add the possibility t use absolute value for varying line of 1D mesh

src/app/mesh/qgsmeshvariablestrokewidthwidget.cpp

@@ -44,6 +44,8 @@ QgsMeshVariableStrokeWidthWidget::QgsMeshVariableStrokeWidthWidget(
            this, &QgsMeshVariableStrokeWidthWidget::widgetChanged );
   connect( mIgnoreOutOfRangecheckBox, &QCheckBox::toggled,
            this, &QgsMeshVariableStrokeWidthWidget::widgetChanged );
+  connect( mUseAbsoluteValueCheckBox, &QCheckBox::toggled,
+           this, &QgsMeshVariableStrokeWidthWidget::widgetChanged );
 }
 
 void QgsMeshVariableStrokeWidthWidget::setVariableStrokeWidth( const QgsInterpolatedLineWidth &variableStrokeWidth )
@@ -53,6 +55,7 @@ void QgsMeshVariableStrokeWidthWidget::setVariableStrokeWidth( const QgsInterpol
   whileBlocking( mWidthMinimumSpinBox )->setValue( variableStrokeWidth.minimumWidth() );
   whileBlocking( mWidthMaximumSpinBox )->setValue( variableStrokeWidth.maximumWidth() );
   whileBlocking( mIgnoreOutOfRangecheckBox )->setChecked( variableStrokeWidth.ignoreOutOfRange() );
+  whileBlocking( mUseAbsoluteValueCheckBox )->setChecked( variableStrokeWidth.useAbsoluteValue() );
 }
 
 void QgsMeshVariableStrokeWidthButton::setDefaultMinMaxValue( double minimum, double maximum )
@@ -69,7 +72,7 @@ QgsInterpolatedLineWidth QgsMeshVariableStrokeWidthWidget::variableStrokeWidth()
   strokeWidth.setMinimumWidth( mWidthMinimumSpinBox->value() );
   strokeWidth.setMaximumWidth( mWidthMaximumSpinBox->value() );
   strokeWidth.setIgnoreOutOfRange( mIgnoreOutOfRangecheckBox->isChecked() );
-
+  strokeWidth.setUseAbsoluteValue( mUseAbsoluteValueCheckBox->isChecked() );
   return strokeWidth;
 }
 

src/core/symbology/qgsinterpolatedlinerenderer.cpp

@@ -277,6 +277,9 @@ double QgsInterpolatedLineWidth::strokeWidth( double value ) const
     if ( mNeedUpdateFormula )
       updateLinearFormula();
 
+    if ( mUseAbsoluteValue )
+      value = std::fabs( value );
+
     if ( value > mMaximumValue )
     {
       if ( mIgnoreOutOfRange )
@@ -312,6 +315,7 @@ QDomElement QgsInterpolatedLineWidth::writeXml( QDomDocument &doc, const QgsRead
   elem.setAttribute( QStringLiteral( "minimum-width" ), mMinimumWidth );
   elem.setAttribute( QStringLiteral( "maximum-width" ), mMaximumWidth );
   elem.setAttribute( QStringLiteral( "ignore-out-of-range" ), mIgnoreOutOfRange ? 1 : 0 );
+  elem.setAttribute( QStringLiteral( "use-absolute-value" ), mUseAbsoluteValue ? 1 : 0 );
 
   return elem;
 }
@@ -327,6 +331,17 @@ void QgsInterpolatedLineWidth::readXml( const QDomElement &elem, const QgsReadWr
   mMinimumWidth = elem.attribute( QStringLiteral( "minimum-width" ) ).toDouble();
   mMaximumWidth = elem.attribute( QStringLiteral( "maximum-width" ) ).toDouble();
   mIgnoreOutOfRange = elem.attribute( QStringLiteral( "ignore-out-of-range" ) ).toInt();
+  mUseAbsoluteValue = elem.attribute( QStringLiteral( "use-absolute-value" ) ).toInt();
+}
+
+bool QgsInterpolatedLineWidth::useAbsoluteValue() const
+{
+  return mUseAbsoluteValue;
+}
+
+void QgsInterpolatedLineWidth::setUseAbsoluteValue( bool useAbsoluteValue )
+{
+  mUseAbsoluteValue = useAbsoluteValue;
 }
 
 double QgsInterpolatedLineWidth::fixedStrokeWidth() const

src/core/symbology/qgsinterpolatedlinerenderer.h

@@ -134,6 +134,11 @@ class CORE_EXPORT QgsInterpolatedLineWidth
     //! Sets whether the variable width ignores out of range value
     void setIgnoreOutOfRange( bool ignoreOutOfRange );
 
+    //! Returns whether absolute value are used as input
+    bool useAbsoluteValue() const;
+    //! Sets whether absolute value are used as input
+    void setUseAbsoluteValue( bool useAbsoluteValue );
+
     //! Returns whether the width is variable
     bool isVariableWidth() const;
     //! Returns whether the width is variable
@@ -162,6 +167,7 @@ class CORE_EXPORT QgsInterpolatedLineWidth
     double mMinimumWidth = DEFAULT_LINE_WIDTH;
     double mMaximumWidth = 3;
     bool mIgnoreOutOfRange = false;
+    bool mUseAbsoluteValue = false;
 
     mutable double mLinearCoef = 1;
     mutable bool mNeedUpdateFormula = true;

src/ui/mesh/qgsmeshvariablestrokewidthwidgetbase.ui

@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>268</width>
+    <width>340</width>
     <height>220</height>
    </rect>
   </property>
@@ -14,7 +14,24 @@
    <string notr="true">Form</string>
   </property>
   <layout class="QGridLayout" name="gridLayout">
-   <item row="8" column="0">
+   <item row="0" column="0">
+    <widget class="QLabel" name="label_3">
+     <property name="text">
+      <string>Input Values</string>
+     </property>
+    </widget>
+   </item>
+   <item row="7" column="1">
+    <widget class="QgsDoubleSpinBox" name="mWidthMinimumSpinBox">
+     <property name="value">
+      <double>1.000000000000000</double>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="1">
+    <widget class="QLineEdit" name="mValueMinimumLineEdit"/>
+   </item>
+   <item row="9" column="0">
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
@@ -27,6 +44,9 @@
      </property>
     </spacer>
    </item>
+   <item row="2" column="1">
+    <widget class="QLineEdit" name="mValueMaximumLineEdit"/>
+   </item>
    <item row="1" column="2" rowspan="2">
     <widget class="QPushButton" name="mDefaultMinMaxButton">
      <property name="sizePolicy">
@@ -50,14 +70,21 @@
      </property>
     </widget>
    </item>
-   <item row="1" column="0">
-    <widget class="QLabel" name="label_4">
+   <item row="7" column="0">
+    <widget class="QLabel" name="label">
      <property name="text">
-      <string>Min value</string>
+      <string>Min Width</string>
      </property>
     </widget>
    </item>
-   <item row="5" column="0" colspan="3">
+   <item row="8" column="0">
+    <widget class="QLabel" name="label_2">
+     <property name="text">
+      <string>Max Width</string>
+     </property>
+    </widget>
+   </item>
+   <item row="6" column="0" colspan="3">
     <widget class="Line" name="line">
      <property name="minimumSize">
       <size>
@@ -70,60 +97,47 @@
      </property>
     </widget>
    </item>
-   <item row="7" column="0">
-    <widget class="QLabel" name="label_2">
+   <item row="2" column="0">
+    <widget class="QLabel" name="label_5">
      <property name="text">
-      <string>Max width</string>
+      <string>Max Value</string>
      </property>
     </widget>
    </item>
-   <item row="7" column="1">
+   <item row="1" column="0">
+    <widget class="QLabel" name="label_4">
+     <property name="text">
+      <string>Min Value</string>
+     </property>
+    </widget>
+   </item>
+   <item row="8" column="1">
     <widget class="QgsDoubleSpinBox" name="mWidthMaximumSpinBox">
      <property name="value">
       <double>5.000000000000000</double>
      </property>
     </widget>
    </item>
-   <item row="0" column="0">
-    <widget class="QLabel" name="label_3">
-     <property name="text">
-      <string>Input values</string>
-     </property>
-    </widget>
-   </item>
-   <item row="6" column="0">
-    <widget class="QLabel" name="label">
-     <property name="text">
-      <string>Min width</string>
-     </property>
-    </widget>
-   </item>
-   <item row="2" column="0">
-    <widget class="QLabel" name="label_5">
-     <property name="text">
-      <string>Max value</string>
-     </property>
-    </widget>
-   </item>
-   <item row="6" column="1">
-    <widget class="QgsDoubleSpinBox" name="mWidthMinimumSpinBox">
-     <property name="value">
-      <double>1.000000000000000</double>
-     </property>
-    </widget>
-   </item>
    <item row="3" column="0" colspan="3">
+    <layout class="QHBoxLayout" name="horizontalLayout">
+     <property name="bottomMargin">
+      <number>0</number>
+     </property>
+     <item>
       <widget class="QCheckBox" name="mIgnoreOutOfRangecheckBox">
        <property name="text">
-      <string>Ignore out of range values</string>
+        <string>Ignore Out of Range Values</string>
        </property>
       </widget>
      </item>
-   <item row="1" column="1">
-    <widget class="QLineEdit" name="mValueMinimumLineEdit"/>
+     <item>
+      <widget class="QCheckBox" name="mUseAbsoluteValueCheckBox">
+       <property name="text">
+        <string>Use Absolute Value</string>
+       </property>
+      </widget>
      </item>
-   <item row="2" column="1">
-    <widget class="QLineEdit" name="mValueMaximumLineEdit"/>
+    </layout>
    </item>
   </layout>
  </widget>
@@ -138,7 +152,6 @@
   <tabstop>mValueMinimumLineEdit</tabstop>
   <tabstop>mValueMaximumLineEdit</tabstop>
   <tabstop>mDefaultMinMaxButton</tabstop>
-  <tabstop>mIgnoreOutOfRangecheckBox</tabstop>
   <tabstop>mWidthMinimumSpinBox</tabstop>
   <tabstop>mWidthMaximumSpinBox</tabstop>
  </tabstops>