DGNLib：阅读与写入DGN文件的C/C++库

Title: ISFF




Table of Contents
=================

    Intergraph Standard File Formats (Element Structure)
    

Intergraph Standard File Formats (Element Structure)
====================================================

The Intergraph Standard File Formats (ISFF) are the file formats common to 
    MicroStation and Intergraph's Interactive Graphics Design System 
    (IGDS). ISFF is now available to the public. This enables Intergraph 
    customers and third-party developers to create custom applications for 
    MicroStation that read and write ISFF format without a license from 
    Intergaph.
    
    Types of Files
    Design File Header
    Primitive and complex elements
    Element Representation
    Common Element Parameters
    Level Symbology (Type 10)
    Library Cell Header (Type 1)
    Cell Header (Type 2)

    Line Elements (Type 3)
    Line String (Type 4), Shape (Type 6), Curve (Type 11), and B-spline 
    Pole Element (Type 21)
    Text Node Header (Type 7)
    Complex Chain Headers (Type 12) and Complex Shape Headers (Type 14)
    Ellipse Elements (Type 15)
    Arc Elements (Type 16)
    Text Elements (Type 17)
    3D Surface Header (Type 18) and 3D Solid Header (Type 19)
    Point String Elements (Type 22)
    Cone Elements (Type 23)
    B-spline Elements (Type 21, 24, 25, 26, 27, 28)
    Raster Header Element (Type 87)
    Raster Data Elements (Type 88)
    Group Data Elements (Type 5)
    MicroStation Application Elements (Type 66)
 

Types of Files
--------------

ISFF consists of several types of binary files
 *  Design files are sequential, variable-length files with variable-length 
    records for the Design File Header, file set-up information, graphic 
    elements, and non-graphic data.
    User-defined elements begin with the fourth element.
    Design files are typically designated with the extension ".dgn."
 *  Cell libraries store cell definitions for placement in design files. A 
    cell library consists of a file header (type 5) element followed by 
    individual cell descriptions. Each cell is a complex element that