src/core/qgis.h

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/***************************************************************************
                          qgis.h - QGIS namespace
                             -------------------
    begin                : Sat Jun 30 2002
    copyright            : (C) 2002 by Gary E.Sherman
    email                : sherman at mrcc.com
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program 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.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGIS_H
#define QGIS_H

#include <QEvent>
#include <QString>
#include <QMetaType>
#include <QVariant>
#include <stdlib.h>
#include <cfloat>
#include <cmath>
#include <qnumeric.h>

class CORE_EXPORT QGis
{
  public:
    // Version constants
    //
    // Version string
    static const char* QGIS_VERSION;
    // Version number used for comparing versions using the "Check QGIS Version" function
    static const int QGIS_VERSION_INT;
    // Release name
    static const char* QGIS_RELEASE_NAME;
    // The development version
    static const char* QGIS_DEV_VERSION;

    // Enumerations
    //

    // Feature types
    enum WkbType
    {
      WKBUnknown = 0,
      WKBPoint = 1,
      WKBLineString,
      WKBPolygon,
      WKBMultiPoint,
      WKBMultiLineString,
      WKBMultiPolygon,
      WKBNoGeometry = 100, //attributes only
      WKBPoint25D = 0x80000001,
      WKBLineString25D,
      WKBPolygon25D,
      WKBMultiPoint25D,
      WKBMultiLineString25D,
      WKBMultiPolygon25D,
    };

    static WkbType singleType( WkbType type )
    {
      switch ( type )
      {
        case WKBMultiPoint:         return WKBPoint;
        case WKBMultiLineString:    return WKBLineString;
        case WKBMultiPolygon:       return WKBPolygon;
        case WKBMultiPoint25D:      return WKBPoint25D;
        case WKBMultiLineString25D: return WKBLineString25D;
        case WKBMultiPolygon25D:    return WKBPolygon25D;
        default:                    return type;
      }
    }

    static WkbType flatType( WkbType type )
    {
      switch ( type )
      {
        case WKBPoint25D:           return WKBPoint;
        case WKBLineString25D:      return WKBLineString;
        case WKBPolygon25D:         return WKBPolygon;
        case WKBMultiPoint25D:      return WKBMultiPoint;
        case WKBMultiLineString25D: return WKBMultiLineString;
        case WKBMultiPolygon25D:    return WKBMultiPolygon;
        default:                    return type;
      }
    }

    static int wkbDimensions( WkbType type )
    {
      switch ( type )
      {
        case WKBUnknown:            return 0;
        case WKBNoGeometry:         return 0;
        case WKBPoint25D:           return 3;
        case WKBLineString25D:      return 3;
        case WKBPolygon25D:         return 3;
        case WKBMultiPoint25D:      return 3;
        case WKBMultiLineString25D: return 3;
        case WKBMultiPolygon25D:    return 3;
        default:                    return 2;
      }
    }

    enum GeometryType
    {
      Point,
      Line,
      Polygon,
      UnknownGeometry,
      NoGeometry
    };

    static const char *vectorGeometryType( GeometryType type )
    {
      switch ( type )
      {
        case Point:           return "Point";
        case Line:            return "Line";
        case Polygon:         return "Polygon";
        case UnknownGeometry: return "Unknown geometry";
        case NoGeometry:      return "No geometry";
        default:              return "Invalid type";
      }
    }

    static const char *featureType( WkbType type )
    {
      switch ( type )
      {
        case WKBUnknown:            return "WKBUnknown";
        case WKBPoint:              return "WKBPoint";
        case WKBLineString:         return "WKBLineString";
        case WKBPolygon:            return "WKBPolygon";
        case WKBMultiPoint:         return "WKBMultiLineString";
        case WKBMultiPolygon:       return "WKBMultiPolygon";
        case WKBNoGeometry:         return "WKBNoGeometry";
        case WKBPoint25D:           return "WKBPoint25D";
        case WKBLineString25D:      return "WKBLineString25D";
        case WKBPolygon25D:         return "WKBPolygon25D";
        case WKBMultiPoint25D:      return "WKBMultiPoint25D";
        case WKBMultiLineString25D: return "WKBMultiLineString25D";
        case WKBMultiPolygon25D:    return "WKBMultiPolygon25D";
        default:                    return "invalid wkbtype";
      }
    }

    enum DataType
    {                UnknownDataType = 0,        Byte = 1,     UInt16 = 2,        Int16 = 3,  UInt32 = 4,     Int32 = 5,      Float32 = 6,     Float64 = 7,                              CInt16 = 8,                              CInt32 = 9,                            CFloat32 = 10,                            CFloat64 = 11,                      ARGB32 = 12,        ARGB32_Premultiplied = 13
    };


    enum UnitType
    {
      Meters = 0,
      Feet = 1,
      Degrees = 2, //for 1.0 api backwards compatibility
      UnknownUnit = 3,

      // for [1.4;1.8] api compatibility
      DecimalDegrees = 2,         // was 2
      DegreesMinutesSeconds = 2,  // was 4
      DegreesDecimalMinutes = 2,  // was 5
    };

    // Added in version 2.0
    static QString toLiteral( QGis::UnitType unit );
    // Added in version 2.0
    static UnitType fromLiteral( QString  literal, QGis::UnitType defaultType = UnknownUnit );
    // Added in version 2.0
    static QString tr( QGis::UnitType unit );

    enum UserEvent
    {
      // These first two are useful for threads to alert their parent data providers

      ProviderExtentCalcEvent = ( QEvent::User + 1 ),

      ProviderCountCalcEvent
    };

    static const double DEFAULT_IDENTIFY_RADIUS;

  private:
    // String representation of unit types (set in qgis.cpp)
    static const char *qgisUnitTypes[];

};

// hack to workaround warnings when casting void pointers
// retrieved from QLibrary::resolve to function pointers.
// It's assumed that this works on all systems supporting
// QLibrary
inline void ( *cast_to_fptr( void *p ) )()
{
  union
  {
    void *p;
    void ( *f )();
  } u;

  u.p = p;
  return u.f;
}

//
// compare two doubles (but allow some difference)
//
inline bool qgsDoubleNear( double a, double b, double epsilon = 4 * DBL_EPSILON )
{
  const double diff = a - b;
  return diff > -epsilon && diff <= epsilon;
}

//
// compare two doubles using specified number of significant digits
//
inline bool qgsDoubleNearSig( double a, double b, int significantDigits = 10 )
{
  // The most simple would be to print numbers as %.xe and compare as strings
  // but that is probably too costly
  // Then the fastest would be to set some bits directly, but little/big endian
  // has to be considered (maybe TODO)
  // Is there a better way?
  int aexp, bexp;
  double ar = frexp( a, &aexp );
  double br = frexp( b, &bexp );

  return aexp == bexp &&
         qRound( ar * pow( 10.0, significantDigits ) ) == qRound( br * pow( 10.0, significantDigits ) ) ;
}

bool qgsVariantLessThan( const QVariant& lhs, const QVariant& rhs );

bool qgsVariantGreaterThan( const QVariant& lhs, const QVariant& rhs );

void CORE_EXPORT *qgsMalloc( size_t size );

void CORE_EXPORT *qgsCalloc( size_t nmemb, size_t size );

void CORE_EXPORT qgsFree( void *ptr );

extern CORE_EXPORT const QString GEOWKT;
extern CORE_EXPORT const QString PROJECT_SCALES;

extern CORE_EXPORT const QString GEOPROJ4;
const long GEOSRID = 4326;
const long GEOCRS_ID = 3452;
const long GEO_EPSG_CRS_ID = 4326;
extern CORE_EXPORT const QString GEO_EPSG_CRS_AUTHID;
const int PROJ_PREFIX_LEN = 6;
const int ELLPS_PREFIX_LEN = 7;
const int LAT_PREFIX_LEN = 7;
const int USER_CRS_START_ID = 100000;

// Added in version 2.0
extern CORE_EXPORT const QString GEO_NONE;

//
// Constants for point symbols
//

const double MINIMUM_POINT_SIZE = 0.1;
const double DEFAULT_POINT_SIZE = 2.0;
const double DEFAULT_LINE_WIDTH = 0.26;

const double DEFAULT_SEGMENT_EPSILON = 1e-8;

typedef QMap<QString, QString> QgsStringMap;

// FIXME: also in qgisinterface.h
#ifndef QGISEXTERN
#ifdef WIN32
#  define QGISEXTERN extern "C" __declspec( dllexport )
#  ifdef _MSC_VER
// do not warn about C bindings returing QString
#    pragma warning(disable:4190)
#  endif
#else
#  define QGISEXTERN extern "C"
#endif
#endif

#endif