问题描述
有很多将 wmf 转换为位图的示例，例如:可靠的 .wmf/wmf 到基于像素的图像转换>
但我需要反向操作.我不寻找矢量化器.我只想在 wmf 文件中嵌入图片，而不必担心 wmf 格式的位和字节.我需要一个 .NET 解决方案，最好使用 C#.
我最初认为这可以完成工作:
using (Image img = Image.FromFile (path)) {img.Save (myStream, System.Drawing.Imaging.ImageFormat.Wmf);}但这在运行时会抱怨编码器为空.我在哪里/如何构建这样的编码器?我不需要复杂的，只需要一个将图像包装成 wmf 的.WMF 支持的格式有什么要求吗?我想支持 png 和 bmp，但也支持 gif 吗?
来自 此处:
<块引用>当您使用 Save 方法保存一个作为 Windows 图元文件的图形图像格式 (WMF) 或增强型元文件格式(EMF)文件，生成的文件保存为便携式网络图形 (PNG) 文件代替.这出现行为是因为 GDI+.NET Framework 的组件没有可以使用的编码器将文件另存为 .wmf 或 .emf 文件.
但我想你已经做到了 :)
这里有人将位图放入 FileStream.
metafileStream = MakeMetafileStream(gdiBitmap);MakeMetafileStream() 为:
private static MemoryStream MakeMetafileStream(Bitmap image){图形图形 = 空；图元文件图元文件=空；var stream = new MemoryStream();尝试{使用 (graphics = Graphics.FromImage(image)){var hdc = graphics.GetHdc();元文件=新元文件(流，hdc)；graphics.ReleaseHdc(hdc);}使用 (graphics = Graphics.FromImage(metafile)){ graphics.DrawImage(image, 0, 0);}}最后{如果(图形！= null){ graphics.Dispose();}如果(元文件！= null){ 元文件.处置()；}}返回流；}有趣的东西.但至于编码器的事情...
此处 MS 的 Peter Huang 发布了这种非托管方法:
[DllImport("gdiplus.dll")]私有静态外部 uint GdipEmfToWmfBits (IntPtr _hEmf, uint _bufferSize,byte[] _buffer, int _mappingMode, EmfToWmfBitsFlags _flags);[DllImport("gdi32.dll")]私有静态外部 IntPtr SetMetaFileBitsEx (uint _bufferSize,字节[] _buffer);[DllImport("gdi32.dll")]private static extern IntPtr CopyMetaFile (IntPtr hWmf,字符串文件名);[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){图形 g= this.CreateGraphics();IntPtr hDC = g.GetHdc();图元文件 mf = 新图元文件(hDC，EmfType.EmfOnly)；g.ReleaseHdc(hDC);g.Dispose();g=Graphics.FromImage(mf);//Pen p = new Pen(Color.White,5);g.DrawArc(Pens.Black,0,0,200,200,0,360);//g.DrawImage(Bitmap.FromFile(@"c: emp est.bmp"),0,0);g.Dispose();IntPtr _hEmf= mf.GetHenhmetafile();uint _bufferSize = GdipEmfToWmfBits(_hEmf, 0, null, MM_ANISOTROPIC,EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);字节[] _buffer = 新字节[_bufferSize];GdipEmfToWmfBits(_hEmf, _bufferSize, _buffer, MM_ANISOTROPIC,EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);IntPtr hmf = SetMetaFileBitsEx(_bufferSize, _buffer);CopyMetaFile(hmf, "C:\ConvertedMetafile.wmf");删除元文件(hmf)；DeleteEnhMetaFile(_hEmf);}希望这能让你到达那里:)
There are plenty of examples of converting a wmf into a bitmap like: Reliable .wmf/wmf to Pixel based image conversion
But I need the reverse operation. I do not look for a vectorizer. I just want to embed a picture inside a wmf file without having to bother about the bits and bytes of the wmf format. I need a solution for .NET preferably in C#.
I first thought this would do the job:
using (Image img = Image.FromFile (path)) {
img.Save (myStream, System.Drawing.Imaging.ImageFormat.Wmf);
}
But this complains at runtime that the encoder is null. Where/How can I build such an encoder? I do not need a complicated one, just one that wraps an image into a wmf. Are there some requirements on the supported formats in WMF? I suppose png and bmp are supported but is gif also supported?
From here:
When you use the Save method to save a graphic image as a Windows Metafile Format (WMF) or Enhanced Metafile Format (EMF) file, the resulting file is saved as a Portable Network Graphics (PNG) file instead. This behavior occurs because the GDI+ component of the .NET Framework does not have an encoder that you can use to save files as .wmf or .emf files.
But I guess you already got that far :)
Here someone is putting a bitmap in a FileStream.
metafileStream = MakeMetafileStream(gdiBitmap);
with MakeMetafileStream() being:
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;
}
Interesting stuff. But as to the encoder thing...
Here Peter Huang from MS posted this unmanaged approach:
[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);
//Pen p = new Pen(Color.White,5);
g.DrawArc(Pens.Black,0,0,200,200,0,360);
//g.DrawImage(Bitmap.FromFile(@"c: emp est.bmp"),0,0);
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);
}
Hope this'll get you there :)
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