/// <summary>
/// Renders the tab thumbnail (<paramref name="image" />) using the given dimensions and coordinates and blends it properly with the underlying desktop
/// elements.
/// </summary>
/// <param name="image">Thumbnail to display.</param>
/// <param name="opacity">Opacity that <paramref name="image" /> should be displayed with.</param>
/// <param name="width">Width of <paramref name="image" />.</param>
/// <param name="height">Height of <paramref name="image" />.</param>
/// <param name="position">Screen position that <paramref name="image" /> should be displayed at.</param>
public void UpdateWindow(Bitmap image, byte opacity, int width, int height, POINT position)
{
IntPtr windowHandle = User32.GetWindowDC(Handle);
IntPtr deviceContextHandle = Gdi32.CreateCompatibleDC(windowHandle);
IntPtr bitmapHandle = image.GetHbitmap(Color.FromArgb(0));
IntPtr oldBitmapHandle = Gdi32.SelectObject(deviceContextHandle, bitmapHandle);
SIZE size = new SIZE
{
cx = 0,
cy = 0
};
POINT destinationPosition = new POINT
{
x = 0,
y = 0
};
if (width == -1 || height == -1)
{
// No width and height specified, use the size of the image
size.cx = image.Width;
size.cy = image.Height;
}
else
{
// Use whichever size is smallest, so that the image will be clipped if necessary
size.cx = Math.Min(image.Width, width);
size.cy = Math.Min(image.Height, height);
}
// Set the opacity and blend the image with the underlying desktop elements using User32.UpdateLayeredWindow
BLENDFUNCTION blendFunction = new BLENDFUNCTION
{
BlendOp = Convert.ToByte((int) AC.AC_SRC_OVER),
SourceConstantAlpha = opacity,
AlphaFormat = Convert.ToByte((int) AC.AC_SRC_ALPHA),
BlendFlags = 0
};
User32.UpdateLayeredWindow(Handle, windowHandle, ref position, ref size, deviceContextHandle, ref destinationPosition, 0, ref blendFunction, ULW.ULW_ALPHA);
Gdi32.SelectObject(deviceContextHandle, oldBitmapHandle);
Gdi32.DeleteObject(bitmapHandle);
Gdi32.DeleteDC(deviceContextHandle);
User32.ReleaseDC(Handle, windowHandle);
}
/// <summary>
/// Renders the tabs and then calls <see cref="User32.UpdateLayeredWindow" /> to blend the tab content with the underlying window (
/// <see cref="_parentForm" />).
/// </summary>
/// <param name="cursorPosition">Current position of the cursor.</param>
/// <param name="forceRedraw">Flag indicating whether a full render should be forced.</param>
public void Render(Point cursorPosition, bool forceRedraw = false)
{
if (!IsDisposed && _parentForm.TabRenderer != null && _parentForm.WindowState != FormWindowState.Minimized && _parentForm.ClientRectangle.Width > 0)
{
cursorPosition = GetRelativeCursorPosition(cursorPosition);
using (Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format32bppArgb))
{
using (Graphics graphics = Graphics.FromImage(bitmap))
{
DrawTitleBarBackground(graphics);
// Since classic mode themes draw over the *entire* titlebar, not just the area immediately behind the tabs, we have to offset the tabs
// when rendering in the window
Point offset = _parentForm.WindowState != FormWindowState.Maximized && DisplayType == DisplayType.Classic
? new Point(0, SystemInformation.CaptionButtonSize.Height)
: _parentForm.WindowState != FormWindowState.Maximized
? new Point(0, SystemInformation.VerticalResizeBorderThickness - SystemInformation.BorderSize.Height)
: new Point(0, 0);
// Render the tabs into the bitmap
_parentForm.TabRenderer.Render(_parentForm.Tabs, graphics, offset, cursorPosition, forceRedraw);
// Cut out a hole in the background so that the control box on the underlying window can be shown
if (DisplayType == DisplayType.Classic && (_parentForm.ControlBox || _parentForm.MaximizeBox || _parentForm.MinimizeBox))
{
int boxWidth = 0;
if (_parentForm.ControlBox)
boxWidth += SystemInformation.CaptionButtonSize.Width;
if (_parentForm.MinimizeBox)
boxWidth += SystemInformation.CaptionButtonSize.Width;
if (_parentForm.MaximizeBox)
boxWidth += SystemInformation.CaptionButtonSize.Width;
CompositingMode oldCompositingMode = graphics.CompositingMode;
graphics.CompositingMode = CompositingMode.SourceCopy;
graphics.FillRectangle(
new SolidBrush(Color.Transparent), Width - boxWidth, 0, boxWidth, SystemInformation.CaptionButtonSize.Height);
graphics.CompositingMode = oldCompositingMode;
}
IntPtr screenDc = User32.GetDC(IntPtr.Zero);
IntPtr memDc = Gdi32.CreateCompatibleDC(screenDc);
IntPtr oldBitmap = IntPtr.Zero;
IntPtr bitmapHandle = IntPtr.Zero;
try
{
// Copy the contents of the bitmap into memDc
bitmapHandle = bitmap.GetHbitmap(Color.FromArgb(0));
oldBitmap = Gdi32.SelectObject(memDc, bitmapHandle);
SIZE size = new SIZE
{
cx = bitmap.Width,
cy = bitmap.Height
};
POINT pointSource = new POINT
{
x = 0,
y = 0
};
POINT topPos = new POINT
{
x = Left,
y = Top
};
BLENDFUNCTION blend = new BLENDFUNCTION
{
// We want to blend the bitmap's content with the screen content under it
BlendOp = Convert.ToByte((int) AC.AC_SRC_OVER),
BlendFlags = 0,
SourceConstantAlpha = 255,
// We use the bitmap's alpha channel for blending instead of a pre-defined transparency key
AlphaFormat = Convert.ToByte((int) AC.AC_SRC_ALPHA)
};
// Blend the tab content with the underlying content
if (!User32.UpdateLayeredWindow(
Handle, screenDc, ref topPos, ref size, memDc, ref pointSource, 0, ref blend, ULW.ULW_ALPHA))
{
int error = Marshal.GetLastWin32Error();
throw new Win32Exception(error, "Error while calling UpdateLayeredWindow().");
}
}
// Clean up after ourselves
finally
{
User32.ReleaseDC(IntPtr.Zero, screenDc);
if (bitmapHandle != IntPtr.Zero)
{
Gdi32.SelectObject(memDc, oldBitmap);
Gdi32.DeleteObject(bitmapHandle);
}
Gdi32.DeleteDC(memDc);
}
}
}
}
}