'\" '\" Generated from file 'png\&.man' by tcllib/doctools with format 'nroff' '\" Copyright (c) 2004, Code: Aaron Faupell '\" Copyright (c) 2004, Doc: Andreas Kupries '\" .TH "png" 3tcl 0\&.3 tcllib "Image manipulation" .\" The -*- nroff -*- definitions below are for supplemental macros used .\" in Tcl/Tk manual entries. .\" .\" .AP type name in/out ?indent? .\" Start paragraph describing an argument to a library procedure. .\" type is type of argument (int, etc.), in/out is either "in", "out", .\" or "in/out" to describe whether procedure reads or modifies arg, .\" and indent is equivalent to second arg of .IP (shouldn't ever be .\" needed; use .AS below instead) .\" .\" .AS ?type? ?name? .\" Give maximum sizes of arguments for setting tab stops. Type and .\" name are examples of largest possible arguments that will be passed .\" to .AP later. If args are omitted, default tab stops are used. .\" .\" .BS .\" Start box enclosure. From here until next .BE, everything will be .\" enclosed in one large box. .\" .\" .BE .\" End of box enclosure. .\" .\" .CS .\" Begin code excerpt. .\" .\" .CE .\" End code excerpt. .\" .\" .VS ?version? ?br? .\" Begin vertical sidebar, for use in marking newly-changed parts .\" of man pages. The first argument is ignored and used for recording .\" the version when the .VS was added, so that the sidebars can be .\" found and removed when they reach a certain age. If another argument .\" is present, then a line break is forced before starting the sidebar. .\" .\" .VE .\" End of vertical sidebar. .\" .\" .DS .\" Begin an indented unfilled display. .\" .\" .DE .\" End of indented unfilled display. .\" .\" .SO ?manpage? .\" Start of list of standard options for a Tk widget. The manpage .\" argument defines where to look up the standard options; if .\" omitted, defaults to "options". The options follow on successive .\" lines, in three columns separated by tabs. .\" .\" .SE .\" End of list of standard options for a Tk widget. .\" .\" .OP cmdName dbName dbClass .\" Start of description of a specific option. cmdName gives the .\" option's name as specified in the class command, dbName gives .\" the option's name in the option database, and dbClass gives .\" the option's class in the option database. .\" .\" .UL arg1 arg2 .\" Print arg1 underlined, then print arg2 normally. .\" .\" .QW arg1 ?arg2? .\" Print arg1 in quotes, then arg2 normally (for trailing punctuation). .\" .\" .PQ arg1 ?arg2? .\" Print an open parenthesis, arg1 in quotes, then arg2 normally .\" (for trailing punctuation) and then a closing parenthesis. .\" .\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b .\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ta \\n()Au \\n()Bu .ie !"\\$3"" \{\ \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. .\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out .\" # BS - start boxed text .\" # ^y = starting y location .\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. .\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. .\" # VS - start vertical sidebar .\" # ^Y = starting y location .\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$2"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. .\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. .\" # Special macro to handle page bottom: finish off current .\" # box/sidebar if in box/sidebar mode, then invoked standard .\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. .\" # DS - begin display .de DS .RS .nf .sp .. .\" # DE - end display .de DE .fi .RE .sp .. .\" # SO - start of list of standard options .de SO 'ie '\\$1'' .ds So \\fBoptions\\fR 'el .ds So \\fB\\$1\\fR .SH "STANDARD OPTIONS" .LP .nf .ta 5.5c 11c .ft B .. .\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\*(So manual entry for details on the standard options. .. .\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. .\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. .\" # CE - end code excerpt .de CE .fi .RE .. .\" # UL - underline word .de UL \\$1\l'|0\(ul'\\$2 .. .\" # QW - apply quotation marks to word .de QW .ie '\\*(lq'"' ``\\$1''\\$2 .\"" fix emacs highlighting .el \\*(lq\\$1\\*(rq\\$2 .. .\" # PQ - apply parens and quotation marks to word .de PQ .ie '\\*(lq'"' (``\\$1''\\$2)\\$3 .\"" fix emacs highlighting .el (\\*(lq\\$1\\*(rq\\$2)\\$3 .. .\" # QR - quoted range .de QR .ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3 .\"" fix emacs highlighting .el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3 .. .\" # MT - "empty" string .de MT .QW "" .. .BS .SH NAME png \- PNG querying and manipulation of meta data .SH SYNOPSIS package require \fBTcl 8\&.2\fR .sp package require \fBcrc32 \fR .sp package require \fBpng ?0\&.3?\fR .sp \fB::png::validate\fR \fIfile\fR .sp \fB::png::isPNG\fR \fIfile\fR .sp \fB::png::imageInfo\fR \fIfile\fR .sp \fB::png::getTimestamp\fR \fIfile\fR .sp \fB::png::setTimestamp\fR \fIfile\fR \fItime\fR .sp \fB::png::getComments\fR \fIfile\fR .sp \fB::png::removeComments\fR \fIfile\fR .sp \fB::png::addComment\fR \fIfile\fR \fIkeyword\fR \fItext\fR .sp \fB::png::addComment\fR \fIfile\fR \fIkeyword\fR \fIlang\fR \fIkeyword2\fR \fItext\fR .sp \fB::png::getPixelDimension\fR \fIfile\fR .sp \fB::png::image\fR \fIfile\fR .sp \fB::png::write\fR \fIfile\fR \fIdata\fR .sp .BE .SH DESCRIPTION .PP This package provides commands to query and modify PNG images\&. PNG stands for \fIPortable Network Graphics\fR and is specified at \fIhttp://www\&.libpng\&.org/pub/png/spec/1\&.2\fR\&. .SH COMMANDS .TP \fB::png::validate\fR \fIfile\fR Returns a value indicating if \fIfile\fR is a valid PNG file\&. The file is checked for PNG signature, each chunks checksum is verified, existence of a data chunk is verified, first chunk is checked for header, last chunk is checked for ending\&. Things \fInot\fR checked for are: validity of values within a chunk, multiple header chunks, noncontiguous data chunks, end chunk before actual eof\&. This procedure can take lots of time\&. .sp Possible return values: .RS .TP OK File is a valid PNG file\&. .TP SIG no/broken PNG signature\&. .TP BADLEN corrupt chunk length\&. .TP EOF premature end of file\&. .TP NOHDR missing header chunk\&. .TP CKSUM crc mismatch\&. .TP NODATA missing data chunk(s)\&. .TP NOEND missing end marker\&. .RE .TP \fB::png::isPNG\fR \fIfile\fR Returns a boolean value indicating if the file \fIfile\fR starts with a PNG signature\&. This is a much faster and less intensive check than \fB::png::validate\fR as it does not check if the PNG data is valid\&. .TP \fB::png::imageInfo\fR \fIfile\fR Returns a dictionary with keys \fBwidth\fR, \fBheight\fR, \fBdepth\fR, \fBcolor\fR, \fBcompression\fR, \fBfilter\fR, and \fBinterlace\fR\&. The values are the associated properties of the PNG image in \fIfile\fR\&. Throws an error if file is not a PNG image, or if the checksum of the header is invalid\&. For information on interpreting the values for the returned properties see \fIhttp://www\&.libpng\&.org/pub/png/spec/1\&.2/PNG-Chunks\&.html\fR\&. .TP \fB::png::getTimestamp\fR \fIfile\fR Returns the epoch time if a timestamp chunk is found in the PNG image contained in the \fIfile\fR, otherwise returns the empty string\&. Does not attempt to verify the checksum of the timestamp chunk\&. Throws an error if the \fIfile\fR is not a valid PNG image\&. .TP \fB::png::setTimestamp\fR \fIfile\fR \fItime\fR Writes a new timestamp to the \fIfile\fR, either replacing the old timestamp, or adding one just before the data chunks if there was no previous timestamp\&. \fItime\fR is the new time in the gmt epoch format\&. Throws an error if \fIfile\fR is not a valid PNG image\&. .TP \fB::png::getComments\fR \fIfile\fR Currently supports only uncompressed comments\&. Does not attempt to verify the checksums of the comment chunks\&. Returns a list where each element is a comment\&. Each comment is itself a list\&. The list for a plain text comment consists of 2 elements: the human readable keyword, and the text data\&. A unicode (international) comment consists of 4 elements: the human readable keyword, the language identifier, the translated keyword, and the unicode text data\&. Throws an error if \fIfile\fR is not a valid PNG image\&. .TP \fB::png::removeComments\fR \fIfile\fR Removes all comments from the PNG image in \fIfile\fR\&. Beware - This uses memory equal to the file size minus comments, to hold the intermediate result\&. Throws an error if \fIfile\fR is not a valid PNG image\&. .TP \fB::png::addComment\fR \fIfile\fR \fIkeyword\fR \fItext\fR Adds a plain \fItext\fR comment to the PNG image in \fIfile\fR, just before the first data chunk\&. Will throw an error if no data chunk is found\&. \fIkeyword\fR has to be less than 80 characters long to conform to the PNG specification\&. .TP \fB::png::addComment\fR \fIfile\fR \fIkeyword\fR \fIlang\fR \fIkeyword2\fR \fItext\fR Adds a unicode (international) comment to the PNG image in \fIfile\fR, just before the first data chunk\&. Will throw an error if no data chunk is found\&. \fIkeyword\fR has to be less than 80 characters long to conform to the PNG specification\&. \fIkeyword2\fR is the translated \fIkeyword\fR, in the language specified by the language identifier \fIlang\fR\&. .TP \fB::png::getPixelDimension\fR \fIfile\fR Returns a dictionary with keys \fBppux\fR, \fBppuy\fR and \fBunit\fR if the information is present\&. Otherwise, it returns the empty string\&. .sp The values of \fBppux\fR and \fBppuy\fR return the pixel per unit value in X or Y direction\&. .sp The allowed values for key \fBunit\fR are \fBmeter\fR and \fBunknown\fR\&. In the case of meter, the dpi value can be calculated by multiplying with the conversion factor \fB0\&.0254\fR\&. .TP \fB::png::image\fR \fIfile\fR Given a PNG file returns the image in the list of scanlines format used by Tk_GetColor\&. .TP \fB::png::write\fR \fIfile\fR \fIdata\fR Takes a list of scanlines in the Tk_GetColor format and writes the represented image to \fIfile\fR\&. .PP .SH "BUGS, IDEAS, FEEDBACK" This document, and the package it describes, will undoubtedly contain bugs and other problems\&. Please report such in the category \fIpng\fR of the \fITcllib Trackers\fR [http://core\&.tcl\&.tk/tcllib/reportlist]\&. Please also report any ideas for enhancements you may have for either package and/or documentation\&. .PP When proposing code changes, please provide \fIunified diffs\fR, i\&.e the output of \fBdiff -u\fR\&. .PP Note further that \fIattachments\fR are strongly preferred over inlined patches\&. Attachments can be made by going to the \fBEdit\fR form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar\&. .SH KEYWORDS comment, image, png, timestamp .SH CATEGORY File formats .SH COPYRIGHT .nf Copyright (c) 2004, Code: Aaron Faupell Copyright (c) 2004, Doc: Andreas Kupries .fi