LibGUI+Apps: Let Splitters select which resizee to set fixed

This gives Splitters more versatility when the right resizee is
intended to remain fixed or be toggled on and off.

Userland/Applications/CharacterMap/CharacterMapWindow.gml

@@ -30,6 +30,8 @@
     }
 
     @GUI::HorizontalSplitter {
+        fixed_resizee: "Second"
+
         @GUI::Widget {
             layout: @GUI::VerticalBoxLayout {}
 

Userland/Applications/FontEditor/FontEditorWindow.gml

@@ -59,6 +59,8 @@
             }
 
             @GUI::HorizontalSplitter {
+                fixed_resizee: "Second"
+
                 @GUI::Widget {
                     layout: @GUI::VerticalBoxLayout {}
 

Userland/Applications/TextEditor/TextEditorWindow.gml

@@ -14,6 +14,8 @@
     }
 
     @GUI::HorizontalSplitter {
+        fixed_resizee: "Second"
+
         @GUI::TextEditor {
             name: "editor"
         }

Userland/Libraries/LibGUI/Splitter.cpp

@@ -20,6 +20,9 @@ Splitter::Splitter(Orientation orientation)
 {
     REGISTER_INT_PROPERTY("first_resizee_minimum_size", first_resizee_minimum_size, set_first_resizee_minimum_size);
     REGISTER_INT_PROPERTY("second_resizee_minimum_size", second_resizee_minimum_size, set_second_resizee_minimum_size);
+    REGISTER_ENUM_PROPERTY("fixed_resizee", fixed_resizee, set_fixed_resizee, FixedResizee,
+        { FixedResizee::First, "First" },
+        { FixedResizee::Second, "Second" });
 
     set_background_role(ColorRole::Button);
     set_layout<BoxLayout>(orientation);
@@ -218,11 +221,11 @@ void Splitter::mousemove_event(MouseEvent& event)
     }
 
     if (m_orientation == Orientation::Horizontal) {
-        m_first_resizee->set_fixed_width(new_first_resizee_size.width());
-        m_second_resizee->set_fixed_width(-1);
+        m_first_resizee->set_fixed_width(fixed_resizee() == FixedResizee::First ? new_first_resizee_size.width() : -1);
+        m_second_resizee->set_fixed_width(fixed_resizee() == FixedResizee::Second ? new_second_resizee_size.width() : -1);
     } else {
-        m_first_resizee->set_fixed_height(new_first_resizee_size.height());
-        m_second_resizee->set_fixed_height(-1);
+        m_first_resizee->set_fixed_height(fixed_resizee() == FixedResizee::First ? new_first_resizee_size.height() : -1);
+        m_second_resizee->set_fixed_height(fixed_resizee() == FixedResizee::Second ? new_second_resizee_size.height() : -1);
     }
 
     invalidate_layout();

Userland/Libraries/LibGUI/Splitter.h

@@ -14,6 +14,11 @@ class Splitter : public Widget {
     C_OBJECT(Splitter);
 
 public:
+    enum class FixedResizee {
+        First,
+        Second
+    };
+
     virtual ~Splitter() override;
 
     int first_resizee_minimum_size() { return m_first_resizee_minimum_size; }
@@ -33,6 +38,9 @@ protected:
 
     virtual void did_layout() override;
 
+    FixedResizee fixed_resizee() const { return m_fixed_resizee; }
+    void set_fixed_resizee(FixedResizee resizee) { m_fixed_resizee = resizee; }
+
 private:
     void override_cursor(bool do_override);
     Gfx::IntRect rect_between_widgets(GUI::Widget const& first_widget, GUI::Widget const& second_widget, bool honor_grabbable_margins) const;
@@ -47,6 +55,7 @@ private:
     Gfx::IntSize m_second_resizee_start_size;
     int m_first_resizee_minimum_size { 0 };
     int m_second_resizee_minimum_size { 0 };
+    FixedResizee m_fixed_resizee { FixedResizee::First };
 
     void recompute_grabbables();