/// <summary>
/// Construct an icon from the raw image data.
/// </summary>
/// <returns></returns>
/// <remarks></remarks>
private Icon _constructIcon()
{
Icon _constructIconRet = default;
if (_hIcon != IntPtr.Zero)
{
User32.DestroyIcon(_hIcon);
_hIcon = IntPtr.Zero;
}
MemPtr mm = (MemPtr)_image;
var bmp = mm.ToStruct <BITMAPINFOHEADER>();
IntPtr hBmp;
IntPtr ptr;
IntPtr ppBits = new IntPtr();
var lpicon = default(ICONINFO);
IntPtr hicon;
IntPtr hBmpMask = new IntPtr();
bool hasMask;
if (bmp.biHeight == bmp.biWidth * 2)
{
hasMask = true;
bmp.biHeight = (int)(bmp.biHeight / 2d);
}
else
{
hasMask = false;
}
bmp.biSizeImage = (int)(bmp.biWidth * bmp.biHeight * (bmp.biBitCount / 8d));
bmp.biXPelsPerMeter = (int)(24.5d * 1000d);
bmp.biYPelsPerMeter = (int)(24.5d * 1000d);
bmp.biClrUsed = 0;
bmp.biClrImportant = 0;
bmp.biPlanes = 1;
Marshal.StructureToPtr(bmp, mm.Handle, false);
ptr = mm.Handle + bmp.biSize;
if (bmp.biSize != 40)
{
return(null);
}
hBmp = User32.CreateDIBSection(IntPtr.Zero, mm.Handle, 0U, ref ppBits, IntPtr.Zero, 0);
Native.MemCpy(ptr, ppBits, bmp.biSizeImage);
if (hasMask)
{
ptr = ptr + bmp.biSizeImage;
bmp.biBitCount = 1;
bmp.biSizeImage = 0;
Marshal.StructureToPtr(bmp, mm.Handle, false);
hBmpMask = User32.CreateDIBSection(IntPtr.Zero, mm.Handle, 0U, ref ppBits, IntPtr.Zero, 0);
Native.MemCpy(ptr, ppBits, (long)(Math.Max(bmp.biWidth, 32) * bmp.biHeight / 8d));
}
lpicon.fIcon = 1;
lpicon.hbmColor = hBmp;
lpicon.hbmMask = hBmpMask;
hicon = User32.CreateIconIndirect(ref lpicon);
NativeShell.DeleteObject(hBmp);
if (hasMask)
{
NativeShell.DeleteObject(hBmpMask);
}
_constructIconRet = Icon.FromHandle(hicon);
_hIcon = hicon;
mm.Free();
return(_constructIconRet);
}