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1 /* $Header$ */
2
3 /*
4 * Copyright (c) 1991-1997 Sam Leffler
5 * Copyright (c) 1991-1997 Silicon Graphics, Inc.
6 *
7 * Permission to use, copy, modify, distribute, and sell this software and
8 * its documentation for any purpose is hereby granted without fee, provided
9 * that (i) the above copyright notices and this permission notice appear in
10 * all copies of the software and related documentation, and (ii) the names of
11 * Sam Leffler and Silicon Graphics may not be used in any advertising or
12 * publicity relating to the software without the specific, prior written
13 * permission of Sam Leffler and Silicon Graphics.
14 *
15 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
17 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
18 *
19 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
20 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
21 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
22 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
23 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
24 * OF THIS SOFTWARE.
25 */
26
27 /*
28 * TIFF Library.
29 *
30 * Strip-organized Image Support Routines.
31 */
32 #include "tiffiop.h"
33
34 /*
35 * Compute which strip a (row,sample) value is in.
36 */
37 tstrip_t
38 TIFFComputeStrip(TIFF* tif, uint32 row, tsample_t sample)
39 {
40 TIFFDirectory *td = &tif->tif_dir;
41 tstrip_t strip;
42
43 strip = row / td->td_rowsperstrip;
44 if (td->td_planarconfig == PLANARCONFIG_SEPARATE) {
45 if (sample >= td->td_samplesperpixel) {
46 TIFFError(tif->tif_name,
47 "%u: Sample out of range, max %u",
48 sample, td->td_samplesperpixel);
49 return ((tstrip_t) 0);
50 }
51 strip += sample*td->td_stripsperimage;
52 }
53 return (strip);
54 }
55
56 /*
57 * Compute how many strips are in an image.
58 */
59 tstrip_t
60 TIFFNumberOfStrips(TIFF* tif)
61 {
62 TIFFDirectory *td = &tif->tif_dir;
63 tstrip_t nstrips;
64
65 nstrips = (td->td_rowsperstrip == (uint32) -1 ?
66 (td->td_imagelength != 0 ? 1 : 0) :
67 TIFFhowmany(td->td_imagelength, td->td_rowsperstrip));
68 if (td->td_planarconfig == PLANARCONFIG_SEPARATE)
69 nstrips *= td->td_samplesperpixel;
70 return (nstrips);
71 }
72
73 /*
74 * Compute the # bytes in a variable height, row-aligned strip.
75 */
76 tsize_t
77 TIFFVStripSize(TIFF* tif, uint32 nrows)
78 {
79 TIFFDirectory *td = &tif->tif_dir;
80
81 if (nrows == (uint32) -1)
82 nrows = td->td_imagelength;
83 #ifdef YCBCR_SUPPORT
84 if (td->td_planarconfig == PLANARCONFIG_CONTIG &&
85 td->td_photometric == PHOTOMETRIC_YCBCR &&
86 !isUpSampled(tif)) {
87 /*
88 * Packed YCbCr data contain one Cb+Cr for every
89 * HorizontalSampling*VerticalSampling Y values.
90 * Must also roundup width and height when calculating
91 * since images that are not a multiple of the
92 * horizontal/vertical subsampling area include
93 * YCbCr data for the extended image.
94 */
95 tsize_t w =
96 TIFFroundup(td->td_imagewidth, td->td_ycbcrsubsampling[0]);
97 tsize_t scanline = TIFFhowmany(w*td->td_bitspersample, 8);
98 tsize_t samplingarea =
99 td->td_ycbcrsubsampling[0]*td->td_ycbcrsubsampling[1];
100 nrows = TIFFroundup(nrows, td->td_ycbcrsubsampling[1]);
101 /* NB: don't need TIFFhowmany here 'cuz everything is rounded */
102 return ((tsize_t)
103 (nrows*scanline + 2*(nrows*scanline / samplingarea)));
104 } else
105 #endif
106 return ((tsize_t)(nrows * TIFFScanlineSize(tif)));
107 }
108
109 /*
110 * Compute the # bytes in a (row-aligned) strip.
111 *
112 * Note that if RowsPerStrip is larger than the
113 * recorded ImageLength, then the strip size is
114 * truncated to reflect the actual space required
115 * to hold the strip.
116 */
117 tsize_t
118 TIFFStripSize(TIFF* tif)
119 {
120 TIFFDirectory* td = &tif->tif_dir;
121 uint32 rps = td->td_rowsperstrip;
122 if (rps > td->td_imagelength)
123 rps = td->td_imagelength;
124 return (TIFFVStripSize(tif, rps));
125 }
126
127 /*
128 * Compute a default strip size based on the image
129 * characteristics and a requested value. If the
130 * request is <1 then we choose a strip size according
131 * to certain heuristics.
132 */
133 uint32
134 TIFFDefaultStripSize(TIFF* tif, uint32 request)
135 {
136 return (*tif->tif_defstripsize)(tif, request);
137 }
138
139 uint32
140 _TIFFDefaultStripSize(TIFF* tif, uint32 s)
141 {
142 if ((int32) s < 1) {
143 /*
144 * If RowsPerStrip is unspecified, try to break the
145 * image up into strips that are approximately 8Kbytes.
146 */
147 tsize_t scanline = TIFFScanlineSize(tif);
148 s = (uint32)(8*1024) / (scanline == 0 ? 1 : scanline);
149 if (s == 0) /* very wide images */
150 s = 1;
151 }
152 return (s);
153 }
154
155 /*
156 * Return the number of bytes to read/write in a call to
157 * one of the scanline-oriented i/o routines. Note that
158 * this number may be 1/samples-per-pixel if data is
159 * stored as separate planes.
160 */
161 tsize_t
162 TIFFScanlineSize(TIFF* tif)
163 {
164 TIFFDirectory *td = &tif->tif_dir;
165 tsize_t scanline;
166
167 scanline = td->td_bitspersample * td->td_imagewidth;
168 if (td->td_planarconfig == PLANARCONFIG_CONTIG)
169 scanline *= td->td_samplesperpixel;
170 return ((tsize_t) TIFFhowmany(scanline, 8));
171 }
172
173 /*
174 * Return the number of bytes required to store a complete
175 * decoded and packed raster scanline (as opposed to the
176 * I/O size returned by TIFFScanlineSize which may be less
177 * if data is store as separate planes).
178 */
179 tsize_t
180 TIFFRasterScanlineSize(TIFF* tif)
181 {
182 TIFFDirectory *td = &tif->tif_dir;
183 tsize_t scanline;
184
185 scanline = td->td_bitspersample * td->td_imagewidth;
186 if (td->td_planarconfig == PLANARCONFIG_CONTIG) {
187 scanline *= td->td_samplesperpixel;
188 return ((tsize_t) TIFFhowmany(scanline, 8));
189 } else
190 return ((tsize_t)
191 TIFFhowmany(scanline, 8)*td->td_samplesperpixel);
192 }