// Start a double buffer drawing operation.
internal void Start(Graphics graphics)
{
// Re-create the pixmap object if the widget size has changed.
if (!usesXdbe)
{
if (widget.width != width || widget.height != height)
{
try
{
IntPtr display = dpy.Lock();
if (handle != XDrawable.Zero)
{
Xlib.XFreePixmap(display, (XPixmap)handle);
}
handle = (XDrawable)
Xlib.XCreatePixmap
(display, (XDrawable)
Xlib.XRootWindowOfScreen(screen.screen),
(uint)(widget.Width),
(uint)(widget.Height),
(uint)Xlib.XDefaultDepthOfScreen
(screen.screen));
}
finally
{
dpy.Unlock();
}
}
}
// Copy the width and height values from the widget.
width = widget.Width;
height = widget.Height;
}
/// <summary>
/// <para>Constructs a new <see cref="T:Xsharp.Pixmap"/> instance
/// that represents an off-screen pixmap. The pixmap is created
/// on the default screen of the primary display.</para>
/// </summary>
///
/// <param name="width">
/// <para>The width of the new pixmap.</para>
/// </param>
///
/// <param name="height">
/// <para>The height of the new pixmap.</para>
/// </param>
///
/// <exception cref="T:Xsharp.XException">
/// <para>The <paramref name="width"/> or <paramref name="height"/>
/// values are out of range.</para>
/// </exception>
public Pixmap(int width, int height)
: base(Xsharp.Application.Primary.Display,
Xsharp.Application.Primary.Display.DefaultScreenOfDisplay,
DrawableKind.Pixmap)
{
if (width < 1 || width > 32767 ||
height < 1 || height > 32767)
{
throw new XException(S._("X_InvalidPixmapSize"));
}
try
{
IntPtr display = dpy.Lock();
SetPixmapHandle(Xlib.XCreatePixmap
(display, (XDrawable)
Xlib.XRootWindowOfScreen(screen.screen),
(uint)width, (uint)height,
(uint)Xlib.XDefaultDepthOfScreen(screen.screen)));
this.width = width;
this.height = height;
}
finally
{
dpy.Unlock();
}
}
/// <summary>
/// <para>Constructs a new <see cref="T:Xsharp.DoubleBuffer"/>
/// instance.</para>
/// </summary>
///
/// <param name="widget">
/// <para>The widget to attach the double buffer to.</para>
/// </param>
///
/// <exception cref="T:System.ArgumentNullException">
/// <para>Raised if <paramref name="widget"/> is <see langword="null"/>.
/// </para>
/// </exception>
public DoubleBuffer(InputOutputWidget widget)
: base(GetDisplay(widget), GetScreen(widget),
DrawableKind.DoubleBuffer)
{
this.widget = widget;
this.width = widget.width;
this.height = widget.height;
try
{
IntPtr display = dpy.Lock();
// Determine if the X server supports double buffering.
try
{
Xlib.Xint major, minor;
if (Xlib.XdbeQueryExtension
(display, out major, out minor)
!= XStatus.Zero)
{
usesXdbe = true;
}
else
{
usesXdbe = false;
}
}
catch (Exception)
{
// Xdbe functions are not present in "Xext".
usesXdbe = false;
}
// Create the back buffer or pixmap, as appropriate.
if (usesXdbe)
{
handle = Xlib.XdbeAllocateBackBufferName
(display, widget.GetWidgetHandle(),
Xlib.XdbeSwapAction.Background);
}
else
{
handle = (XDrawable)
Xlib.XCreatePixmap
(display, (XDrawable)
Xlib.XRootWindowOfScreen(screen.screen),
(uint)width, (uint)height,
(uint)Xlib.XDefaultDepthOfScreen
(screen.screen));
}
}
finally
{
dpy.Unlock();
}
}
