[feature] Add expression for square by diagonal and rectangle from 3 …

…points

With the new class QgsQuadrilateral, we can add expressions to create a square by a diagonal and rectangles by 3 points

resources/function_help/json/make_rectangle_3points

@@ -0,0 +1,17 @@
+{
+  "name": "make_rectangle_3points",
+  "type": "function",
+  "description": "Creates a rectangle from 3 points.",
+  "variableLenArguments": true,
+  "arguments": [
+    {"arg":"point1", "description": "First point."},
+    {"arg":"point2", "description": "Second point."},
+    {"arg":"point3", "description": "Third point."},
+    {"arg":"option", "optional": true, "default": "0", "description":
+    "An optional argument to construct the rectangle. By default this value is 0. Value can be 0 (distance) or 1 (projected). Option distance: Second distance is equal to the distance between 2nd and 3rd point. Option projected: Second distance is equal to the distance of the perpendicular projection of the 3rd point on the segment or its extension."}
+  ],
+  "examples": [
+    { "expression":"geom_to_wkt(make_rectangle(make_point(0, 0), make_point(0,5), make_point(5, 5), 0)))", "returns":"'Polygon ((0 0, 0 5, 5 5, 5 0, 0 0))'"},
+    { "expression":"geom_to_wkt(make_rectangle(make_point(0, 0), make_point(0,5), make_point(5, 3), 1)))", "returns":"'Polygon ((0 0, 0 5, 5 5, 5 0, 0 0))'"}
+  ]
+}

resources/function_help/json/make_square

@@ -0,0 +1,14 @@
+{
+  "name": "make_square",
+  "type": "function",
+  "description": "Creates a square from a diagonal.",
+  "variableLenArguments": true,
+  "arguments": [
+    {"arg":"point1", "description": "First point of the regular polygon"},
+    {"arg":"point2", "description": "Second point"}
+  ],
+  "examples": [
+    { "expression":"geom_to_wkt(make_square( make_point(0,0), make_point(5,5)))", "returns":"'Polygon ((0 0, -0 5, 5 5, 5 0, 0 0))'"},
+    { "expression":"geom_to_wkt(make_square( make_point(5,0), make_point(5,5)))", "returns":"'Polygon ((5 0, 2.5 2.5, 5 5, 7.5 2.5, 5 0))'"}
+  ]
+}

src/core/expression/qgsexpressionfunction.cpp

@@ -30,6 +30,7 @@
 #include "qgstriangle.h"
 #include "qgscurve.h"
 #include "qgsregularpolygon.h"
+#include "qgsquadrilateral.h"
 #include "qgsmultipolygon.h"
 #include "qgsogcutils.h"
 #include "qgsdistancearea.h"
@@ -2487,6 +2488,60 @@ static QVariant fcnMakeRegularPolygon( const QVariantList &values, const QgsExpr
 
 }
 
+static QVariant fcnMakeSquare( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
+{
+  QgsGeometry pt1 = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
+  if ( pt1.isNull() )
+    return QVariant();
+  if ( pt1.type() != QgsWkbTypes::PointGeometry || pt1.isMultipart() )
+    return QVariant();
+
+  QgsGeometry pt2 = QgsExpressionUtils::getGeometry( values.at( 1 ), parent );
+  if ( pt2.isNull() )
+    return QVariant();
+  if ( pt2.type() != QgsWkbTypes::PointGeometry || pt2.isMultipart() )
+    return QVariant();
+
+  const QgsPoint *point1 = qgsgeometry_cast< const QgsPoint *>( pt1.constGet() );
+  const QgsPoint *point2 = qgsgeometry_cast< const QgsPoint *>( pt2.constGet() );
+  QgsQuadrilateral square = QgsQuadrilateral::squareFromDiagonal( *point1, *point2 );
+
+  return QVariant::fromValue( QgsGeometry( square.toPolygon() ) );
+}
+
+static QVariant fcnMakeRectangleFrom3Points( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
+{
+  QgsGeometry pt1 = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
+  if ( pt1.isNull() )
+    return QVariant();
+  if ( pt1.type() != QgsWkbTypes::PointGeometry || pt1.isMultipart() )
+    return QVariant();
+
+  QgsGeometry pt2 = QgsExpressionUtils::getGeometry( values.at( 1 ), parent );
+  if ( pt2.isNull() )
+    return QVariant();
+  if ( pt2.type() != QgsWkbTypes::PointGeometry || pt2.isMultipart() )
+    return QVariant();
+
+  QgsGeometry pt3 = QgsExpressionUtils::getGeometry( values.at( 2 ), parent );
+  if ( pt3.isNull() )
+    return QVariant();
+  if ( pt3.type() != QgsWkbTypes::PointGeometry || pt3.isMultipart() )
+    return QVariant();
+
+  QgsQuadrilateral::ConstructionOption option = static_cast< QgsQuadrilateral::ConstructionOption >( QgsExpressionUtils::getIntValue( values.at( 3 ), parent ) );
+  if ( ( option < QgsQuadrilateral::Distance ) || ( option > QgsQuadrilateral::Projected ) )
+  {
+    parent->setEvalErrorString( QObject::tr( "Option can be 0 (distance) or 1 (projected)" ) );
+    return QVariant();
+  }
+  const QgsPoint *point1 = qgsgeometry_cast< const QgsPoint *>( pt1.constGet() );
+  const QgsPoint *point2 = qgsgeometry_cast< const QgsPoint *>( pt2.constGet() );
+  const QgsPoint *point3 = qgsgeometry_cast< const QgsPoint *>( pt3.constGet() );
+  QgsQuadrilateral rect = QgsQuadrilateral::rectangleFrom3Points( *point1, *point2, *point3, option );
+  return QVariant::fromValue( QgsGeometry( rect.toPolygon() ) );
+}
+
 static QVariant pointAt( const QVariantList &values, const QgsExpressionContext *context, QgsExpression *parent ) // helper function
 {
   FEAT_FROM_CONTEXT( context, f );
@@ -4888,8 +4943,17 @@ const QList<QgsExpressionFunction *> &QgsExpression::Functions()
                                             << QgsExpressionFunction::Parameter( QStringLiteral( "geometry" ) )
                                             << QgsExpressionFunction::Parameter( QStringLiteral( "number_sides" ) )
                                             << QgsExpressionFunction::Parameter( QStringLiteral( "circle" ), true, 0 ),
-                                            fcnMakeRegularPolygon, QStringLiteral( "GeometryGroup" ) );
-
+                                            fcnMakeRegularPolygon, QStringLiteral( "GeometryGroup" ) )
+        << new QgsStaticExpressionFunction( QStringLiteral( "make_square" ), QgsExpressionFunction::ParameterList()
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "point1" ) )
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "point2" ) ),
+                                            fcnMakeSquare, QStringLiteral( "GeometryGroup" ) )
+        << new QgsStaticExpressionFunction( QStringLiteral( "make_rectangle_3points" ), QgsExpressionFunction::ParameterList()
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "point1" ) )
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "point2" ) )
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "point3" ) )
+                                            << QgsExpressionFunction::Parameter( QStringLiteral( "option" ), true, 0 ),
+                                            fcnMakeRectangleFrom3Points, QStringLiteral( "GeometryGroup" ) );
     QgsStaticExpressionFunction *xAtFunc = new QgsStaticExpressionFunction( QStringLiteral( "$x_at" ), 1, fcnXat, QStringLiteral( "GeometryGroup" ), QString(), true, QSet<QString>(), false, QStringList() << QStringLiteral( "xat" ) << QStringLiteral( "x_at" ) );
     xAtFunc->setIsStatic( false );
     sFunctions << xAtFunc;

tests/src/core/testqgsexpression.cpp

@@ -944,6 +944,21 @@ class TestQgsExpression: public QObject
       QTest::newRow( "make_regular_polygon bad (numEdges < 3)" ) << "make_regular_polygon(make_point(0,0), make_point(0,5), 2)" << true << QVariant();
       QTest::newRow( "make_regular_polygon" ) << "geom_to_wkt(make_regular_polygon(make_point(0,0), make_point(0,5), 5), 2)" << false << QVariant( "Polygon ((0 5, 4.76 1.55, 2.94 -4.05, -2.94 -4.05, -4.76 1.55, 0 5))" );
       QTest::newRow( "make_regular_polygon" ) << "geom_to_wkt(make_regular_polygon(make_point(0,0), project(make_point(0,0), 4.0451, radians(36)), 5, 1), 2)" << false << QVariant( "Polygon ((0 5, 4.76 1.55, 2.94 -4.05, -2.94 -4.05, -4.76 1.55, 0 5))" );
+      QTest::newRow( "make_square not geom (point 1)" ) << "make_square(make_line(make_point(1,2), make_point(3,4)), make_point(5,5))" << false << QVariant();
+      QTest::newRow( "make_square not geom (point 2)" ) << "make_square(make_point(0,0), make_line(make_point(1,2), make_point(3,4)))" << false << QVariant();
+      QTest::newRow( "make_square bad (point 1)" ) << "make_square('a', make_point(5,5))" << true << QVariant();
+      QTest::newRow( "make_square bad (point 2)" ) << "make_square(make_point(0,0), 'a')" << true << QVariant();
+      QTest::newRow( "make_square" ) << "geom_to_wkt(make_square(make_point(5, 5), make_point(1, 1)))" << false << QVariant( "Polygon ((5 5, 5 1, 1 1, 1 5, 5 5))" );
+      QTest::newRow( "make_rectangle_3points not geom (point 1)" ) << "make_rectangle_3points( make_line(make_point(1,2), make_point(3,4)), make_point(0,5), make_point(5,5))" << false << QVariant();
+      QTest::newRow( "make_rectangle_3points not geom (point 2)" ) << "make_rectangle_3points(make_point(0,0), make_line(make_point(1,2), make_point(3,4)), make_point(5,5))" << false << QVariant();
+      QTest::newRow( "make_rectangle_3points not geom (point 3)" ) << "make_rectangle_3points(make_point(0,0), make_point(0,5), make_line(make_point(1,2), make_point(3,4)))" << false << QVariant();
+      QTest::newRow( "make_rectangle_3points bad (point 1)" ) << "make_rectangle_3points('a', make_point(0,5), make_point(5,5))" << true << QVariant();
+      QTest::newRow( "make_rectangle_3points bad (point 2)" ) << "make_rectangle_3points(make_point(0,0), 'a', make_point(5,5))" << true << QVariant();
+      QTest::newRow( "make_rectangle_3points bad (point 3)" ) << "make_rectangle_3points(make_point(0,0), make_point(0,5), 'a')" << true << QVariant();
+      QTest::newRow( "make_rectangle_3points bad (invalid option)" ) << "make_rectangle_3points(make_point(0,0), make_point(0,5), make_point(5,5), 2)" << true << QVariant();
+      QTest::newRow( "make_rectangle_3points (distance default)" ) << "geom_to_wkt(make_rectangle_3points(make_point(0, 0), make_point(0,5), make_point(5, 5)))" << false << QVariant( "Polygon ((0 0, 0 5, 5 5, 5 0, 0 0))" );
+      QTest::newRow( "make_rectangle_3points (distance)" ) << "geom_to_wkt(make_rectangle_3points(make_point(0, 0), make_point(0,5), make_point(5, 5), 0))" << false << QVariant( "Polygon ((0 0, 0 5, 5 5, 5 0, 0 0))" );
+      QTest::newRow( "make_rectangle_3points (projected)" ) << "geom_to_wkt(make_rectangle_3points(make_point(0, 0), make_point(0,5), make_point(5, 3), 1))" << false << QVariant( "Polygon ((0 0, 0 5, 5 5, 5 0, 0 0))" );
       QTest::newRow( "x point" ) << "x(make_point(2.2,4.4))" << false << QVariant( 2.2 );
       QTest::newRow( "y point" ) << "y(make_point(2.2,4.4))" << false << QVariant( 4.4 );
       QTest::newRow( "z point" ) << "z(make_point(2.2,4.4,6.6))" << false << QVariant( 6.6 );