[PD] improve face selection for Pad/Pocket

- this PR extends PR #7191 as described in this forum thread: https://forum.freecadweb.org/viewtopic.php?f=3&t=70327

src/Mod/PartDesign/Gui/TaskExtrudeParameters.cpp

@@ -220,7 +220,7 @@ void TaskExtrudeParameters::connectSlots()
         this, &TaskExtrudeParameters::onReversedChanged);
     connect(ui->changeMode, qOverload<int>(&QComboBox::currentIndexChanged),
         this, &TaskExtrudeParameters::onModeChanged);
-    connect(ui->buttonFace, &QPushButton::clicked,
+    connect(ui->buttonFace, &QPushButton::toggled,
         this, &TaskExtrudeParameters::onButtonFace);
     connect(ui->lineFaceName, &QLineEdit::textEdited,
         this, &TaskExtrudeParameters::onFaceName);
@@ -255,7 +255,7 @@ void TaskExtrudeParameters::onSelectionChanged(const Gui::SelectionChanges& msg)
                 ui->lineFaceName->setProperty("FeatureName", QByteArray(msg.pObjectName));
                 ui->lineFaceName->setProperty("FaceName", QByteArray(msg.pSubName));
                 // Turn off reference selection mode
-                onButtonFace(false);
+                ui->buttonFace->setChecked(false);
             }
             else {
                 clearFaceName();
@@ -468,7 +468,7 @@ void TaskExtrudeParameters::setCheckboxes(Modes mode, Type type)
         QMetaObject::invokeMethod(ui->lineFaceName, "setFocus", Qt::QueuedConnection);
         // Go into reference selection mode if no face has been selected yet
         if (ui->lineFaceName->property("FeatureName").isNull())
-            onButtonFace(true);
+            ui->buttonFace->setChecked(true);
     }
     else if (mode == Modes::TwoDimensions) {
         isLengthEditVisible = true;
@@ -507,7 +507,7 @@ void TaskExtrudeParameters::setCheckboxes(Modes mode, Type type)
     ui->buttonFace->setEnabled(isFaceEditEnabled);
     ui->lineFaceName->setEnabled(isFaceEditEnabled);
     if (!isFaceEditEnabled) {
-        onButtonFace(false);
+        ui->buttonFace->setChecked(false);
     }
 }
 
@@ -681,16 +681,18 @@ void TaskExtrudeParameters::getReferenceAxis(App::DocumentObject*& obj, std::vec
     }
 }
 
-void TaskExtrudeParameters::onButtonFace(const bool pressed)
+void TaskExtrudeParameters::onButtonFace(const bool checked)
 {
+    if (!checked && ui->lineFaceName->text().isEmpty())
+        ui->lineFaceName->setPlaceholderText(tr("No face selected"));
+    else if (checked && ui->lineFaceName->text().isEmpty())
+        handleLineFaceName(); // sets placeholder text
+
     // to distinguish that this is the direction selection
     selectionFace = true;
 
     // only faces are allowed
-    TaskSketchBasedParameters::onSelectReference(pressed ? AllowSelection::FACE : AllowSelection::NONE);
-
-    // Update button if onButtonFace() is called explicitly
-    ui->buttonFace->setChecked(pressed);
+    TaskSketchBasedParameters::onSelectReference(checked ? AllowSelection::FACE : AllowSelection::NONE);
 }
 
 void TaskExtrudeParameters::onFaceName(const QString& text)
@@ -890,4 +892,9 @@ void TaskExtrudeParameters::translateModeList(int)
     // implement in sub-class
 }
 
+void TaskExtrudeParameters::handleLineFaceName(void)
+{
+    ui->lineFaceName->setPlaceholderText(tr("Click on a face in the model"));
+}
+
 #include "moc_TaskExtrudeParameters.cpp"

src/Mod/PartDesign/Gui/TaskExtrudeParameters.h

@@ -90,7 +90,7 @@ protected Q_SLOTS:
     void onZDirectionEditChanged(double);
     void onMidplaneChanged(bool);
     void onReversedChanged(bool);
-    void onButtonFace(const bool pressed = true);
+    void onButtonFace(const bool checked = true);
     void onFaceName(const QString& text);
     virtual void onModeChanged(int);
 
@@ -118,6 +118,7 @@ protected:
     virtual void updateUI(int index);
     void updateDirectionEdits(void);
     void setDirectionMode(int index);
+    void handleLineFaceName(void);
 
 private:
     void tryRecomputeFeature();

src/Mod/PartDesign/Gui/TaskPadParameters.cpp

@@ -104,6 +104,10 @@ void TaskPadParameters::onModeChanged(int index)
         break;
     case Modes::ToFace:
         pcPad->Type.setValue("UpToFace");
+        if (ui->lineFaceName->text().isEmpty()) {
+            ui->buttonFace->setChecked(true);
+            handleLineFaceName(); // sets placeholder text
+        }
         break;
     case Modes::TwoDimensions:
         pcPad->Type.setValue("TwoLengths");

src/Mod/PartDesign/Gui/TaskPadPocketParameters.ui

@@ -141,7 +141,7 @@ the sketch plane's normal vector will be used</string>
            </property>
           </widget>
          </item>
-        <item row="0" column="1">
+         <item row="0" column="1">
           <widget class="Gui::DoubleSpinBox" name="XDirectionEdit">
            <property name="toolTip">
             <string>x-component of direction vector</string>
@@ -224,7 +224,7 @@ the sketch plane's normal vector will be used</string>
            </property>
           </widget>
          </item>
-         </layout>
+        </layout>
        </widget>
       </item>
       <item row="3" column="0">
@@ -336,14 +336,27 @@ measured along the specified direction</string>
    <item>
     <layout class="QGridLayout" name="gridLayout_5">
      <item row="0" column="0">
-      <widget class="QPushButton" name="buttonFace">
+      <widget class="QToolButton" name="buttonFace">
+       <property name="minimumSize">
+        <size>
+         <width>0</width>
+         <height>22</height>
+        </size>
+       </property>
        <property name="text">
-        <string>Face</string>
+        <string>Select face</string>
+       </property>
+       <property name="checkable">
+        <bool>true</bool>
        </property>
       </widget>
      </item>
      <item row="0" column="1">
-      <widget class="QLineEdit" name="lineFaceName"/>
+      <widget class="QLineEdit" name="lineFaceName">
+       <property name="readOnly">
+        <bool>true</bool>
+       </property>
+      </widget>
      </item>
     </layout>
    </item>

src/Mod/PartDesign/Gui/TaskPocketParameters.cpp

@@ -114,6 +114,10 @@ void TaskPocketParameters::onModeChanged(int index)
             pcPocket->Type.setValue("UpToFace");
             pcPocket->Length.setValue(0.0);
             ui->lengthEdit->setValue(0.0);
+            if (ui->lineFaceName->text().isEmpty()) {
+                ui->buttonFace->setChecked(true);
+                handleLineFaceName(); // sets placeholder text
+            }
             break;
         case Modes::TwoDimensions:
             oldLength = pcPocket->Length.getValue();