## class fltk::DoubleBufferWindow

### Class Hierarchy

    fltk::Window
       |
       +----fltk::DoubleBufferWindow

### Include Files

    #include <fltk/DoubleBufferWindow.h>

### Description

The `fltk::DoubleBufferWindow` class provides a double-buffered window. If possible this will use the X double buffering extension (Xdbe). If not, it will draw the window data into an off-screen pixmap, and then copy it to the on-screen window.

It is highly recommended that you put the following code before the first `show()` of any window in your program:

    fltk::visual(fltk::DOUBLE|fltk::INDEX)

This makes sure you can use Xdbe on servers where double buffering does not exist for every visual.

### Methods

- fltk::DoubleBufferWindow
- ~DoubleBufferWindow
- pixmap

#### fltk::DoubleBufferWindow::DoubleBufferWindow(int x, int y, int w, int h, const char *label = 0)

Creates a new `fltk::DoubleBufferWindow` widget using the given position, size, and label (title) string.

#### virtual fltk::DoubleBufferWindow::~DoubleBufferWindow()

The destructor also deletes all the children. This allows a whole tree to be deleted at once, without having to keep a pointer to all the children in the user code.

#### ulong fltk::DoubleBufferWindow::pixmap() const

Returns the off-screen pixmap or back buffer. This value is zero until the first time `flush()` is called.