tk4.2 C API - CrtWindow






NAME

     Tk_CreateWindow, Tk_CreateWindowFromPath,  Tk_DestroyWindow,
     Tk_MakeWindowExist - create or delete window


SYNOPSIS

     #include <tk.h>

     Tk_Window
     Tk_CreateWindow(interp, parent, name, topLevScreen)

     Tk_Window
     Tk_CreateWindowFromPath(interp, tkwin, pathName, topLevScreen)

     Tk_DestroyWindow(tkwin)

     Tk_MakeWindowExist(tkwin)


ARGUMENTS

     Tcl_Interp   *interp         (out)     Tcl  interpreter   to
                                            use for error report-
                                            ing.   If  no   error
                                            occurs,  then *interp
                                            isn't modified.

     Tk_Window    parent          (in)      Token for the  window
                                            that  is  to serve as
                                            the logical parent of
                                            the new window.

     char         *name           (in)      Name to use for  this
                                            window.     Must   be
                                            unique   among    all
                                            children  of the same
                                            parent.

     char         *topLevScreen   (in)      Has  same  format  as
                                            screenName.  If NULL,
                                            then  new  window  is
                                            created  as an inter-
                                            nal window.  If  non-
                                            NULL,  new  window is
                                            created  as  a   top-
                                            level    window    on
                                            screen  topLevScreen.
                                            If topLevScreen is an
                                            empty  string  (``'')
                                            then  new  window  is
                                            created as  top-level
                                            window   of  parent's
                                            screen.

     Tk_Window    tkwin           (in)      Token for window.

     char         *pathName       (in)      Name of  new  window,
                                            specified   as   path
                                            name within  applica-
                                            tion (e.g. .a.b.c).





DESCRIPTION

     The procedures Tk_CreateWindow  and  Tk_CreateWindowFromPath  |
     are  used to create new windows for use in Tk-based applica-  |
     tions.  Each of the procedures returns a token that  can  be  |
     used  to  manipulate  the  window  in  other calls to the Tk  |
     library.  If the window couldn't  be  created  successfully,  |
     then NULL is returned and interp->result is modified to hold  |
     an error message.                                             |

     Tk supports two different kinds of windows:   internal  win-  |
     dows  and top-level windows.  An internal window is an inte-
     rior window of a Tk application, such as a scrollbar or menu
     bar or button.  A top-level window is one that is created as
     a child of a screen's root window, rather than as  an  inte-
     rior  window,  but  which is logically part of some existing
     main window.  Examples of top-level windows are pop-up menus
     and dialog boxes.

     New windows may be created by calling  Tk_CreateWindow.   If
     the  topLevScreen argument is NULL, then the new window will
     be an internal window.  If topLevScreen  is  non-NULL,  then
     the  new  window  will  be  a top-level window: topLevScreen
     indicates the name of a screen and the new  window  will  be
     created  as  a child of the root window of topLevScreen.  In
     either case Tk will consider the new window to be the  logi-
     cal  child  of  parent:   the  new  window's  path name will
     reflect this fact, options may be specified for the new win-
     dow  under  this assumption, and so on.  The only difference
     is that new X window for a top-level window will  not  be  a
     child of parent's X window.  For example, a pull-down menu's
     parent would be the button-like window used  to  invoke  it,
     which  would  in  turn be a child of the menu bar window.  A
     dialog box might have the application's main window  as  its
     parent.

     Tk_CreateWindowFromPath offers an alternate way of  specify-
     ing  new windows.  In Tk_CreateWindowFromPath the new window
     is specified with a token  for  any  window  in  the  target
     application  (tkwin),  plus  a path name for the new window.
     It produces the same effect as  Tk_CreateWindow  and  allows
     both top-level and internal windows to be created, depending
     on   the   value   of    topLevScreen.     In    calls    to
     Tk_CreateWindowFromPath, as in calls to Tk_CreateWindow, the
     parent of the new window must exist at the time of the call,
     but the new window must not already exist.

     The window creation procedures don't actually issue the com-
     mand  to X to create a window.  Instead, they create a local
     data structure associated with  the  window  and  defer  the
     creation  of  the  X  window.   The  window will actually be
     created by the first call to Tk_MapWindow.  Deferred  window
     creation  allows  various aspects of the window (such as its
     size, background color, etc.) to be modified after its crea-
     tion  without  incurring any overhead in the X server.  When
     the window is finally mapped all of  the  window  attributes
     can be set while creating the window.

     The value returned by a window-creation procedure is not the
     X  token  for  the  window (it can't be, since X hasn't been
     asked to create the window yet).  Instead, it is a token for
     Tk's  local  data  structure for the window.  Most of the Tk
     library procedures take  Tk_Window  tokens,  rather  than  X
     identifiers.    The   actual  X  window  identifier  can  be
     retrieved  from  the  local   data   structure   using   the
     Tk_WindowId macro;  see the manual entry for Tk_WindowId for
     details.

     Tk_DestroyWindow deletes a window and all  the  data  struc-
     tures  associated  with  it,  including  any  event handlers
     created   with    Tk_CreateEventHandler.     In    addition,
     Tk_DestroyWindow  will  delete  any children of tkwin recur-
     sively (where children are defined in the Tk sense, consist-
     ing  of  all windows that were created with the given window
     as parent).  If tkwin was created by Tk_CreateInternalWindow
     then event handlers interested in destroy events are invoked
     immediately.  If tkwin is a top-level or main  window,  then
     the  event  handlers will be invoked later, after X has seen
     the request and returned an event for it.

     If a window has been created but hasn't been mapped, so no X
     window exists, it is possible to force the creation of the X
     window by calling Tk_MakeWindowExist.  This procedure issues
     the X commands to instantiate the window given by tkwin.



KEYWORDS

     create, deferred creation, destroy, display,  internal  win-
     dow, screen, top-level window, window