DOKK / manpages / debian 10 / tk8.6-doc / Tk_MaintainGeometry.3tk.en
Tk_MaintainGeometry(3tk) Tk Library Procedures Tk_MaintainGeometry(3tk) 







Tk_MaintainGeometry, Tk_UnmaintainGeometry - maintain geometry of
    one window relative to another








#include <tk.h>

Tk_MaintainGeometry(slave, master, x, y, width, height)

Tk_UnmaintainGeometry(slave, master)









  
Tk_Window slave (in)

  
Window whose geometry is to be controlled.

  
Tk_Window master (in)

  
Window relative to which slave's geometry will be controlled.

  
int x (in)

  
Desired x-coordinate of slave in master, measured in pixels
      from the inside of master's left border to the outside of
      slave's left border.

  
int y (in)

  
Desired y-coordinate of slave in master, measured in pixels
      from the inside of master's top border to the outside of
      slave's top border.

  
int width (in)

  
Desired width for slave, in pixels.

  
int height (in)

  
Desired height for slave, in pixels.
    
    

    

  










Tk_MaintainGeometry and Tk_UnmaintainGeometry make
    it easier for geometry managers to deal with slaves whose masters are not
    their parents. Three problems arise if the master for a slave is not its
    parent:



  
[1]

  
The x- and y-position of the slave must be translated from the coordinate
      system of the master to that of the parent before positioning the
    slave.

  
[2]

  
If the master window, or any of its ancestors up to the slave's parent, is
      moved, then the slave must be repositioned within its parent in order to
      maintain the correct position relative to the master.

  
[3]

  
If the master or one of its ancestors is mapped or unmapped, then the
      slave must be mapped or unmapped to correspond.




None of these problems is an issue if the parent and master are
    the same. For example, if the master or one of its ancestors is unmapped,
    the slave is automatically removed by the screen by X.


Tk_MaintainGeometry deals with these problems for slaves
    whose masters are not their parents, as well as handling the simpler case of
    slaves whose masters are their parents. Tk_MaintainGeometry is
    typically called by a window manager once it has decided where a slave
    should be positioned relative to its master. Tk_MaintainGeometry
    translates the coordinates to the coordinate system of slave's parent
    and then moves and resizes the slave appropriately. Furthermore, it
    remembers the desired position and creates event handlers to monitor the
    master and all of its ancestors up to (but not including) the slave's
    parent. If any of these windows is moved, mapped, or unmapped, the slave
    will be adjusted so that it is mapped only when the master is mapped and its
    geometry relative to the master remains as specified by x, y,
    width, and height.


When a window manager relinquishes control over a window, or if it
    decides that it does not want the window to appear on the screen under any
    conditions, it calls Tk_UnmaintainGeometry.
    Tk_UnmaintainGeometry unmaps the window and cancels any previous
    calls to Tk_MaintainGeometry for the master-slave pair,
    so that the slave's geometry and mapped state are no longer maintained
    automatically. Tk_UnmaintainGeometry need not be called by a geometry
    manager if the slave, the master, or any of the master's ancestors is
    destroyed: Tk will call it automatically.


If Tk_MaintainGeometry is called repeatedly for the same
    master-slave pair, the information from the most recent call
    supersedes any older information. If Tk_UnmaintainGeometry is called
    for a master-slave pair that is is not currently managed, the
    call has no effect.








geometry manager, map, master, parent, position, slave, unmap







  

    4.0
    Tk