| '\" |
| '\" Copyright (c) 1994 The Australian National University |
| '\" Copyright (c) 1994-1997 Sun Microsystems, Inc. |
| '\" |
| '\" See the file "license.terms" for information on usage and redistribution |
| '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| '\" |
| '\" Author: Paul Mackerras (paulus@cs.anu.edu.au), |
| '\" Department of Computer Science, |
| '\" Australian National University. |
| '\" |
| '\" RCS: @(#) $Id: CrtPhImgFmt.3,v 1.5 2001/08/23 19:11:22 hobbs Exp $ |
| '\" |
| '\" The 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", |
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| '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| '\" needed; use .AS below instead) |
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| '\" .AS ?type? ?name? |
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| '\" name are examples of largest possible arguments that will be passed |
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| '\" of man pages. The first argument is ignored and used for recording |
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| '\" |
| '\" .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. |
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| '\" .UL arg1 arg2 |
| '\" Print arg1 underlined, then print arg2 normally. |
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| '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| '\" |
| '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| .if t .wh -1.3i ^B |
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| '\" # Start an argument description |
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| .ie !"\\$4"" .TP \\$4 |
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| .AS Tcl_Interp Tcl_CreateInterp in/out |
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| .SH "STANDARD OPTIONS" |
| .LP |
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| .ta 5.5c 11c |
| .ft B |
| .. |
| '\" # SE - end of list of standard options |
| .de SE |
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| .ft R |
| .LP |
| See the \\fBoptions\\fR manual entry for details on the standard options. |
| .. |
| '\" # OP - start of full description for a single option |
| .de OP |
| .LP |
| .nf |
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| Command-Line Name: \\fB\\$1\\fR |
| Database Name: \\fB\\$2\\fR |
| Database Class: \\fB\\$3\\fR |
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| \\$1\l'|0\(ul'\\$2 |
| .. |
| .TH Tk_CreatePhotoImageFormat 3 8.3 Tk "Tk Library Procedures" |
| .BS |
| .SH NAME |
| Tk_CreatePhotoImageFormat \- define new file format for photo images |
| .SH SYNOPSIS |
| .nf |
| \fB#include <tk.h>\fR |
| .sp |
| \fBTk_CreatePhotoImageFormat\fR(\fIformatPtr\fR) |
| .SH ARGUMENTS |
| .AS Tk_PhotoImageFormat *formatPtr |
| .AP Tk_PhotoImageFormat *formatPtr in |
| Structure that defines the new file format. |
| .BE |
| |
| .SH DESCRIPTION |
| .PP |
| \fBTk_CreatePhotoImageFormat\fR is invoked to define a new file format |
| for image data for use with photo images. The code that implements an |
| image file format is called an image file format handler, or |
| handler for short. The photo image code |
| maintains a list of handlers that can be used to read and |
| write data to or from a file. Some handlers may also |
| support reading image data from a string or converting image data to a |
| string format. |
| The user can specify which handler to use with the \fB\-format\fR |
| image configuration option or the \fB\-format\fR option to the |
| \fBread\fR and \fBwrite\fR photo image subcommands. |
| .PP |
| An image file format handler consists of a collection of procedures |
| plus a Tk_PhotoImageFormat structure, which contains the name of the |
| image file format and pointers to six procedures provided by the |
| handler to deal with files and strings in this format. The |
| Tk_PhotoImageFormat structure contains the following fields: |
| .CS |
| typedef struct Tk_PhotoImageFormat { |
| char *\fIname\fR; |
| Tk_ImageFileMatchProc *\fIfileMatchProc\fR; |
| Tk_ImageStringMatchProc *\fIstringMatchProc\fR; |
| Tk_ImageFileReadProc *\fIfileReadProc\fR; |
| Tk_ImageStringReadProc *\fIstringReadProc\fR; |
| Tk_ImageFileWriteProc *\fIfileWriteProc\fR; |
| Tk_ImageStringWriteProc *\fIstringWriteProc\fR; |
| } Tk_PhotoImageFormat; |
| .CE |
| .PP |
| The handler need not provide implementations of all six procedures. |
| For example, the procedures that handle string data would not be |
| provided for a format in which the image data are stored in binary, |
| and could therefore contain null characters. If any procedure is not |
| implemented, the corresponding pointer in the Tk_PhotoImageFormat |
| structure should be set to NULL. The handler must provide the |
| \fIfileMatchProc\fR procedure if it provides the \fIfileReadProc\fR |
| procedure, and the \fIstringMatchProc\fR procedure if it provides the |
| \fIstringReadProc\fR procedure. |
| |
| .SH PORTABILITY |
| .PP |
| In Tk 8.2 and earlier, a different interface was used. Tk 8.3 will |
| still support the old format handlers if the format name is in upper |
| case. If you still want to compile old format handlers with Tk8.3, |
| use the flag -DUSE_OLD_IMAGE. This will restore all function prototypes |
| to match the pre-8.3 situation. |
| |
| .SH NAME |
| .PP |
| \fIformatPtr->name\fR provides a name for the image type. |
| Once \fBTk_CreatePhotoImageFormat\fR returns, this name may be used |
| in the \fB\-format\fR photo image configuration and subcommand option. |
| The manual page for the photo image (photo(n)) describes how image |
| file formats are chosen based on their names and the value given to |
| the \fB\-format\fR option. For new format handlers, the name should |
| be in lower case. Pre-8.3 format handlers are assumed to be in |
| upper case. |
| |
| .SH FILEMATCHPROC |
| \fIformatPtr->fileMatchProc\fR provides the address of a procedure for |
| Tk to call when it is searching for an image file format handler |
| suitable for reading data in a given file. |
| \fIformatPtr->fileMatchProc\fR must match the following prototype: |
| .CS |
| typedef int Tk_ImageFileMatchProc( |
| Tcl_Channel \fIchan\fR, |
| CONST char *\fIfileName\fR, |
| Tcl_Obj *\fIformat\fR, |
| int *\fIwidthPtr\fR, |
| int *\fIheightPtr\fR, |
| Tcl_Interp *\fIinterp\fR); |
| .CE |
| The \fIfileName\fR argument is the name of the file containing the |
| image data, which is open for reading as \fIchan\fR. The |
| \fIformat\fR argument contains the value given for the |
| \fB\-format\fR option, or NULL if the option was not specified. |
| If the data in the file appears to be in the format supported by this |
| handler, the \fIformatPtr->fileMatchProc\fR procedure should store the |
| width and height of the image in *\fIwidthPtr\fR and *\fIheightPtr\fR |
| respectively, and return 1. Otherwise it should return 0. |
| |
| .SH STRINGMATCHPROC |
| \fIformatPtr->stringMatchProc\fR provides the address of a procedure for |
| Tk to call when it is searching for an image file format handler for |
| suitable for reading data from a given string. |
| \fIformatPtr->stringMatchProc\fR must match the following prototype: |
| .CS |
| typedef int Tk_ImageStringMatchProc( |
| Tcl_Obj *\fIdata\fR, |
| Tcl_Obj *\fIformat\fR, |
| int *\fIwidthPtr\fR, |
| int *\fIheightPtr\fR, |
| Tcl_Interp *\fIinterp\fR); |
| .CE |
| The \fIdata\fR argument points to the object containing the image |
| data. The \fIformat\fR argument contains the value given for |
| the \fB\-format\fR option, or NULL if the option was not specified. |
| If the data in the string appears to be in the format supported by |
| this handler, the \fIformatPtr->stringMatchProc\fR procedure should |
| store the width and height of the image in *\fIwidthPtr\fR and |
| *\fIheightPtr\fR respectively, and return 1. Otherwise it should |
| return 0. |
| |
| .SH FILEREADPROC |
| \fIformatPtr->fileReadProc\fR provides the address of a procedure for |
| Tk to call to read data from an image file into a photo image. |
| \fIformatPtr->fileReadProc\fR must match the following prototype: |
| .CS |
| typedef int Tk_ImageFileReadProc( |
| Tcl_Interp *\fIinterp\fR, |
| Tcl_Channel \fIchan\fR, |
| CONST char *\fIfileName\fR, |
| Tcl_Obj *\fIformat\fR, |
| PhotoHandle \fIimageHandle\fR, |
| int \fIdestX\fR, int \fIdestY\fR, |
| int \fIwidth\fR, int \fIheight\fR, |
| int \fIsrcX\fR, int \fIsrcY\fR); |
| .CE |
| The \fIinterp\fR argument is the interpreter in which the command was |
| invoked to read the image; it should be used for reporting errors. |
| The image data is in the file named \fIfileName\fR, which is open for |
| reading as \fIchan\fR. The \fIformat\fR argument contains the |
| value given for the \fB\-format\fR option, or NULL if the option was |
| not specified. The image data in the file, or a subimage of it, is to |
| be read into the photo image identified by the handle |
| \fIimageHandle\fR. The subimage of the data in the file is of |
| dimensions \fIwidth\fR x \fIheight\fR and has its top-left corner at |
| coordinates (\fIsrcX\fR,\fIsrcY\fR). It is to be stored in the photo |
| image with its top-left corner at coordinates |
| (\fIdestX\fR,\fIdestY\fR) using the \fBTk_PhotoPutBlock\fR procedure. |
| The return value is a standard Tcl return value. |
| |
| .SH STRINGREADPROC |
| \fIformatPtr->stringReadProc\fR provides the address of a procedure for |
| Tk to call to read data from a string into a photo image. |
| \fIformatPtr->stringReadProc\fR must match the following prototype: |
| .CS |
| typedef int Tk_ImageStringReadProc( |
| Tcl_Interp *\fIinterp\fR, |
| Tcl_Obj *\fIdata\fR, |
| Tcl_Obj *\fIformat\fR, |
| PhotoHandle \fIimageHandle\fR, |
| int \fIdestX\fR, int \fIdestY\fR, |
| int \fIwidth\fR, int \fIheight\fR, |
| int \fIsrcX\fR, int \fIsrcY\fR); |
| .CE |
| The \fIinterp\fR argument is the interpreter in which the command was |
| invoked to read the image; it should be used for reporting errors. |
| The \fIdata\fR argument points to the image data in object form. |
| The \fIformat\fR argument contains the |
| value given for the \fB\-format\fR option, or NULL if the option was |
| not specified. The image data in the string, or a subimage of it, is to |
| be read into the photo image identified by the handle |
| \fIimageHandle\fR. The subimage of the data in the string is of |
| dimensions \fIwidth\fR x \fIheight\fR and has its top-left corner at |
| coordinates (\fIsrcX\fR,\fIsrcY\fR). It is to be stored in the photo |
| image with its top-left corner at coordinates |
| (\fIdestX\fR,\fIdestY\fR) using the \fBTk_PhotoPutBlock\fR procedure. |
| The return value is a standard Tcl return value. |
| |
| .SH FILEWRITEPROC |
| \fIformatPtr->fileWriteProc\fR provides the address of a procedure for |
| Tk to call to write data from a photo image to a file. |
| \fIformatPtr->fileWriteProc\fR must match the following prototype: |
| .CS |
| typedef int Tk_ImageFileWriteProc( |
| Tcl_Interp *\fIinterp\fR, |
| CONST char *\fIfileName\fR, |
| Tcl_Obj *\fIformat\fR, |
| Tk_PhotoImageBlock *\fIblockPtr\fR); |
| .CE |
| The \fIinterp\fR argument is the interpreter in which the command was |
| invoked to write the image; it should be used for reporting errors. |
| The image data to be written are in memory and are described by the |
| Tk_PhotoImageBlock structure pointed to by \fIblockPtr\fR; see the |
| manual page FindPhoto(3) for details. The \fIfileName\fR argument |
| points to the string giving the name of the file in which to write the |
| image data. The \fIformat\fR argument contains the |
| value given for the \fB\-format\fR option, or NULL if the option was |
| not specified. The format string can contain extra characters |
| after the name of the format. If appropriate, the |
| \fIformatPtr->fileWriteProc\fR procedure may interpret these |
| characters to specify further details about the image file. |
| The return value is a standard Tcl return value. |
| |
| .SH STRINGWRITEPROC |
| \fIformatPtr->stringWriteProc\fR provides the address of a procedure for |
| Tk to call to translate image data from a photo image into a string. |
| \fIformatPtr->stringWriteProc\fR must match the following prototype: |
| .CS |
| typedef int Tk_ImageStringWriteProc( |
| Tcl_Interp *\fIinterp\fR, |
| Tcl_Obj *\fIformat\fR, |
| Tk_PhotoImageBlock *\fIblockPtr\fR); |
| .CE |
| The \fIinterp\fR argument is the interpreter in which the command was |
| invoked to convert the image; it should be used for reporting errors. |
| The image data to be converted are in memory and are described by the |
| Tk_PhotoImageBlock structure pointed to by \fIblockPtr\fR; see the |
| manual page FindPhoto(3) for details. The data for the string |
| should be put in the interpreter \fIinterp\fR result. |
| The \fIformat\fR argument contains the |
| value given for the \fB\-format\fR option, or NULL if the option was |
| not specified. The format string can contain extra characters |
| after the name of the format. If appropriate, the |
| \fIformatPtr->stringWriteProc\fR procedure may interpret these |
| characters to specify further details about the image file. |
| The return value is a standard Tcl return value. |
| |
| .SH "SEE ALSO" |
| Tk_FindPhoto, Tk_PhotoPutBlock |
| |
| .SH KEYWORDS |
| photo image, image file |