DviFile Class Reference

Represents a DVI file. More...

#include <DviFile.h>

List of all members.

Public Types
enum	DviUnits {   unit_BAD, unit_pt, unit_pc, unit_in,   unit_bp, unit_cm, unit_mm, unit_dd,   unit_cc, unit_sp, unit_pixels, unit_dvi }
	Units of length. More...
Public Member Functions
	DviFile (string &s, int resolution=0, double magmag=1.0, bool read_postamble=true, bool seekable=true) throw (DviError)
	Constructs a new DviFile object.
	~DviFile ()
bool	eof ()
	Indicates whether we are at the end of the DVI file.
DviFileEvent *	getEvent ()
	Gets an event from the DVI file.
DviFileEvent *	getEndOfPage ()
	Skips to the end of the page.
int	currH (DviUnits units=unit_pixels) const throw (DviError)
	Obtains the current horizontal position.
int	currV (DviUnits units=unit_pixels) const throw (DviError)
	Obtains the current vertical position.
int	hSize ()
	Obtains the `width of the widest page'.
int	vSize ()
	Obtains the `height plus depth of the tallest page'.
double	magnification () const
	Return the net magnification factor for the DVI file.
int	pt2px (double npt) const
	Converts a length in points to one in pixels, using the current magnifications and any other relevant parameters.
const string *	filename () const
	Gets the name of this DVI file.
const PkFont *	getFallbackFont (const PkFont *desired)
	Returns a fallback font, for use when a requested font is not available.
bool	haveReadPostamble () const
	Reports whether the DVI file postamble was read when this file was opened.
const FontSet *	getFontSet () const
	Obtains a representation of the set of fonts contained in this DVI file.
Static Public Member Functions
DviUnits	unitType (string unitString)
	Convert a string to a unit.
string	unitString (DviUnits unit)
	Gets the string representation of a DVI unit.
double	convertFromScaledPoints (int sp, DviUnits units, DviFile *dvif=0) throw (DviError)
	Convert a TeX scaled point to another unit.
double	convertToScaledPoints (double length, DviUnits units, DviFile *dvif=0) throw (DviError)
	Convert a length to TeX scaled points.
double	convertUnits (double length, DviUnits from_units, DviUnits to_units, DviFile *dvif=0) throw (DviError)
	Convert a length from one set of units to another.
verbosities	verbosity (const verbosities level)
	Sets the verbosity of this module.

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Detailed Description

Represents a DVI file.

See the DVI Driver standard [driv-std] for details of the parameters here.

[driv-std] Level-0 DVI Driver Standard, available on-line on CTAN, in the directory dviware/driv-standard.

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Member Enumeration Documentation

enum DviFile::DviUnits

Units of length. Used in currH and currV, and other conversions are available through method convertFromScaledPoints. Enumeration values: unit_BAD  An invalid unit. unit_pt  Traditional printer's point. There are 72.27pt in 1in. unit_pc  Pica; 1pc=12pt. unit_in  Inch; 1in=25.4mm. unit_bp  The big point; 72bp=1in. Postscript points are bigpoints in this terminology. unit_cm  Centimetre; 1cm=10E-2m. unit_mm  Millimetre; 1mm=10E-3m. One metre is the distance light travels, in vacuum, in a time 1/299792458 seconds. Conversion factors: 1mm=2.84527559pt; 1pt=0.3515mm. unit_dd  Didot point; 1157dd=1238pt. unit_cc  Cicero; 1cc=12dd. unit_sp  TeX `scaled points'. These are the dimensions which TeX itself works in, where 65536sp=1pt, or 1sp=5.36434 . 10-9 metres. Light at that wavelength is classed as soft X-rays, and is a health-hazard (so don't examine your scaled points too closely); it's also the distance light travels in 1.78885 . 10-17 seconds. Why am I telling you this? I don't know! unit_pixels  Pixel units. The DVI standard calls these `device units', and refers to them with the notation hh. unit_dvi  DVI units. All dimensions within the DVI file are expressed in these units, written as h in the standard. The conversion of DVI units to physical units is governed by the values in the preamble. DVI files written by TeX (that is, essentially all of them, except those written by converters such as dtl, which write compatible ones) have a preamble which ensures that the DVI units are scaled points, times the overall magnification factor.

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Constructor & Destructor Documentation

DviFile::DviFile (  string &  fn, int  res = 0, double  externalmag = 1.0, bool  read_post = true, bool  seekable = true )  throw (DviError)

Constructs a new DviFile object. Once the DVI file has been opened in this way, its contents can be processed in an event-based fashion, by repeatedly calling getEvent and handling the returned object. The DVI file may be specified as "-", in which case the DVI file will be read from stdin. In fact, this is just a synonym for the expression, <osfd>0, as understood by InputByteStream (qv). In this case, the postamble is not read, irrespective of the value of parameter read_post, and this is known not to be seekable, so the value of parameter seekable is ignored. After the DVI file has been opened using this constructor, the preamble may or may not be read (this may be specified in future versions). If you need to ensure that the preamble is read (for example if you wish to call convertUnits), then you should call getEvent once to retrieve the DviFilePreamble event which it returns the first time it is called. Parameters: fn  the name of the DVI file. The given name is searched for both as-is, and with an extension .dvi added. res  the base DPI to be used for processing the file, in pixels-per-inch. If given as zero, default to the resolution returned by PkFont#dpiBase. externalmag  the factor by which the DVI file's internal magnification factor should itself be magnified, specified externally to the DVI file (on a command line, for example); default is 1.0 read_post  if true, then the DVI postamble will be read; if false, it will be skipped. This is false by default, but if the postamble is read, then the font declarations there will be read and acted on, which may speed things up. seekable  if true, the input file is seekable; if false, it is not seekable, the value of read_post is ignored (taken to be false), and the file is opened without attempting to add any .dvi extension. Exceptions: DviError  if the DVI file cannot be opened

DviFile::~DviFile (   )

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Member Function Documentation

double DviFile::convertFromScaledPoints (  int  sp, DviUnits  units, DviFile *  dvif = 0 )  throw (DviError) [static]

Convert a TeX scaled point to another unit. It is possible to convert to pixel units with this method; however it is generally better to either get pixel positions directly (through currH or currV for example). The conversions to DVIunits and pixels are not universal, but are instead dependent on a particular DVI file; if you wish to convert to either of these units, you must supply a reference to a DVI file. If not, and argument here is ignored, and may be zero (the default). Parameters: sp  the length in scaled points units  the unit to convert it to dvif  a DVI file, if pixels or DVIunits are requested Returns: the converted unit Exceptions: DviError  if pixels or DVIunits were requested and no dvif parameter was supplied See also: convertToScaledPoints convertUnits

double DviFile::convertToScaledPoints (  double  length, DviUnits  units, DviFile *  dvif = 0 )  throw (DviError) [static]

Convert a length to TeX scaled points. The conversions from DVIunits and pixels are not universal, but are instead dependent on a particular DVI file; if you wish to convert from either of these units, you must supply a reference to a DVI file. If not, and argument here is ignored, and may be zero (the default). Parameters: length  the length to be converted units  the units in which the length is currently dvif  a DVI file, if pixels or DVIunits are requested Returns: the input length as a multiple of the TeX scaled-point Exceptions: DviError  if pixels or DVIunits were requested and no dvif parameter was supplied See also: convertFromScaledPoints convertUnits

double DviFile::convertUnits (  double  length, DviUnits  from_units, DviUnits  to_units, DviFile *  dvif = 0 )  throw (DviError) [static]

Convert a length from one set of units to another. The conversions to DVIunits and pixels are not universal, but are instead dependent on a particular DVI file; if you wish to convert to either of these units, you must supply a reference to a DVI file. If not, and argument here is ignored, and may be zero (the default). Parameters: length  the length to be converted from_units  the units in which length is currently expressed to_units  the target units dvif  a DVI file, if pixels or DVIunits are requested Returns: the length expressed as a multiple of the target unit Exceptions: DviError  if pixels or DVIunits were requested and no dvif parameter was supplied See also: convertFromScaledPoints convertToScaledPoints

int DviFile::currH (  DviUnits  units = unit_pixels  )  const throw (DviError) [inline]

Obtains the current horizontal position. The position can be reported in any of unit_pixels, unit_dvi or unit_sp; it is an error to call this function with any other of the defined units. The conversion to pixel units includes any drift correction, and is correctly rounded. Scaled points are calculated as DVI units times the overall magnification (that is, we ignore the general case of DVI files with odd preamble scalings). Returns: the horizontal position, in the chosen units Exceptions: DviError  if we are invoked with an inappropriate unit argument

int DviFile::currV (  DviUnits  units = unit_pixels  )  const throw (DviError) [inline]

Obtains the current vertical position. See currH, to which this is precisely analogous.

bool DviFile::eof (   )

Indicates whether we are at the end of the DVI file. This is true if the underlying file is closed, or if we have read all the pages and getEvent has returned a DviFilePostamble event. Returns: true if we are at EOF

const string* DviFile::filename (   )  const [inline]

Gets the name of this DVI file. Returns: the open file name as a string

DviFileEvent * DviFile::getEndOfPage (   )

Skips to the end of the page. This reads the DVI file at high speed until it finds the next end-of-page event, which it returns, leaving the DVI file positioned appropriately. If there are in fact no more pages -- if the last end-of-page event has already been returned -- then return either a DviFilePostamble event or zero, just like getEvent. Returns: the next end-of-page event

DviFileEvent * DviFile::getEvent (   )

Gets an event from the DVI file. This is the routine which does most of the actual work. It scans through the file reading opcodes. Most of these it handles itself, but certain ones it handles by returning an event to the calling routine. The first event this method will return is the DviFilePreamble event, and the last one is a DviFilePostamble event, after which eof() will be true, and this method will return only zero. The events which can be returned are all of the subclasses of DviFileEvent, qv. When you are finished with the returned event, you should release it by a call to the event's release method, after which you should make no further reference to it. Returns: the next event from the DVI file, or zero if eof() is true

const PkFont * DviFile::getFallbackFont (  const PkFont *  desired  )

Returns a fallback font, for use when a requested font is not available. The font returned depends on whether the DVI postamble was read or not, on what fonts have already been seen in the file, and on the font desired. This flexibility will not, however, stray beyond the liberty given by section 4.4, `Missing fonts', in the DVI standard. Parameters: desired  a pointer to the font which was requested (but not, presumably, loaded), or 0 if this information is not available Returns: a pointer to a fallback font, or zero if absolutely no fonts are available

const FontSet* DviFile::getFontSet (   )  const [inline]

Obtains a representation of the set of fonts contained in this DVI file. If the postamble was read, then the FontSet returned by this method will be complete; if not, it will simply represent the set of fonts read so far in the file. Returns: a pointer to the FontSet for this file

bool DviFile::haveReadPostamble (   )  const [inline]

Reports whether the DVI file postamble was read when this file was opened. This affects the semantics of such methods as getFontSet. Note that this only reports whether the postamble was read at the start of processing, and it does not become true when the postamble is discovered at the end; it is not an end-of-file indicator. For that, see the eof method. Returns: true if the postamble was (successfully) read

int DviFile::hSize (   )

Obtains the `width of the widest page'. This is either the value obtained from the postamble of the DVI file, if that was read, or else the maximum value of the horizontal position (as returned by currH()), if that is larger. If the postamble has not been read, then this is initialised to -1. Note that this isn't the same as the maximum value of currH, any more than 0 is the minimum, but if the origin is set `appropriately' (ie, at (1in,1in)), then everything should fit on. It's not a precise figure, but can be useful as a scale for initialising bitmap sizes, for example. Returns: the horizontal size of the largest `page', in pixels

double DviFile::magnification (   )  const [inline]

Return the net magnification factor for the DVI file. Returns: the overall magnification factor applied to lengths in the DVI file. A value of 1.0 implies no magnification at all.

int DviFile::pt2px (  double  npt  )  const [inline]

Converts a length in points to one in pixels, using the current magnifications and any other relevant parameters. Parameters: npt  a length in points Returns: the given length, in pixels

string DviFile::unitString (  DviFile::DviUnits  unit  )  [static]

Gets the string representation of a DVI unit. Parameters: unit  the unit in question Returns: a string representing the unit

DviFile::DviUnits DviFile::unitType (  string  unitString  )  [static]

Convert a string to a unit. Parameters: unitString  one of the strings representing a DVI unit Returns: the appropriate member of the DviUnits enum, or unit_BAD if the unit string is not recognised

verbosities DviFile::verbosity (  const verbosities  level  )  [static]

Sets the verbosity of this module. Parameters: level  the required verbosity Returns: the previous verbosity level

int DviFile::vSize (   )

Obtains the `height plus depth of the tallest page'. This is either the value obtained from the postamble of the DVI file, if that was read, or else the maximum value of the vertical position (as returned by currV()), if that is larger. If the postamble has not been read, then this is initialised to -1. Note that this isn't the same as the maximum value of currV, any more than 0 is the minimum, but if the origin is set `appropriately' (ie, at (1in,1in)), then everything should fit on. It's not a precise figure, but can be useful as a scale for initialising bitmap sizes, for example. Returns: the vertical size of the largest `page', in pixels

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The documentation for this class was generated from the following files:

• DviFile.h
• DviFile.cc

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