[FEATURE] Add choice of simplification method to simplify map tool

Allows different techniques to be used for simplification, including the more cartographically pleasing "Visvalingam" simplification algorithm. Fixes #18083
qgis · Feb 26, 2018 · dce2188 · dce2188
1 parent c0b8fbf
commit dce2188
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Showing 4 changed files with 137 additions and 32 deletions.
diff --git a/src/app/qgsmaptoolsimplify.cpp b/src/app/qgsmaptoolsimplify.cpp
@@ -23,7 +23,7 @@
 #include "qgstolerance.h"
 #include "qgisapp.h"
 #include "qgssettings.h"
-
+#include "qgsmaptopixelgeometrysimplifier.h"
 #include <QMouseEvent>
 
 #include <cmath>
@@ -35,12 +35,22 @@ QgsSimplifyDialog::QgsSimplifyDialog( QgsMapToolSimplify *tool, QWidget *parent
 {
   setupUi( this );
 
+  mMethodComboBox->addItem( tr( "Simplify by distance" ), ( int )QgsVectorSimplifyMethod::Distance );
+  mMethodComboBox->addItem( tr( "Simplify by snapping to grid" ), ( int )QgsVectorSimplifyMethod::SnapToGrid );
+  mMethodComboBox->addItem( tr( "Simplify by area (Visvalingam)" ), ( int )QgsVectorSimplifyMethod::Visvalingam );
+
   spinTolerance->setValue( mTool->tolerance() );
+  spinTolerance->setShowClearButton( false );
   cboToleranceUnits->setCurrentIndex( ( int ) mTool->toleranceUnits() );
+  mMethodComboBox->setCurrentIndex( mMethodComboBox->findData( mTool->method() ) );
 
   // communication with map tool
   connect( spinTolerance, static_cast < void ( QDoubleSpinBox::* )( double ) > ( &QDoubleSpinBox::valueChanged ), mTool, &QgsMapToolSimplify::setTolerance );
   connect( cboToleranceUnits, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), mTool, &QgsMapToolSimplify::setToleranceUnits );
+  connect( mMethodComboBox, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), mTool, [ = ]
+  {
+    mTool->setMethod( static_cast< QgsMapToPixelSimplifier::SimplifyAlgorithm >( mMethodComboBox->currentData().toInt() ) );
+  } );
   connect( okButton, &QAbstractButton::clicked, mTool, &QgsMapToolSimplify::storeSimplified );
 }
 
@@ -70,6 +80,7 @@ QgsMapToolSimplify::QgsMapToolSimplify( QgsMapCanvas *canvas )
   QgsSettings settings;
   mTolerance = settings.value( QStringLiteral( "digitizing/simplify_tolerance" ), 1 ).toDouble();
   mToleranceUnits = settings.enumValue( QStringLiteral( "digitizing/simplify_tolerance_units" ), QgsTolerance::LayerUnits );
+  mMethod = static_cast< QgsMapToPixelSimplifier::SimplifyAlgorithm >( settings.value( QStringLiteral( "digitizing/simplify_method" ), 0 ).toInt() );
 
   mSimplifyDialog = new QgsSimplifyDialog( this, canvas->topLevelWidget() );
 }
@@ -111,9 +122,10 @@ void QgsMapToolSimplify::updateSimplificationPreview()
   mReducedHasErrors = false;
   mReducedVertexCount = 0;
   int i = 0;
+
   Q_FOREACH ( const QgsFeature &fSel, mSelectedFeatures )
   {
-    QgsGeometry g = fSel.geometry().simplify( layerTolerance );
+    QgsGeometry g = processGeometry( fSel.geometry(), layerTolerance );
     if ( !g.isNull() )
     {
       mReducedVertexCount += g.constGet()->nCoordinates();
@@ -128,6 +140,39 @@ void QgsMapToolSimplify::updateSimplificationPreview()
   mSimplifyDialog->enableOkButton( !mReducedHasErrors );
 }
 
+QgsGeometry QgsMapToolSimplify::processGeometry( const QgsGeometry &geometry, double tolerance ) const
+{
+  switch ( mMethod )
+  {
+    case QgsMapToPixelSimplifier::Distance:
+      return geometry.simplify( tolerance );
+
+    case QgsMapToPixelSimplifier::SnapToGrid:
+    case QgsMapToPixelSimplifier::Visvalingam:
+    {
+      QgsMapToPixelSimplifier simplifier( QgsMapToPixelSimplifier::SimplifyGeometry, tolerance, mMethod );
+      return simplifier.simplify( geometry );
+    }
+  }
+  return QgsGeometry(); //no warnings
+}
+
+QgsMapToPixelSimplifier::SimplifyAlgorithm QgsMapToolSimplify::method() const
+{
+  return mMethod;
+}
+
+void QgsMapToolSimplify::setMethod( QgsMapToPixelSimplifier::SimplifyAlgorithm method )
+{
+  mMethod = method;
+
+  QgsSettings settings;
+  settings.setValue( QStringLiteral( "digitizing/simplify_method" ), method );
+
+  if ( !mSelectedFeatures.isEmpty() )
+    updateSimplificationPreview();
+}
+
 void QgsMapToolSimplify::storeSimplified()
 {
   QgsVectorLayer *vlayer = currentVectorLayer();
@@ -136,7 +181,7 @@ void QgsMapToolSimplify::storeSimplified()
   vlayer->beginEditCommand( tr( "Geometry simplified" ) );
   Q_FOREACH ( const QgsFeature &feat, mSelectedFeatures )
   {
-    QgsGeometry g = feat.geometry().simplify( layerTolerance );
+    QgsGeometry g = processGeometry( feat.geometry(), layerTolerance );
     if ( !g.isNull() )
     {
       vlayer->changeGeometry( feat.id(), g );

diff --git a/src/app/qgsmaptoolsimplify.h b/src/app/qgsmaptoolsimplify.h
@@ -23,6 +23,7 @@
 #include "qgsfeature.h"
 #include "qgstolerance.h"
 #include "qgis_app.h"
+#include "qgsmaptopixelgeometrysimplifier.h"
 
 class QgsRubberBand;
 class QgsMapToolSimplify;
@@ -71,6 +72,10 @@ class APP_EXPORT QgsMapToolSimplify: public QgsMapToolEdit
 
     QString statusText() const;
 
+    QgsMapToPixelSimplifier::SimplifyAlgorithm method() const;
+
+    void setMethod( QgsMapToPixelSimplifier::SimplifyAlgorithm method );
+
   public slots:
     //! Slot to change display when slidebar is moved
     void setTolerance( double tolerance );
@@ -89,6 +94,12 @@ class APP_EXPORT QgsMapToolSimplify: public QgsMapToolEdit
 
     void updateSimplificationPreview();
 
+    /**
+     * Simplifies a \a geometry to the specified \a tolerance, respecting the preset
+     * simplification method.
+     */
+    QgsGeometry processGeometry( const QgsGeometry &geometry, double tolerance ) const;
+
     // data
     //! Dialog with slider to set correct tolerance value
     QgsSimplifyDialog *mSimplifyDialog = nullptr;
@@ -113,6 +124,9 @@ class APP_EXPORT QgsMapToolSimplify: public QgsMapToolEdit
     int mOriginalVertexCount = 0;
     int mReducedVertexCount = 0;
     bool mReducedHasErrors = false;
+
+    QgsMapToPixelSimplifier::SimplifyAlgorithm mMethod = QgsMapToPixelSimplifier::Distance;
+
 };
 
 #endif
diff --git a/src/ui/qgssimplifytolerancedialog.ui b/src/ui/qgssimplifytolerancedialog.ui
@@ -7,21 +7,24 @@
     <x>0</x>
     <y>0</y>
     <width>527</width>
-    <height>63</height>
+    <height>98</height>
    </rect>
   </property>
   <property name="windowTitle">
    <string>Simplification Tool</string>
   </property>
   <layout class="QGridLayout" name="gridLayout">
-   <item row="0" column="3">
-    <widget class="QPushButton" name="okButton">
+   <item row="1" column="0">
+    <widget class="QLabel" name="label">
      <property name="text">
-      <string>OK</string>
+      <string>Tolerance</string>
      </property>
     </widget>
    </item>
-   <item row="0" column="2">
+   <item row="3" column="0" colspan="4">
+    <widget class="QLabel" name="labelStatus"/>
+   </item>
+   <item row="1" column="2">
     <widget class="QComboBox" name="cboToleranceUnits">
      <item>
       <property name="text">
@@ -40,15 +43,8 @@
      </item>
     </widget>
    </item>
-   <item row="0" column="0">
-    <widget class="QLabel" name="label">
-     <property name="text">
-      <string>Tolerance</string>
-     </property>
-    </widget>
-   </item>
-   <item row="0" column="1">
-    <widget class="QDoubleSpinBox" name="spinTolerance">
+   <item row="1" column="1">
+    <widget class="QgsDoubleSpinBox" name="spinTolerance">
      <property name="decimals">
       <number>6</number>
      </property>
@@ -60,12 +56,34 @@
      </property>
     </widget>
    </item>
-   <item row="1" column="0" colspan="4">
-    <widget class="QLabel" name="labelStatus"/>
+   <item row="0" column="0">
+    <widget class="QLabel" name="label_2">
+     <property name="text">
+      <string>Method</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="3">
+    <widget class="QPushButton" name="okButton">
+     <property name="text">
+      <string>OK</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="1" colspan="2">
+    <widget class="QComboBox" name="mMethodComboBox"/>
    </item>
   </layout>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>QgsDoubleSpinBox</class>
+   <extends>QDoubleSpinBox</extends>
+   <header>qgsdoublespinbox.h</header>
+  </customwidget>
+ </customwidgets>
  <tabstops>
+  <tabstop>mMethodComboBox</tabstop>
   <tabstop>spinTolerance</tabstop>
   <tabstop>cboToleranceUnits</tabstop>
   <tabstop>okButton</tabstop>

diff --git a/src/ui/qgsvectorlayerpropertiesbase.ui b/src/ui/qgsvectorlayerpropertiesbase.ui
@@ -345,7 +345,7 @@
           </sizepolicy>
          </property>
          <property name="currentIndex">
-          <number>0</number>
+          <number>12</number>
          </property>
          <widget class="QWidget" name="mOptsPage_Information">
           <layout class="QVBoxLayout" name="verticalLayout_5">
@@ -421,8 +421,8 @@
                <rect>
                 <x>0</x>
                 <y>0</y>
-                <width>651</width>
-                <height>537</height>
+                <width>285</width>
+                <height>399</height>
                </rect>
               </property>
               <layout class="QVBoxLayout" name="verticalLayout_9">
@@ -696,8 +696,8 @@ border-radius: 2px;</string>
                <rect>
                 <x>0</x>
                 <y>0</y>
-                <width>651</width>
-                <height>537</height>
+                <width>100</width>
+                <height>30</height>
                </rect>
               </property>
               <layout class="QVBoxLayout" name="verticalLayout_18">
@@ -882,8 +882,8 @@ border-radius: 2px;</string>
                <rect>
                 <x>0</x>
                 <y>0</y>
-                <width>651</width>
-                <height>537</height>
+                <width>104</width>
+                <height>102</height>
                </rect>
               </property>
               <layout class="QVBoxLayout" name="verticalLayout_23">
@@ -1277,8 +1277,8 @@ border-radius: 2px;</string>
                <rect>
                 <x>0</x>
                 <y>0</y>
-                <width>651</width>
-                <height>537</height>
+                <width>100</width>
+                <height>30</height>
                </rect>
               </property>
               <layout class="QVBoxLayout" name="verticalLayout_21">
@@ -1451,8 +1451,8 @@ border-radius: 2px;</string>
                <rect>
                 <x>0</x>
                 <y>0</y>
-                <width>696</width>
-                <height>521</height>
+                <width>671</width>
+                <height>522</height>
                </rect>
               </property>
               <layout class="QVBoxLayout" name="verticalLayout_32">
@@ -1905,8 +1905,8 @@ border-radius: 2px;</string>
                <rect>
                 <x>0</x>
                 <y>0</y>
-                <width>651</width>
-                <height>537</height>
+                <width>639</width>
+                <height>656</height>
                </rect>
               </property>
               <layout class="QVBoxLayout" name="verticalLayout_13">
@@ -2467,6 +2467,34 @@ border-radius: 2px;</string>
  </tabstops>
  <resources>
   <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
+  <include location="../../images/images.qrc"/>
  </resources>
  <connections>
   <connection>