Taskbar: Let's custom paint the background instead of using GUI::Frame

Previously we were wasting the bottom pixel row on darkness. Use the
base button color all the way to the bottom row and offset the top
highlight by one pixel instead.

Author: awesomekling

Services/Taskbar/TaskbarWindow.cpp

@@ -33,11 +33,31 @@
 #include <LibGUI/Button.h>
 #include <LibGUI/Desktop.h>
 #include <LibGUI/Frame.h>
+#include <LibGUI/Painter.h>
 #include <LibGUI/Window.h>
+#include <LibGfx/Palette.h>
 #include <stdio.h>
 
 //#define EVENT_DEBUG
 
+class TaskbarWidget final : public GUI::Widget {
+    C_OBJECT(TaskbarWidget);
+
+public:
+    virtual ~TaskbarWidget() override {}
+
+private:
+    TaskbarWidget() {}
+
+    virtual void paint_event(GUI::PaintEvent& event) override
+    {
+        GUI::Painter painter(*this);
+        painter.add_clip_rect(event.rect());
+        painter.fill_rect(rect(), palette().button());
+        painter.draw_line({ 0, 1 }, { width() - 1, 1 }, palette().threed_highlight());
+    }
+};
+
 TaskbarWindow::TaskbarWindow()
 {
     set_window_type(GUI::WindowType::Taskbar);
@@ -47,14 +67,10 @@ TaskbarWindow::TaskbarWindow()
 
     GUI::Desktop::the().on_rect_change = [this](const Gfx::Rect& rect) { on_screen_rect_change(rect); };
 
-    auto& widget = set_main_widget<GUI::Frame>();
-    widget.set_fill_with_background_color(true);
+    auto& widget = set_main_widget<TaskbarWidget>();
     widget.set_layout<GUI::HorizontalBoxLayout>();
     widget.layout()->set_margins({ 3, 2, 3, 2 });
     widget.layout()->set_spacing(3);
-    widget.set_frame_thickness(1);
-    widget.set_frame_shape(Gfx::FrameShape::Panel);
-    widget.set_frame_shadow(Gfx::FrameShadow::Raised);
 
     m_default_icon = Gfx::Bitmap::load_from_file("/res/icons/16x16/window.png");