xtiffio.h File Reference

Definitions relating GeoTIFF functions from geotiff.h to the TIFF library (usually libtiff). More...

#include "tiffio.h"
#include "geo_config.h"

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Defines
#define	TIFFTAG_GEOPIXELSCALE   33550
#define	TIFFTAG_INTERGRAPH_MATRIX   33920
#define	TIFFTAG_GEOTIEPOINTS   33922
#define	TIFFTAG_GEOTRANSMATRIX   34264
#define	TIFFTAG_GEOKEYDIRECTORY   34735
#define	TIFFTAG_GEODOUBLEPARAMS   34736
#define	TIFFTAG_GEOASCIIPARAMS   34737
#define	TIFFPRINT_GEOKEYDIRECTORY   0x80000000
#define	TIFFPRINT_GEOKEYPARAMS   0x40000000
Functions
void CPL_DLL	XTIFFInitialize ()
	Registers an extension with libtiff for adding GeoTIFF tags.
TIFF CPL_DLL *	XTIFFOpen (const char *name, const char *mode)
	GeoTIFF compatible TIFF file open function.
TIFF CPL_DLL *	XTIFFFdOpen (int fd, const char *name, const char *mode)
void CPL_DLL	XTIFFClose (TIFF *tif)
	Close a file opened with XTIFFOpen().
TIFF CPL_DLL *	XTIFFClientOpen (const char *name, const char *mode, thandle_t thehandle, TIFFReadWriteProc, TIFFReadWriteProc, TIFFSeekProc, TIFFCloseProc, TIFFSizeProc, TIFFMapFileProc, TIFFUnmapFileProc)

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Detailed Description

Definitions relating GeoTIFF functions from geotiff.h to the TIFF library (usually libtiff).

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Function Documentation

void CPL_DLL XTIFFClose

(

TIFF *

tif

)

Close a file opened with XTIFFOpen().

Parameters:

tif

The file handle returned by XTIFFOpen().

If a GTIF structure was created with GTIFNew() for this file, it should be freed with GTIFFree() before calling XTIFFClose().

{
    TIFFClose(tif);
}

void CPL_DLL XTIFFInitialize

(

void

)

Registers an extension with libtiff for adding GeoTIFF tags.

After this one-time intialization, any TIFF open function may be called in the usual manner to create a TIFF file that compatible with libgeotiff. The XTIFF open functions are simply for convenience: they call this and then pass their parameters on to the appropriate TIFF open function.

This function may be called any number of times safely, since it will only register the extension the first time it is called.

{
    static int first_time=1;
        
    if (! first_time) return; /* Been there. Done that. */
    first_time = 0;
        
    /* Grab the inherited method and install */
    _ParentExtender = TIFFSetTagExtender(_XTIFFDefaultDirectory);
}

TIFF CPL_DLL* XTIFFOpen	(	const char *	name,
		const char *	mode
	)

GeoTIFF compatible TIFF file open function.

Parameters:

	name	The filename of a TIFF file to open.
	mode	The open mode ("r", "w" or "a").

Returns:

a TIFF * for the file, or NULL if the open failed.

This function is used to open GeoTIFF files instead of TIFFOpen() from libtiff. Internally it calls TIFFOpen(), but sets up some extra hooks so that GeoTIFF tags can be extracted from the file. If XTIFFOpen() isn't used, GTIFNew() won't work properly. Files opened with XTIFFOpen() should be closed with XTIFFClose().

The name of the file to be opened should be passed as name, and an opening mode ("r", "w" or "a") acceptable to TIFFOpen() should be passed as the mode.

If XTIFFOpen() fails it will return NULL. Otherwise, normal TIFFOpen() error reporting steps will have already taken place.

{
    TIFF *tif;

    /* Set up the callback */
    XTIFFInitialize();  
        
    /* Open the file; the callback will set everything up
     */
    tif = TIFFOpen(name, mode);
    if (!tif) return tif;
        
    return tif;
}