/// <summary>
/// <para>Subtract another region from this one.</para>
/// </summary>
///
/// <param name="r">
/// <para>The other region to subtract from this one. If
/// <paramref name="r"/> is <see langword="null"/> or disposed,
/// the method does nothing.</para>
/// </param>
///
/// <remarks>
/// <para>If this region has been disposed, then it will be re-created
/// with its initial contents set to empty.</para>
/// </remarks>
public void Subtract(Region r)
{
lock (typeof(Region))
{
if (region == IntPtr.Zero)
{
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
else if (r == null || r.region == IntPtr.Zero)
{
// Nothing to do here: subtracting an empty region.
}
else if (r == this)
{
// Subtract the region from itself: result is empty.
Xlib.XDestroyRegion(region);
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
else
{
Xlib.XSubtractRegion(region, r.region, region);
}
}
}
/// <summary>
/// <para>Xor another region with this one.</para>
/// </summary>
///
/// <param name="r">
/// <para>The other region to xor with this one. If
/// <paramref name="r"/> is <see langword="null"/> or disposed,
/// then it will be treated as the empty region.</para>
/// </param>
///
/// <remarks>
/// <para>If this region has been disposed, then it will be treated
/// as empty prior to the xor operation.</para>
/// </remarks>
public void Xor(Region r)
{
lock (typeof(Region))
{
if (region == IntPtr.Zero)
{
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
if (r == null || r.region == IntPtr.Zero)
{
// Xor of an empty and a non-empty region gives
// the non-empty region as the result.
}
else if (r == this)
{
// Xor the region with itself: result is empty.
Xlib.XDestroyRegion(region);
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
else
{
Xlib.XXorRegion(region, r.region, region);
}
}
}
/// <summary>
/// <para>Subtract an explicitly-specified rectangle from
/// this region.</para>
/// </summary>
///
/// <param name="x">
/// <para>The X co-ordinate of the top-left corner of the rectangle.</para>
/// </param>
///
/// <param name="y">
/// <para>The Y co-ordinate of the top-left corner of the rectangle.</para>
/// </param>
///
/// <param name="width">
/// <para>The width of the rectangle.</para>
/// </param>
///
/// <param name="height">
/// <para>The height of the rectangle.</para>
/// </param>
///
/// <exception cref="T:Xsharp.XException">
/// <para>Raised if the rectangle co-ordinates are out of range.</para>
/// </exception>
///
/// <remarks>
/// <para>If this region has been disposed, then it will be re-created
/// with its initial contents set to empty.</para>
/// </remarks>
public void Subtract(int x, int y, int width, int height)
{
lock (typeof(Region))
{
if (region == IntPtr.Zero)
{
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
else
{
XRectangle xrect = new XRectangle(x, y, width, height);
IntPtr reg = Xlib.XCreateRegion();
if (reg == IntPtr.Zero)
{
Display.OutOfMemory();
}
Xlib.XUnionRectWithRegion(ref xrect, reg, reg);
Xlib.XSubtractRegion(region, reg, region);
Xlib.XDestroyRegion(reg);
}
}
}
/// <summary>
/// <para>Intersect another region with this one.</para>
/// </summary>
///
/// <param name="r">
/// <para>The other region to intersect with this one. If
/// <paramref name="r"/> is <see langword="null"/> or disposed,
/// the method operates as an intersection with the empty region.</para>
/// </param>
///
/// <remarks>
/// <para>If this region has been disposed, then it will be re-created
/// with its initial contents set to empty.</para>
/// </remarks>
public void Intersect(Region r)
{
lock (typeof(Region))
{
if (region == IntPtr.Zero)
{
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
else if (r == null || r.region == IntPtr.Zero)
{
Xlib.XDestroyRegion(region);
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
else if (r != this)
{
Xlib.XIntersectRegion(r.region, region, region);
}
}
}
/// <summary>
/// <para>Intersect a rectangle with this region.</para>
/// </summary>
///
/// <param name="rect">
/// <para>The rectangle to intersect with this region.</para>
/// </param>
///
/// <exception cref="T:Xsharp.XException">
/// <para>Raised if the rectangle co-ordinates are out of range.</para>
/// </exception>
///
/// <remarks>
/// <para>If this region has been disposed, then it will be re-created
/// with its initial contents set to empty.</para>
/// </remarks>
public void Intersect(Rectangle rect)
{
lock (typeof(Region))
{
if (region == IntPtr.Zero)
{
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
else
{
IntPtr reg = Xlib.XCreateRegion();
if (reg == IntPtr.Zero)
{
Display.OutOfMemory();
}
XRectangle xrect = new XRectangle
(rect.x, rect.y, rect.width, rect.height);
Xlib.XUnionRectWithRegion(ref xrect, reg, reg);
Xlib.XIntersectRegion(reg, region, region);
Xlib.XDestroyRegion(reg);
}
}
}
/// <summary>
/// <para>Determine if another region overlaps with this region.</para>
/// </summary>
///
/// <param name="r">
/// <para>The other region to test against this region.</para>
/// </param>
///
/// <returns>
/// <para>Returns <see langword="true"/> if <paramref name="r"/> overlaps
/// with this region; <see langword="false"/> otherwise.</para>
/// </returns>
public bool Overlaps(Region r)
{
lock (typeof(Region))
{
if (region == IntPtr.Zero)
{
return(false);
}
else if (r == null || r.region == IntPtr.Zero)
{
return(false);
}
else if (r == this)
{
return(true);
}
else
{
IntPtr reg = Xlib.XCreateRegion();
if (reg == IntPtr.Zero)
{
Display.OutOfMemory();
}
Xlib.XIntersectRegion(region, r.region, reg);
bool result = (Xlib.XEmptyRegion(reg) == 0);
Xlib.XDestroyRegion(reg);
return(result);
}
}
}
/// <summary>
/// <para>Dispose an instance of <see cref="T:Xsharp.Region"/>.</para>
/// </summary>
///
/// <remarks>
/// <para>This method implements the <see cref="T:System.IDisposeable"/>
/// interface.</para>
/// </remarks>
public void Dispose()
{
lock (typeof(Region))
{
if (region != IntPtr.Zero)
{
Xlib.XDestroyRegion(region);
region = IntPtr.Zero;
}
}
}
/// <summary>
/// <para>Set this region to empty.</para>
/// </summary>
public void SetEmpty()
{
lock (typeof(Region))
{
if (region != IntPtr.Zero)
{
Xlib.XDestroyRegion(region);
}
region = Xlib.XCreateRegion();
if (region == IntPtr.Zero)
{
Display.OutOfMemory();
}
}
}
