using System; using System.Drawing;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Interop;
struct BITMAPFILEHEADER
{
public short bfType;
public int bfSize;
public short bfReserved1;
public short bfReserved2;
public int bfOffBits;
}
public static System.Drawing.Image GetDwgImage(string FileName)
{
if (!(File.Exists(FileName)))
{
throw new FileNotFoundException("文件没有被找到");
}
FileStream DwgF = null; //文件流
int PosSentinel; //文件描述块的位置
BinaryReader br = null; //读取二进制文件
int TypePreview; //缩略图格式
int PosBMP; //缩略图位置
int LenBMP; //缩略图大小
short biBitCount; //缩略图比特深度
BITMAPFILEHEADER biH; //BMP文件头，DWG文件中不包含位图文件头，要自行加上去
byte[] BMPInfo; //包含在DWG文件中的BMP文件体
MemoryStream BMPF = new MemoryStream(); //保存位图的内存文件流
BinaryWriter bmpr = new BinaryWriter(BMPF); //写二进制文件类
System.Drawing.Image myImg = null;
try
{
DwgF = new FileStream(FileName, FileMode.Open, FileAccess.Read); //文件流
br = new BinaryReader(DwgF);
DwgF.Seek(13, SeekOrigin.Begin); //从第十三字节开始读取
PosSentinel = br.ReadInt32(); //第13到17字节指示缩略图描述块的位置
DwgF.Seek(PosSentinel + 30, SeekOrigin.Begin); //将指针移到缩略图描述块的第31字节
TypePreview = br.ReadByte(); //第31字节为缩略图格式信息，2 为BMP格式，3为WMF格式
if (TypePreview == 1)
{
}
else if (TypePreview == 2 || TypePreview == 3)
{
PosBMP = br.ReadInt32(); //DWG文件保存的位图所在位置
LenBMP = br.ReadInt32(); //位图的大小
DwgF.Seek(PosBMP + 14, SeekOrigin.Begin); //移动指针到位图块
biBitCount = br.ReadInt16(); //读取比特深度
DwgF.Seek(PosBMP, SeekOrigin.Begin); //从位图块开始处读取全部位图内容备用
BMPInfo = br.ReadBytes(LenBMP); //不包含文件头的位图信息
br.Close();
DwgF.Close();
biH.bfType = 19778; //建立位图文件头
if (biBitCount < 9)
{
biH.bfSize = 54 + 4 * (int)(Math.Pow(2, biBitCount)) + LenBMP;
}
else
{
biH.bfSize = 54 + LenBMP;
}
biH.bfReserved1 = 0; //保留字节
biH.bfReserved2 = 0; //保留字节
biH.bfOffBits = 14 + 40 + 1024; //图像数据偏移
//以下开始写入位图文件头
bmpr.Write(biH.bfType); //文件类型
bmpr.Write(biH.bfSize); //文件大小
bmpr.Write(biH.bfReserved1); //0
bmpr.Write(biH.bfReserved2); //0
bmpr.Write(biH.bfOffBits); //图像数据偏移
bmpr.Write(BMPInfo); //写入位图
BMPF.Seek(0, SeekOrigin.Begin); //指针移到文件开始处
myImg = System.Drawing.Image.FromStream(BMPF); //创建位图文件对象
bmpr.Close();
BMPF.Close();
}
return myImg;
}
catch (EndOfStreamException)
{
throw new EndOfStreamException("文件不是标准的DWG格式文件，无法预览！");
}
catch (IOException ex)
{
if (ex.Message == "试图将文件指针移到文件开头之前。/r/n")
{
throw new IOException("文件不是标准的DWG格式文件，无法预览！");
}
else if (ex.Message == "文件“" + FileName + "”正由另一进程使用，因此该进程无法访问该文件。")
{
//复制文件，继续预览
//File.Copy(FileName, System.Windows.Forms.Application.StartupPath + @"/linshi.dwg", true);
//System.Drawing.Image image = GetDwgImage(Application.StartupPath + @"/linshi.dwg");
//File.Delete(Application.StartupPath + @"/linshi.dwg");
//return image;
throw new IOException("文件“" + FileName + "”正由另一进程使用，因此该进程无法访问该文件。");
}
else
{
throw new Exception(ex.Message);
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
if (DwgF != null)
{
DwgF.Close();
}
if (br != null)
{
br.Close();
}
bmpr.Close();
BMPF.Close();
}
}
///读取出来的背景色为白色，效果比较差，很多颜色显示不出来，当时认为显示DWG文件出错误了，问了些高手，（呵呵，别人告诉自己本身取出的就是白色背景，需要自己改变背景色，在此鄙视一下自己）所以继续用C#操作返回的IMAGE对象，改变背景色
///<summary>
///显示DWG文件
///</summary>
///<param name="Pwidth">要显示的宽度</param>
///<param name="PHeight">要显示的高度</param>
///<returns></returns>
public static System.Drawing.Image ShowDWG(int Pwidth, int PHeight, string FilePath)
{
System.Drawing.Image image = GetDwgImage(FilePath);
Bitmap bitmap = new Bitmap(image);
int Height = bitmap.Height;
int Width = bitmap.Width;
Bitmap newbitmap = new Bitmap(Width, Height);
Bitmap oldbitmap = (Bitmap)bitmap;
System.Drawing.Color pixel;
for (int x = 1; x < Width; x++)
{
for (int y = 1; y < Height; y++)
{
pixel = oldbitmap.GetPixel(x, y);
int r = pixel.R, g = pixel.G, b = pixel.B;
if (pixel.Name == "ffffffff" || pixel.Name == "ff000000")
{
r = 255 - pixel.R;
g = 255 - pixel.G;
b = 255 - pixel.B;
}
newbitmap.SetPixel(x, y, Color.FromArgb(r, g, b));
}
}
Bitmap bt = new Bitmap(newbitmap, Pwidth, PHeight);
return newbitmap;
}
/// <summary>
/// Bitmap转ImageSource
/// </summary>
/// <param name="hObject"></param>
/// <returns></returns>
[DllImport("gdi32.dll", SetLastError = true)]
private static extern bool DeleteObject(IntPtr hObject);
public static ImageSource ToImageSource( Bitmap bitmap)
{
IntPtr hBitmap = bitmap.GetHbitmap();
ImageSource wpfBitmap = Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
// 记得要进行内存释放。否则会有内存不足的报错。
if (!DeleteObject(hBitmap))
{
throw new Win32Exception();
}
return wpfBitmap;
}
public static ImageSource BitmapToImageSource(System.Drawing.Image processImage)
{
Bitmap bmp = new Bitmap(processImage);
IntPtr hBitmap = bmp.GetHbitmap();
ImageSource wpfBitmap = Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
return wpfBitmap;
}