protected override void OnPaint(PaintEventArgs e)
{
var outerBounds = new Rectangle(0, 0, Width, Height);
using (var target = new Bitmap(outerBounds.Width, outerBounds.Height, PixelFormat.Format32bppArgb))
{
using (var targetGraphics = Graphics.FromImage(target))
{
// The top and bottom borders extend over the sides of the window.
// The left and right borders do no. This means that we need to
// update the bounds to make it seem like the left and right
// borders do extend outside of the window.
if (Border == DropShadowBorder.Left || Border == DropShadowBorder.Right)
{
outerBounds = new Rectangle(
outerBounds.Left,
outerBounds.Top - _borderWidth,
outerBounds.Width,
outerBounds.Height + _borderWidth * 2
);
}
if (Border == DropShadowBorder.Left || Border == DropShadowBorder.Top)
{
DrawImage(targetGraphics, _imageCache.CornerNW,
new Point(outerBounds.Left, outerBounds.Top)
);
}
if (Border == DropShadowBorder.Right || Border == DropShadowBorder.Top)
{
DrawImage(targetGraphics, _imageCache.CornerNE,
new Point(outerBounds.Right - _cornerSize, outerBounds.Top)
);
}
if (Border == DropShadowBorder.Bottom || Border == DropShadowBorder.Left)
{
DrawImage(targetGraphics, _imageCache.CornerSW,
new Point(outerBounds.Left, outerBounds.Bottom - _cornerSize)
);
}
if (Border == DropShadowBorder.Bottom || Border == DropShadowBorder.Right)
{
DrawImage(targetGraphics, _imageCache.CornerSE,
new Point(outerBounds.Right - _cornerSize, outerBounds.Bottom - _cornerSize)
);
}
if (Border == DropShadowBorder.Top)
{
DrawBorder(targetGraphics, _imageCache.BorderN,
new Rectangle(
outerBounds.Left + _cornerSize,
outerBounds.Top,
outerBounds.Width - _cornerSize * 2,
_borderWidth
)
);
}
if (Border == DropShadowBorder.Bottom)
{
DrawBorder(targetGraphics, _imageCache.BorderS,
new Rectangle(
outerBounds.Left + _cornerSize,
outerBounds.Bottom - _borderWidth,
outerBounds.Width - _cornerSize * 2,
_borderWidth
)
);
}
if (Border == DropShadowBorder.Left)
{
DrawBorder(targetGraphics, _imageCache.BorderW,
new Rectangle(
outerBounds.Left,
outerBounds.Top + _cornerSize,
_borderWidth,
outerBounds.Height - _cornerSize * 2
)
);
}
if (Border == DropShadowBorder.Right)
{
DrawBorder(targetGraphics, _imageCache.BorderE,
new Rectangle(
outerBounds.Right - _borderWidth,
outerBounds.Top + _cornerSize,
_borderWidth,
outerBounds.Height - _cornerSize * 2
)
);
}
}
// Get device contexts
var screenDc = PI.GetDC(IntPtr.Zero);
var memDc = PI.CreateCompatibleDC(screenDc);
var hBitmap = IntPtr.Zero;
var hOldBitmap = IntPtr.Zero;
try
{
// Get handle to the new bitmap and select it into the current device context
hBitmap = target.GetHbitmap(Color.FromArgb(0));
hOldBitmap = PI.SelectObject(memDc, hBitmap); // Set parameters for layered window update
var newSize = new PI.SIZE(target.Size); // Size window to match bitmap
var sourceLocation = new PI.POINT(Point.Empty);
var newLocation = new PI.POINT(Location); // Same as this window
var blend = new PI.BLENDFUNCTION
{
BlendOp = PI.AC_SRC_OVER, // Only works with a 32bpp bitmap
BlendFlags = 0, // Always 0
SourceConstantAlpha = 255, // Set to 255 for per-pixel alpha values
AlphaFormat = PI.AC_SRC_ALPHA // Only works when the bitmap contains an alpha channel
};
// Update the window
PI.UpdateLayeredWindow(
Handle, screenDc, ref newLocation, ref newSize,
memDc, ref sourceLocation, 0, ref blend,
PI.ULW_ALPHA
);
}
finally
{
// Release device context
PI.ReleaseDC(IntPtr.Zero, screenDc);
if (hBitmap != IntPtr.Zero)
{
PI.SelectObject(memDc, hOldBitmap);
PI.DeleteObject(hBitmap); // Remove bitmap resources
}
PI.DeleteDC(memDc);
}
}
}
