[processing] Expose data defined button for dynamic numeric parameters

When running algorithms through the toolbox, which have dynamic
numeric parameters, add a data defined property override button
next to the widget so that users can set the overrides for these
parameters.

Previously this was available only in the backend, but not
exposed anywhere in the GUI.

Note that currently no algorithms support dynamic parameters,
so don't expect to see this everywhere. It's also only available
in toolbox/batch processing modes, not in models.

python/plugins/processing/gui/NumberInputPanel.py

@@ -34,10 +34,13 @@
 from qgis.PyQt.QtWidgets import QDialog
 
 from qgis.core import (QgsExpression,
+                       QgsProperty,
                        QgsProcessingParameterNumber,
                        QgsProcessingOutputNumber,
                        QgsProcessingParameterDefinition,
-                       QgsProcessingModelChildParameterSource)
+                       QgsProcessingModelChildParameterSource,
+                       QgsProcessingFeatureSourceDefinition,
+                       QgsProcessingUtils)
 from qgis.gui import QgsExpressionBuilderDialog
 from processing.tools.dataobjects import createExpressionContext, createContext
 
@@ -71,6 +74,11 @@ def __init__(self, param, modelParametersDialog):
         self.btnSelect.clicked.connect(self.showExpressionsBuilder)
         self.leText.textChanged.connect(lambda: self.hasChanged.emit())
 
+        # remove data defined button from modeler
+        self.layout().removeWidget(self.btnDataDefined)
+        sip.delete(self.btnDataDefined)
+        self.btnDataDefined = None
+
     def showExpressionsBuilder(self):
         context = createExpressionContext()
         processing_context = createContext()
@@ -188,10 +196,31 @@ def __init__(self, param):
         sip.delete(self.btnSelect)
         self.btnSelect = None
 
+        if not self.param.isDynamic():
+            # only show data defined button for dynamic properties
+            self.layout().removeWidget(self.btnDataDefined)
+            sip.delete(self.btnDataDefined)
+            self.btnDataDefined = None
+        else:
+            self.btnDataDefined.init(0, QgsProperty(), self.param.dynamicPropertyDefinition())
+
         self.spnValue.valueChanged.connect(lambda: self.hasChanged.emit())
 
+    def setDynamicLayer(self, layer):
+        context = createContext()
+        try:
+            if isinstance(layer, QgsProcessingFeatureSourceDefinition):
+                layer, ok = layer.source.valueAsString(context.expressionContext())
+            if isinstance(layer, str):
+                layer = QgsProcessingUtils.mapLayerFromString(layer, context)
+            self.btnDataDefined.setVectorLayer(layer)
+        except:
+            pass
+
     def getValue(self):
-        if self.allowing_null and self.spnValue.value() == self.spnValue.minimum():
+        if self.btnDataDefined is not None and self.btnDataDefined.isActive():
+            return self.btnDataDefined.toProperty()
+        elif self.allowing_null and self.spnValue.value() == self.spnValue.minimum():
             return None
         else:
             return self.spnValue.value()

python/plugins/processing/gui/wrappers.py

@@ -671,6 +671,17 @@ def setValue(self, value):
     def value(self):
         return self.widget.getValue()
 
+    def postInitialize(self, wrappers):
+        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH) and self.param.isDynamic():
+            for wrapper in wrappers:
+                if wrapper.param.name() == self.param.dynamicLayerParameterName():
+                    self.widget.setDynamicLayer(wrapper.value())
+                    wrapper.widgetValueHasChanged.connect(self.parentLayerChanged)
+                    break
+
+    def parentLayerChanged(self, wrapper):
+        self.widget.setDynamicLayer(wrapper.value())
+
 
 class RangeWidgetWrapper(WidgetWrapper):
 

python/plugins/processing/ui/widgetNumberSelector.ui

@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>249</width>
-    <height>37</height>
+    <width>380</width>
+    <height>52</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -61,6 +61,19 @@
      </property>
     </widget>
    </item>
+   <item>
+    <widget class="QgsPropertyOverrideButton" name="btnDataDefined">
+     <property name="sizePolicy">
+      <sizepolicy hsizetype="Fixed" vsizetype="Preferred">
+       <horstretch>0</horstretch>
+       <verstretch>0</verstretch>
+      </sizepolicy>
+     </property>
+     <property name="text">
+      <string>...</string>
+     </property>
+    </widget>
+   </item>
   </layout>
  </widget>
  <customwidgets>
@@ -70,6 +83,11 @@
    <header>qgis.gui</header>
    <container>1</container>
   </customwidget>
+  <customwidget>
+   <class>QgsPropertyOverrideButton</class>
+   <extends>QToolButton</extends>
+   <header>qgis.gui</header>
+  </customwidget>
  </customwidgets>
  <resources/>
  <connections/>