private void TestBitmapInfoHeaderWithData()
{
BitmapInfoHeaderWithData w1 = new BitmapInfoHeaderWithData();
FillBMI(w1, 0);
w1.bmiColors = new int[] { 1, 2, 3 };
w1.Compression = 3;
IntPtr ip = w1.GetPtr();
BitmapInfoHeaderWithData w2 = BitmapInfoHeader.PtrToBMI(ip) as BitmapInfoHeaderWithData;
Marshal.FreeCoTaskMem(ip);
}
private void TestBitmapInfoHeaderWithData3()
{
BitmapInfoHeaderWithData w1 = new BitmapInfoHeaderWithData();
FillBMI(w1, 0);
w1.bmiColors = new int[256];
w1.Compression = 0;
w1.ClrUsed = 0;
w1.BitCount = 8;
for (int x = 0; x < 256; x++)
{
w1.bmiColors[x] = x + 7;
}
IntPtr ip = w1.GetPtr();
BitmapInfoHeaderWithData w2 = BitmapInfoHeader.PtrToBMI(ip) as BitmapInfoHeaderWithData;
Marshal.FreeCoTaskMem(ip);
}
public static BitmapInfoHeader PtrToBMI(IntPtr pNativeData)
{
int iEntries;
int biCompression;
int biClrUsed;
int biBitCount;
biBitCount = Marshal.ReadInt16(pNativeData, 14);
biCompression = Marshal.ReadInt32(pNativeData, 16);
biClrUsed = Marshal.ReadInt32(pNativeData, 32);
if (biCompression == 3) // BI_BITFIELDS
{
iEntries = 3;
}
else if (biClrUsed > 0)
{
iEntries = biClrUsed;
}
else if (biBitCount <= 8)
{
iEntries = 1 << biBitCount;
}
else
{
iEntries = 0;
}
BitmapInfoHeader bmi;
if (iEntries == 0)
{
// Create a simple BitmapInfoHeader struct
bmi = new BitmapInfoHeader();
Marshal.PtrToStructure(pNativeData, bmi);
}
else
{
BitmapInfoHeaderWithData ext = new BitmapInfoHeaderWithData();
ext.Size = Marshal.ReadInt32(pNativeData, 0);
ext.Width = Marshal.ReadInt32(pNativeData, 4);
ext.Height = Marshal.ReadInt32(pNativeData, 8);
ext.Planes = Marshal.ReadInt16(pNativeData, 12);
ext.BitCount = Marshal.ReadInt16(pNativeData, 14);
ext.Compression = Marshal.ReadInt32(pNativeData, 16);
ext.ImageSize = Marshal.ReadInt32(pNativeData, 20);
ext.XPelsPerMeter = Marshal.ReadInt32(pNativeData, 24);
ext.YPelsPerMeter = Marshal.ReadInt32(pNativeData, 28);
ext.ClrUsed = Marshal.ReadInt32(pNativeData, 32);
ext.ClrImportant = Marshal.ReadInt32(pNativeData, 36);
bmi = ext as BitmapInfoHeader;
ext.bmiColors = new int[iEntries];
IntPtr ip2 = new IntPtr(pNativeData.ToInt64() + Marshal.SizeOf(typeof(BitmapInfoHeader)));
Marshal.Copy(ip2, ext.bmiColors, 0, iEntries);
}
return bmi;
}
