pdf.js/lib/font/dfont.coffee

A PDF generation library for Node.js

fs = require 'fs'
Data = require '../data'

class DFont
    @open: (filename) ->
        contents = fs.readFileSync filename
        new DFont(contents)
        
    constructor: (contents) ->
        @contents = new Data(contents)
        @parse @contents
        
    parse: (data) ->
        dataOffset = data.readInt()
        mapOffset = data.readInt()
        dataLength = data.readInt()
        mapLength = data.readInt()
        
        @map = {}
        data.pos = mapOffset + 24 # skip header copy, next map handle, file reference, and attrs
        
        typeListOffset = data.readShort() + mapOffset
        nameListOffset = data.readShort() + mapOffset
        
        data.pos = typeListOffset
        maxIndex = data.readShort()
        
        for i in [0..maxIndex]
            type = data.readString(4)
            maxTypeIndex = data.readShort()
            refListOffset = data.readShort()
            
            @map[type] =
                list: []
                named: {}
                
            pos = data.pos
            data.pos = typeListOffset + refListOffset
            
            for i in[0..maxTypeIndex]
                id = data.readShort()
                nameOfs = data.readShort()
                attr = data.readByte()
                
                b2 = data.readByte() << 16
                b3 = data.readByte() << 8
                b4 = data.readByte()
                dataOfs = dataOffset + (0 | b2 | b3 | b4)
                
                handle = data.readUInt32()
                entry = 
                    id: id
                    attributes: attr
                    offset: dataOfs
                    handle: handle
                    
                if nameListOffset + nameOfs < mapOffset + mapLength
                    p = data.pos
                    data.pos = nameOfs + nameListOffset
                    
                    len = data.readByte()
                    entry.name = data.readString(len)
                    
                    data.pos = p
                
                @map[type].list.push entry
                @map[type].named[entry.name] = entry if entry.name
                
            data.pos = pos
        
        return
        
    getNamedFont: (name) ->
        data = @contents
        pos = data.pos
        
        entry = @map.sfnt.named[name]
        throw new Error "Font #{name} not found in DFont file." unless entry
        
        data.pos = entry.offset
        length = data.readUInt32()
        ret = data.slice(data.pos, data.pos + length)
        
        data.pos = pos
        return ret
        
module.exports = DFont