1Pamtotiff User Manual(0) Pamtotiff User Manual(0)
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6 pamtotiff - convert a Netpbm image to a TIFF file
7
10 pamtotiff
11 [-none | -packbits | -lzw | -g3 | -g4 | -flate | -adobeflate]
13 [-2d]
15 [-fill]
17 [-predictor=n]
19 [-msb2lsb|-lsb2msb]
21 [-rowsperstrip=n]
23 [-minisblack|-miniswhite|mb|mw]
25 [-truecolor]
27 [-color]
29 [-indexbits=bitwidthlist] [-xresolution=xres]
31 [-yresolution=yres] [-resolutionunit={inch | centimeter | none | in |
33 cm | no}]
34 [-append]
36 [-tag=taglist]
38 [pamfile]
40 You can use the minimum unique abbreviation of the options. You can
42 use two hyphens instead of one. You can separate an option name from
43 its value with white space instead of an equals sign.
44
47 This program is part of Netpbm(1).
48 pamtotiff reads a PNM or PAM image as input and produces a TIFF file as
50 output.
51 Actually, it handles multi-image Netpbm streams, producing multi-image
53 TIFF streams (i.e. a TIFF stream with multiple "directories"). But
54 before Netpbm 10.27 (March 2005), it ignored all but the first Netpbm
55 image in the input stream.
56 The Output File
59 By default, the output goes to Standard Output. Alternatively, you can
60 specify an output file with the -output option and pamtotiff will write
61 its output directly to that file.
62 Because of the way the TIFF library (which pamtotiff uses) works, when
64 the program writes to Standard Output, it generates the entire TIFF
65 image in a temporary file and then copies it to Standard Output; you
66 may see negative performance effects of this.
67 The -output method avoids the performance effects of the copy through
69 the temporary file, but there are restrictions on the output file: it
70 must be seekable and it must be readable. The program fails if it is
71 not. With Standard Output, neither of those restrictions applies.
72 With -output, if the file already exists and has data in it, pamtotiff
74 appends the image to the existing TIFF file. (A TIFF file may contain
75 multiple images).
76 By default, pamtotiff creates the file named by -output if it does not
78 already exist. But if you also specify -append, the program fails if
79 the file named by -output does not already exist.
80 Before Netpbm 10.67 (June 2014), there is no -output option and Stan‐
82 dard Output must be seekable. So pipes are out.
83 Before Netpbm 10.67 (June 2014), you could append to Standard Output.
85 See below. The current program does not have the ability; you must use
86 -output to append to an existing TIFF file.
87 The difference above means current pamtotiff is actually not backward
89 compatible, which is a rare thing for Netpbm. But it's a good thing
90 because the previous function was very strange and probably hardly ever
91 exploited.
92 Old Versions
95 As alluded to above, pamtotiff does output very differently in releases
97 before 10.67. The following describes the old function, which is
98 unusual both for Netpbm and for Unix programs in general.
99 · The output file must be seekable. pamtotiff does not write it
103 sequentially. Therefore, you can't use a pipe; you can't pipe
104 the output of pamtotiff to some other program. But any regular
105 file should work.
106 · If the output file descriptor is readable, you must either spec‐
109 ify -append so as to add to the existing file, or make sure the
110 file is empty. Otherwise, pamtotiff will fail with an unhelpful
111 message telling you that a TIFF library function failed to open
112 the TIFF output stream.
113 · If you are converting multiple images (your input stream con‐
116 tains multiple images), the output file must be both readable
117 and writable.
118 If you're using a Unix command shell to run pamtotiff, you use facili‐
122 ties of your shell to set up Standard Output. In Bash, for example,
123 you would set up a write-only Standard Output to the file /tmp/myim‐
124 age.tiff like this:
125 $ pamtotiff myimage.pnm >/tmp/myimage.tiff
127 In Bash, you would set up a read/write Standard Output to the file
129 /tmp/myimage.tiff like this:
130 $ pamtotiff myimage.pnm 1<>/tmp/myimage.tiff
132 TIFF Capability
135 pamtotiff uses the Libtiff.org TIFF library (or whatever equivalent you
136 provide) to generate the TIFF output. Details of the format it pro‐
137 duces are therefore controlled by that library.
138
141 Compression
142 By default, pamtotiff creates a TIFF file with no compression. This is
143 your best bet most of the time. If you want to try another compression
144 scheme or tweak some of the other even more obscure output options,
145 there are a number of options which to play.
146 Before Netpbm 8.4 (April 2000), the default was to use LZW compression.
148 But then new releases of the TIFF library started omitting the LZW com‐
149 pression capability because of concern about patents on LZW. So since
150 then, the default has been no compression. The LZW patents have now
151 expired and new TIFF libraries do LZW, but the pamtotiff behavior
152 remains the same for compatibility with older TIFF libraries and appli‐
153 cations of pamtotiff.
154 The -none, -packbits, -lzw, -g3, -g4, -flate, and -adobeflate options
156 are used to override the default and set the compression scheme used in
157 creating the output file.
158 The -predictor option is meaningful only with LZW compression: a pre‐
160 dictor value of 2 causes each scanline of the output image to undergo
161 horizontal differencing before it is encoded; a value of 1 forces each
162 scanline to be encoded without differencing. By default, pamtotiff
163 creates a TIFF file with msb-to-lsb fill order. The -msb2lsb and
164 -lsb2msb options are used to override the default and set the fill
165 order used in creating the file.
166 With some older TIFF libraries, -lzw doesn't work because the TIFF
168 library doesn't do LZW compression. This is because of concerns about
169 Unisys's patent on LZW which was then in force. Actually, with very
170 old TIFF libraries, -lzw works because no distributors of the TIFF
171 library were sensitive yet to the patent issue.
172 -flate chooses "flate" compression, which is the patent-free compres‐
174 sion common in the Unix world implemented by the "Z" library. It is
175 what the PNG format uses.
176 Fax Compression
178 If you have bilevel data (e.g. PBM), you can generate a TIFF that uses
180 the same compression scheme specified for use by fax machines. See the
181 Fax Format(1) page for more information on these compression schemes.
182 These formats all relate to ITU Group 3 and Group 4 fax machine stan‐
184 dards.
185 The -g3 option chooses MH or MR compression: MR with the additional
187 option -2d; MH without it. -g4 selects MMR. The option names are a
188 little unfortunate and historical, but are consistent with the TIFF
189 specification.
190 MMR has a better compression ratio than the other two.
192 -fill specifies that for MH or MR compression, each encoded scanline
194 shall be zero-filled to a byte boundary.
195 -2d and -fill are meaningful only with -g3.
197 Fill Order
201 The -msb2lsb and lsb2msb options control the fill order.
202 The fill order is the order in which pixels are packed into a byte in
204 the Tiff raster, in the case that there are multiple pixels per byte.
205 msb-to-lsb means that the leftmost columns go into the most significant
206 bits of the byte in the Tiff image. However, there is considerable
207 confusion about the meaning of fill order. Some believe it means
208 whether 16 bit sample values in the Tiff image are little-endian or
209 big-endian. This is totally erroneous (The endianness of integers in a
210 Tiff image is designated by the image's magic number). However,
211 ImageMagick and older Netpbm both have been known to implement that
212 interpretation. 2001.09.06.
213 If the image does not have sub-byte pixels, these options have no
215 effect other than to set the value of the FILLORDER tag in the Tiff
216 image (which may be useful for those programs that misinterpret the tag
217 with reference to 16 bit samples).
218 Color Space
221 -color tells pamtotiff to produce a color, as opposed to grayscale,
222 TIFF image if the input is PPM, even if it contains only shades of
223 gray. Without this option, pamtotiff produces a grayscale TIFF image
224 if the input is PPM and contains only shades of gray, and at most 256
225 shades. Otherwise, it produces a color TIFF output. For PBM and PGM
226 input, pamtotiff always produces grayscale TIFF output and this option
227 has no effect.
228 The -color option can prevent pamtotiff from making two passes through
230 the input file, thus improving speed and memory usage. See Multiple
231 Passes ⟨#multipass⟩ .
232 -truecolor tells pamtotiff to produce the 24-bit RGB form of TIFF out‐
234 put if it is producing a color TIFF image. Without this option, pamto‐
235 tiff produces a colormapped (paletted) TIFF image unless there are more
236 than 256 colors (and in the latter case, issues a warning).
237 The -truecolor option can prevent pamtotiff from making two passes
239 through the input file, thus improving speed and memory usage. See
240 Multiple Passes ⟨#multipass⟩ .
241 The -color and -truecolor options did not exist before Netpbm 9.21
243 (December 2001).
244 If pamtotiff produces a grayscale TIFF image, this option has no
246 effect.
247 The -minisblack and -miniswhite options force the output image to have
249 a "minimum is black" or "minimum is white" photometric, respectively.
250 If you don't specify either, pamtotiff uses minimum is black except
251 when using Group 3 or Group 4 compression, in which case pamtotiff fol‐
252 lows CCITT fax standards and uses "minimum is white." This usually
253 results in better compression and is generally preferred for bilevel
254 coding. These photometrics are for grayscale images, so these options
255 are invalid if the image is color (but only if it is truly color; they
256 are valid with, for example, a PPM image that contains only shades of
257 gray).
258 Before Netpbm 9.11 (February 200)1, pamtotiff always produced "minimum
260 is black," because of a bug. In either case, pamtotiff sets the photo‐
261 metric interpretation tag in the TIFF output according to which photo‐
262 metric is actually used.
263 Before Netpbm 10.78 (March 2017), pamtotiff respected -miniswhite and
265 -minisblack even with color images, producing invalid TIFF images that
266 have the indicated photometric but red, green, and blue raster planes.
267 The -indexbits option is meaningful only for a colormapped (paletted)
269 image. In this kind of image, the raster contains values which are
270 indexes into a table of colors, with the indexes normally taking less
271 space that the color description in the table. pamtotiff can generate
272 indexes of 1, 2, 4, or 8 bits. By default, it will use 8, because many
273 programs that interpret TIFF images can't handle any other width.
274 But if you have a small number of colors, you can make your image con‐
276 siderably smaller by allowing fewer than 8 bits per index, using the
277 -indexbits option. The value is a comma-separated list of the bit
278 widths you allow. pamtotiff chooses the smallest width you allow that
279 allows it to index the entire color table. If you don't allow any such
280 width, pamtotiff fails. Normally, the only useful value for this
281 option is 1,2,4,8, because a program either understands the 8 bit width
282 (default) or understands them all.
283 In a Baseline TIFF image, according to the 1992 TIFF 6.0 specification,
285 4 and 8 are the only valid widths. There are no formal standards that
286 allow any other values.
287 This option was added in June 2002. Before that, only 8 bit indices
289 were possible.
290 Extra Tags
293 There are lots of tag types in the TIFF format that don't correspond to
294 any information in the PNM format or to anything in the conversion
295 process. For example, a TIFF_ARTIST tag names the artist who created
296 the image.
297 You can tell pamtotiff explicitly to include tags such as this in its
299 output with the -tag option. You identify a list of tag types and val‐
300 ues and pamtotiff includes a tag in the output for each item in your
301 list.
302 The value of -tag is the list of tags, like this example:
304 -tag=subfiletype=reducedimage,documentname=Fred,xposition=25
306 As you see, it is a list of tag specifications separated by commas.
308 Each tag specification is a name and a value separated by an equal
309 sign. The name is the name of the tag type, except in arbitrary
310 upper/lower case. One place to see the names of TIFF tag types is in
311 the TIFF library's tiff.h file, where there is a macro defined for each
312 consisting of "TIFF_" plus the name. E.g. for the SUBFILETYPE tag
313 type, there is a macro TIFF_SUBFILETYPE.
314 The format of the value specification for a tag (stuff after the equal
316 sign) depends upon what kind of value the tag type has:
317 · Integer: a decimal number
321 · Floating point number: a decimal number
324 · String: a string
327 · Enumerated (For example, a 'subfiletype' tag takes an enumerated
330 value. Its possible values are REDUCEDIMAGE, PAGE, and MASK.):
331 The name of the value. You can see the possible value names in
332 the TIFF library's tiff.h file, where there is a macro defined
333 for each consisting of a qualifier plus the value name. E.g.
334 for the REDUCEDIMAGE value of a SUBFILETYPE tag, you see the
335 macro FILETYPE_REDUCEDIMAGE.
336 The TIFF format assigns a unique number to each enumerated value
338 and you can specify that number, in decimal, as an alternative.
339 This is useful if you are using an extension of TIFF that pamto‐
340 tiff doesn't know about.
341 If you specify a tag type with -tag that is not independent of the con‐
345 tent of your PNM source image and pamtotiff's conversion process (i.e.
346 a tag type in which pamtotiff is interested), pamtotiff fails. For
347 example, you cannot specify an IMAGEWIDTH tag with -tag, because pamto‐
348 tiff generates an IMAGEWIDTH tag that gives the actual width of the
349 image.
350 -tag was new in Netpbm 10.31 (December 2005).
352 Output
355 See The Output File ⟨output⟩ .
356 -output names the output file. Without this option pamtotiff writes to
358 Standard Output.
359 The -append option tells pamtotiff only to append to the file named by
361 output; not create it. Without this option, the program creates the
362 file it does not already exist. But even then, if the file does
363 already exist, the program appends the image to what is in the file
364 already. (A TIFF file may contain multiple images).
365 -append has no effect if you don't also specify -output.
367 Before Netpbm 10.67 (June 2014), -append means something rather differ‐
369 ent: it means to append the image to the output TIFF file (which is
370 always Standard Output in 10.67) instead of replacing its contents.
371 -append was new in Netpbm 10.27 (March 2005).
373 Other
378 You can use the -rowsperstrip option to set the number of rows (scan‐
379 lines) in each strip of data in the output file. By default, the out‐
380 put file has the number of rows per strip set to a value that will
381 ensure each strip is no more than 8 kilobytes long.
382
386 There are myriad variations of the TIFF format, and this program gener‐
387 ates only a few of them. pamtotiff creates a grayscale TIFF file if
388 its input is a PBM (monochrome) or PGM (grayscale) or equivalent PAM
389 file. pamtotiff also creates a grayscale file if it input is PPM
390 (color) or equivalent PAM, but there is only one color in the image.
391 If the input is a PPM (color) file and there are 256 colors or fewer,
393 but more than 1, pamtotiff generates a color palette TIFF file. If
394 there are more colors than that, pamtotiff generates an RGB (not RGBA)
395 single plane TIFF file. Use pnmtotiffcmyk to generate the cyan-
396 magenta-yellow-black ink color separation TIFF format.
397 The number of bits per sample in the TIFF output is determined by the
399 maxval of the Netpbm input. If the maxval is less than 256, the bits
400 per sample in the output is the smallest number that can encode the
401 maxval. If the maxval is greater than or equal to 256, there are 16
402 bits per sample in the output.
403 Extra Channels
406 Like most Netpbm programs, pamtotiff's function is mostly undefined if
407 the input is PAM image with tuple type other than BLACKANDWHITE,
408 GRAYSCALE, or RGB. Most of the statements in this manual assume the
409 input is not such an exotic PAM. But there is a little defined pro‐
410 cessing of other PAM subformats.
411 pamtotiff assumes any 1 plane PAM image is BLACKANDWHITE or GRAYSCALE
413 (and doesn't distinguish between those two).
414 pamtotiff assumes a PAM with more than 1 plane is of tuple type RGB
416 except with that number of planes instead of 3. pamtotiff doesn't
417 really understand red, green, and blue, so it has no trouble with a
418 2-component or 5-component color space. The TIFF format allows an
419 arbitrary number of color components, so pamtotiff simply maps the PAM
420 planes directly to TIFF color components. I don't know if the meanings
421 of 5 components in a TIFF image are standard at all, but the function
422 is there if you want to use it.
423 Note that pamtotiff may generate either a truecolor or colormapped
425 image with an arbitrary number of color components. In the truecolor
426 case, the raster has that number of planes. In the colormapped case,
427 the raster has of course 1 plane, but the color map has all the color
428 components in it.
429 The most common reason for a PAM to have extra planes is when the tuple
431 type is xxx_ALPHA, which means the highest numbered plane is a trans‐
432 parency plane (alpha channel). At least one user found that a TIFF
433 with an extra plane for transparency was useful.
434 Note that the grayscale detection works on N-component colors, so if
436 your planes aren't really color components, you'll want to disable this
437 via the -color option.
438 Multiple Passes
442 pamtotiff reads the input image once if it can, and otherwise twice.
443 It needs that second pass (which happens before the main pass, of
444 course) to analyze the colors in the image and generate a color map
445 (palette) and determine if the image is grayscale. So the second pass
446 happens only when the input is PPM. And you can avoid it then by spec‐
447 ifying both the -truecolor and -color options.
448 If the input image is small enough to fit in your system's file cache,
450 the second pass is very fast. If not, it requires reading from disk
451 twice, which can be slow.
452 When the input is from a file that cannot be rewound and reread, pamto‐
454 tiff reads the entire input image into a temporary file which can, and
455 works from that. Even if it needs only one pass.
456 Before Netpbm 9.21 (December 2001), pamtotiff always read the entire
458 image into virtual memory and then did one, two, or three passes
459 through the memory copy. The -truecolor and -color options did not
460 exist. The passes through memory would involve page faults if the
461 entire image did not fit into real memory. The image in memory
462 required considerably more memory (12 bytes per pixel) than the cached
463 file version of the image would.
464 Resolution
468 A Tiff image may contain information about the resolution of the image,
469 which means how big in real dimensions (centimeters, etc.) each pixel
470 in the raster is. That information is in the TIFF XRESOLUTION, YRESO‐
471 LUTION, and RESOLUTIONUNIT tags. By default, pamtotiff does not
472 include any tags of these types, but you can specify them with the
473 -tags option.
474 There are also options -xresolution, -yresolution, and -resolutionunit,
476 but those are obsolete. Before -tags existed (before Netpbm 10.31
477 (December 2005), they were the only way.
478 Note that the number of pixels in the image and how much information
480 each contains is determined independently from the setting of the reso‐
481 lution tags. The number of pixels in the output is the same as in the
482 input, and each pixel contains the same information. For your resolu‐
483 tion tags to be meaningful, they have to consistent with whatever cre‐
484 ated the PNM input. E.g. if a scanner turned a 10 centimeter wide
485 image into a 1000 pixel wide PNM image, then your horizontal resolution
486 is 100 pixels per centimeter, and if your XRESOLUTION tag says anything
487 else, something that prints your TIFF image won't print the proper 10
488 centimeter image.
489 The value of the XRESOLUTION tag is a floating point decimal number
491 that tells how many pixels there are per unit of distance in the hori‐
492 zontal direction. -yresolution is analogous for the vertical direc‐
493 tion.
494 The unit of distance is given by the value of the RESOLUTIONUNIT
496 option. That value is either INCH, CENTIMETER, or NONE. NONE means
497 the unit is arbitrary or unspecified. This could mean that the creator
498 and user of the image have a separate agreement as to what the unit is.
499 But usually, it just means that the horizontal and vertical resolution
500 values cannot be used for anything except to determine aspect ratio
501 (because even though the unit is arbitrary or unspecified, it has to be
502 the same for both resolution numbers).
503 If you don't use a -tag option to specify the resolution tag and use
505 the obsolete options instead, note the following:
506 · If you don't include an specify -xresolution, the Tiff image
510 does not contain horizontal resolution information. Likewise
511 for -yresolution. If you don't specify -resolutionunit, the
512 default is inches.
513 · Before Netpbm 10.16 (June 2003), -resolutionunit did not exist
516 and the resolution unit was always inches.
517
522 pamtotiff was originally pnmtotiff and did not handle PAM input. It
523 was extended and renamed in Netpbm 10.30 (October 2005).
524
528 tifftopnm(1), pnmtotiffcmyk(1), pamdepth(1), pamtopnm(1), pam(1)
529
532 Derived by Jef Poskanzer from ras2tiff.c, which is Copyright (c) 1990
533 by Sun Microsystems, Inc. Author: Patrick J. Naughton
534 (naughton@wind.sun.com).
535
537 This manual page was generated by the Netpbm tool 'makeman' from HTML
538 source. The master documentation is at
539 http://netpbm.sourceforge.net/doc/pamtotiff.html
541netpbm documentation 05 April 2017 Pamtotiff User Manual(0)