improve boxlayout growing

src/BoxLayout.cpp

@@ -24,15 +24,19 @@ void BoxLayout::run() {
         if (i >= working_slots.size()) {
             // widgets which are outside the pre-defined slot range
 
-            if (child->rect().max_dimension_at(m_direction) != -1 || child->rect().min_dimension_at(m_direction) != -1) {
-                // if the widget has a minimum or maximum size, we'll make a slot for its preferred size
+            bool widget_has_fixed_size = child->rect().max_dimension_at(m_direction) != -1 || child->rect().min_dimension_at(m_direction) != -1;
+            bool widget_grows = child->grows();
+            bool is_widget_unslotted = !widget_has_fixed_size && widget_grows;
+
+            if (is_widget_unslotted) {
+                // we can consider non-growing widgets with no size perference "unslotted". these widgets will be evenly spaced amongst themselves.
+                unslotted_widgets++;
+                working_slots.push_back(Slot{ 0, 0, SlotType::Auto });
+            } else {
+                // if the widget has a size preference, we will use its dimensions instead
                 child->rect().update();
                 working_slots.push_back(Slot { 0, child->rect().dimension_at(m_direction), SlotType::Pixel });
                 free_space -= child->rect().dimension_at(m_direction) + m_spacing;
-            } else {
-                // we can consider widgets with no size perference "unslotted". these widgets will be evenly spaced amongst themselves.
-                unslotted_widgets++;
-                working_slots.push_back(Slot{ 0, 0, SlotType::Auto });
             }
         } else {
             // widgets which have a pre-defined slot

src/Widget.hpp

@@ -92,6 +92,9 @@ public:
     bool absolute() { return m_absolute; }
     void set_absolute(bool absolute) { m_absolute = absolute; } 
 
+    bool grows() { return m_grows; }
+    void set_grows(bool grows) { m_grows = grows; }
+
     void set_layout(std::shared_ptr<Layout> layout);
     std::shared_ptr<Layout> layout() { return m_layout; }
 
@@ -146,6 +149,7 @@ private:
     bool m_consumes_hits { false };
     bool m_accepts_events { true };
     bool m_absolute { false };
+    bool m_grows { true };
     ControlWidgetType m_control_type { ControlWidgetType::Widget };
 };