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161 lines
4.3 KiB
CoffeeScript
161 lines
4.3 KiB
CoffeeScript
PDFFont = require '../font'
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PDFObject = require '../object'
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class EmbeddedFont extends PDFFont
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constructor: (@document, @font, @id) ->
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@subset = @font.createSubset()
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@unicode = [[0]]
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@widths = [@font.widthOfGlyph 0]
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@name = @font.postscriptName
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@ascender = @font.ascent
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@decender = @font.descent
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@lineGap = @font.lineGap
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@bbox = @font.bbox
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includeGlyph: (gid) ->
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return @subset.includeGlyph gid
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encode: (text, features) ->
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glyphs = @font.glyphsForString text, features
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advances = @font.advancesForGlyphs glyphs, features
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res = []
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for glyph, i in glyphs
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gid = @includeGlyph glyph.id
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res.push ('0000' + gid.toString(16)).slice(-4)
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@widths[gid] ?= @font.widthOfGlyph glyph.id
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@unicode[gid] ?= glyph.codePoints
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advances[i] -= @widths[gid]
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return [res, advances]
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widthOfString: (string, size, features) ->
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glyphs = @font.glyphsForString '' + string, features
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advances = @font.advancesForGlyphs glyphs, features
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width = 0
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for advance in advances
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width += advance
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scale = size / 1000
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return width * scale
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embed: ->
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isCFF = @subset.cff?
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fontFile = @document.ref()
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if isCFF
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fontFile.data.Subtype = 'CIDFontType0C'
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@subset.encodeStream().pipe(fontFile)
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familyClass = (@font['OS/2']?.sFamilyClass or 0) >> 8
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flags = 0
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flags |= 1 << 0 if @font.post.isFixedPitch
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flags |= 1 << 1 if 1 <= familyClass <= 7
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flags |= 1 << 2 # assume the font uses non-latin characters
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flags |= 1 << 3 if familyClass is 10
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flags |= 1 << 6 if @font.head.macStyle.italic
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# generate a random tag (6 uppercase letters. 65 is the char code for 'A')
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tag = (String.fromCharCode Math.random() * 26 + 65 for i in [0...6]).join ''
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name = tag + '+' + @font.postscriptName
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descriptor = @document.ref
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Type: 'FontDescriptor'
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FontName: name
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Flags: flags
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FontBBox: @font.bbox
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ItalicAngle: @font.italicAngle
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Ascent: @font.ascent
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Descent: @font.descent
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CapHeight: @font.capHeight or @font.ascent
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XHeight: @font.xHeight or 0
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StemV: 0 # not sure how to calculate this
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if isCFF
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descriptor.data.FontFile3 = fontFile
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else
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descriptor.data.FontFile2 = fontFile
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descriptor.end()
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descendantFont = @document.ref
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Type: 'Font'
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Subtype: if isCFF then 'CIDFontType0' else 'CIDFontType2'
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BaseFont: name
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CIDSystemInfo:
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Registry: PDFObject.s 'Adobe'
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Ordering: PDFObject.s 'Identity'
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Supplement: 0
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FontDescriptor: descriptor
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W: [0, @widths]
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descendantFont.end()
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@dictionary.data =
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Type: 'Font'
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Subtype: 'Type0'
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BaseFont: name
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Encoding: 'Identity-H'
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DescendantFonts: [descendantFont]
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ToUnicode: @toUnicodeCmap()
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@dictionary.end()
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toHex = (codePoints...) ->
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codes = for code in codePoints
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('0000' + code.toString(16)).slice(-4)
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return codes.join ''
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# Maps the glyph ids encoded in the PDF back to unicode strings
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# Because of ligature substitutions and the like, there may be one or more
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# unicode characters represented by each glyph.
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toUnicodeCmap: ->
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cmap = @document.ref()
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entries = []
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for codePoints in @unicode
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encoded = []
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# encode codePoints to utf16
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for value in codePoints
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if value > 0xffff
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value -= 0x10000
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encoded.push toHex value >>> 10 & 0x3ff | 0xd800
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value = 0xdc00 | value & 0x3ff
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encoded.push toHex value
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entries.push "<#{encoded.join ' '}>"
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cmap.end """
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/CIDInit /ProcSet findresource begin
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12 dict begin
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begincmap
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/CIDSystemInfo <<
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/Registry (Adobe)
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/Ordering (UCS)
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/Supplement 0
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>> def
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/CMapName /Adobe-Identity-UCS def
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/CMapType 2 def
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1 begincodespacerange
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<0000><ffff>
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endcodespacerange
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1 beginbfrange
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<0000> <#{toHex entries.length - 1}> [#{entries.join ' '}]
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endbfrange
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endcmap
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CMapName currentdict /CMap defineresource pop
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end
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end
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"""
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return cmap
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module.exports = EmbeddedFont
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