charwidth $v for $c")
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if firstc+1 < c
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println(uhex(firstc), "..", uhex(c-1), "; ", lastv)
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else
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println(uhex(firstc), "; ", lastv)
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end
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firstc = c
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lastv = v
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end
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end
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