GTabWidget: Allow putting the tabs on the bottom of the widget.

They're still painted as if they are top tabs, but the subwidget placement
logic is all there.

2 files changed, 47 insertions, 3 deletions

diff --git a/Libraries/LibGUI/GTabWidget.cpp b/Libraries/LibGUI/GTabWidget.cpp
index 374390fd3f..d0663c5b7e 100644
--- a/Libraries/LibGUI/GTabWidget.cpp
+++ b/Libraries/LibGUI/GTabWidget.cpp
@@ -45,7 +45,13 @@ void GTabWidget::resize_event(GResizeEvent& event)
 
 Rect GTabWidget::child_rect_for_size(const Size& size) const
 {
-    return { { container_padding(), bar_height() + container_padding() }, { size.width() - container_padding() * 2, size.height() - bar_height() - container_padding() * 2 } };
+    switch (m_tab_position) {
+    case TabPosition::Top:
+        return { { container_padding(), bar_height() + container_padding() }, { size.width() - container_padding() * 2, size.height() - bar_height() - container_padding() * 2 } };
+    case TabPosition::Bottom:
+        return { { container_padding(), container_padding() }, { size.width() - container_padding() * 2, size.height() - bar_height() - container_padding() * 2 } };
+    }
+    ASSERT_NOT_REACHED();
 }
 
 void GTabWidget::child_event(CChildEvent& event)
@@ -73,7 +79,24 @@ void GTabWidget::child_event(CChildEvent& event)
 
 Rect GTabWidget::bar_rect() const
 {
-    return { 0, 0, width(), bar_height() };
+    switch (m_tab_position) {
+    case TabPosition::Top:
+        return { 0, 0, width(), bar_height() };
+    case TabPosition::Bottom:
+        return { 0, height() - bar_height(), width(), bar_height() };
+    }
+    ASSERT_NOT_REACHED();
+}
+
+Rect GTabWidget::container_rect() const
+{
+    switch (m_tab_position) {
+    case TabPosition::Top:
+        return { 0, bar_height(), width(), height() - bar_height() };
+    case TabPosition::Bottom:
+        return { 0, 0, width(), height() - bar_height() };
+    }
+    ASSERT_NOT_REACHED();
 }
 
 void GTabWidget::paint_event(GPaintEvent& event)
@@ -81,7 +104,7 @@ void GTabWidget::paint_event(GPaintEvent& event)
     GPainter painter(*this);
     painter.add_clip_rect(event.rect());
 
-    Rect container_rect { 0, bar_height(), width(), height() - bar_height() };
+    auto container_rect = this->container_rect();
     auto padding_rect = container_rect;
     for (int i = 0; i < container_padding(); ++i) {
         painter.draw_rect(padding_rect, background_color());
@@ -124,6 +147,7 @@ Rect GTabWidget::button_rect(int index) const
         rect.move_by(-2, 0);
         rect.set_width(rect.width() + 4);
     }
+    rect.move_by(bar_rect().location());
     return rect;
 }
 
@@ -174,3 +198,13 @@ void GTabWidget::update_bar()
     invalidation_rect.set_height(invalidation_rect.height() + 1);
     update(invalidation_rect);
 }
+
+void GTabWidget::set_tab_position(TabPosition tab_position)
+{
+    if (m_tab_position == tab_position)
+        return;
+    m_tab_position = tab_position;
+    if (m_active_widget)
+        m_active_widget->set_relative_rect(child_rect_for_size(size()));
+    update();
+}
diff --git a/Libraries/LibGUI/GTabWidget.h b/Libraries/LibGUI/GTabWidget.h
index ac679f21c8..9eedaa35b9 100644
--- a/Libraries/LibGUI/GTabWidget.h
+++ b/Libraries/LibGUI/GTabWidget.h
@@ -5,9 +5,17 @@
 class GTabWidget : public GWidget {
     C_OBJECT(GTabWidget)
 public:
+    enum TabPosition {
+        Top,
+        Bottom,
+    };
+
     explicit GTabWidget(GWidget* parent);
     virtual ~GTabWidget() override;
 
+    TabPosition tab_position() const { return m_tab_position; }
+    void set_tab_position(TabPosition);
+
     GWidget* active_widget() const { return m_active_widget; }
     void set_active_widget(GWidget*);
 
@@ -28,6 +36,7 @@ private:
     Rect child_rect_for_size(const Size&) const;
     Rect button_rect(int index) const;
     Rect bar_rect() const;
+    Rect container_rect() const;
     void update_bar();
 
     GWidget* m_active_widget { nullptr };
@@ -39,5 +48,6 @@ private:
         GWidget* widget { nullptr };
     };
     Vector<TabData> m_tabs;
+    TabPosition m_tab_position { TabPosition::Top };
     int m_hovered_tab_index { -1 };
 };