VFCommandCharacterPackets

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de.dante.extex.font.type.vf.command
Class VFCommandCharacterPackets

java.lang.Object
  de.dante.extex.font.type.vf.command.VFCommand
      de.dante.extex.font.type.vf.command.VFCommandCharacterPackets

All Implemented Interfaces:: PlFormat, XMLWriterConvertible

public class VFCommandCharacterPackets
extends VFCommand
implements PlFormat

VFCommand: character packets

The preamble is followed by zero or more character packets, where each character packet begins with a byte that is <<243. Character packets have two formats, one long and one short:

    long_char  242     pl[4]  cc[4]   tfm[4]  dvi[pl]

This long form specifies a virtual character in the general case.

    short_char 0..241=pl[1]  cc[1]   tfm[3]  dvi[pl]

This short form specifies a virtual character in the common case when 0 <= pl <242 and 0 <= cc <256 and 0 < <= tfm < 2^24. The ccode is pl!

Here pl denotes the packet length following the tfm value; cc is the character code; and tfm is the character width copied from the TFM file for this virtual font. There should be at most one character packet having any given cc code.

The dvi bytes are a sequence of complete DVI commands, properly nested with respect to push and pop. All DVI operations are permitted except bop, eop, and commands with opcodes >=243. Font selection commands (fnt_num0 through fnt4) must refer to fonts defined in the preamble.

Dimensions that appear in the DVI instructions are analogous to fix_word quantities; i.e., they are integer multiples of 2^-20 times the design size of the virtual font. For example, if the virtual font has design size 10pt, the DVI command to move down 5pt would be a down instruction with parameter 2^19. The virtual font itself might be used at a different size, say 12pt; then that down instruction would move down 6pt instead. Each dimension must be less than 2^24 in absolute value.

Device drivers processing VF files treat the sequences of dvi bytes as subroutines or macros, implicitly enclosing them with push and pop. Each subroutine begins with w=x=y=z=0, and with current font f the number of the first-defined in the preamble (undefined if there's no such font). After the dvi commands have been performed, the h and v position registers of DVI format and the current font f are restored to their former values; then, if the subroutine has been invoked by a set_char or set command, h is increased by the TFM width (properly scaled) - just as if a simple character had been typeset.

Version:: $Revision: 1.11 $
Author:: Michael Niedermair

Field Summary

Fields inherited from class de.dante.extex.font.type.vf.command.VFCommand

FNT_DEF_1, FNT_DEF_2, FNT_DEF_3, FNT_DEF_4, MAX_CHARACTER, MIN_CHARACTER, POST, PRE, SHIFT16, SHIFT8

Constructor Summary
`VFCommandCharacterPackets(RandomAccessR rar, int ccode, FontFactory fontfac, java.util.Map fontm, TFMFont mtfm)` Create e new object.

Method Summary
`void`	`addGlyph(org.jdom.Element element)` Add glyph to the element
`int`	`getCharactercode()` Returns the charactercode.
`byte[]`	`getDvi()` Returns the dvi.
`int`	`getPacketlength()` Returns the packetlength.
`TFMFixWord`	`getWidth()` Returns the width.
`void`	`toPL(PlWriter out)` Print all information (jn PL-format) to the writer.
`void`	`writeXML(XMLStreamWriter writer)` Write the data to a XMLStreamWriter.

Methods inherited from class de.dante.extex.font.type.vf.command.VFCommand

getCommandCode, getInstance

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail