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author | rjohnson <rjohnson> | 1998-04-01 09:37:39 (GMT) |
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committer | rjohnson <rjohnson> | 1998-04-01 09:37:39 (GMT) |
commit | 13242623d2ff3ea02ab6a62bfb48a7dbb5c27e22 (patch) | |
tree | 3100714738a7941b590efee466a774862f9671c3 /doc/GetBitmap.3 | |
parent | e4ab1102029f9ac557ff190bfb9d34408340f345 (diff) | |
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diff --git a/doc/GetBitmap.3 b/doc/GetBitmap.3 new file mode 100644 index 0000000..efe7760 --- /dev/null +++ b/doc/GetBitmap.3 @@ -0,0 +1,266 @@ +'\" +'\" 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: @(#) GetBitmap.3 1.27 97/08/22 18:52:11 +'\" +.so man.macros +.TH Tk_GetBitmap 3 8.0 Tk "Tk Library Procedures" +.BS +.SH NAME +Tk_GetBitmap, Tk_DefineBitmap, Tk_NameOfBitmap, Tk_SizeOfBitmap, Tk_FreeBitmap, Tk_GetBitmapFromData \- maintain database of single-plane pixmaps +.SH SYNOPSIS +.nf +\fB#include <tk.h>\fR +.sp +Pixmap +\fBTk_GetBitmap(\fIinterp, tkwin, id\fB)\fR +.sp +int +\fBTk_DefineBitmap(\fIinterp, nameId, source, width, height\fB)\fR +.sp +Tk_Uid +\fBTk_NameOfBitmap(\fIdisplay, bitmap\fB)\fR +.sp +\fBTk_SizeOfBitmap(\fIdisplay, bitmap, widthPtr, heightPtr\fB)\fR +.sp +\fBTk_FreeBitmap(\fIdisplay, bitmap\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 bitmap will be used. +.AP Tk_Uid id in +Description of bitmap; see below for possible values. +.AP Tk_Uid nameId in +Name for new bitmap to be defined. +.AP char *source in +Data for bitmap, in standard bitmap format. +Must be stored in static memory whose value will never change. +.AP "int" width in +Width of bitmap. +.AP "int" height in +Height of bitmap. +.AP "int" *widthPtr out +Pointer to word to fill in with \fIbitmap\fR's width. +.AP "int" *heightPtr out +Pointer to word to fill in with \fIbitmap\fR's height. +.AP Display *display in +Display for which \fIbitmap\fR was allocated. +.AP Pixmap bitmap in +Identifier for a bitmap allocated by \fBTk_GetBitmap\fR. +.BE + +.SH DESCRIPTION +.PP +These procedures manage a collection of bitmaps (one-plane pixmaps) +being used by an application. The procedures allow bitmaps to be +re-used efficiently, thereby avoiding server overhead, and also +allow bitmaps to be named with character strings. +.PP +\fBTk_GetBitmap\fR takes as argument a Tk_Uid describing a bitmap. +It returns a Pixmap identifier for a bitmap corresponding to the +description. It re-uses an existing bitmap, if possible, and +creates a new one otherwise. At present, \fIid\fR must have +one of the following forms: +.TP 20 +\fB@\fIfileName\fR +\fIFileName\fR must be the name of a file containing a bitmap +description in the standard X11 or X10 format. +.TP 20 +\fIname\fR +\fIName\fR must be the name of a bitmap defined previously with +a call to \fBTk_DefineBitmap\fR. The following names are pre-defined +by Tk: +.RS +.TP 12 +\fBerror\fR +The international "don't" symbol: a circle with a diagonal line +across it. +.VS "" br +.TP 12 +\fBgray75\fR +75% gray: a checkerboard pattern where three out of four bits are on. +.VE +.TP 12 +\fBgray50\fR +50% gray: a checkerboard pattern where every other bit is on. +.VS "" br +.TP 12 +\fBgray25\fR +25% gray: a checkerboard pattern where one out of every four bits is on. +.VE +.TP 12 +\fBgray12\fR +12.5% gray: a pattern where one-eighth of the bits are on, consisting of +every fourth pixel in every other row. +.TP 12 +\fBhourglass\fR +An hourglass symbol. +.TP 12 +\fBinfo\fR +A large letter ``i''. +.TP 12 +\fBquesthead\fR +The silhouette of a human head, with a question mark in it. +.TP 12 +\fBquestion\fR +A large question-mark. +.TP 12 +\fBwarning\fR +A large exclamation point. +.PP +In addition, the following pre-defined names are available only on the +\fBMacintosh\fR platform: +.TP 12 +\fBdocument\fR +A generic document. +.TP 12 +\fBstationery\fR +Document stationery. +.TP 12 +\fBedition\fR +The \fIedition\fR symbol. +.TP 12 +\fBapplication\fR +Generic application icon. +.TP 12 +\fBaccessory\fR +A desk accessory. +.TP 12 +\fBfolder\fR +Generic folder icon. +.TP 12 +\fBpfolder\fR +A locked folder. +.TP 12 +\fBtrash\fR +A trash can. +.TP 12 +\fBfloppy\fR +A floppy disk. +.TP 12 +\fBramdisk\fR +A floppy disk with chip. +.TP 12 +\fBcdrom\fR +A cd disk icon. +.TP 12 +\fBpreferences\fR +A folder with prefs symbol. +.TP 12 +\fBquerydoc\fR +A database document icon. +.TP 12 +\fBstop\fR +A stop sign. +.TP 12 +\fBnote\fR +A face with ballon words. +.TP 12 +\fBcaution\fR +A triangle with an exclamation point. +.RE +.LP +Under normal conditions, \fBTk_GetBitmap\fR +returns an identifier for the requested bitmap. If an error +occurs in creating the bitmap, such as when \fIid\fR refers +to a non-existent file, then \fBNone\fR is returned and an error +message is left in \fIinterp->result\fR. +.PP +\fBTk_DefineBitmap\fR associates a name with +in-memory bitmap data so that the name can be used in later +calls to \fBTk_GetBitmap\fR. The \fInameId\fR +argument gives a name for the bitmap; it must not previously +have been used in a call to \fBTk_DefineBitmap\fR. +The arguments \fIsource\fR, \fIwidth\fR, and \fIheight\fR +describe the bitmap. +\fBTk_DefineBitmap\fR normally returns TCL_OK; if an error occurs +(e.g. a bitmap named \fInameId\fR has already been defined) then +TCL_ERROR is returned and an error message is left in +\fIinterp->result\fR. +Note: \fBTk_DefineBitmap\fR expects the memory pointed to by +\fIsource\fR to be static: \fBTk_DefineBitmap\fR doesn't make +a private copy of this memory, but uses the bytes pointed to +by \fIsource\fR later in calls to \fBTk_GetBitmap\fR. +.PP +Typically \fBTk_DefineBitmap\fR is used by \fB#include\fR-ing a +bitmap file directly into a C program and then referencing +the variables defined by the file. +For example, suppose there exists a file \fBstip.bitmap\fR, +which was created by the \fBbitmap\fR program and contains +a stipple pattern. +The following code uses \fBTk_DefineBitmap\fR to define a +new bitmap named \fBfoo\fR: +.CS +Pixmap bitmap; +#include "stip.bitmap" +Tk_DefineBitmap(interp, Tk_GetUid("foo"), stip_bits, + stip_width, stip_height); +\&... +bitmap = Tk_GetBitmap(interp, tkwin, Tk_GetUid("foo")); +.CE +This code causes the bitmap file to be read +at compile-time and incorporates the bitmap information into +the program's executable image. The same bitmap file could be +read at run-time using \fBTk_GetBitmap\fR: +.CS +Pixmap bitmap; +bitmap = Tk_GetBitmap(interp, tkwin, Tk_GetUid("@stip.bitmap")); +.CE +The second form is a bit more flexible (the file could be modified +after the program has been compiled, or a different string could be +provided to read a different file), but it is a little slower and +requires the bitmap file to exist separately from the program. +.PP +\fBTk_GetBitmap\fR maintains a +database of all the bitmaps that are currently in use. +Whenever possible, it will return an existing bitmap rather +than creating a new one. +This approach can substantially reduce server overhead, so +\fBTk_GetBitmap\fR should generally be used in preference to Xlib +procedures like \fBXReadBitmapFile\fR. +.PP +The bitmaps returned by \fBTk_GetBitmap\fR +are shared, so callers should never modify them. +If a bitmap must be modified dynamically, then it should be +created by calling Xlib procedures such as \fBXReadBitmapFile\fR +or \fBXCreatePixmap\fR directly. +.PP +The procedure \fBTk_NameOfBitmap\fR is roughly the inverse of +\fBTk_GetBitmap\fR. +Given an X Pixmap argument, it returns the \fIid\fR that was +passed to \fBTk_GetBitmap\fR when the bitmap was created. +\fIBitmap\fR must have been the return value from a previous +call to \fBTk_GetBitmap\fR. +.PP +\fBTk_SizeOfBitmap\fR returns the dimensions of its \fIbitmap\fR +argument in the words pointed to by the \fIwidthPtr\fR and +\fIheightPtr\fR arguments. As with \fBTk_NameOfBitmap\fR, +\fIbitmap\fR must have been created by \fBTk_GetBitmap\fR. +.PP +When a bitmap returned by \fBTk_GetBitmap\fR +is no longer needed, \fBTk_FreeBitmap\fR should be called to release it. +There should be exactly one call to \fBTk_FreeBitmap\fR for +each call to \fBTk_GetBitmap\fR. +When a bitmap is no longer in use anywhere (i.e. it has been freed as +many times as it has been gotten) \fBTk_FreeBitmap\fR will release +it to the X server and delete it from the database. + +.SH BUGS +In determining whether an existing bitmap can be used to satisfy +a new request, \fBTk_GetBitmap\fR +considers only the immediate value of its \fIid\fR argument. For +example, when a file name is passed to \fBTk_GetBitmap\fR, +\fBTk_GetBitmap\fR will assume it is safe to re-use an existing +bitmap 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. + +.SH KEYWORDS +bitmap, pixmap |