feat(ui): highlight the stratigraphic unit on map when clicked in column (#129)

* feat: highlight the selected stratigraphic unit on the map

Select a unit row in the stratigraphic column to select the features of
that unit in the units layer, so that QGIS highlights them on the map.
The match uses the unit-name field set under the column. Select an
unconformity row, or clear the selection, to remove the highlight.

Focus on a field of a unit row also selects that row, because clicks on
the row's fields do not reach the list.

* feat: apply stratigraphic thickness to the map layer

Add a button to the stratigraphic column that writes a 'strat_thickness'
field onto the selected units layer. The field holds the thickness of
the matching unit in the column. Features that do not match a unit stay
empty. The layer then gets a graduated renderer with one class for each
thickness value, coloured with the selected colour ramp.

Move the colour ramp lookup into a helper, so that the age and thickness
styling use the same lookup.

* style: apply black formatting

Author: lachlangrose

loopstructural/gui/modelling/stratigraphic_column/stratigraphic_column.py

@@ -1,5 +1,5 @@
 from LoopStructural.modelling.core.stratigraphic_column import StratigraphicColumnElementType
-from qgis.core import QgsApplication, QgsMapLayerProxyModel, QgsStyle
+from qgis.core import QgsApplication, QgsExpression, QgsMapLayerProxyModel, QgsStyle
 from qgis.gui import QgsFieldComboBox, QgsMapLayerComboBox
 from qgis.PyQt.QtCore import QSize
 from qgis.PyQt.QtGui import QIcon
@@ -67,10 +67,15 @@ def __init__(self, parent=None, data_manager=None):
         # layer/field is selected, so the name-match warning is skipped.
         self._known_unit_names = None
 
+        # The layer whose features were selected to highlight the selected
+        # unit on the map, so the selection can be cleared later.
+        self._highlighted_layer = None
+
         # Main list widget
         self.unitList = QListWidget()
         self.unitList.setDragDropMode(QAbstractItemView.DragDropMode.InternalMove)
         self.unitList.model().rowsMoved.connect(self.update_order)
+        self.unitList.itemSelectionChanged.connect(self.highlight_selected_unit)
         layout.addWidget(self.unitList)
 
         # A single row of icon-only actions for building/clearing the column.
@@ -170,6 +175,18 @@ def __init__(self, parent=None, data_manager=None):
         )
         applyAgeButton.clicked.connect(self.apply_age_to_layer)
         ageRow.addWidget(applyAgeButton)
+
+        applyThicknessButton = self._make_tool_button(
+            "mActionMeasure.svg", "Apply Stratigraphic Thickness to Map Layer"
+        )
+        applyThicknessButton.setToolTip(
+            "Apply Stratigraphic Thickness to Map Layer\n"
+            "Write a 'strat_thickness' field (the thickness of each unit in the "
+            "column) onto the selected layer above and style it with a graduated "
+            "colour ramp."
+        )
+        applyThicknessButton.clicked.connect(self.apply_thickness_to_layer)
+        ageRow.addWidget(applyThicknessButton)
         layout.addLayout(ageRow)
 
         self._guess_units_layer()
@@ -413,6 +430,7 @@ def _on_units_field_changed(self, _field_name):
         """Persist and re-validate when the unit-name field selection changes."""
         self._persist_units_layer_selection()
         self._revalidate_unit_names()
+        self.highlight_selected_unit()
 
     def _on_units_layer_changed(self, layer):
         """Update the field combo box when the units layer changes."""
@@ -424,6 +442,7 @@ def _on_units_layer_changed(self, layer):
                 self.unitsLayerFieldComboBox.setField(unit_match)
         self._persist_units_layer_selection()
         self._revalidate_unit_names()
+        self.highlight_selected_unit()
 
     def _get_known_unit_names(self):
         """Return the set of exact unit-name values in the selected geology layer/field.
@@ -454,6 +473,47 @@ def _revalidate_unit_names(self):
             if hasattr(widget, 'set_known_unit_names'):
                 widget.set_known_unit_names(self._known_unit_names)
 
+    def highlight_selected_unit(self):
+        """Select the features of the selected unit in the units layer, so
+        that QGIS highlights them on the map.
+
+        Clears the highlight when no unit row is selected (for example an
+        unconformity row) or when no units layer/field is set.
+        """
+        try:
+            items = self.unitList.selectedItems()
+        except RuntimeError:
+            # Widget was deleted
+            return
+        widget = self.unitList.itemWidget(items[0]) if items else None
+        layer = self.unitsLayerComboBox.currentLayer()
+        field_name = self.unitsLayerFieldComboBox.currentField()
+
+        self._clear_unit_highlight()
+        if (
+            not isinstance(widget, StratigraphicUnitWidget)
+            or not widget.name
+            or layer is None
+            or not field_name
+            or layer.fields().indexFromName(field_name) < 0
+        ):
+            return
+        expression = f"{QgsExpression.quotedColumnRef(field_name)} = {QgsExpression.quotedValue(widget.name)}"
+        layer.selectByExpression(expression)
+        self._highlighted_layer = layer
+
+    def _clear_unit_highlight(self):
+        """Remove the feature selection made by highlight_selected_unit."""
+        layer = self._highlighted_layer
+        self._highlighted_layer = None
+        if layer is None:
+            return
+        try:
+            layer.removeSelection()
+        except RuntimeError:
+            # Layer was removed from the project
+            pass
+
     def apply_colours_to_layer(self):
         """Push the stratigraphic column's colours onto the selected units layer."""
         if not self.data_manager:
@@ -514,6 +574,39 @@ def apply_age_to_layer(self):
                 "units, or no features matched a stratigraphic unit.",
             )
 
+    def apply_thickness_to_layer(self):
+        """Write each unit's thickness onto the selected units layer and style it by a graduated ramp."""
+        if not self.data_manager:
+            print("Error: Data manager is not initialized.")
+            return
+        layer = self.unitsLayerComboBox.currentLayer()
+        field_name = self.unitsLayerFieldComboBox.currentField()
+        if layer is None or not field_name:
+            QMessageBox.warning(
+                self,
+                "Apply Stratigraphic Thickness to Map Layer",
+                "Please select a units layer and unit name field above.",
+            )
+            return
+        ramp_name = self.strat_ageColorRampComboBox.currentText()
+        applied = self.data_manager.apply_stratigraphic_thickness_to_layer(
+            layer, field_name, ramp_name=ramp_name
+        )
+        if applied:
+            QMessageBox.information(
+                self,
+                "Apply Stratigraphic Thickness to Map Layer",
+                f"Applied stratigraphic thickness and graduated styling to layer "
+                f"'{layer.name()}'.",
+            )
+        else:
+            QMessageBox.warning(
+                self,
+                "Apply Stratigraphic Thickness to Map Layer",
+                "Could not apply stratigraphic thickness. The stratigraphic column may "
+                "have no units, or no features matched a stratigraphic unit.",
+            )
+
     def add_unit(self, *, unit_data=None, create_new=True):
         if unit_data is None:
             unit_data = {'type': 'unit', 'name': ''}
@@ -545,6 +638,7 @@ def add_unit(self, *, unit_data=None, create_new=True):
         unit_widget.nameChanged.connect(
             lambda: self.update_element(unit_widget)
         )  # Connect name change signal
+        unit_widget.nameChanged.connect(lambda: self._on_unit_name_changed(unit_widget))
 
         unit_widget.thicknessChanged.connect(
             lambda: self.update_element(unit_widget)
@@ -561,6 +655,7 @@ def add_unit(self, *, unit_data=None, create_new=True):
         item.setSizeHint(unit_widget.sizeHint())
         self._add_list_item(item, at_top=create_new)
         self.unitList.setItemWidget(item, unit_widget)
+        unit_widget.focused.connect(lambda: self.unitList.setCurrentItem(item))
         unit_widget.setData(unit_data)  # Set data for the unit widget
         unit_widget.set_known_unit_names(self._known_unit_names)
 
@@ -608,6 +703,15 @@ def add_unconformity(self, *, unconformity_data=None, create_new=True):
         # Cache the widget for efficient updates
         self._widget_cache[unconformity.uuid] = (unconformity_widget, item)
 
+    def _on_unit_name_changed(self, unit_widget):
+        """Update the map highlight when the selected unit is renamed."""
+        try:
+            items = self.unitList.selectedItems()
+        except RuntimeError:
+            return
+        if items and self.unitList.itemWidget(items[0]) is unit_widget:
+            self.highlight_selected_unit()
+
     def _add_list_item(self, item, *, at_top):
         """Add a row to the list. A new element goes on top of the column
         (the end of `order`), so it is shown in the first row."""

loopstructural/gui/modelling/stratigraphic_column/stratigraphic_unit.py

@@ -17,6 +17,7 @@ class StratigraphicUnitWidget(QWidget):
     dragHandlePressed = pyqtSignal()  # Drag handle mouse-down
     dragHandleMoved = pyqtSignal(QPoint)  # Drag handle mouse-move (global pos)
     dragHandleReleased = pyqtSignal()  # Drag handle mouse-up
+    focused = pyqtSignal()  # One of the row's fields got keyboard focus
 
     def __init__(
         self,
@@ -53,8 +54,15 @@ def __init__(
         self._dragging_handle = False
         self.dragHandle.setCursor(Qt.CursorShape.SizeVerCursor)
         self.dragHandle.installEventFilter(self)
+        # Clicks on the row's fields do not reach the QListWidget, so tell the
+        # column when one of them gets focus, to make this the selected row.
+        self._focus_widgets = (self.lineEditName, self.spinBoxThickness, self.buttonColour)
+        for widget in self._focus_widgets:
+            widget.installEventFilter(self)
 
     def eventFilter(self, obj, event):
+        if obj in self._focus_widgets and event.type() == QEvent.Type.FocusIn:
+            self.focused.emit()
         if obj is self.dragHandle:
             event_type = event.type()
             if (

loopstructural/main/data_manager.py

@@ -31,6 +31,17 @@
 from .vectorLayerWrapper import qgsLayerToGeoDataFrame
 
 
+def _lookup_colour_ramp(ramp_name):
+    """Return the named QGIS colour ramp, or the first available ramp if it is not found."""
+    style = QgsStyle().defaultStyle()
+    ramp = style.colorRamp(ramp_name) if ramp_name else None
+    if ramp is None:
+        ramp_names = style.colorRampNames()
+        if ramp_names:
+            ramp = style.colorRamp(ramp_names[0])
+    return ramp
+
+
 def _colour_to_qcolor(colour):
     """Convert a stratigraphic unit colour (hex string, colour name, or RGB tuple/array) to a QColor."""
     if colour is None:
@@ -619,12 +630,7 @@ def apply_stratigraphic_age_to_layer(self, layer, field_name, ramp_name=None):
             )
             return False
 
-        style = QgsStyle().defaultStyle()
-        ramp = style.colorRamp(ramp_name) if ramp_name else None
-        if ramp is None:
-            ramp_names = style.colorRampNames()
-            if ramp_names:
-                ramp = style.colorRamp(ramp_names[0])
+        ramp = _lookup_colour_ramp(ramp_name)
 
         n = len(unique_values)
         ranges = []
@@ -642,6 +648,114 @@ def apply_stratigraphic_age_to_layer(self, layer, field_name, ramp_name=None):
         )
         return True
 
+    def apply_stratigraphic_thickness_to_layer(self, layer, field_name, ramp_name=None):
+        """Write each unit's thickness onto a layer and style it with a graduated colour ramp.
+
+        Writes a 'strat_thickness' field to ``layer`` holding the thickness
+        set for the matching unit in the stratigraphic column (matched via
+        ``field_name``), then applies a graduated renderer over that field.
+        Features that do not match a unit are left empty.
+
+        Parameters
+        ----------
+        layer : QgsVectorLayer
+            The layer to update (e.g. the geological units/geology layer).
+        field_name : str
+            Name of the field on ``layer`` holding the stratigraphic unit name.
+        ramp_name : str, optional
+            Name of a QGIS colour ramp (from QgsStyle) to use for the
+            graduated renderer. Falls back to any available ramp if not found.
+
+        Returns
+        -------
+        bool
+            True if the field was written and the renderer applied, False otherwise.
+        """
+        if layer is None or not field_name:
+            self.logger(
+                message="No layer/unit name field set, cannot apply stratigraphic thickness."
+            )
+            return False
+        if layer.fields().indexFromName(field_name) < 0:
+            self.logger(message=f"Field '{field_name}' not found on layer '{layer.name()}'.")
+            return False
+
+        thicknesses = {}
+        for unit in self._stratigraphic_column.order:
+            if unit.element_type != StratigraphicColumnElementType.UNIT:
+                continue
+            if unit.thickness is None:
+                continue
+            thicknesses[unit.name] = float(unit.thickness)
+        if not thicknesses:
+            self.logger(
+                message="Stratigraphic column has no units, cannot apply stratigraphic thickness."
+            )
+            return False
+
+        thickness_field_name = "strat_thickness"
+        try:
+            from qgis.core import QgsField
+
+            from loopstructural.gui.compatibility import QVariantCompat
+
+            layer.startEditing()
+            if layer.fields().indexFromName(thickness_field_name) < 0:
+                layer.dataProvider().addAttributes(
+                    [QgsField(thickness_field_name, QVariantCompat.Double)]
+                )
+                layer.updateFields()
+            thickness_index = layer.fields().indexFromName(thickness_field_name)
+            for feature in layer.getFeatures():
+                value = feature[field_name]
+                unit_name = None if value is None else str(value).strip()
+                layer.changeAttributeValue(
+                    feature.id(), thickness_index, thicknesses.get(unit_name)
+                )
+            if not layer.commitChanges():
+                raise RuntimeError("; ".join(layer.commitErrors()))
+        except Exception as err:
+            layer.rollBack()
+            self.logger(message=f"Failed to write stratigraphic thickness onto layer: {err}")
+            return False
+
+        unique_values = set()
+        for feature in layer.getFeatures():
+            value = feature[thickness_field_name]
+            if value is None or (hasattr(value, 'isNull') and value.isNull()):
+                continue
+            unique_values.add(float(value))
+        unique_values = sorted(unique_values)
+
+        if not unique_values:
+            self.logger(
+                message="No features matched a stratigraphic unit, cannot style layer by thickness."
+            )
+            return False
+
+        ramp = _lookup_colour_ramp(ramp_name)
+
+        # One class per thickness value, with the class limits half-way
+        # between adjacent values so that each value is in only one class.
+        minimum = unique_values[0]
+        span = unique_values[-1] - minimum
+        ranges = []
+        for i, value in enumerate(unique_values):
+            lower = value if i == 0 else (unique_values[i - 1] + value) / 2
+            upper = value if i == len(unique_values) - 1 else (value + unique_values[i + 1]) / 2
+            symbol = QgsSymbol.defaultSymbol(layer.geometryType())
+            if ramp is not None:
+                symbol.setColor(ramp.color((value - minimum) / span if span > 0 else 0))
+            ranges.append(QgsRendererRange(lower, upper, symbol, f"{value:g}"))
+
+        layer.setRenderer(QgsGraduatedSymbolRenderer(thickness_field_name, ranges))
+        layer.triggerRepaint()
+        self.logger(
+            message=f"Applied stratigraphic thickness field '{thickness_field_name}' and "
+            f"graduated styling to layer '{layer.name()}'."
+        )
+        return True
+
     def get_stratigraphic_unit_names(self):
         """Get the names of the stratigraphic units in the column, youngest first.