2023年12月11日发(作者：)
java打开dwg_用java和c#实现dwg图片预览
[Java]
public class ViewDWG
{
//C# TO JAVA CONVERTER WARNING: Java does not allow user-defined
value types. The behavior of this class will differ from the
original:
//ORIGINAL LINE: struct BITMAPFILEHEADER
private final static class BITMAPFILEHEADER
{
public short bfType;
public int bfSize;
public short bfReserved1;
public short bfReserved2;
public int bfOffBits;
public BITMAPFILEHEADER clone()
{
BITMAPFILEHEADER varCopy = new BITMAPFILEHEADER();
= ;
= ;
rved1 = rved1;
rved2 = rved2;
its = its;
return varCopy;
}
}
public final Image GetDwgImage(String FileName)
{
if (!((new (FileName)).isFile()))
{
throw new FileNotFoundException("文件没有被找到");
}
FileStream DwgF; //文件流
int PosSentinel; //文件描述块的位置BinaryReader br; //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 = new BITMAPFILEHEADER();
//BMP文件头，DWG文件中不包含位图文件头，要自行加上去
//C# TO JAVA CONVERTER WARNING: Unsigned integer types have no
direct equivalent in Java:
//ORIGINAL LINE: byte[] BMPInfo;
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
Image myImg = null;
try
{
DwgF = new FileStream(FileName, , );
//文件流
br = new BinaryReader(DwgF);
(13, ); //从第十三字节开始读取
PosSentinel = t32(); //第13到17字节指示缩略图描述块的位置
(PosSentinel + 30, );
//将指针移到缩略图描述块的第31字节
TypePreview = te(); //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 = t32(); //DWG文件保存的位图所在位置
LenBMP = t32(); //位图的大小
(PosBMP + 14, ); //移动指针到位图块
biBitCount = t16(); //读取比特深度
(PosBMP, ); //从位图块开始处读取全部位图内容备用BMPInfo = tes(LenBMP); //不包含文件头的位图信息
();
();
= 19778; //建立位图文件头
if (biBitCount < 9)
{
= 54 + 4 * (int)((2, biBitCount)) +
LenBMP;
}
else
{
= 54 + LenBMP;
}
rved1 = 0; //保留字节
rved2 = 0; //保留字节
its = 14 + 40 + 1024; //图像数据偏移
//以下开始写入位图文件头
(); //文件类型
(); //文件大小
(rved1); //0
(rved2); //0
(its); //图像数据偏移
(BMPInfo); //写入位图
(0, ); //指针移到文件开始处
myImg = ream(BMPF); //创建位图文件对象
();
();
}
return myImg;
}
catch (RuntimeException ex)
{
throw new RuntimeException(sage());
}}
}
[c#]
最近刚刚接触CAD二次开发，记录下开发的过程。查阅很多资料。
C#读取DWG文件
struct BITMAPFILEHEADER
{
public short bfType;
public int bfSize;
public short bfReserved1;
public short bfReserved2;
public int bfOffBits;
}
public static GetDwgImage(string
FileName)
{
if (!((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
myImg = null;
try
{DwgF = new FileStream(FileName, , );
//文件流
br = new BinaryReader(DwgF);
(13, ); //从第十三字节开始读取
PosSentinel = t32(); //第13到17字节指示缩略图描述块的位置
(PosSentinel + 30, );
//将指针移到缩略图描述块的第31字节
TypePreview = te(); //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 = t32(); //DWG文件保存的位图所在位置
LenBMP = t32(); //位图的大小
(PosBMP + 14, ); //移动指针到位图块
biBitCount = t16(); //读取比特深度
(PosBMP, ); //从位图块开始处读取全部位图内容备用
BMPInfo = tes(LenBMP); //不包含文件头的位图信息
();
();
= 19778; //建立位图文件头
if (biBitCount < 9)
{
= 54 + 4 * (int)((2, biBitCount)) +
LenBMP;
}
else
{
= 54 + LenBMP;
}
rved1 = 0; //保留字节
rved2 = 0; //保留字节
its = 14 + 40 + 1024; //图像数据偏移//以下开始写入位图文件头
(); //文件类型
(); //文件大小
(rved1); //0
(rved2); //0
(its); //图像数据偏移
(BMPInfo); //写入位图
(0, ); //指针移到文件开始处
myImg = ream(BMPF); //创建位图文件对象
();
();
}
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 (e == "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 (e == "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
(FileName, pPath + @"/",
true);
Image image = GetDwgImage(pPath +
@"/");
(pPath + @"/");
return image;}
else
{
throw new Exception(e);
}
}
catch (Exception ex)
{
throw new Exception(e);
}
finally
{
if (DwgF != null)
{
();
}
if (br != null)
{
();
}
();
();
}
}
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
///
///显示DWG文件
///
///
name="Pwidth">要显示的宽度
///
name="PHeight">要显示的高度
///public static ShowDWG(int Pwidth,intPHeight,string FilePath){ image = GetDwgImage(FilePath);Bitmap bitmap = new Bitmap(image);int Height = ;int Width = ;Bitmap newbitmap = new Bitmap(Width, Height);Bitmap oldbitmap = (Bitmap)bitmap;Color pixel;for (int x = 1; x < Width; x++){for (int y = 1; y < Height; y++){pixel = el(x, y);int r = pixel.R, g = pixel.G, b = pixel.B;if ( == "ffffffff" || == "ff000000"){r = 255 - pixel.R;g = 255 - pixel.G;b = 255 - pixel.B;}el(x, y, gb(r, g, b));}}Bitmap bt = new Bitmap(newbitmap, Pwidth, PHeight);return newbitmap;}
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