LibGUI: Allow specifying Layout margins and spacing in the constructor

This is comfier than `my_widget->layout()->set_margins(...)`.

Userland/Libraries/LibGUI/BoxLayout.cpp

@@ -17,8 +17,9 @@ REGISTER_LAYOUT(GUI, VerticalBoxLayout)
 
 namespace GUI {
 
-BoxLayout::BoxLayout(Orientation orientation)
-    : m_orientation(orientation)
+BoxLayout::BoxLayout(Orientation orientation, Margins margins, int spacing)
+    : Layout(margins, spacing)
+    , m_orientation(orientation)
 {
     register_property(
         "orientation", [this] { return m_orientation == Gfx::Orientation::Vertical ? "Vertical" : "Horizontal"; }, nullptr);

Userland/Libraries/LibGUI/BoxLayout.h

@@ -26,7 +26,7 @@ public:
     virtual UISize min_size() const override;
 
 protected:
-    explicit BoxLayout(Gfx::Orientation);
+    explicit BoxLayout(Gfx::Orientation, Margins = {}, int spacing = Layout::default_spacing);
 
 private:
     Gfx::Orientation m_orientation;
@@ -36,8 +36,8 @@ class VerticalBoxLayout final : public BoxLayout {
     C_OBJECT(VerticalBoxLayout);
 
 private:
-    explicit VerticalBoxLayout()
-        : BoxLayout(Gfx::Orientation::Vertical)
+    explicit VerticalBoxLayout(Margins margins = {}, int spacing = Layout::default_spacing)
+        : BoxLayout(Gfx::Orientation::Vertical, margins, spacing)
     {
     }
     virtual ~VerticalBoxLayout() override = default;
@@ -47,8 +47,8 @@ class HorizontalBoxLayout final : public BoxLayout {
     C_OBJECT(HorizontalBoxLayout);
 
 private:
-    explicit HorizontalBoxLayout()
-        : BoxLayout(Gfx::Orientation::Horizontal)
+    explicit HorizontalBoxLayout(Margins margins = {}, int spacing = Layout::default_spacing)
+        : BoxLayout(Gfx::Orientation::Horizontal, margins, spacing)
     {
     }
     virtual ~HorizontalBoxLayout() override = default;

Userland/Libraries/LibGUI/Layout.cpp

@@ -14,7 +14,9 @@ REGISTER_ABSTRACT_CORE_OBJECT(GUI, Layout)
 
 namespace GUI {
 
-Layout::Layout()
+Layout::Layout(Margins initial_margins, int spacing)
+    : m_margins(initial_margins)
+    , m_spacing(spacing)
 {
     REGISTER_INT_PROPERTY("spacing", spacing, set_spacing);
     REGISTER_MARGINS_PROPERTY("margins", margins, set_margins);

Userland/Libraries/LibGUI/Layout.h

@@ -58,11 +58,12 @@ public:
     Margins const& margins() const { return m_margins; }
     void set_margins(Margins const&);
 
+    static constexpr int default_spacing = 3;
     int spacing() const { return m_spacing; }
     void set_spacing(int);
 
 protected:
-    Layout();
+    Layout(Margins, int spacing);
 
     struct Entry {
         enum class Type {
@@ -83,7 +84,7 @@ protected:
     Vector<Entry> m_entries;
 
     Margins m_margins;
-    int m_spacing { 3 };
+    int m_spacing { default_spacing };
 };
 
 }