1\ 2.\" This man page was generated by the Netpbm tool 'makeman' from HTML source. 3.\" Do not hand-hack it! If you have bug fixes or improvements, please find 4.\" the corresponding HTML page on the Netpbm website, generate a patch 5.\" against that, and send it to the Netpbm maintainer. 6.TH "Xwdtopnm User Manual" 0 "8 January 2010" "netpbm documentation" 7 8.SH NAME 9xwdtopnm - convert an X11 or X10 window dump file to a PNM image 10 11.UN synopsis 12.SH SYNOPSIS 13 14\fBxwdtopnm\fP 15[\fB-verbose\fP] 16[\fB-headerdump\fP] 17[\fIxwdfile\fP] 18 19.UN description 20.SH DESCRIPTION 21.PP 22This program is part of 23.BR "Netpbm" (1)\c 24\&. 25.PP 26\fBxwdtopnm\fP reads an X11 or X10 window dump file as input and 27produces a PNM image as output. The type of the output image depends 28on the input file - if it's black and white, the output is PBM. If 29it's grayscale, the output is PGM. Otherwise, it's PPM. The program 30tells you which type it is writing. 31.PP 32Using this program, you can convert anything you can display on an 33X workstation's screen into a PNM image. Just display whatever you're 34interested in, run the \fBxwd\fP program to capture the contents of 35the window, run it through \fBxwdtopnm\fP, and then use \fBpamcut\fP 36to select the part you want. 37.PP 38Note that a pseudocolor XWD image (typically what you get when you 39make a dump of a pseudocolor X window) has maxval 65535, which means 40the PNM file that \fBxwdtopnm\fP generates has maxval 65535. Many 41older image processing programs (that aren't part of the Netpbm 42package and don't use the Netpbm programming library) don't know how 43to handle a PNM image with maxval greater than 255 (because there are 44two bytes instead of one for each sample in the image). So you may 45want to run the output of \fBxwdtopnm\fP through \fBpamdepth\fP 46before feeding it to one of these old programs. 47.PP 48\fBxwdtopnm\fP can't convert every kind of XWD image (which essentially 49means it can't convert an XWD created from every kind of X display 50configuration). In particular, it cannot convert one with more than 24 bits 51per pixel. 52 53 54.UN options 55.SH OPTIONS 56 57 58.TP 59\fB-verbose\fP 60This option causes \fBxwdtopnm\fP to display handy information about the 61input image and the conversion process 62 63.TP 64\fB-headerdump\fP 65This option causes \fBxwdtopnm\fP to display the contents of the 66X11 header. It has no effect when the input is X10. This option was 67new in Netpbm 10.26 (December 2004). 68 69 70 71.UN notes 72.SH NOTES 73 74.UN twobytesamples 75.SS Two Byte Samples 76.PP 77\fBxwdtopnm\fP sometimes produces output with a maxval greater than 255, 78which means the maximum value of a sample (one intensity value, e.g. the 79red component of a pixel) is greater than 255 and therefore each sample 80takes 2 bytes to represent. This can be a problem because some programs 81expect those bytes in a different order from what the Netpbm format specs 82say, which is what \fBxwdtopnm\fP produces, which means they will see totally 83different colors that they should. \fBxv\fP is one such program. 84.PP 85If this is a problem (e.g. you want to look at the output of \fBxwdtopnm\fP 86with \fBxv\fP), there are two ways to fix it: 87 88 89.IP \(bu 90Pass the output through \fBpamendian\fP to produce the format the 91program expects. 92.IP \(bu 93Pass the output through \fBpamdepth\fP to reduce the maxval below 256 94so there is only one byte per sample. 95 96.PP 97Often, there is no good reason to have a maxval greater than 255. It 98happens because in XWD, byte not PNM, each color component of a pixel can have 99different resolution, for example 5 bits for blue (maxval 31), 5 bits for red 100(maxval 31), and 6 bits for green (maxval 63), for a total of 16 bits per 101pixel. In order to reproduce the colors as closely as possible, 102\fBxwdtopnm\fP has to use a large maxval. In this example, it would use 10331 * 63 = 1953, and use 48 bits per pixel. 104.PP 105Because this is a common and frustrating problem when using \fBxwdtopnm\fP, 106the program issues a warning whenever it generates output with two byte 107samples. You can quiet this warning with the \fB-quiet\fP 108.UR index.html#commonoptions 109common option 110.UE 111\&. The warning was new in Netpbm 10.46 112(March 2009). 113 114 115.UN seealso 116.SH SEE ALSO 117.BR "pnmtoxwd" (1)\c 118\&, 119.BR "pamendian" (1)\c 120\&, 121.BR "pamdepth" (1)\c 122\&, 123.BR "pnm" (5)\c 124\&, 125\fBxwd\fP man page 126 127.UN author 128.SH AUTHOR 129 130Copyright (C) 1989, 1991 by Jef Poskanzer. 131.SH DOCUMENT SOURCE 132This manual page was generated by the Netpbm tool 'makeman' from HTML 133source. The master documentation is at 134.IP 135.B http://netpbm.sourceforge.net/doc/xwdtopnm.html 136.PP