'\" '\" Copyright (c) 1990 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" SCCS: @(#) GetCursor.3 1.23 96/08/27 13:21:26 '\" '\" 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", '\" 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 '\" Start of list of standard options for a Tk widget. The '\" options follow on successive lines, in four 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. '\" '\" SCCS: @(#) man.macros 1.9 97/08/22 18:50:59 '\" '\" # 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 .\} .ie !"\\$3"" \{\ .ta \\n()Au \\n()Bu \&\\$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 .SH "STANDARD OPTIONS" .LP .nf .ta 4c 8c 12c .ft B .. '\" # SE - end of list of standard options .de SE .fi .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 .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 .. .de UL \\$1\l'|0\(ul'\\$2 .. .TH Tk_GetCursor 3 4.1 Tk "Tk Library Procedures" .BS .SH NAME Tk_GetCursor, Tk_GetCursorFromData, Tk_NameOfCursor, Tk_FreeCursor \- maintain database of cursors .SH SYNOPSIS .nf \fB#include \fR .sp Tk_Cursor \fBTk_GetCursor(\fIinterp, tkwin, nameId\fB)\fR .sp Tk_Cursor \fBTk_GetCursorFromData(\fIinterp, tkwin, source, mask, width, height, xHot, yHot, fg, bg\fB)\fR .sp char * \fBTk_NameOfCursor(\fIdisplay, cursor\fB)\fR .sp \fBTk_FreeCursor(\fIdisplay, cursor\fB)\fR .SH ARGUMENTS .AS "unsigned long" *pixelPtr .AP Tcl_Interp *interp in Interpreter to use for error reporting. .AP Tk_Window tkwin in Token for window in which the cursor will be used. .AP Tk_Uid nameId in Description of cursor; see below for possible values. .AP char *source in Data for cursor bitmap, in standard bitmap format. .AP char *mask in Data for mask bitmap, in standard bitmap format. .AP "int" width in Width of \fIsource\fR and \fImask\fR. .AP "int" height in Height of \fIsource\fR and \fImask\fR. .AP "int" xHot in X-location of cursor hot-spot. .AP "int" yHot in Y-location of cursor hot-spot. .AP Tk_Uid fg in Textual description of foreground color for cursor. .AP Tk_Uid bg in Textual description of background color for cursor. .AP Display *display in Display for which \fIcursor\fR was allocated. .AP Tk_Cursor cursor in Opaque Tk identifier for cursor. If passed to\fBTk_FreeCursor\fR, must have been returned by some previous call to \fBTk_GetCursor\fR or \fBTk_GetCursorFromData\fR. .BE .SH DESCRIPTION .PP These procedures manage a collection of cursors being used by an application. The procedures allow cursors to be re-used efficiently, thereby avoiding server overhead, and also allow cursors to be named with character strings (actually Tk_Uids). .PP \fBTk_GetCursor\fR takes as argument a Tk_Uid describing a cursor, and returns an opaque Tk identifier for a cursor corresponding to the description. It re-uses an existing cursor if possible and creates a new one otherwise. \fINameId\fR must be a standard Tcl list with one of the following forms: .TP \fIname\fR\0[\fIfgColor\fR\0[\fIbgColor\fR]] \fIName\fR is the name of a cursor in the standard X cursor font, i.e., any of the names defined in \fBcursorfont.h\fR, without the \fBXC_\fR. Some example values are \fBX_cursor\fR, \fBhand2\fR, or \fBleft_ptr\fR. Appendix B of ``The X Window System'' by Scheifler & Gettys has illustrations showing what each of these cursors looks like. If \fIfgColor\fR and \fIbgColor\fR are both specified, they give the foreground and background colors to use for the cursor (any of the forms acceptable to \fBTk_GetColor\fR may be used). If only \fIfgColor\fR is specified, then there will be no background color: the background will be transparent. If no colors are specified, then the cursor will use black for its foreground color and white for its background color. The Macintosh version of Tk also supports all of the X cursors. Tk on the Mac will also accept any of the standard Mac cursors including \fBibeam\fR, \fBcrosshair\fR, \fBwatch\fR, \fBplus\fR, and \fBarrow\fR. In addition, Tk will load Macintosh cursor resources of the types \fBcrsr\fR (color) and \fBCURS\fR (black and white) by the name of the of the resource. The application and all its open dynamic library's resource files will be searched for the named cursor. If there are conflicts color cursors will always be loaded in preference to black and white cursors. .TP \fB@\fIsourceName\0maskName\0fgColor\0bgColor\fR In this form, \fIsourceName\fR and \fImaskName\fR are the names of files describing bitmaps for the cursor's source bits and mask. Each file must be in standard X11 or X10 bitmap format. \fIFgColor\fR and \fIbgColor\fR indicate the colors to use for the cursor, in any of the forms acceptable to \fBTk_GetColor\fR. This form of the command will not work on Macintosh or Windows computers. .TP \fB@\fIsourceName\0fgColor\fR This form is similar to the one above, except that the source is used as mask also. This means that the cursor's background is transparent. This form of the command will not work on Macintosh or Windows computers. .PP \fBTk_GetCursorFromData\fR allows cursors to be created from in-memory descriptions of their source and mask bitmaps. \fISource\fR points to standard bitmap data for the cursor's source bits, and \fImask\fR points to standard bitmap data describing which pixels of \fIsource\fR are to be drawn and which are to be considered transparent. \fIWidth\fR and \fIheight\fR give the dimensions of the cursor, \fIxHot\fR and \fIyHot\fR indicate the location of the cursor's hot-spot (the point that is reported when an event occurs), and \fIfg\fR and \fIbg\fR describe the cursor's foreground and background colors textually (any of the forms suitable for \fBTk_GetColor\fR may be used). Typically, the arguments to \fBTk_GetCursorFromData\fR are created by including a cursor file directly into the source code for a program, as in the following example: .CS Tk_Cursor cursor; #include "source.cursor" #include "mask.cursor" cursor = Tk_GetCursorFromData(interp, tkwin, source_bits, mask_bits, source_width, source_height, source_x_hot, source_y_hot, Tk_GetUid("red"), Tk_GetUid("blue")); .CE .PP Under normal conditions, \fBTk_GetCursor\fR and \fBTk_GetCursorFromData\fR will return an identifier for the requested cursor. If an error occurs in creating the cursor, such as when \fInameId\fR refers to a non-existent file, then \fBNone\fR is returned and an error message will be stored in \fIinterp->result\fR. .PP \fBTk_GetCursor\fR and \fBTk_GetCursorFromData\fR maintain a database of all the cursors they have created. Whenever possible, a call to \fBTk_GetCursor\fR or \fBTk_GetCursorFromData\fR will return an existing cursor rather than creating a new one. This approach can substantially reduce server overhead, so the Tk procedures should generally be used in preference to Xlib procedures like \fBXCreateFontCursor\fR or \fBXCreatePixmapCursor\fR, which create a new cursor on each call. .PP The procedure \fBTk_NameOfCursor\fR is roughly the inverse of \fBTk_GetCursor\fR. If its \fIcursor\fR argument was created by \fBTk_GetCursor\fR, then the return value is the \fInameId\fR argument that was passed to \fBTk_GetCursor\fR to create the cursor. If \fIcursor\fR was created by a call to \fBTk_GetCursorFromData\fR, or by any other mechanism, then the return value is a hexadecimal string giving the X identifier for the cursor. Note: the string returned by \fBTk_NameOfCursor\fR is only guaranteed to persist until the next call to \fBTk_NameOfCursor\fR. Also, this call is not portable except for cursors returned by \fBTk_GetCursor\fR. .PP When a cursor returned by \fBTk_GetCursor\fR or \fBTk_GetCursorFromData\fR is no longer needed, \fBTk_FreeCursor\fR should be called to release it. There should be exactly one call to \fBTk_FreeCursor\fR for each call to \fBTk_GetCursor\fR or \fBTk_GetCursorFromData\fR. When a cursor is no longer in use anywhere (i.e. it has been freed as many times as it has been gotten) \fBTk_FreeCursor\fR will release it to the X server and remove it from the database. .SH BUGS In determining whether an existing cursor can be used to satisfy a new request, \fBTk_GetCursor\fR and \fBTk_GetCursorFromData\fR consider only the immediate values of their arguments. For example, when a file name is passed to \fBTk_GetCursor\fR, \fBTk_GetCursor\fR will assume it is safe to re-use an existing cursor created from the same file name: it will not check to see whether the file itself has changed, or whether the current directory has changed, thereby causing the name to refer to a different file. Similarly, \fBTk_GetCursorFromData\fR assumes that if the same \fIsource\fR pointer is used in two different calls, then the pointers refer to the same data; it does not check to see if the actual data values have changed. .SH KEYWORDS cursor