#  Copyright (c) 1990-1993 The Regents of the University of California.
#  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.
#
#

=head1 NAME

Tk_WindowId, Tk_Parent, Tk_Display, Tk_DisplayName, Tk_ScreenNumber, Tk_Screen, Tk_X, Tk_Y, Tk_Width, Tk_Height, Tk_Changes, Tk_Attributes, Tk_IsMapped, Tk_IsTopLevel, Tk_ReqWidth, Tk_ReqHeight, Tk_InternalBorderWidth, Tk_Visual, Tk_Depth, Tk_Colormap  - retrieve information from Tk's local data structure

=for category C Programming

=head1 SYNOPSIS

B<#include E<lt>tk.hE<gt>>

Window
B<Tk_WindowId>(I<tkwin>)

Tk_Window
B<Tk_Parent>(I<tkwin>)

Display *
B<Tk_Display>(I<tkwin>)

char *
B<Tk_DisplayName>(I<tkwin>)

int
B<Tk_ScreenNumber>(I<tkwin>)

Screen *
B<Tk_Screen>(I<tkwin>)

int
B<Tk_X>(I<tkwin>)

int
B<Tk_Y>(I<tkwin>)

int
B<Tk_Width>(I<tkwin>)

int
B<Tk_Height>(I<tkwin>)

XWindowChanges *
B<Tk_Changes>(I<tkwin>)

XSetWindowAttributes *
B<Tk_Attributes>(I<tkwin>)

int
B<Tk_IsMapped>(I<tkwin>)

int
B<Tk_IsTopLevel>(I<tkwin>)

int
B<Tk_ReqWidth>(I<tkwin>)

int
B<Tk_ReqHeight>(I<tkwin>)

int
B<Tk_InternalBorderWidth>(I<tkwin>)

Visual *
B<Tk_Visual>(I<tkwin>)

int
B<Tk_Depth>(I<tkwin>)

Colormap
B<Tk_Colormap>(I<tkwin>)

=head1 ARGUMENTS

=over 4

=item Tk_Window tkwin (in)

Token for window.

=back

=head1 DESCRIPTION

B<Tk_WindowID> and the other names listed above are
all macros that return fields from Tk's local data structure
for I<tkwin>.  None of these macros requires any
interaction with the server;  it is safe to assume that
all are fast.

B<Tk_WindowId> returns the X identifier for I<tkwin>,
or B<NULL> if no X window has been created for I<tkwin>
yet.

B<Tk_Parent> returns Tk's token for the logical parent of
I<tkwin>.  The parent is the token that was specified when
I<tkwin> was created, or NULL for main windows.

B<Tk_Display> returns a pointer to the Xlib display structure
corresponding to I<tkwin>.  B<Tk_DisplayName> returns an
ASCII string identifying I<tkwin>'s display.  B<Tk_ScreenNumber>
returns the index of I<tkwin>'s screen among all the screens
of I<tkwin>'s display.  B<Tk_Screen> returns a pointer to
the Xlib structure corresponding to I<tkwin>'s screen.

B<Tk_X>, B<Tk_Y>, B<Tk_Width>, and B<Tk_Height>
return information about I<tkwin's> location within its
parent and its size.  The location information refers to the
upper-left pixel in the window, or its border if there is one.
The width and height information refers to the interior size
of the window, not including any border.  B<Tk_Changes>
returns a pointer to a structure containing all of the above
information plus a few other fields.  B<Tk_Attributes>
returns a pointer to an XSetWindowAttributes structure describing
all of the attributes of the I<tkwin>'s window, such as background
pixmap, event mask, and so on (Tk keeps track of all this information
as it is changed by the application).  Note: it is essential that
applications use Tk procedures like B<Tk_ResizeWindow> instead
of X procedures like B<XResizeWindow>, so that Tk can keep its
data structures up-to-date.

B<Tk_IsMapped> returns a non-zero value if I<tkwin>
is mapped and zero if I<tkwin> isn't mapped.

B<Tk_IsTopLevel> returns a non-zero value if I<tkwin>
is a top-level window (its X parent is the root window of the
screen) and zero if I<tkwin> isn't a top-level window.

B<Tk_ReqWidth> and B<Tk_ReqHeight> return information about
the window's requested size.  These values correspond to the last
call to B<Tk_GeometryRequest> for I<tkwin>.

B<Tk_InternalBorderWidth> returns the width of internal border
that has been requested for I<tkwin>, or 0 if no internal border
was requested.  The return value is simply the last value passed
to B<Tk_SetInternalBorder> for I<tkwin>.

B<Tk_Visual>, B<Tk_Depth>, and B<Tk_Colormap> return
information about the visual characteristics of a window.
B<Tk_Visual> returns the visual type for
the window, B<Tk_Depth> returns the number of bits per pixel,
and B<Tk_Colormap> returns the current
colormap for the window.  The visual characteristics are
normally set from the defaults for the window's screen, but
they may be overridden by calling B<Tk_SetWindowVisual>.

=head1 KEYWORDS

attributes, colormap, depth, display, height, geometry manager,
identifier, mapped, requested size, screen, top-level,
visual, width, window, x, y