1 files changed, 74 insertions, 0 deletions
diff --git a/doc/GetGC.3 b/doc/GetGC.3
new file mode 100644
index 0000000..6908e9d
--- /dev/null
+++ b/doc/GetGC.3
@@ -0,0 +1,74 @@
+'\"
+'\" 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: @(#) GetGC.3 1.11 96/03/26 18:10:14
+'\" 
+.so man.macros
+.TH Tk_GetGC 3 "" Tk "Tk Library Procedures"
+.BS
+.SH NAME
+Tk_GetGC, Tk_FreeGC \- maintain database of read-only graphics contexts
+.SH SYNOPSIS
+.nf
+\fB#include <tk.h>\fR
+.sp
+GC
+\fBTk_GetGC\fR(\fItkwin, valueMask, valuePtr\fR)
+.sp
+\fBTk_FreeGC(\fIdisplay, gc\fR)
+.SH ARGUMENTS
+.AS "unsigned long" valueMask
+.AP Tk_Window tkwin in
+Token for window in which the graphics context will be used.
+.AP "unsigned long" valueMask in
+Mask of bits (such as \fBGCForeground\fR or \fBGCStipple\fR)
+indicating which fields of \fI*valuePtr\fR are valid.
+.AP XGCValues *valuePtr in
+Pointer to structure describing the desired values for the
+graphics context.
+.AP Display *display in
+Display for which \fIgc\fR was allocated.
+.AP GC gc in
+X identifier for graphics context that is no longer needed.
+Must have been allocated by \fBTk_GetGC\fR.
+.BE
+
+.SH DESCRIPTION
+.PP
+\fBTk_GetGC\fR and \fBTk_FreeGC\fR manage a collection of graphics contexts
+being used by an application.  The procedures allow graphics contexts to be
+shared, thereby avoiding the server overhead that would be incurred
+if a separate GC were created for each use.  \fBTk_GetGC\fR takes arguments
+describing the desired graphics context and returns an X identifier
+for a GC that fits the description.  The graphics context that is returned
+will have default values in all of the fields not specified explicitly
+by \fIvalueMask\fR and \fIvaluePtr\fR.
+.PP
+\fBTk_GetGC\fR maintains a
+database of all the graphics contexts it has created.  Whenever possible,
+a call to \fBTk_GetGC\fR will
+return an existing graphics context rather than creating a new one.  This
+approach can substantially reduce server overhead, so \fBTk_GetGC\fR
+should generally be used in preference to the Xlib procedure
+\fBXCreateGC\fR, which creates a new graphics context on each call.
+.PP
+Since the return values of \fBTk_GetGC\fR
+are shared, callers should never modify the graphics contexts
+returned by \fBTk_GetGC\fR.
+If a graphics context must be modified dynamically, then it should be
+created by calling \fBXCreateGC\fR instead of \fBTk_GetGC\fR.
+.PP
+When a graphics context
+is no longer needed, \fBTk_FreeGC\fR should be called to release it.
+There should be exactly one call to \fBTk_FreeGC\fR for
+each call to \fBTk_GetGC\fR.
+When a graphics context is no longer in use anywhere (i.e. it has
+been freed as many times as it has been gotten) \fBTk_FreeGC\fR
+will release it to the X server and delete it from the database.
+
+.SH KEYWORDS
+graphics context