Add QgsScaleExpression subclass for sized based expressions

qgis · Apr 29, 2015 · 70b91b6 · 70b91b6
1 parent 9b56618
commit 70b91b6
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diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
@@ -162,6 +162,7 @@ SET(QGIS_CORE_SRCS
   qgsrectangle.cpp
   qgsrunprocess.cpp
   qgsscalecalculator.cpp
+  qgsscaleexpression.cpp
   qgsscaleutils.cpp
   qgssimplifymethod.cpp
   qgssnapper.cpp
@@ -546,6 +547,7 @@ SET(QGIS_CORE_HDRS
   qgsrenderchecker.h
   qgsrendercontext.h
   qgsscalecalculator.h
+  qgsscaleexpression.h
   qgsscaleutils.h
   qgssimplifymethod.h
   qgssnapper.h

diff --git a/src/core/qgsscaleexpression.cpp b/src/core/qgsscaleexpression.cpp
@@ -0,0 +1,104 @@
+
+/***************************************************************************
+ qgsscaleexpression.cpp
+ ---------------------
+ begin                : November 2015
+ copyright            : (C) 2015 by Vincent Mora
+ email                : vincent dor mora at oslandia dot 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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsscaleexpression.h"
+
+#include <QStringList>
+#include <qmath.h>
+
+void QgsScaleExpression::init()
+{
+  bool ok;
+  if ( rootNode() )
+  {
+    const NodeFunction * f = dynamic_cast<const NodeFunction*>( rootNode() );
+    if ( f )
+    {
+      QList<Node*> args = f->args()->list();
+      if ( "scale_linear" == Functions()[f->fnIndex()]->name() )
+      {
+        mType = Linear;
+      }
+      if ( "scale_exp" == Functions()[f->fnIndex()]->name() )
+      {
+        const double exp = QgsExpression( args[5]->dump() ).evaluate().toDouble( &ok );
+        if ( ! ok ) return;
+        if ( qAbs( exp - .57 ) < .001 ) mType = Flannery;
+        else if ( qAbs( exp - .5 ) < .001 ) mType = Area;
+        else return;
+      }
+      mMinValue = QgsExpression( args[1]->dump() ).evaluate().toDouble( &ok );
+      if ( ! ok ) return;
+      mMaxValue = QgsExpression( args[2]->dump() ).evaluate().toDouble( &ok );
+      if ( ! ok ) return;
+      mMinSize = QgsExpression( args[3]->dump() ).evaluate().toDouble( &ok );
+      if ( ! ok ) return;
+      mMaxSize = QgsExpression( args[4]->dump() ).evaluate().toDouble( &ok );
+      if ( ! ok ) return;
+      mExpression = args[0]->dump();
+    }
+  }
+}
+
+QgsScaleExpression::QgsScaleExpression( const QString & expr )
+    : QgsExpression( expr )
+{
+  init();
+}
+
+QgsScaleExpression::QgsScaleExpression( Type type, const QString & baseExpr, double minValue, double maxValue, double minSize, double maxSize )
+    : QgsExpression( createExpression( type, baseExpr, minValue, maxValue, minSize, maxSize ) )
+{
+  init();
+}
+
+QString QgsScaleExpression::createExpression( Type type, const QString & baseExpr, double minValue, double maxValue, double minSize, double maxSize )
+{
+  switch ( type )
+  {
+    case Linear:
+      return "scale_linear(" + baseExpr
+             + ", " + QString::number( minValue )
+             + ", " + QString::number( maxValue )
+             + ", " + QString::number( minSize )
+             + ", " + QString::number( maxSize ) + ")";
+    case Area:
+      return "scale_exp(" + baseExpr
+             + ", " + QString::number( minValue )
+             + ", " + QString::number( maxValue )
+             + ", " + QString::number( minSize )
+             + ", " + QString::number( maxSize ) + ", .5)";
+    case Flannery:
+      return "scale_exp(" + baseExpr
+             + ", " + QString::number( minValue )
+             + ", " + QString::number( maxValue )
+             + ", " + QString::number( minSize )
+             + ", " + QString::number( maxSize ) + ", .57)";
+  }
+  return "";
+}
+
+
+double QgsScaleExpression::size( double value ) const
+{
+  switch ( mType )
+  {
+    case Linear: return mMinSize + ( qBound( mMinValue, value, mMaxValue ) - mMinValue ) * ( mMaxSize - mMinSize ) / ( mMaxValue - mMinValue );
+    case Area: return qPow( qBound( mMinValue, value, mMaxValue ) - mMinValue, .5 ) * ( mMaxSize - mMinSize ) / qPow( mMaxValue - mMinValue, .5 );
+    case Flannery: return qPow( qBound( mMinValue, value, mMaxValue ) - mMinValue, .57 ) * ( mMaxSize - mMinSize ) / qPow( mMaxValue - mMinValue, .57 );
+  }
+  return 0;
+}
diff --git a/src/core/qgsscaleexpression.h b/src/core/qgsscaleexpression.h
@@ -0,0 +1,63 @@
+
+/***************************************************************************
+ qgsscaleexpression.h
+ ---------------------
+ begin                : November 2015
+ copyright            : (C) 2015 by Vincent Mora
+ email                : vincent dor mora at oslandia dot 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 QGSSCALEEXPRESSION_H
+#define QGSSCALEEXPRESSION_H
+
+#include "qgsexpression.h"
+
+//! Class to retrieve parameters of a
+//! scale expression (size or width)
+//!
+//! It derives from QgsExpression,
+class QgsScaleExpression: public QgsExpression
+{
+public:
+  enum Type {Linear, Area, Flannery};
+
+  //! parse string like an expression and
+  //! detemine if it's a size expression
+  QgsScaleExpression( const QString & expr );
+
+  //! setup expression from parameters
+  QgsScaleExpression( Type type, const QString & baseExpr, double minValue, double maxValue, double minSize, double maxSize );
+
+  operator bool() const { return ! mExpression.isEmpty(); }
+  double size( double value ) const;
+
+  double minSize() const { return mMinSize; }
+  double maxSize() const { return mMaxSize; }
+  double minValue() const { return mMinValue; }
+  double maxValue() const { return mMaxValue; }
+  QString baseExpression() const { return mExpression; }
+  Type type() const { return mType; }
+
+private:
+  QString mExpression;
+  Type mType;
+  double mMinSize;
+  double mMaxSize;
+  double mMinValue;
+  double mMaxValue;
+
+  void init();
+  static QString createExpression( Type type, const QString & baseExpr, double minValue, double maxValue, double minSize, double maxSize );
+
+};
+
+#endif
+
+
+
diff --git a/tests/src/core/CMakeLists.txt b/tests/src/core/CMakeLists.txt
@@ -83,6 +83,7 @@ ADD_QGIS_TEST(applicationtest testqgsapplication.cpp)
 ADD_QGIS_TEST(diagramtest testqgsdiagram.cpp)
 ADD_QGIS_TEST(diagramexpressiontest testqgsdiagramexpression.cpp)
 ADD_QGIS_TEST(expressiontest testqgsexpression.cpp)
+ADD_QGIS_TEST(scaleexpressiontest testqgsscaleexpression.cpp)
 ADD_QGIS_TEST(filewritertest testqgsvectorfilewriter.cpp)
 ADD_QGIS_TEST(projecttest testqgsproject.cpp)
 ADD_QGIS_TEST(regression992 regression992.cpp)

diff --git a/tests/src/core/testqgsscaleexpression.cpp b/tests/src/core/testqgsscaleexpression.cpp
@@ -0,0 +1,105 @@
+/***************************************************************************
+     test_template.cpp
+     --------------------------------------
+    Date                 : Sun Sep 16 12:22:23 AKDT 2007
+    Copyright            : (C) 2007 by Gary E. Sherman
+    Email                : sherman at mrcc dot 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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+#include <QtTest/QtTest>
+#include <QObject>
+#include <QString>
+#include <QObject>
+#include <QtConcurrentMap>
+#include <QSharedPointer>
+
+#include <qgsapplication.h>
+//header for class being tested
+#include <qgsscaleexpression.h>
+#include <qgsfeature.h>
+#include <qgsfeaturerequest.h>
+#include <qgsgeometry.h>
+#include <qgsrenderchecker.h>
+
+#if QT_VERSION < 0x40701
+// See http://hub.qgis.org/issues/4284
+Q_DECLARE_METATYPE( QVariant )
+#endif
+
+class TestQgsScaleExpression: public QObject
+{
+    Q_OBJECT
+  private slots:
+
+    void initTestCase()
+    {
+      //
+      // Runs once before any tests are run
+      //
+      // init QGIS's paths - true means that all path will be inited from prefix
+      QgsApplication::init();
+      QgsApplication::initQgis();
+      // Will make sure the settings dir with the style file for color ramp is created
+      QgsApplication::createDB();
+      QgsApplication::showSettings();
+    }
+
+    void cleanupTestCase()
+    {
+      QgsApplication::exitQgis();
+    }
+
+    void parsing()
+    {
+      {
+        QgsScaleExpression exp( "scale_linear(column, 1, 7, 2, 10)" );
+        QCOMPARE( bool(exp), true );
+        QCOMPARE( exp.type(), QgsScaleExpression::Linear );
+        QCOMPARE( exp.baseExpression(), QString("column") );
+        QCOMPARE( exp.minValue(), 1. );
+        QCOMPARE( exp.maxValue(), 7. );
+        QCOMPARE( exp.minSize(), 2. );
+        QCOMPARE( exp.maxSize(), 10. );
+      }
+      {
+        QgsScaleExpression exp( "scale_exp(column, 1, 7, 2, 10, 0.5)" );
+        QCOMPARE( bool(exp), true );
+        QCOMPARE( exp.type(), QgsScaleExpression::Area );
+      }
+      {
+        QgsScaleExpression exp( "scale_exp(column, 1, 7, 2, 10, 0.57)" );
+        QCOMPARE( bool(exp), true );
+        QCOMPARE( exp.type(), QgsScaleExpression::Flannery );
+      }
+      {
+        QgsScaleExpression exp( "scale_exp(column, 1, 7, 2, 10, 0.51)" );
+        QCOMPARE( bool(exp), false );
+      }
+      {
+        QgsScaleExpression exp( "scale_exp(column, 1, 7, a, 10, 0.5)" );
+        QCOMPARE( bool(exp), false );
+      }
+      {
+        QgsScaleExpression exp( QgsScaleExpression::Linear, "column", 1, 7, 2, 10 );
+        QCOMPARE( bool(exp), true );
+        QCOMPARE( exp.type(), QgsScaleExpression::Linear );
+        QCOMPARE( exp.baseExpression(), QString("column") );
+        QCOMPARE( exp.minValue(), 1. );
+        QCOMPARE( exp.maxValue(), 7. );
+        QCOMPARE( exp.minSize(), 2. );
+        QCOMPARE( exp.maxSize(), 10. );
+      }
+
+    }
+};
+
+QTEST_MAIN( TestQgsScaleExpression )
+
+#include "testqgsscaleexpression.moc"
+