Dxf库中的DL_Codes类

在 DXF 文件格式中，DL_Codes 通常是一个用于表示不同类型数据的枚举类或常量集合。这些代码用于标识 DXF 文件中各种数据元素的类型，例如实体类型、属性类型、颜色值等。通过使用 DL_Codes，您可以更轻松地解析和处理 DXF 文件中的数据。

以下是一个简单的示例，展示了如何在 DXF 文件解析中使用 DL_Codes：

enum DL_Codes {
    // 实体类型代码
    ENTITY_TYPE_LINE = 0,
    ENTITY_TYPE_CIRCLE = 1,
    ENTITY_TYPE_ARC = 2,

    // 颜色代码
    COLOR_RED = 1,
    COLOR_GREEN = 2,
    COLOR_BLUE = 3,

    // 线型代码
    LINE_TYPE_CONTINUOUS = 0,
    LINE_TYPE_DASHED = 1,
    LINE_TYPE_DOTTED = 2
};

// 解析 DXF 文件中的实体
void parseEntity(int type, int color, int lineType) {
    if (type == ENTITY_TYPE_LINE) {
        // 处理线段实体
    } else if (type == ENTITY_TYPE_CIRCLE) {
        // 处理圆实体
    } else if (type == ENTITY_TYPE_ARC) {
        // 处理圆弧实体
    }

    // 根据颜色和线型处理其他属性
}

// 在解析过程中使用 DL_Codes
parseEntity(ENTITY_TYPE_LINE, COLOR_RED, LINE_TYPE_DASHED);

在上面的示例中，我们定义了一个简单的 DL_Codes 枚举类，其中包含了实体类型、颜色、线型等代码的常量定义。然后，在解析 DXF 文件时，我们可以使用这些常量来识别并处理不同类型的数据元素。

请注意，上面的示例是一个简化的示例，实际的 DXF 文件解析过程可能会更复杂，具体取决于您的需求和处理逻辑。您可以根据您所使用的 DXF 文件解析库的 API 设计和文档，了解如何正确使用 DL_Codes 或类似的枚举类型。

源码：

/****************************************************************************
** Copyright (C) 2001-2013 RibbonSoft, GmbH. All rights reserved.
** Copyright (C) 2001 Robert J. Campbell Jr.
**
** This file is part of the dxflib project.
**
** This file is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** Licensees holding valid dxflib Professional Edition licenses may use
** this file in accordance with the dxflib Commercial License
** Agreement provided with the Software.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.ribbonsoft.com for further details.
**
** Contact info@ribbonsoft.com if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/

/**
 * Defines common DXF codes and constants.
 */

#ifndef DXF_CODES_H
#define DXF_CODES_H

#include "dl_global.h"

#if defined(__OS2__)||defined(__EMX__)
#define strcasecmp( s, t ) stricmp( s, t )
#endif

#if defined(_WIN32)
#ifndef strcasecmp  // on mingw, strcasecmp is defined
#define strcasecmp( s, t ) stricmp( s, t )
#endif
#endif


#ifdef _WIN32
#undef M_PI
#define M_PI 3.14159265358979323846
#endif

#ifndef M_PI
#define M_PI 3.1415926535897932384626433832795
#endif

#define DL_DXF_MAXLINE      1024
#define DL_DXF_MAXGROUPCODE 1100

// used to mark invalid vectors:
// #define DL_DXF_MAXDOUBLE 1.0E+10

/**
 * Codes for colors and DXF versions.
 */
class DXFLIB_EXPORT DL_Codes
{
public:
    /**
     * Standard DXF colors.
     */
    enum color
    {
        black   = 250,
        green   = 3,
        red = 1,
        brown   = 15,
        yellow  = 2,
        cyan = 4,
        magenta = 6,
        gray    = 8,
        blue    = 5,
        l_blue  = 163,
        l_green = 121,
        l_cyan  = 131,
        l_red = 23,
        l_magenta = 221,
        l_gray  = 252,
        white   = 7,
        bylayer = 256,
        byblock = 0
    };

    /**
     * Version numbers for the DXF Format.
     */
    enum version
    {
        AC1009_MIN,     // R12, minimalistic
        AC1009,         // R12
        AC1012,
        AC1014,
        AC1015          // R2000
    };
};


// Extended color palette:
// The first entry is only for direct indexing starting w