从这里得知:
当您使用Save方法将图形图像保存为Windows Metafile Format(WMF)或Enhanced Metafile Format(EMF)文件时,生成的文件将被保存为Portable Network Graphics(PNG)文件。这种行为是由于.NET Framework的GDI+组件没有编码器可用于将文件保存为.wmf或.emf文件。
但我猜你已经了解到这一点了 :)
这里有人将位图放入FileStream中。
metafileStream = MakeMetafileStream(gdiBitmap);
使用MakeMetafileStream()函数:
private static MemoryStream MakeMetafileStream(Bitmap image)
{
Graphics graphics = null;
Metafile metafile= null;
var stream = new MemoryStream();
try
{
using (graphics = Graphics.FromImage(image))
{
var hdc = graphics.GetHdc();
metafile= new Metafile(stream, hdc);
graphics.ReleaseHdc(hdc);
}
using (graphics = Graphics.FromImage(metafile))
{ graphics.DrawImage(image, 0, 0); }
}
finally
{
if (graphics != null)
{ graphics.Dispose(); }
if (metafile!= null)
{ metafile.Dispose(); }
}
return stream;
}
有趣的东西。
但是关于编码器的事情...
这里,微软的Peter Huang发布了这个非托管的方法:
[DllImport("gdiplus.dll")]
private static extern uint GdipEmfToWmfBits (IntPtr _hEmf, uint _bufferSize,
byte[] _buffer, int _mappingMode, EmfToWmfBitsFlags _flags);
[DllImport("gdi32.dll")]
private static extern IntPtr SetMetaFileBitsEx (uint _bufferSize,
byte[] _buffer);
[DllImport("gdi32.dll")]
private static extern IntPtr CopyMetaFile (IntPtr hWmf,
string filename);
[DllImport("gdi32.dll")]
private static extern bool DeleteMetaFile (IntPtr hWmf);
[DllImport("gdi32.dll")]
private static extern bool DeleteEnhMetaFile (IntPtr hEmf);
private void button4_Click(object sender, System.EventArgs e)
{
Graphics g= this.CreateGraphics();
IntPtr hDC = g.GetHdc();
Metafile mf = new Metafile(hDC,EmfType.EmfOnly);
g.ReleaseHdc(hDC);
g.Dispose();
g=Graphics.FromImage(mf);
g.DrawArc(Pens.Black,0,0,200,200,0,360);
g.Dispose();
IntPtr _hEmf= mf.GetHenhmetafile();
uint _bufferSize = GdipEmfToWmfBits(_hEmf, 0, null, MM_ANISOTROPIC,
EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);
byte[] _buffer = new byte[_bufferSize];
GdipEmfToWmfBits(_hEmf, _bufferSize, _buffer, MM_ANISOTROPIC,
EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);
IntPtr hmf = SetMetaFileBitsEx(_bufferSize, _buffer);
CopyMetaFile(hmf, "C:\\ConvertedMetafile.wmf");
DeleteMetaFile(hmf);
DeleteEnhMetaFile(_hEmf);
}
希望这能帮助你到达目的地 :)