add point cloud elevation calibration button

src/app/pointcloud/qgspointcloudelevationpropertieswidget.cpp

@@ -33,6 +33,7 @@ QgsPointCloudElevationPropertiesWidget::QgsPointCloudElevationPropertiesWidget(
 
   connect( mOffsetZSpinBox, qgis::overload<double >::of( &QDoubleSpinBox::valueChanged ), this, &QgsPointCloudElevationPropertiesWidget::onChanged );
   connect( mScaleZSpinBox, qgis::overload<double >::of( &QDoubleSpinBox::valueChanged ), this, &QgsPointCloudElevationPropertiesWidget::onChanged );
+  connect( mShifPointCloudZAxisButton, &QPushButton::clicked, this, &QgsPointCloudElevationPropertiesWidget::shiftPointCloudZAxis );
 }
 
 void QgsPointCloudElevationPropertiesWidget::syncToLayer( QgsMapLayer *layer )
@@ -63,6 +64,15 @@ void QgsPointCloudElevationPropertiesWidget::onChanged()
     emit widgetChanged();
 }
 
+void QgsPointCloudElevationPropertiesWidget::shiftPointCloudZAxis()
+{
+  QgsDoubleRange range = mLayer->elevationProperties()->calculateZRange( mLayer );
+  if ( !range.isEmpty() )
+  {
+    mOffsetZSpinBox->setValue( -range.lower() + mOffsetZSpinBox->value() );
+  }
+}
+
 //
 // QgsPointCloudElevationPropertiesWidgetFactory
 //

src/app/pointcloud/qgspointcloudelevationpropertieswidget.h

@@ -38,7 +38,7 @@ class QgsPointCloudElevationPropertiesWidget : public QgsMapLayerConfigWidget, p
   private slots:
 
     void onChanged();
-
+    void shiftPointCloudZAxis();
   private:
 
     QgsPointCloudLayer *mLayer = nullptr;

src/ui/pointcloud/qgspointcloudelevationpropertieswidgetbase.ui

@@ -57,6 +57,16 @@
         </property>
        </widget>
       </item>
+      <item row="0" column="0" colspan="2">
+       <widget class="QLabel" name="label_3">
+        <property name="text">
+         <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;&lt;span style=&quot; font-weight:600;&quot;&gt;Elevation scaling and offset can be used to manually correct elevation values in the point cloud at render time.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;The scale is applied to the point cloud elevation values before adding the offset.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
+        </property>
+        <property name="wordWrap">
+         <bool>true</bool>
+        </property>
+       </widget>
+      </item>
       <item row="1" column="0">
        <widget class="QLabel" name="label_2">
         <property name="text">
@@ -84,20 +94,20 @@
         </property>
        </widget>
       </item>
-      <item row="3" column="0">
+      <item row="4" column="0">
        <widget class="Line" name="line_3">
         <property name="orientation">
          <enum>Qt::Vertical</enum>
         </property>
        </widget>
       </item>
-      <item row="0" column="0" colspan="2">
-       <widget class="QLabel" name="label_3">
-        <property name="text">
-         <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;&lt;span style=&quot; font-weight:600;&quot;&gt;Elevation scaling and offset can be used to manually correct elevation values in the point cloud at render time.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;The scale is applied to the point cloud elevation values before adding the offset.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
+      <item row="3" column="0" colspan="2">
+       <widget class="QPushButton" name="mShifPointCloudZAxisButton">
+        <property name="toolTip">
+         <string/>
         </property>
-        <property name="wordWrap">
-         <bool>true</bool>
+        <property name="text">
+         <string>Shift point cloud Z axis</string>
         </property>
        </widget>
       </item>
@@ -120,17 +130,17 @@
   </layout>
  </widget>
  <customwidgets>
+  <customwidget>
+   <class>QgsDoubleSpinBox</class>
+   <extends>QDoubleSpinBox</extends>
+   <header>qgsdoublespinbox.h</header>
+  </customwidget>
   <customwidget>
    <class>QgsCollapsibleGroupBox</class>
    <extends>QGroupBox</extends>
    <header>qgscollapsiblegroupbox.h</header>
    <container>1</container>
   </customwidget>
-  <customwidget>
-   <class>QgsDoubleSpinBox</class>
-   <extends>QDoubleSpinBox</extends>
-   <header>qgsdoublespinbox.h</header>
-  </customwidget>
  </customwidgets>
  <resources/>
  <connections/>