1Pamtotiff User Manual(0) Pamtotiff User Manual(0)
2
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 In addition to the options common to all programs based on libnetpbm
142 (most notably -quiet, see
143 Common Options ⟨index.html#commonoptions⟩ ), pamtotiff recognizes the
144 following command line options:
145 Compression
148 By default, pamtotiff creates a TIFF file with no compression. This is
149 your best bet most of the time. If you want to try another compression
150 scheme or tweak some of the other even more obscure output options,
151 there are a number of options which to play.
152 Before Netpbm 8.4 (April 2000), the default was to use LZW compression.
154 But then new releases of the TIFF library started omitting the LZW com‐
155 pression capability because of concern about patents on LZW. So since
156 then, the default has been no compression. The LZW patents have now
157 expired and new TIFF libraries do LZW, but the pamtotiff behavior
158 remains the same for compatibility with older TIFF libraries and appli‐
159 cations of pamtotiff.
160 The -none, -packbits, -lzw, -g3, -g4, -flate, and -adobeflate options
162 are used to override the default and set the compression scheme used in
163 creating the output file.
164 The -predictor option is meaningful only with LZW compression: a pre‐
166 dictor value of 2 causes each scanline of the output image to undergo
167 horizontal differencing before it is encoded; a value of 1 forces each
168 scanline to be encoded without differencing. By default, pamtotiff
169 creates a TIFF file with msb-to-lsb fill order. The -msb2lsb and
170 -lsb2msb options are used to override the default and set the fill
171 order used in creating the file.
172 With some older TIFF libraries, -lzw doesn't work because the TIFF
174 library doesn't do LZW compression. This is because of concerns about
175 Unisys's patent on LZW which was then in force. Actually, with very
176 old TIFF libraries, -lzw works because no distributors of the TIFF
177 library were sensitive yet to the patent issue.
178 -flate chooses "flate" compression, which is the patent-free compres‐
180 sion common in the Unix world implemented by the "Z" library. It is
181 what the PNG format uses.
182 Fax Compression
184 If you have bilevel data (e.g. PBM), you can generate a TIFF that uses
186 the same compression scheme specified for use by fax machines. See the
187 Fax Format(1) page for more information on these compression schemes.
188 These formats all relate to ITU Group 3 and Group 4 fax machine stan‐
190 dards.
191 The -g3 option chooses MH or MR compression: MR with the additional
193 option -2d; MH without it. -g4 selects MMR. The option names are a
194 little unfortunate and historical, but are consistent with the TIFF
195 specification.
196 MMR has a better compression ratio than the other two.
198 -fill specifies that for MH or MR compression, each encoded scanline
200 shall be zero-filled to a byte boundary.
201 -2d and -fill are meaningful only with -g3.
203 Fill Order
207 The -msb2lsb and lsb2msb options control the fill order.
208 The fill order is the order in which pixels are packed into a byte in
210 the Tiff raster, in the case that there are multiple pixels per byte.
211 msb-to-lsb means that the leftmost columns go into the most significant
212 bits of the byte in the Tiff image. However, there is considerable
213 confusion about the meaning of fill order. Some believe it means
214 whether 16 bit sample values in the Tiff image are little-endian or
215 big-endian. This is totally erroneous (The endianness of integers in a
216 Tiff image is designated by the image's magic number). However,
217 ImageMagick and older Netpbm both have been known to implement that
218 interpretation. 2001.09.06.
219 If the image does not have sub-byte pixels, these options have no
221 effect other than to set the value of the FILLORDER tag in the Tiff
222 image (which may be useful for those programs that misinterpret the tag
223 with reference to 16 bit samples).
224 Color Space
227 -color tells pamtotiff to produce a color, as opposed to grayscale,
228 TIFF image if the input is PPM, even if it contains only shades of
229 gray. Without this option, pamtotiff produces a grayscale TIFF image
230 if the input is PPM and contains only shades of gray, and at most 256
231 shades. Otherwise, it produces a color TIFF output. For PBM and PGM
232 input, pamtotiff always produces grayscale TIFF output and this option
233 has no effect.
234 The -color option can prevent pamtotiff from making two passes through
236 the input file, thus improving speed and memory usage. See Multiple
237 Passes ⟨#multipass⟩ .
238 -truecolor tells pamtotiff to produce the 24-bit RGB form of TIFF out‐
240 put if it is producing a color TIFF image. Without this option, pamto‐
241 tiff produces a colormapped (paletted) TIFF image unless there are more
242 than 256 colors (and in the latter case, issues a warning).
243 The -truecolor option can prevent pamtotiff from making two passes
245 through the input file, thus improving speed and memory usage. See
246 Multiple Passes ⟨#multipass⟩ .
247 The -color and -truecolor options did not exist before Netpbm 9.21
249 (December 2001).
250 If pamtotiff produces a grayscale TIFF image, this option has no
252 effect.
253 The -minisblack and -miniswhite options force the output image to have
255 a "minimum is black" or "minimum is white" photometric, respectively.
256 If you don't specify either, pamtotiff uses minimum is black except
257 when using Group 3 or Group 4 compression, in which case pamtotiff fol‐
258 lows CCITT fax standards and uses "minimum is white." This usually
259 results in better compression and is generally preferred for bilevel
260 coding. These photometrics are for grayscale images, so these options
261 are invalid if the image is color (but only if it is truly color; they
262 are valid with, for example, a PPM image that contains only shades of
263 gray).
264 Before Netpbm 9.11 (February 200)1, pamtotiff always produced "minimum
266 is black," because of a bug. In either case, pamtotiff sets the photo‐
267 metric interpretation tag in the TIFF output according to which photo‐
268 metric is actually used.
269 Before Netpbm 10.78 (March 2017), pamtotiff respected -miniswhite and
271 -minisblack even with color images, producing invalid TIFF images that
272 have the indicated photometric but red, green, and blue raster planes.
273 The -indexbits option is meaningful only for a colormapped (paletted)
275 image. In this kind of image, the raster contains values which are
276 indexes into a table of colors, with the indexes normally taking less
277 space that the color description in the table. pamtotiff can generate
278 indexes of 1, 2, 4, or 8 bits. By default, it will use 8, because many
279 programs that interpret TIFF images can't handle any other width.
280 But if you have a small number of colors, you can make your image con‐
282 siderably smaller by allowing fewer than 8 bits per index, using the
283 -indexbits option. The value is a comma-separated list of the bit
284 widths you allow. pamtotiff chooses the smallest width you allow that
285 allows it to index the entire color table. If you don't allow any such
286 width, pamtotiff fails. Normally, the only useful value for this
287 option is 1,2,4,8, because a program either understands the 8 bit width
288 (default) or understands them all.
289 In a Baseline TIFF image, according to the 1992 TIFF 6.0 specification,
291 4 and 8 are the only valid widths. There are no formal standards that
292 allow any other values.
293 This option was added in June 2002. Before that, only 8 bit indices
295 were possible.
296 Extra Tags
299 There are lots of tag types in the TIFF format that don't correspond to
300 any information in the PNM format or to anything in the conversion
301 process. For example, a TIFF_ARTIST tag names the artist who created
302 the image.
303 You can tell pamtotiff explicitly to include tags such as this in its
305 output with the -tag option. You identify a list of tag types and val‐
306 ues and pamtotiff includes a tag in the output for each item in your
307 list.
308 The value of -tag is the list of tags, like this example:
310 -tag=subfiletype=reducedimage,documentname=Fred,xposition=25
312 As you see, it is a list of tag specifications separated by commas.
314 Each tag specification is a name and a value separated by an equal
315 sign. The name is the name of the tag type, except in arbitrary
316 upper/lower case. One place to see the names of TIFF tag types is in
317 the TIFF library's tiff.h file, where there is a macro defined for each
318 consisting of "TIFF_" plus the name. E.g. for the SUBFILETYPE tag
319 type, there is a macro TIFF_SUBFILETYPE.
320 The format of the value specification for a tag (stuff after the equal
322 sign) depends upon what kind of value the tag type has:
323 · Integer: a decimal number
327 · Floating point number: a decimal number
330 · String: a string
333 · Enumerated (For example, a 'subfiletype' tag takes an enumerated
336 value. Its possible values are REDUCEDIMAGE, PAGE, and MASK.):
337 The name of the value. You can see the possible value names in
338 the TIFF library's tiff.h file, where there is a macro defined
339 for each consisting of a qualifier plus the value name. E.g.
340 for the REDUCEDIMAGE value of a SUBFILETYPE tag, you see the
341 macro FILETYPE_REDUCEDIMAGE.
342 The TIFF format assigns a unique number to each enumerated value
344 and you can specify that number, in decimal, as an alternative.
345 This is useful if you are using an extension of TIFF that pamto‐
346 tiff doesn't know about.
347 If you specify a tag type with -tag that is not independent of the con‐
351 tent of your PNM source image and pamtotiff's conversion process (i.e.
352 a tag type in which pamtotiff is interested), pamtotiff fails. For
353 example, you cannot specify an IMAGEWIDTH tag with -tag, because pamto‐
354 tiff generates an IMAGEWIDTH tag that gives the actual width of the
355 image.
356 -tag was new in Netpbm 10.31 (December 2005).
358 Output
361 See The Output File ⟨#output⟩ .
362 -output names the output file. Without this option pamtotiff writes to
364 Standard Output.
365 The -append option tells pamtotiff only to append to the file named by
367 output; not create it. Without this option, the program creates the
368 file it does not already exist. But even then, if the file does
369 already exist, the program appends the image to what is in the file
370 already. (A TIFF file may contain multiple images).
371 -append has no effect if you don't also specify -output.
373 Before Netpbm 10.67 (June 2014), -append means something rather differ‐
375 ent: it means to append the image to the output TIFF file (which is
376 always Standard Output in 10.67) instead of replacing its contents.
377 -append was new in Netpbm 10.27 (March 2005).
379 Other
384 You can use the -rowsperstrip option to set the number of rows (scan‐
385 lines) in each strip of data in the output file. By default, the out‐
386 put file has the number of rows per strip set to a value that will
387 ensure each strip is no more than 8 kilobytes long.
388
392 There are myriad variations of the TIFF format, and this program gener‐
393 ates only a few of them. pamtotiff creates a grayscale TIFF file if
394 its input is a PBM (monochrome) or PGM (grayscale) or equivalent PAM
395 file. pamtotiff also creates a grayscale file if it input is PPM
396 (color) or equivalent PAM, but there is only one color in the image.
397 If the input is a PPM (color) file and there are 256 colors or fewer,
399 but more than 1, pamtotiff generates a color palette TIFF file. If
400 there are more colors than that, pamtotiff generates an RGB (not RGBA)
401 single plane TIFF file. Use pnmtotiffcmyk to generate the cyan-
402 magenta-yellow-black ink color separation TIFF format.
403 The number of bits per sample in the TIFF output is determined by the
405 maxval of the Netpbm input. If the maxval is less than 256, the bits
406 per sample in the output is the smallest number that can encode the
407 maxval. If the maxval is greater than or equal to 256, there are 16
408 bits per sample in the output.
409 Extra Channels
412 Like most Netpbm programs, pamtotiff's function is mostly undefined if
413 the input is PAM image with tuple type other than BLACKANDWHITE,
414 GRAYSCALE, or RGB. Most of the statements in this manual assume the
415 input is not such an exotic PAM. But there is a little defined pro‐
416 cessing of other PAM subformats.
417 pamtotiff assumes any 1 plane PAM image is BLACKANDWHITE or GRAYSCALE
419 (and doesn't distinguish between those two).
420 pamtotiff assumes a PAM with more than 1 plane is of tuple type RGB
422 except with that number of planes instead of 3. pamtotiff doesn't
423 really understand red, green, and blue, so it has no trouble with a
424 2-component or 5-component color space. The TIFF format allows an
425 arbitrary number of color components, so pamtotiff simply maps the PAM
426 planes directly to TIFF color components. I don't know if the meanings
427 of 5 components in a TIFF image are standard at all, but the function
428 is there if you want to use it.
429 Note that pamtotiff may generate either a truecolor or colormapped
431 image with an arbitrary number of color components. In the truecolor
432 case, the raster has that number of planes. In the colormapped case,
433 the raster has of course 1 plane, but the color map has all the color
434 components in it.
435 The most common reason for a PAM to have extra planes is when the tuple
437 type is xxx_ALPHA, which means the highest numbered plane is a trans‐
438 parency plane (alpha channel). At least one user found that a TIFF
439 with an extra plane for transparency was useful.
440 Note that the grayscale detection works on N-component colors, so if
442 your planes aren't really color components, you'll want to disable this
443 via the -color option.
444 Multiple Passes
448 pamtotiff reads the input image once if it can, and otherwise twice.
449 It needs that second pass (which happens before the main pass, of
450 course) to analyze the colors in the image and generate a color map
451 (palette) and determine if the image is grayscale. So the second pass
452 happens only when the input is PPM. And you can avoid it then by spec‐
453 ifying both the -truecolor and -color options.
454 If the input image is small enough to fit in your system's file cache,
456 the second pass is very fast. If not, it requires reading from disk
457 twice, which can be slow.
458 When the input is from a file that cannot be rewound and reread, pamto‐
460 tiff reads the entire input image into a temporary file which can, and
461 works from that. Even if it needs only one pass.
462 Before Netpbm 9.21 (December 2001), pamtotiff always read the entire
464 image into virtual memory and then did one, two, or three passes
465 through the memory copy. The -truecolor and -color options did not
466 exist. The passes through memory would involve page faults if the
467 entire image did not fit into real memory. The image in memory
468 required considerably more memory (12 bytes per pixel) than the cached
469 file version of the image would.
470 Resolution
474 A Tiff image may contain information about the resolution of the image,
475 which means how big in real dimensions (centimeters, etc.) each pixel
476 in the raster is. That information is in the TIFF XRESOLUTION, YRESO‐
477 LUTION, and RESOLUTIONUNIT tags. By default, pamtotiff does not
478 include any tags of these types, but you can specify them with the
479 -tags option.
480 There are also options -xresolution, -yresolution, and -resolutionunit,
482 but those are obsolete. Before -tags existed (before Netpbm 10.31
483 (December 2005), they were the only way.
484 Note that the number of pixels in the image and how much information
486 each contains is determined independently from the setting of the reso‐
487 lution tags. The number of pixels in the output is the same as in the
488 input, and each pixel contains the same information. For your resolu‐
489 tion tags to be meaningful, they have to consistent with whatever cre‐
490 ated the PNM input. E.g. if a scanner turned a 10 centimeter wide
491 image into a 1000 pixel wide PNM image, then your horizontal resolution
492 is 100 pixels per centimeter, and if your XRESOLUTION tag says anything
493 else, something that prints your TIFF image won't print the proper 10
494 centimeter image.
495 The value of the XRESOLUTION tag is a floating point decimal number
497 that tells how many pixels there are per unit of distance in the hori‐
498 zontal direction. -yresolution is analogous for the vertical direc‐
499 tion.
500 The unit of distance is given by the value of the RESOLUTIONUNIT
502 option. That value is either INCH, CENTIMETER, or NONE. NONE means
503 the unit is arbitrary or unspecified. This could mean that the creator
504 and user of the image have a separate agreement as to what the unit is.
505 But usually, it just means that the horizontal and vertical resolution
506 values cannot be used for anything except to determine aspect ratio
507 (because even though the unit is arbitrary or unspecified, it has to be
508 the same for both resolution numbers).
509 If you don't use a -tag option to specify the resolution tag and use
511 the obsolete options instead, note the following:
512 · If you don't include an specify -xresolution, the Tiff image
516 does not contain horizontal resolution information. Likewise
517 for -yresolution. If you don't specify -resolutionunit, the
518 default is inches.
519 · Before Netpbm 10.16 (June 2003), -resolutionunit did not exist
522 and the resolution unit was always inches.
523
528 pamtotiff was originally pnmtotiff and did not handle PAM input. It
529 was extended and renamed in Netpbm 10.30 (October 2005).
530
534 tifftopnm(1), pnmtotiffcmyk(1), pamdepth(1), pamtopnm(1), pam(1)
535
538 Derived by Jef Poskanzer from ras2tiff.c, which is Copyright (c) 1990
539 by Sun Microsystems, Inc. Author: Patrick J. Naughton
540 (naughton@wind.sun.com).
541
543 This manual page was generated by the Netpbm tool 'makeman' from HTML
544 source. The master documentation is at
545 http://netpbm.sourceforge.net/doc/pamtotiff.html
547netpbm documentation 05 April 2017 Pamtotiff User Manual(0)