LibGUI: Make the calendar widget scrollable

Author: https://github.com/implicitfield
Commit: https://github.com/SerenityOS/serenity/commit/e504b63406
Pull-request: https://github.com/SerenityOS/serenity/pull/19513
Reviewed-by: https://github.com/alimpfard

Userland/Libraries/LibGUI/Calendar.cpp

@@ -39,6 +39,7 @@ Calendar::Calendar(Core::DateTime date_time, Mode mode)
     m_weekend_length = weekend_length;
 
     set_fill_with_background_color(true);
+    set_scrollbars_enabled(false);
 
     for (int i = 0; i < 7; i++) {
         Day day;
@@ -777,6 +778,17 @@ void Calendar::mousedown_event(GUI::MouseEvent& event)
     }
 }
 
+void Calendar::mousewheel_event(GUI::MouseEvent& event)
+{
+    if (event.wheel_delta_y() > 0)
+        show_next_date();
+    else
+        show_previous_date();
+
+    if (on_scroll)
+        on_scroll();
+}
+
 void Calendar::doubleclick_event(GUI::MouseEvent& event)
 {
     int months;

Userland/Libraries/LibGUI/Calendar.h

@@ -11,13 +11,14 @@
 #include <AK/DeprecatedString.h>
 #include <LibConfig/Listener.h>
 #include <LibCore/DateTime.h>
+#include <LibGUI/AbstractScrollableWidget.h>
 #include <LibGUI/Frame.h>
 #include <LibGUI/Widget.h>
 
 namespace GUI {
 
 class Calendar final
-    : public GUI::Frame
+    : public GUI::AbstractScrollableWidget
     , public Config::Listener {
     C_OBJECT(Calendar)
 
@@ -77,6 +78,7 @@ public:
     virtual void config_string_did_change(StringView, StringView, StringView, StringView) override;
     virtual void config_i32_did_change(StringView, StringView, StringView, i32 value) override;
 
+    Function<void()> on_scroll;
     Function<void()> on_tile_click;
     Function<void()> on_tile_doubleclick;
     Function<void()> on_month_click;
@@ -92,6 +94,7 @@ private:
     virtual void mousemove_event(GUI::MouseEvent&) override;
     virtual void mousedown_event(MouseEvent&) override;
     virtual void mouseup_event(MouseEvent&) override;
+    virtual void mousewheel_event(MouseEvent&) override;
     virtual void doubleclick_event(MouseEvent&) override;
     virtual void leave_event(Core::Event&) override;
 

Userland/Services/Taskbar/ClockWidget.cpp

@@ -83,6 +83,10 @@ ClockWidget::ClockWidget()
     m_calendar = calendar_container.add<GUI::Calendar>();
     m_selected_calendar_button->set_text(m_calendar->formatted_date().release_value_but_fixme_should_propagate_errors());
 
+    m_calendar->on_scroll = [&] {
+        update_selected_calendar_button();
+    };
+
     m_calendar->on_tile_click = [&] {
         m_selected_calendar_button->set_text(m_calendar->formatted_date().release_value_but_fixme_should_propagate_errors());
     };