Profiler: Add a statusbar and show the timeline selection info in it :^)

Userland/DevTools/Profiler/TimelineTrack.cpp

@@ -75,26 +75,14 @@ void TimelineTrack::paint_event(GUI::PaintEvent& event)
     painter.fill_rect({ select_start_x, frame_thickness(), select_end_x - select_start_x, height() - frame_thickness() * 2 }, Color(0, 0, 0, 60));
     painter.fill_rect({ select_hover_x, frame_thickness(), 1, height() - frame_thickness() * 2 }, Color::NamedColor::Black);
 
-    {
-        StringBuilder timeline_desc_builder;
-
-        timeline_desc_builder.appendff("{} ({}), ", m_process.executable, m_process.pid);
-
-        timeline_desc_builder.appendff("Time: {} ms", normalized_hover_time - start_of_trace);
-        if (normalized_start_time != normalized_end_time) {
-            auto start = normalized_start_time - start_of_trace;
-            auto end = normalized_end_time - start_of_trace;
-            timeline_desc_builder.appendff(", Selection: {} - {} ms", start, end);
-        }
-        const auto text = timeline_desc_builder.build();
-        Gfx::IntRect rect {
-            frame_thickness() + 3,
-            frame_thickness() + 3,
-            font().width(text),
-            font().glyph_height()
-        };
-        painter.draw_text(rect, text, font());
-    }
+    auto text = String::formatted("{} ({})", m_process.executable, m_process.pid);
+    Gfx::IntRect text_rect {
+        frame_thickness() + 3,
+        frame_thickness() + 3,
+        font().width(text),
+        font().glyph_height()
+    };
+    painter.draw_text(text_rect, text, font());
 }
 
 u64 TimelineTrack::timestamp_at_x(int x) const

Userland/DevTools/Profiler/TimelineView.h

@@ -18,6 +18,8 @@ class TimelineView final : public GUI::Widget {
 public:
     virtual ~TimelineView() override;
 
+    Function<void()> on_selection_change;
+
     bool is_selecting() const { return m_selecting; }
     u64 select_start_time() const { return m_select_start_time; }
     u64 select_end_time() const { return m_select_end_time; }
@@ -25,23 +27,37 @@ public:
 
     void set_selecting(Badge<TimelineTrack>, bool value)
     {
+        if (m_selecting == value)
+            return;
         m_selecting = value;
-        update();
     }
+
     void set_select_start_time(Badge<TimelineTrack>, u64 value)
     {
+        if (m_select_start_time == value)
+            return;
         m_select_start_time = value;
         update();
+        if (on_selection_change)
+            on_selection_change();
     }
     void set_select_end_time(Badge<TimelineTrack>, u64 value)
     {
+        if (m_select_end_time == value)
+            return;
         m_select_end_time = value;
         update();
+        if (on_selection_change)
+            on_selection_change();
     }
     void set_hover_time(Badge<TimelineTrack>, u64 value)
     {
+        if (m_hover_time == value)
+            return;
         m_hover_time = value;
         update();
+        if (on_selection_change)
+            on_selection_change();
     }
 
 private:

Userland/DevTools/Profiler/main.cpp

@@ -27,6 +27,7 @@
 #include <LibGUI/ProcessChooser.h>
 #include <LibGUI/ScrollableContainerWidget.h>
 #include <LibGUI/Splitter.h>
+#include <LibGUI/Statusbar.h>
 #include <LibGUI/TabWidget.h>
 #include <LibGUI/TableView.h>
 #include <LibGUI/TreeView.h>
@@ -140,6 +141,28 @@ int main(int argc, char** argv)
         individual_sample_view.set_model(move(model));
     };
 
+    const u64 start_of_trace = profile->first_timestamp();
+    const u64 end_of_trace = start_of_trace + profile->length_in_ms();
+    const auto clamp_timestamp = [start_of_trace, end_of_trace](u64 timestamp) -> u64 {
+        return min(end_of_trace, max(timestamp, start_of_trace));
+    };
+
+    auto& statusbar = main_widget.add<GUI::Statusbar>();
+    timeline_view->on_selection_change = [&] {
+        auto& view = *timeline_view;
+        StringBuilder builder;
+        u64 normalized_start_time = clamp_timestamp(min(view.select_start_time(), view.select_end_time()));
+        u64 normalized_end_time = clamp_timestamp(max(view.select_start_time(), view.select_end_time()));
+        u64 normalized_hover_time = clamp_timestamp(view.hover_time());
+        builder.appendff("Time: {} ms", normalized_hover_time - start_of_trace);
+        if (normalized_start_time != normalized_end_time) {
+            auto start = normalized_start_time - start_of_trace;
+            auto end = normalized_end_time - start_of_trace;
+            builder.appendff(", Selection: {} - {} ms", start, end);
+        }
+        statusbar.set_text(builder.to_string());
+    };
+
     auto menubar = GUI::Menubar::construct();
     auto& file_menu = menubar->add_menu("&File");
     file_menu.add_action(GUI::CommonActions::make_quit_action([&](auto&) { app->quit(); }));