LibGUI+Applications: Govern Splitter resizing by opportunistic growth

This patch replaces the concept of fixed resizees with opportunistic
ones which use the new SpecialDimension::OpportunisticGrow UISize.
This lets us simplify splitter resize code and take advantage of
the layout system's automatic calculations for minimum size and
expansion. Functionally the same as before, but fixes Splitter's
unintended ability to grow window size.

Userland/Applications/FileManager/FileManagerWindow.gml

@@ -43,11 +43,10 @@
 
     @GUI::HorizontalSplitter {
         name: "splitter"
-        first_resizee_minimum_size: 80
 
         @GUI::TreeView {
             name: "tree_view"
-            fixed_width: 175
+            preferred_width: 175
         }
     }
 

Userland/Applications/FontEditor/FontEditorWindow.gml

@@ -62,7 +62,7 @@
             }
 
             @GUI::HorizontalSplitter {
-                fixed_resizee: "Second"
+                opportunistic_resizee: "First"
 
                 @GUI::Widget {
                     layout: @GUI::VerticalBoxLayout {}
@@ -217,7 +217,7 @@
 
                 @GUI::Widget {
                     name: "unicode_block_container"
-                    fixed_width: 175
+                    preferred_width: 175
                     layout: @GUI::VerticalBoxLayout {}
 
                     @GUI::TextBox {

Userland/Applications/Help/HelpWindow.gml

@@ -17,7 +17,7 @@
 
         @GUI::TabWidget {
             name: "tab_widget"
-            fixed_width: 200
+            preferred_width: 200
             container_margins: [6]
 
             @GUI::TreeView {

Userland/Libraries/LibGUI/Splitter.cpp

@@ -20,11 +20,9 @@ namespace GUI {
 Splitter::Splitter(Orientation orientation)
     : m_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" });
+    REGISTER_ENUM_PROPERTY("opportunistic_resizee", opportunisitic_resizee, set_opportunisitic_resizee, OpportunisticResizee,
+        { OpportunisticResizee::First, "First" },
+        { OpportunisticResizee::Second, "Second" });
 
     set_background_role(ColorRole::Button);
     set_layout<BoxLayout>(orientation);
@@ -197,7 +195,6 @@ void Splitter::recompute_grabbables()
         set_hovered_grabbable(&m_grabbables[old_hovered_index.value()]);
 }
 
-// FIXME: Respect the child widgets min and max sizes
 void Splitter::mousemove_event(MouseEvent& event)
 {
     auto* grabbable = grabbable_at(event.position());
@@ -206,50 +203,33 @@ void Splitter::mousemove_event(MouseEvent& event)
         override_cursor(grabbable != nullptr);
         return;
     }
-    auto delta = event.position() - m_resize_origin;
     if (!m_first_resizee || !m_second_resizee) {
-        // One or both of the resizees were deleted during an ongoing resize, screw this.
         m_resizing = false;
         return;
     }
-    auto new_first_resizee_size = m_first_resizee_start_size;
-    auto new_second_resizee_size = m_second_resizee_start_size;
 
-    new_first_resizee_size.set_primary_size_for_orientation(m_orientation, new_first_resizee_size.primary_size_for_orientation(m_orientation) + delta.primary_offset_for_orientation(m_orientation));
-    new_second_resizee_size.set_primary_size_for_orientation(m_orientation, new_second_resizee_size.primary_size_for_orientation(m_orientation) - delta.primary_offset_for_orientation(m_orientation));
-
-    if (new_first_resizee_size.primary_size_for_orientation(m_orientation) < m_first_resizee_minimum_size) {
-        int correction = m_first_resizee_minimum_size - new_first_resizee_size.primary_size_for_orientation(m_orientation);
-        new_first_resizee_size.set_primary_size_for_orientation(m_orientation, new_first_resizee_size.primary_size_for_orientation(m_orientation) + correction);
-        new_second_resizee_size.set_primary_size_for_orientation(m_orientation, new_second_resizee_size.primary_size_for_orientation(m_orientation) - correction);
-    }
-    if (new_second_resizee_size.primary_size_for_orientation(m_orientation) < m_second_resizee_minimum_size) {
-        int correction = m_second_resizee_minimum_size - new_second_resizee_size.primary_size_for_orientation(m_orientation);
-        new_second_resizee_size.set_primary_size_for_orientation(m_orientation, new_second_resizee_size.primary_size_for_orientation(m_orientation) + correction);
-        new_first_resizee_size.set_primary_size_for_orientation(m_orientation, new_first_resizee_size.primary_size_for_orientation(m_orientation) - correction);
-    }
+    auto delta = (event.position() - m_resize_origin).primary_offset_for_orientation(m_orientation);
+    auto new_first_resizee_size = clamp(m_first_resizee_start_size.primary_size_for_orientation(m_orientation) + delta, 0, m_first_resizee_max_size);
+    auto new_second_resizee_size = clamp(m_second_resizee_start_size.primary_size_for_orientation(m_orientation) - delta, 0, m_second_resizee_max_size);
 
     if (m_orientation == Orientation::Horizontal) {
-        if (fixed_resizee() == FixedResizee::First) {
-            m_first_resizee->set_fixed_width(new_first_resizee_size.width());
-            m_second_resizee->set_min_width(SpecialDimension::Shrink);
-            m_second_resizee->set_max_width(SpecialDimension::Grow);
+        if (opportunisitic_resizee() == OpportunisticResizee::First) {
+            m_first_resizee->set_preferred_width(SpecialDimension::OpportunisticGrow);
+            m_second_resizee->set_preferred_width(new_second_resizee_size);
         } else {
-            VERIFY(fixed_resizee() == FixedResizee::Second);
-            m_second_resizee->set_fixed_width(new_second_resizee_size.width());
-            m_first_resizee->set_min_width(SpecialDimension::Shrink);
-            m_first_resizee->set_max_width(SpecialDimension::Grow);
+            VERIFY(opportunisitic_resizee() == OpportunisticResizee::Second);
+            m_second_resizee->set_preferred_width(SpecialDimension::OpportunisticGrow);
+            m_first_resizee->set_preferred_width(new_first_resizee_size);
         }
     } else {
-        if (fixed_resizee() == FixedResizee::First) {
-            m_first_resizee->set_fixed_height(new_first_resizee_size.height());
-            m_second_resizee->set_min_height(SpecialDimension::Shrink);
-            m_second_resizee->set_max_height(SpecialDimension::Grow);
+        if (opportunisitic_resizee() == OpportunisticResizee::First) {
+            m_first_resizee->set_preferred_height(SpecialDimension::OpportunisticGrow);
+            m_second_resizee->set_preferred_height(new_second_resizee_size);
+
         } else {
-            VERIFY(fixed_resizee() == FixedResizee::Second);
-            m_second_resizee->set_fixed_height(new_second_resizee_size.height());
-            m_first_resizee->set_min_height(SpecialDimension::Shrink);
-            m_first_resizee->set_max_height(SpecialDimension::Grow);
+            VERIFY(opportunisitic_resizee() == OpportunisticResizee::Second);
+            m_second_resizee->set_preferred_height(SpecialDimension::OpportunisticGrow);
+            m_first_resizee->set_preferred_height(new_first_resizee_size);
         }
     }
 
@@ -272,13 +252,13 @@ void Splitter::custom_layout()
     if (m_last_child_count > child_widgets.size()) {
         bool has_child_to_fill_space = false;
         for (auto& child : child_widgets) {
-            if (child.max_size().primary_size_for_orientation(m_orientation).is_grow()) {
+            if (child.preferred_size().primary_size_for_orientation(m_orientation).is_opportunistic_grow()) {
                 has_child_to_fill_space = true;
                 break;
             }
         }
         if (!has_child_to_fill_space)
-            child_widgets.last().set_preferred_size(SpecialDimension::Grow);
+            child_widgets.last().set_preferred_size(SpecialDimension::OpportunisticGrow);
     }
 }
 

Userland/Libraries/LibGUI/Splitter.h

@@ -15,18 +15,13 @@ class Splitter : public Widget {
     C_OBJECT(Splitter);
 
 public:
-    enum class FixedResizee {
+    enum class OpportunisticResizee {
         First,
         Second
     };
 
     virtual ~Splitter() override = default;
 
-    int first_resizee_minimum_size() { return m_first_resizee_minimum_size; }
-    void set_first_resizee_minimum_size(int minimum_size) { m_first_resizee_minimum_size = minimum_size; }
-    int second_resizee_minimum_size() { return m_second_resizee_minimum_size; }
-    void set_second_resizee_minimum_size(int minimum_size) { m_second_resizee_minimum_size = minimum_size; }
-
 protected:
     explicit Splitter(Gfx::Orientation);
 
@@ -40,8 +35,8 @@ protected:
     virtual void did_layout() override;
     virtual void custom_layout() override;
 
-    FixedResizee fixed_resizee() const { return m_fixed_resizee; }
-    void set_fixed_resizee(FixedResizee resizee) { m_fixed_resizee = resizee; }
+    OpportunisticResizee opportunisitic_resizee() const { return m_opportunistic_resizee; }
+    void set_opportunisitic_resizee(OpportunisticResizee resizee) { m_opportunistic_resizee = resizee; }
 
 private:
     void override_cursor(bool do_override);
@@ -55,9 +50,7 @@ private:
     WeakPtr<Widget> m_second_resizee;
     Gfx::IntSize m_first_resizee_start_size;
     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 };
+    OpportunisticResizee m_opportunistic_resizee { OpportunisticResizee::Second };
     size_t m_last_child_count { 0 };
     int m_first_resizee_max_size { 0 };
     int m_second_resizee_max_size { 0 };