Next: 7.4 glutKeyboardFunc Up: 7 Callback Registration Previous: 7.2 glutOverlayDisplayFunc

## 7.3 glutReshapeFunc

`glutReshapeFunc` sets the reshape callback for the current window.

Usage

    void glutReshapeFunc(void (*func)(int width, int height));

`func`
  The new reshape callback function.

Description

`glutReshapeFunc` sets the reshape callback for the current window. The reshape callback is triggered when a window is reshaped. A reshape callback is also triggered immediately before a window's first display callback after a window is created or whenever an overlay for the window is established. The `width` and `height` parameters of the callback specify the new window size in pixels. Before the callback, the current window is set to the window that has been reshaped.

If a reshape callback is not registered for a window or `NULL` is passed to `glutReshapeFunc` (to deregister a previously registered callback), the default reshape callback is used. This default callback will simply call `glViewport(0,0,width,height)` on the normal plane (and on the overlay if one exists).

If an overlay is established for the window, a single reshape callback is generated. It is the callback's responsibility to update both the normal plane and overlay for the window (changing the layer in use as necessary).

When a top-level window is reshaped, subwindows are not reshaped. It is up to the GLUT program to manage the size and positions of subwindows within a top-level window. Still, reshape callbacks will be triggered for subwindows when their size is changed using `glutReshapeWindow`.

Next: 7.4 glutKeyboardFunc Up: 7 Callback Registration Previous: 7.2 glutOverlayDisplayFunc