private IntPtr CreateCompatibleDIB(IntPtr hdc, IntPtr hpal, int ulWidth, int ulHeight, ref IntPtr ppvBits)
{
if (hdc == IntPtr.Zero)
{
throw new ArgumentNullException("hdc");
}
IntPtr zero = IntPtr.Zero;
System.Drawing.NativeMethods.BITMAPINFO_FLAT pbmi = new System.Drawing.NativeMethods.BITMAPINFO_FLAT();
switch (System.Drawing.UnsafeNativeMethods.GetObjectType(new HandleRef(null, hdc)))
{
case 3:
case 4:
case 10:
case 12:
if (this.bFillBitmapInfo(hdc, hpal, ref pbmi))
{
pbmi.bmiHeader_biWidth = ulWidth;
pbmi.bmiHeader_biHeight = ulHeight;
if (pbmi.bmiHeader_biCompression == 0)
{
pbmi.bmiHeader_biSizeImage = 0;
}
else if (pbmi.bmiHeader_biBitCount == 0x10)
{
pbmi.bmiHeader_biSizeImage = (ulWidth * ulHeight) * 2;
}
else if (pbmi.bmiHeader_biBitCount == 0x20)
{
pbmi.bmiHeader_biSizeImage = (ulWidth * ulHeight) * 4;
}
else
{
pbmi.bmiHeader_biSizeImage = 0;
}
pbmi.bmiHeader_biClrUsed = 0;
pbmi.bmiHeader_biClrImportant = 0;
zero = SafeNativeMethods.CreateDIBSection(new HandleRef(null, hdc), ref pbmi, 0, ref ppvBits, IntPtr.Zero, 0);
Win32Exception exception = null;
if (zero == IntPtr.Zero)
{
exception = new Win32Exception(Marshal.GetLastWin32Error());
}
if (exception != null)
{
throw exception;
}
}
return(zero);
}
throw new ArgumentException(System.Drawing.SR.GetString("DCTypeInvalid"));
}
/// <summary>
/// Create a DIB section with an optimal format w.r.t. the specified hdc.
///
/// If DIB <= 8bpp, then the DIB color table is initialized based on the
/// specified palette. If the palette handle is NULL, then the system
/// palette is used.
///
/// Note: The hdc must be a direct DC (not an info or memory DC).
///
/// Note: On palettized displays, if the system palette changes the
/// UpdateDIBColorTable function should be called to maintain
/// the identity palette mapping between the DIB and the display.
/// </summary>
/// <returns>A valid bitmap handle if successful, IntPtr.Zero otherwise.</returns>
private IntPtr CreateCompatibleDIB(IntPtr hdc, IntPtr hpal, int ulWidth, int ulHeight, ref IntPtr ppvBits)
{
if (hdc == IntPtr.Zero)
{
throw new ArgumentNullException(nameof(hdc));
}
IntPtr hbmRet = IntPtr.Zero;
var pbmi = new NativeMethods.BITMAPINFO_FLAT();
// Validate hdc.
int objType = UnsafeNativeMethods.GetObjectType(new HandleRef(null, hdc));
switch (objType)
{
case NativeMethods.OBJ_DC:
case NativeMethods.OBJ_METADC:
case NativeMethods.OBJ_MEMDC:
case NativeMethods.OBJ_ENHMETADC:
break;
default:
throw new ArgumentException(SR.DCTypeInvalid);
}
if (FillBitmapInfo(hdc, hpal, ref pbmi))
{
// Change bitmap size to match specified dimensions.
pbmi.bmiHeader_biWidth = ulWidth;
pbmi.bmiHeader_biHeight = ulHeight;
if (pbmi.bmiHeader_biCompression == NativeMethods.BI_RGB)
{
pbmi.bmiHeader_biSizeImage = 0;
}
else
{
if (pbmi.bmiHeader_biBitCount == 16)
{
pbmi.bmiHeader_biSizeImage = ulWidth * ulHeight * 2;
}
else if (pbmi.bmiHeader_biBitCount == 32)
{
pbmi.bmiHeader_biSizeImage = ulWidth * ulHeight * 4;
}
else
{
pbmi.bmiHeader_biSizeImage = 0;
}
}
pbmi.bmiHeader_biClrUsed = 0;
pbmi.bmiHeader_biClrImportant = 0;
// Create the DIB section. Let Win32 allocate the memory and return
// a pointer to the bitmap surface.
hbmRet = SafeNativeMethods.CreateDIBSection(new HandleRef(null, hdc), ref pbmi, NativeMethods.DIB_RGB_COLORS, ref ppvBits, IntPtr.Zero, 0);
Win32Exception ex = null;
if (hbmRet == IntPtr.Zero)
{
ex = new Win32Exception(Marshal.GetLastWin32Error());
}
if (ex != null)
{
throw ex;
}
}
return(hbmRet);
}
