Refactor QgsCoordinateUtils to expose precision from crs method

(cherry picked from commit fccb273)
qgis · Mar 2, 2023 · 68ade5e · 68ade5e
1 parent e626419
commit 68ade5e
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Showing 3 changed files with 31 additions and 1 deletion.
diff --git a/src/core/qgscoordinateutils.cpp b/src/core/qgscoordinateutils.cpp
@@ -96,6 +96,11 @@ int QgsCoordinateUtils::calculateCoordinatePrecisionForCrs( const QgsCoordinateR
     return prj->readNumEntry( QStringLiteral( "PositionPrecision" ), QStringLiteral( "/DecimalPlaces" ), 6 );
   }
 
+  return calculateCoordinatePrecision( crs );
+}
+
+int QgsCoordinateUtils::calculateCoordinatePrecision( const QgsCoordinateReferenceSystem &crs )
+{
   const QgsUnitTypes::DistanceUnit unit = crs.mapUnits();
   if ( unit == QgsUnitTypes::DistanceDegrees )
   {

diff --git a/src/core/qgscoordinateutils.h b/src/core/qgscoordinateutils.h
@@ -62,14 +62,28 @@ class CORE_EXPORT QgsCoordinateUtils
     Q_INVOKABLE static int calculateCoordinatePrecision( double mapUnitsPerPixel, const QgsCoordinateReferenceSystem &mapCrs, QgsProject *project = nullptr );
 
     /**
-     * Calculates coordinate precision for a CRS / Project. Considers CRS units and project settings
+     * Calculates coordinate precision for a \a crs and \a project.
+     *
+     * This method checks whether the \a project has explicit precision settings, and if not
+     * calculates a precision based on CRS units.
+     *
      * \param crs Coordinate system
      * \param project QGIS project. Takes QgsProject::instance() if NULL
+     *
      * \returns number of decimal places behind the dot
      * \since QGIS 3.18
      */
     Q_INVOKABLE static int calculateCoordinatePrecisionForCrs( const QgsCoordinateReferenceSystem &crs, QgsProject *project = nullptr );
 
+    /**
+     * Calculates a reasonable coordinate precision for a \a crs.
+     *
+     * This method considers the CRS units only.
+     *
+     * \since QGIS 3.30
+     */
+    Q_INVOKABLE static int calculateCoordinatePrecision( const QgsCoordinateReferenceSystem &crs );
+
     /**
      * Formats a \a point coordinate for use with the specified \a project, respecting the project's
      * coordinate display settings.

diff --git a/tests/src/core/testqgscoordinateutils.cpp b/tests/src/core/testqgscoordinateutils.cpp
@@ -24,6 +24,7 @@ class TestQgsCoordinateUtils : public QObject
     Q_OBJECT
   private slots:
 
+    void testPrecisionForCrs();
     void testDegreeWithSuffix();
     void testLocale();
     void initTestCase();
@@ -42,6 +43,16 @@ void TestQgsCoordinateUtils::cleanupTestCase()
   QgsApplication::exitQgis();
 }
 
+void TestQgsCoordinateUtils::testPrecisionForCrs()
+{
+  // 8 decimal places for degrees based crs
+  QCOMPARE( QgsCoordinateUtils::calculateCoordinatePrecision( QgsCoordinateReferenceSystem( "EPSG:4326" ) ), 8 );
+  // 3 decimal places for others
+  QCOMPARE( QgsCoordinateUtils::calculateCoordinatePrecision( QgsCoordinateReferenceSystem( "EPSG:3857" ) ), 3 );
+  QCOMPARE( QgsCoordinateUtils::calculateCoordinatePrecision( QgsCoordinateReferenceSystem( "EPSG:3111" ) ), 3 );
+  QCOMPARE( QgsCoordinateUtils::calculateCoordinatePrecision( QgsCoordinateReferenceSystem() ), 3 );
+}
+
 void TestQgsCoordinateUtils::testDegreeWithSuffix()
 {
   bool ok = false ;