QGIS API Documentation  2.99.0-Master (0a63d1f)
qgis.h
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1 /***************************************************************************
2  qgis.h - QGIS namespace
3  -------------------
4  begin : Sat Jun 30 2002
5  copyright : (C) 2002 by Gary E.Sherman
6  email : sherman at mrcc.com
7  ***************************************************************************/
8 
9 /***************************************************************************
10  * *
11  * This program is free software; you can redistribute it and/or modify *
12  * it under the terms of the GNU General Public License as published by *
13  * the Free Software Foundation; either version 2 of the License, or *
14  * (at your option) any later version. *
15  * *
16  ***************************************************************************/
17 
18 #ifndef QGIS_H
19 #define QGIS_H
20 
21 #include <QEvent>
22 #include <QString>
23 #include <QRegExp>
24 #include <QMetaType>
25 #include <QVariant>
26 #include <QDateTime>
27 #include <QDate>
28 #include <QTime>
29 #include <QHash>
30 #include <stdlib.h>
31 #include <cfloat>
32 #include <cmath>
33 #include <qnumeric.h>
34 
35 #include "qgswkbtypes.h"
36 #include "qgis_core.h"
37 
41 class CORE_EXPORT Qgis
42 {
43  public:
44  // Version constants
45  //
47  static const QString QGIS_VERSION;
49  static const int QGIS_VERSION_INT;
51  static const QString QGIS_RELEASE_NAME;
53  static const char* QGIS_DEV_VERSION;
54 
55  // Enumerations
56  //
57 
61  enum DataType
62  {
63  UnknownDataType = 0,
64  Byte = 1,
65  UInt16 = 2,
66  Int16 = 3,
67  UInt32 = 4,
68  Int32 = 5,
69  Float32 = 6,
70  Float64 = 7,
71  CInt16 = 8,
72  CInt32 = 9,
73  CFloat32 = 10,
74  CFloat64 = 11,
75  ARGB32 = 12,
76  ARGB32_Premultiplied = 13
77  };
78 
80  enum UserEvent
81  {
82  // These first two are useful for threads to alert their parent data providers
83 
85  ProviderExtentCalcEvent = ( QEvent::User + 1 ),
86 
88  ProviderCountCalcEvent
89  };
90 
93  static const double DEFAULT_SEARCH_RADIUS_MM;
94 
96  static const float DEFAULT_MAPTOPIXEL_THRESHOLD;
97 
101  static const QColor DEFAULT_HIGHLIGHT_COLOR;
102 
105  static const double DEFAULT_HIGHLIGHT_BUFFER_MM;
106 
109  static const double DEFAULT_HIGHLIGHT_MIN_WIDTH_MM;
110 
115  static const double SCALE_PRECISION;
116 
117 };
118 
119 // hack to workaround warnings when casting void pointers
120 // retrieved from QLibrary::resolve to function pointers.
121 // It's assumed that this works on all systems supporting
122 // QLibrary
123 #define cast_to_fptr(f) f
124 
132 // based on Boojum's code from http://stackoverflow.com/questions/3556687/prevent-firing-signals-in-qt
133 template<class Object> class QgsSignalBlocker // clazy:exclude=rule-of-three
134 {
135  public:
136 
140  explicit QgsSignalBlocker( Object* object )
141  : mObject( object )
142  , mPreviousState( object->blockSignals( true ) )
143  {}
144 
146  {
147  mObject->blockSignals( mPreviousState );
148  }
149 
151  Object* operator->() { return mObject; }
152 
153  private:
154 
155  Object* mObject;
156  bool mPreviousState;
157 
158 };
159 
172 // based on Boojum's code from http://stackoverflow.com/questions/3556687/prevent-firing-signals-in-qt
173 template<class Object> inline QgsSignalBlocker<Object> whileBlocking( Object* object )
174 {
175  return QgsSignalBlocker<Object>( object );
176 }
177 
181 inline QString qgsDoubleToString( double a, int precision = 17 )
182 {
183  if ( precision )
184  return QString::number( a, 'f', precision ).remove( QRegExp( "\\.?0+$" ) );
185  else
186  return QString::number( a, 'f', precision );
187 }
188 
193 inline bool qgsDoubleNear( double a, double b, double epsilon = 4 * DBL_EPSILON )
194 {
195  const double diff = a - b;
196  return diff > -epsilon && diff <= epsilon;
197 }
198 
203 inline bool qgsFloatNear( float a, float b, float epsilon = 4 * FLT_EPSILON )
204 {
205  const float diff = a - b;
206  return diff > -epsilon && diff <= epsilon;
207 }
208 
210 inline bool qgsDoubleNearSig( double a, double b, int significantDigits = 10 )
211 {
212  // The most simple would be to print numbers as %.xe and compare as strings
213  // but that is probably too costly
214  // Then the fastest would be to set some bits directly, but little/big endian
215  // has to be considered (maybe TODO)
216  // Is there a better way?
217  int aexp, bexp;
218  double ar = frexp( a, &aexp );
219  double br = frexp( b, &bexp );
220 
221  return aexp == bexp &&
222  qRound( ar * pow( 10.0, significantDigits ) ) == qRound( br * pow( 10.0, significantDigits ) );
223 }
224 
226 inline double qgsRound( double x )
227 {
228  return x < 0.0 ? std::ceil( x - 0.5 ) : std::floor( x + 0.5 );
229 }
230 
239 CORE_EXPORT double qgsPermissiveToDouble( QString string, bool& ok );
240 
249 CORE_EXPORT int qgsPermissiveToInt( QString string, bool& ok );
250 
255 CORE_EXPORT bool qgsVariantLessThan( const QVariant& lhs, const QVariant& rhs );
256 
261 CORE_EXPORT bool qgsVariantGreaterThan( const QVariant& lhs, const QVariant& rhs );
262 
263 CORE_EXPORT QString qgsVsiPrefix( const QString& path );
264 
269 void CORE_EXPORT *qgsMalloc( size_t size );
270 
277 void CORE_EXPORT *qgsCalloc( size_t nmemb, size_t size );
278 
282 void CORE_EXPORT qgsFree( void *ptr );
283 
287 extern CORE_EXPORT const QString GEOWKT;
288 extern CORE_EXPORT const QString PROJECT_SCALES;
289 
291 extern CORE_EXPORT const QString GEOPROJ4;
293 const long GEOSRID = 4326;
295 const long GEOCRS_ID = 3452;
297 const long GEO_EPSG_CRS_ID = 4326;
299 extern CORE_EXPORT const QString GEO_EPSG_CRS_AUTHID;
301 const int PROJ_PREFIX_LEN = 6;
303 const int ELLPS_PREFIX_LEN = 7;
305 const int LAT_PREFIX_LEN = 7;
306 
309 const int USER_CRS_START_ID = 100000;
310 
312 extern CORE_EXPORT const QString GEO_NONE;
313 
314 //
315 // Constants for point symbols
316 //
317 
319 const double DEFAULT_POINT_SIZE = 2.0;
320 const double DEFAULT_LINE_WIDTH = 0.26;
321 
323 const double DEFAULT_SEGMENT_EPSILON = 1e-8;
324 
325 typedef QMap<QString, QString> QgsStringMap;
326 
333 typedef unsigned long long qgssize;
334 
335 #if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)) || defined(__clang__)
336 #define Q_NOWARN_DEPRECATED_PUSH \
337  _Pragma("GCC diagnostic push") \
338  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"");
339 #define Q_NOWARN_DEPRECATED_POP \
340  _Pragma("GCC diagnostic pop");
341 #elif defined(_MSC_VER)
342 #define Q_NOWARN_DEPRECATED_PUSH \
343  __pragma(warning(push)) \
344  __pragma(warning(disable:4996))
345 #define Q_NOWARN_DEPRECATED_POP \
346  __pragma(warning(pop))
347 #else
348 #define Q_NOWARN_DEPRECATED_PUSH
349 #define Q_NOWARN_DEPRECATED_POP
350 #endif
351 
352 #ifndef QGISEXTERN
353 #ifdef Q_OS_WIN
354 # define QGISEXTERN extern "C" __declspec( dllexport )
355 # ifdef _MSC_VER
356 // do not warn about C bindings returning QString
357 # pragma warning(disable:4190)
358 # endif
359 #else
360 # if defined(__GNUC__) || defined(__clang__)
361 # define QGISEXTERN extern "C" __attribute__ ((visibility ("default")))
362 # else
363 # define QGISEXTERN extern "C"
364 # endif
365 #endif
366 #endif
367 #endif
368 
369 #if defined(__clang__)
370 #define FALLTHROUGH //[[clang::fallthrough]]
371 #else
372 #define FALLTHROUGH
373 #endif
CORE_EXPORT QString qgsVsiPrefix(const QString &path)
Definition: qgis.cpp:209
static const QString QGIS_VERSION
Version string.
Definition: qgis.h:47
static const char * QGIS_DEV_VERSION
The development version.
Definition: qgis.h:53
bool qgsFloatNear(float a, float b, float epsilon=4 *FLT_EPSILON)
Compare two floats (but allow some difference)
Definition: qgis.h:203
DataType
Raster data types.
Definition: qgis.h:61
static const QColor DEFAULT_HIGHLIGHT_COLOR
Default highlight color.
Definition: qgis.h:101
void CORE_EXPORT * qgsCalloc(size_t nmemb, size_t size)
Allocates memory for an array of nmemb elements of size bytes each and returns a pointer to the alloc...
Definition: qgis.cpp:116
static const int QGIS_VERSION_INT
Version number used for comparing versions using the "Check QGIS Version" function.
Definition: qgis.h:49
QMap< QString, QString > QgsStringMap
Definition: qgis.h:325
~QgsSignalBlocker()
Definition: qgis.h:145
bool qgsDoubleNear(double a, double b, double epsilon=4 *DBL_EPSILON)
Compare two doubles (but allow some difference)
Definition: qgis.h:193
The Qgis class provides global constants for use throughout the application.
Definition: qgis.h:41
CORE_EXPORT bool qgsVariantLessThan(const QVariant &lhs, const QVariant &rhs)
Compares two QVariant values and returns whether the first is less than the second.
Definition: qgis.cpp:136
UserEvent
User defined event types.
Definition: qgis.h:80
double qgsRound(double x)
A round function which returns a double to guard against overflows.
Definition: qgis.h:226
QgsSignalBlocker(Object *object)
Constructor for QgsSignalBlocker.
Definition: qgis.h:140
CORE_EXPORT const QString GEO_NONE
Constant that holds the string representation for "No ellips/No CRS".
Definition: qgis.cpp:71
const double DEFAULT_SEGMENT_EPSILON
Default snapping tolerance for segments.
Definition: qgis.h:323
QString qgsDoubleToString(double a, int precision=17)
Returns a string representation of a double.
Definition: qgis.h:181
const int ELLPS_PREFIX_LEN
The length of the string "+ellps=".
Definition: qgis.h:303
const long GEOCRS_ID
Magic number for a geographic coord sys in QGIS srs.db tbl_srs.srs_id.
Definition: qgis.h:295
static const double DEFAULT_SEARCH_RADIUS_MM
Identify search radius in mm.
Definition: qgis.h:93
CORE_EXPORT double qgsPermissiveToDouble(QString string, bool &ok)
Converts a string to a double in a permissive way, e.g., allowing for incorrect numbers of digits bet...
Definition: qgis.cpp:87
CORE_EXPORT const QString GEOPROJ4
PROJ4 string that represents a geographic coord sys.
Definition: qgis.cpp:50
RAII signal blocking class.
Definition: qgis.h:133
void CORE_EXPORT qgsFree(void *ptr)
Frees the memory space pointed to by ptr.
Definition: qgis.cpp:131
unsigned long long qgssize
Qgssize is used instead of size_t, because size_t is stdlib type, unknown by SIP, and it would be har...
Definition: qgis.h:333
const double DEFAULT_POINT_SIZE
Magic number that determines the default point size for point symbols.
Definition: qgis.h:319
static const float DEFAULT_MAPTOPIXEL_THRESHOLD
Default threshold between map coordinates and device coordinates for map2pixel simplification.
Definition: qgis.h:96
const int USER_CRS_START_ID
Magick number that determines whether a projection crsid is a system (srs.db) or user (~/...
Definition: qgis.h:309
QgsSignalBlocker< Object > whileBlocking(Object *object)
Temporarily blocks signals from a QObject while calling a single method from the object.
Definition: qgis.h:173
const long GEOSRID
Magic number for a geographic coord sys in POSTGIS SRID.
Definition: qgis.h:293
static const QString QGIS_RELEASE_NAME
Release name.
Definition: qgis.h:51
bool qgsDoubleNearSig(double a, double b, int significantDigits=10)
Compare two doubles using specified number of significant digits.
Definition: qgis.h:210
const double DEFAULT_LINE_WIDTH
Definition: qgis.h:320
CORE_EXPORT const QString PROJECT_SCALES
Definition: qgis.cpp:65
const int LAT_PREFIX_LEN
The length of the string "+lat_1=".
Definition: qgis.h:305
static const double DEFAULT_HIGHLIGHT_MIN_WIDTH_MM
Default highlight line/outline minimum width in mm.
Definition: qgis.h:109
const int PROJ_PREFIX_LEN
The length of the string "+proj=".
Definition: qgis.h:301
static const double DEFAULT_HIGHLIGHT_BUFFER_MM
Default highlight buffer in mm.
Definition: qgis.h:105
CORE_EXPORT int qgsPermissiveToInt(QString string, bool &ok)
Converts a string to an integer in a permissive way, e.g., allowing for incorrect numbers of digits b...
Definition: qgis.cpp:94
CORE_EXPORT bool qgsVariantGreaterThan(const QVariant &lhs, const QVariant &rhs)
Compares two QVariant values and returns whether the first is greater than the second.
Definition: qgis.cpp:204
void CORE_EXPORT * qgsMalloc(size_t size)
Allocates size bytes and returns a pointer to the allocated memory.
Definition: qgis.cpp:101
Object * operator->()
Returns pointer to blocked QObject.
Definition: qgis.h:151
const long GEO_EPSG_CRS_ID
Magic number for a geographic coord sys in EpsgCrsId ID format.
Definition: qgis.h:297
static const double SCALE_PRECISION
Fudge factor used to compare two scales.
Definition: qgis.h:115
CORE_EXPORT const QString GEO_EPSG_CRS_AUTHID
Geographic coord sys from EPSG authority.
Definition: qgis.cpp:69
CORE_EXPORT const QString GEOWKT
Wkt string that represents a geographic coord sys.
Definition: qgis.cpp:52