[wxWidgets.git] / src / tiff / man / TIFFRGBAImage.3tiff

.\"
.\" Copyright (c) 1991-1997 Sam Leffler
.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
.\"
.\" Permission to use, copy, modify, distribute, and sell this software and 
.\" its documentation for any purpose is hereby granted without fee, provided
.\" that (i) the above copyright notices and this permission notice appear in
.\" all copies of the software and related documentation, and (ii) the names of
.\" Sam Leffler and Silicon Graphics may not be used in any advertising or
.\" publicity relating to the software without the specific, prior written
.\" permission of Sam Leffler and Silicon Graphics.
.\" 
.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
.\" 
.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
.\" OF THIS SOFTWARE.
.\"
.if n .po 0
.TH TIFFRGBAImage 3TIFF "October 29, 2004" "libtiff"
.SH NAME
TIFFRGBAImageOK, TIFFRGBAImageBegin, TIFFRGBAImageGet, TIFFRGBAImageEnd
\- read and decode an image into a raster
.SH SYNOPSIS
.B "#include <tiffio.h>"
.sp
.B "typedef unsigned char TIFFRGBValue;"
.B "typedef struct _TIFFRGBAImage TIFFRGBAImage;"
.sp
.BI "int TIFFRGBAImageOK(TIFF *" tif ", char " emsg[1024] ")"
.br
.BI "int TIFFRGBAImageBegin(TIFFRGBAImage *" img ", TIFF* " tif ", int " stopOnError ", char " emsg[1024] ")"
.br
.BI "int TIFFRGBAImageGet(TIFFRGBAImage *" img ", uint32* " raster ", uint32 " width " , uint32 " height ")"
.br
.BI "void TIFFRGBAImageEnd(TIFFRGBAImage *" img ")"
.br
.SH DESCRIPTION
The routines described here provide a high-level interface
through which
.SM TIFF
images may be read into memory.
Images may be strip- or tile-based and have a variety of different
characteristics: bits/sample, samples/pixel, photometric, etc.
Decoding state is encapsulated in a
.I TIFFRGBAImage
structure making it possible to capture state for multiple images
and quickly switch between them.
The target raster format can be customized to a particular application's
needs by installing custom routines that manipulate image data
according to application requirements.
.PP
The default usage for these routines is: check if an image can
be processed using
.IR TIFFRGBAImageOK ,
construct a decoder state block using
.IR TIFFRGBAImageBegin ,
read and decode an image into a target raster using
.IR TIFFRGBAImageGet ,
and then
release resources using
.IR TIFFRGBAImageEnd .
.I TIFFRGBAImageGet
can be called multiple times to decode an image using different
state parameters.
If multiple images are to be displayed and there is not enough
space for each of the decoded rasters, multiple state blocks can
be managed and then calls can be made to
.I TIFFRGBAImageGet
as needed to display an image.
.PP
The generated raster is assumed to be an array of
.I width
times
.I height
32-bit entries, where
.I width
must be less than or equal to the width of the image (\c
.I height
may be any non-zero size).
If the raster dimensions are smaller than the image, the image data
is cropped to the raster bounds.
If the raster height is greater than that of the image, then the
image data are placed in the lower part of the raster.
(Note that the raster is assume to be organized such that the pixel
at location (\fIx\fP,\fIy\fP) is \fIraster\fP[\fIy\fP*\fIwidth\fP+\fIx\fP];
with the raster origin in the 
.B lower-left
hand corner.)
.PP
Raster pixels are 8-bit packed red, green, blue, alpha samples.
The macros
.IR TIFFGetR ,
.IR TIFFGetG ,
.IR TIFFGetB ,
and
.I TIFFGetA
should be used to access individual samples.
Images without Associated Alpha matting information have a constant
Alpha of 1.0 (255).
.PP
.I TIFFRGBAImageGet
converts non-8-bit images by scaling sample values.
Palette, grayscale, bilevel, 
.SM CMYK\c
, and YCbCr images are converted to
.SM RGB
transparently.
Raster pixels are returned uncorrected by any colorimetry information
present in the directory.
.PP
The parameter
.I stopOnError
specifies how to act if an error is encountered while reading
the image.
If
.I stopOnError
is non-zero, then an error will terminate the operation; otherwise
.I TIFFRGBAImageGet
will continue processing data until all the possible data in the
image have been requested.
.SH "ALTERNATE RASTER FORMATS"
To use the core support for reading and processing 
.SM TIFF
images, but write the resulting raster data in a different format
one need only override the ``\fIput methods\fP'' used to store raster data.
These methods are are defined in the
.I TIFFRGBAImage
structure and initially setup by
.I TIFFRGBAImageBegin
to point to routines that pack raster data in the default
.SM ABGR
pixel format.
Two different routines are used according to the physical organization
of the image data in the file: 
.IR PlanarConfiguration =1
(packed samples),
and 
.IR PlanarConfiguration =2
(separated samples).
Note that this mechanism can be used to transform the data before
storing it in the raster.
For example one can convert data
to colormap indices for display on a colormap display.
.SH "SIMULTANEOUS RASTER STORE AND DISPLAY"
It is simple to display an image as it is being read into memory
by overriding the put methods as described above for supporting
alternate raster formats.
Simply keep a reference to the default put methods setup by
.I TIFFRGBAImageBegin
and then invoke them before or after each display operation.
For example, the
.IR tiffgt (1)
utility uses the following put method to update the display as
the raster is being filled:
.sp
.nf
.ft C
static void
putContigAndDraw(TIFFRGBAImage* img, uint32* raster,
    uint32 x, uint32 y, uint32 w, uint32 h,
    int32 fromskew, int32 toskew,
    unsigned char* cp)
{
    (*putContig)(img, raster, x, y, w, h, fromskew, toskew, cp);
    if (x+w == width) {
	w = width;
	if (img->orientation == ORIENTATION_TOPLEFT)
	    lrectwrite(0, y-(h-1), w-1, y, raster-x-(h-1)*w);
	else
	    lrectwrite(0, y, w-1, y+h-1, raster);
    }
}
.ft R
.fi
.sp
(the original routine provided by the library is saved in the
variable 
.IR putContig .)
.SH "SUPPORTING ADDITIONAL TIFF FORMATS"
The
.I TIFFRGBAImage
routines support the most commonly encountered flavors of
.SM TIFF.
It is possible to extend this support by overriding the ``\fIget method\fP''
invoked by
.I TIFFRGBAImageGet
to read 
.SM TIFF
image data.
Details of doing this are a bit involved, it is best to make a copy
of an existing get method and modify it to suit the needs of an
application.
.SH NOTES
Samples must be either 1, 2, 4, 8, or 16 bits.
Colorimetric samples/pixel must be either 1, 3, or 4 (i.e.
.I SamplesPerPixel
minus
.IR ExtraSamples ).
.PP
Palette image colormaps that appear to be incorrectly written
as 8-bit values are automatically scaled to 16-bits.
.SH "RETURN VALUES"
All routines return
1 if the operation was successful.
Otherwise, 0 is returned if an error was encountered and
.I stopOnError
is zero.
.SH DIAGNOSTICS
All error messages are directed to the
.IR TIFFError (3TIFF)
routine.
.PP
.BR "Sorry, can not handle %d-bit pictures" .
The image had
.I BitsPerSample
other than 1, 2, 4, 8, or 16.
.PP
.BR "Sorry, can not handle %d-channel images" .
The image had
.I SamplesPerPixel
other than 1, 3, or 4.
.PP
\fBMissing needed "PhotometricInterpretation" tag\fP.
The image did not have a tag that describes how to display
the data.
.PP
\fBNo "PhotometricInterpretation" tag, assuming RGB\fP.
The image was missing a tag that describes how to display it,
but because it has 3 or 4 samples/pixel, it is assumed to be
.SM RGB.
.PP
\fBNo "PhotometricInterpretation" tag, assuming min-is-black\fP.
The image was missing a tag that describes how to display it,
but because it has 1 sample/pixel, it is assumed to be a grayscale
or bilevel image.
.PP
.BR "No space for photometric conversion table" .
There was insufficient memory for a table used to convert
image samples to 8-bit
.SM RGB.
.PP
\fBMissing required "Colormap" tag\fP.
A Palette image did not have a required
.I Colormap
tag.
.PP
.BR "No space for tile buffer" .
There was insufficient memory to allocate an i/o buffer.
.PP
.BR "No space for strip buffer" .
There was insufficient memory to allocate an i/o buffer.
.PP
.BR "Can not handle format" .
The image has a format (combination of
.IR BitsPerSample ,
.IR SamplesPerPixel ,
and
.IR PhotometricInterpretation )
that can not be handled.
.PP
.BR "No space for B&W mapping table" .
There was insufficient memory to allocate a table used to map
grayscale data to
.SM RGB.
.PP
.BR "No space for Palette mapping table" .
There was insufficient memory to allocate a table used to map
data to 8-bit
.SM RGB.
.SH "SEE ALSO"
.BR TIFFOpen (3TIFF),
.BR TIFFReadRGBAImage (3TIFF),
.BR TIFFReadRGBAImageOriented (3TIFF),
.BR TIFFReadRGBAStrip (3TIFF),
.BR TIFFReadRGBATile (3TIFF),
.BR libtiff (3TIFF)
.PP
Libtiff library home page:
.BR http://www.remotesensing.org/libtiff/
Commit	Line	Data
8414a40c VZ	1	.\"
	2	.\" Copyright (c) 1991-1997 Sam Leffler
	3	.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
	4	.\"
	5	.\" Permission to use, copy, modify, distribute, and sell this software and
	6	.\" its documentation for any purpose is hereby granted without fee, provided
	7	.\" that (i) the above copyright notices and this permission notice appear in
	8	.\" all copies of the software and related documentation, and (ii) the names of
	9	.\" Sam Leffler and Silicon Graphics may not be used in any advertising or
	10	.\" publicity relating to the software without the specific, prior written
	11	.\" permission of Sam Leffler and Silicon Graphics.
	12	.\"
	13	.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
	14	.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
	15	.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	16	.\"
	17	.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
	18	.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
	19	.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	20	.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
	21	.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
	22	.\" OF THIS SOFTWARE.
	23	.\"
	24	.if n .po 0
	25	.TH TIFFRGBAImage 3TIFF "October 29, 2004" "libtiff"
	26	.SH NAME
	27	TIFFRGBAImageOK, TIFFRGBAImageBegin, TIFFRGBAImageGet, TIFFRGBAImageEnd
	28	\- read and decode an image into a raster
	29	.SH SYNOPSIS
	30	.B "#include <tiffio.h>"
	31	.sp
	32	.B "typedef unsigned char TIFFRGBValue;"
	33	.B "typedef struct _TIFFRGBAImage TIFFRGBAImage;"
	34	.sp
	35	.BI "int TIFFRGBAImageOK(TIFF *" tif ", char " emsg[1024] ")"
	36	.br
	37	.BI "int TIFFRGBAImageBegin(TIFFRGBAImage " img ", TIFF " tif ", int " stopOnError ", char " emsg[1024] ")"
	38	.br
	39	.BI "int TIFFRGBAImageGet(TIFFRGBAImage " img ", uint32 " raster ", uint32 " width " , uint32 " height ")"
	40	.br
	41	.BI "void TIFFRGBAImageEnd(TIFFRGBAImage *" img ")"
	42	.br
	43	.SH DESCRIPTION
	44	The routines described here provide a high-level interface
	45	through which
	46	.SM TIFF
	47	images may be read into memory.
	48	Images may be strip- or tile-based and have a variety of different
	49	characteristics: bits/sample, samples/pixel, photometric, etc.
	50	Decoding state is encapsulated in a
	51	.I TIFFRGBAImage
	52	structure making it possible to capture state for multiple images
	53	and quickly switch between them.
	54	The target raster format can be customized to a particular application's
	55	needs by installing custom routines that manipulate image data
	56	according to application requirements.
	57	.PP
	58	The default usage for these routines is: check if an image can
	59	be processed using
	60	.IR TIFFRGBAImageOK ,
	61	construct a decoder state block using
	62	.IR TIFFRGBAImageBegin ,
	63	read and decode an image into a target raster using
	64	.IR TIFFRGBAImageGet ,
65	and then
66	release resources using
67	.IR TIFFRGBAImageEnd .
68	.I TIFFRGBAImageGet
69	can be called multiple times to decode an image using different
70	state parameters.
71	If multiple images are to be displayed and there is not enough
72	space for each of the decoded rasters, multiple state blocks can
73	be managed and then calls can be made to
74	.I TIFFRGBAImageGet
75	as needed to display an image.
76	.PP
77	The generated raster is assumed to be an array of
78	.I width
79	times
80	.I height
81	32-bit entries, where
82	.I width
83	must be less than or equal to the width of the image (\c
84	.I height
85	may be any non-zero size).
86	If the raster dimensions are smaller than the image, the image data
87	is cropped to the raster bounds.
88	If the raster height is greater than that of the image, then the
89	image data are placed in the lower part of the raster.
90	(Note that the raster is assume to be organized such that the pixel
91	at location (\fIx\fP,\fIy\fP) is \fIraster\fP[\fIy\fP*\fIwidth\fP+\fIx\fP];
92	with the raster origin in the
93	.B lower-left
94	hand corner.)
95	.PP
96	Raster pixels are 8-bit packed red, green, blue, alpha samples.
97	The macros
98	.IR TIFFGetR ,
99	.IR TIFFGetG ,
100	.IR TIFFGetB ,
101	and
102	.I TIFFGetA
103	should be used to access individual samples.
104	Images without Associated Alpha matting information have a constant
105	Alpha of 1.0 (255).
106	.PP
107	.I TIFFRGBAImageGet
108	converts non-8-bit images by scaling sample values.
109	Palette, grayscale, bilevel,
110	.SM CMYK\c
111	, and YCbCr images are converted to
112	.SM RGB
113	transparently.
114	Raster pixels are returned uncorrected by any colorimetry information
115	present in the directory.
116	.PP
117	The parameter
118	.I stopOnError
119	specifies how to act if an error is encountered while reading
120	the image.
121	If
122	.I stopOnError
123	is non-zero, then an error will terminate the operation; otherwise
124	.I TIFFRGBAImageGet
125	will continue processing data until all the possible data in the
126	image have been requested.
127	.SH "ALTERNATE RASTER FORMATS"
128	To use the core support for reading and processing
129	.SM TIFF
130	images, but write the resulting raster data in a different format
131	one need only override the ``\fIput methods\fP'' used to store raster data.
132	These methods are are defined in the
133	.I TIFFRGBAImage
134	structure and initially setup by
135	.I TIFFRGBAImageBegin
136	to point to routines that pack raster data in the default
137	.SM ABGR
138	pixel format.
139	Two different routines are used according to the physical organization
140	of the image data in the file:
141	.IR PlanarConfiguration =1
142	(packed samples),
143	and
144	.IR PlanarConfiguration =2
145	(separated samples).
146	Note that this mechanism can be used to transform the data before
147	storing it in the raster.
148	For example one can convert data
149	to colormap indices for display on a colormap display.
150	.SH "SIMULTANEOUS RASTER STORE AND DISPLAY"
151	It is simple to display an image as it is being read into memory
152	by overriding the put methods as described above for supporting
153	alternate raster formats.
154	Simply keep a reference to the default put methods setup by
155	.I TIFFRGBAImageBegin
156	and then invoke them before or after each display operation.
157	For example, the
158	.IR tiffgt (1)
159	utility uses the following put method to update the display as
160	the raster is being filled:
161	.sp
162	.nf
163	.ft C
164	static void
165	putContigAndDraw(TIFFRGBAImage* img, uint32* raster,
166	uint32 x, uint32 y, uint32 w, uint32 h,
167	int32 fromskew, int32 toskew,
168	unsigned char* cp)
169	{
170	(*putContig)(img, raster, x, y, w, h, fromskew, toskew, cp);
171	if (x+w == width) {
172	w = width;
173	if (img->orientation == ORIENTATION_TOPLEFT)
174	lrectwrite(0, y-(h-1), w-1, y, raster-x-(h-1)*w);
175	else
176	lrectwrite(0, y, w-1, y+h-1, raster);
177	}
178	}
179	.ft R
180	.fi
181	.sp
182	(the original routine provided by the library is saved in the
183	variable
184	.IR putContig .)
185	.SH "SUPPORTING ADDITIONAL TIFF FORMATS"
186	The
187	.I TIFFRGBAImage
188	routines support the most commonly encountered flavors of
189	.SM TIFF.
190	It is possible to extend this support by overriding the ``\fIget method\fP''
191	invoked by
192	.I TIFFRGBAImageGet
193	to read
194	.SM TIFF
195	image data.
196	Details of doing this are a bit involved, it is best to make a copy
197	of an existing get method and modify it to suit the needs of an
198	application.
199	.SH NOTES
200	Samples must be either 1, 2, 4, 8, or 16 bits.
201	Colorimetric samples/pixel must be either 1, 3, or 4 (i.e.
202	.I SamplesPerPixel
203	minus
204	.IR ExtraSamples ).
205	.PP
206	Palette image colormaps that appear to be incorrectly written
207	as 8-bit values are automatically scaled to 16-bits.
208	.SH "RETURN VALUES"
209	All routines return
210	1 if the operation was successful.
211	Otherwise, 0 is returned if an error was encountered and
212	.I stopOnError
213	is zero.
214	.SH DIAGNOSTICS
215	All error messages are directed to the
216	.IR TIFFError (3TIFF)
217	routine.
218	.PP
219	.BR "Sorry, can not handle %d-bit pictures" .
220	The image had
221	.I BitsPerSample
222	other than 1, 2, 4, 8, or 16.
223	.PP
224	.BR "Sorry, can not handle %d-channel images" .
225	The image had
226	.I SamplesPerPixel
227	other than 1, 3, or 4.
228	.PP
229	\fBMissing needed "PhotometricInterpretation" tag\fP.
230	The image did not have a tag that describes how to display
231	the data.
232	.PP
233	\fBNo "PhotometricInterpretation" tag, assuming RGB\fP.
234	The image was missing a tag that describes how to display it,
235	but because it has 3 or 4 samples/pixel, it is assumed to be
236	.SM RGB.
237	.PP
238	\fBNo "PhotometricInterpretation" tag, assuming min-is-black\fP.
239	The image was missing a tag that describes how to display it,
240	but because it has 1 sample/pixel, it is assumed to be a grayscale
241	or bilevel image.
242	.PP
243	.BR "No space for photometric conversion table" .
244	There was insufficient memory for a table used to convert
245	image samples to 8-bit
246	.SM RGB.
247	.PP
248	\fBMissing required "Colormap" tag\fP.
249	A Palette image did not have a required
250	.I Colormap
251	tag.
252	.PP
253	.BR "No space for tile buffer" .
254	There was insufficient memory to allocate an i/o buffer.
255	.PP
256	.BR "No space for strip buffer" .
257	There was insufficient memory to allocate an i/o buffer.
258	.PP
259	.BR "Can not handle format" .
260	The image has a format (combination of
261	.IR BitsPerSample ,
262	.IR SamplesPerPixel ,
263	and
264	.IR PhotometricInterpretation )
265	that can not be handled.
266	.PP
267	.BR "No space for B&W mapping table" .
268	There was insufficient memory to allocate a table used to map
269	grayscale data to
270	.SM RGB.
271	.PP
272	.BR "No space for Palette mapping table" .
273	There was insufficient memory to allocate a table used to map
274	data to 8-bit
275	.SM RGB.
276	.SH "SEE ALSO"
277	.BR TIFFOpen (3TIFF),
278	.BR TIFFReadRGBAImage (3TIFF),
279	.BR TIFFReadRGBAImageOriented (3TIFF),
280	.BR TIFFReadRGBAStrip (3TIFF),
281	.BR TIFFReadRGBATile (3TIFF),
282	.BR libtiff (3TIFF)
283	.PP
284	Libtiff library home page:
285	.BR http://www.remotesensing.org/libtiff/