org.extex.font.format.xtf.tables
Class TtfTableHDMX

java.lang.Object
  org.extex.font.format.xtf.tables.AbstractXtfTable
      org.extex.font.format.xtf.tables.TtfTableHDMX

All Implemented Interfaces:

XtfGlyphName, XtfTable, XMLWriterConvertible

public class TtfTableHDMX
extends AbstractXtfTable
implements XtfTable, XMLWriterConvertible

The table 'hdmx' (Horizontal Device Metrics).

The hdmx table relates to OpenType fonts with TrueType outlines. The Horizontal Device Metrics table stores integer advance widths scaled to particular pixel sizes. This allows the font manager to build integer width tables without calling the scaler for each glyph. Typically this table contains only selected screen sizes. This table is sorted by pixel size. The checksum for this table applies to both subtables listed.

Note that for non-square pixel grids, the character width (in pixels) will be used to determine which device record to use. For example, a 12 point character on a device with a resolution of 72x96 would be 12 pixels high and 16 pixels wide. The hdmx device record for 16 pixel characters would be used.

If bit 4 of the flag field in the 'head' table is not set, then it is assumed that the font scales linearly; in this case an 'hdmx' table is not necessary and should not be built. If bit 4 of the flag field is set, then one or more glyphs in the font are assumed to scale nonlinearly. In this case, performance can be improved by including the 'hdmx' table with one or more important DeviceRecord's for important sizes.

hdmx Header

Type	Name	Description
USHORT	version		Table version number (0)
SHORT	numRecords	Number of device records.
LONG	sizeDeviceRecord	Size of a device record, long aligned.
DeviceRecord	records[numRecords]	Array of device records.

Device Record

<

Type	Name	Description
BYTE	pixelSize	Pixel size for following widths (as ppem).
BYTE	maxWidth	Maximum width.
BYTE	Widths[numGlyphs]	Array of widths (numGlyphs is from the 'maxp' table).

Version:

$Revision: 6604 $

Author:

Michael Niedermair

Nested Class Summary

class

TtfTableHDMX.DeviceRecord the device record

Constructor Summary

TtfTableHDMX(XtfTableMap tablemap, XtfTableDirectory.Entry de, RandomAccessR rar)
Create a new object

Method Summary

TtfTableHDMX.DeviceRecord[]	getDeviceRecord() Returns the deviceRecord.
int	getNumRecords() Returns the numRecords.
java.lang.String	getShortcut() Returns the table shortcut.
int	getSizeDeviceRecord() Returns the sizeDeviceRecord.
int	getType() Get the table type, as a table directory value.
int	getVersion() Returns the version.
void	init() Initialize the table.
void	writeXML(XMLStreamWriter writer) Write the data to a XMLStreamWriter.

Methods inherited from class org.extex.font.format.xtf.tables.AbstractXtfTable

getGlyphName, getInitOrder, getTableMap, writeStartElement

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.extex.font.format.xtf.tables.XtfTable

getInitOrder, getTableMap

Constructor Detail

TtfTableHDMX

public TtfTableHDMX(XtfTableMap tablemap,
                    XtfTableDirectory.Entry de,
                    RandomAccessR rar)
             throws java.io.IOException

Create a new object

Parameters:

tablemap - the tablemap

de - entry

rar - input

Throws:

java.io.IOException - if an IO-error occurs

Method Detail

getDeviceRecord

public TtfTableHDMX.DeviceRecord[] getDeviceRecord()

Returns the deviceRecord.

Returns:

Returns the deviceRecord.

getNumRecords

public int getNumRecords()

Returns the numRecords.

Returns:

Returns the numRecords.

getShortcut

public java.lang.String getShortcut()

Returns the table shortcut.

Specified by:

getShortcut in interface XtfTable

Returns:

Returns the table shortcut.

See Also:

XtfTable.getShortcut()

getSizeDeviceRecord

public int getSizeDeviceRecord()

Returns the sizeDeviceRecord.

Returns:

Returns the sizeDeviceRecord.

getType

public int getType()

Get the table type, as a table directory value.

Specified by:

getType in interface XtfTable

Returns:

Returns the table type

getVersion

public int getVersion()

Returns the version.

Returns:

Returns the version.

init

public void init()
          throws java.io.IOException

Initialize the table.

Specified by:

init in interface XtfTable

Overrides:

init in class AbstractXtfTable

Throws:

java.io.IOException - if a IO-error is occurred.

See Also:

AbstractXtfTable.init()

writeXML

public void writeXML(XMLStreamWriter writer)
              throws java.io.IOException

Write the data to a XMLStreamWriter.

Specified by:

writeXML in interface XMLWriterConvertible

Parameters:

writer - the XML-Writer

Throws:

java.io.IOException - if an IO-error occurs.

See Also:

XMLWriterConvertible.writeXML( org.extex.util.xml.XMLStreamWriter)