LibGUI+LibDraw: Add "Palette" concept for scoped color theming

GApplication now has a palette. This palette contains all the system
theme colors by default, and is inherited by a new top-level GWidget.
New child widgets inherit their parents palette.

It is possible to override the GApplication palette, and the palette
of any GWidget.

The Palette object contains a bunch of colors, each corresponding to
a ColorRole. Each role has a convenience getter as well.

Each GWidget now has a background_role() and foreground_role(), which
are then looked up in their current palette when painting. This means
that you no longer alter the background color of a widget by setting
it directly, rather you alter either its background role, or the
widget's palette.

9 files changed, 67 insertions, 50 deletions

diff --git a/Servers/WindowServer/WSButton.cpp b/Servers/WindowServer/WSButton.cpp
index f7d9970557..0c6d749d41 100644
--- a/Servers/WindowServer/WSButton.cpp
+++ b/Servers/WindowServer/WSButton.cpp
@@ -18,14 +18,15 @@ WSButton::~WSButton()
 
 void WSButton::paint(Painter& painter)
 {
+    auto& palette = WSWindowManager::the().palette();
     PainterStateSaver saver(painter);
     painter.translate(relative_rect().location());
-    StylePainter::paint_button(painter, rect(), ButtonStyle::Normal, m_pressed, m_hovered);
+    StylePainter::paint_button(painter, rect(), palette, ButtonStyle::Normal, m_pressed, m_hovered);
     auto x_location = rect().center();
     x_location.move_by(-(m_bitmap->width() / 2), -(m_bitmap->height() / 2));
     if (m_pressed)
         x_location.move_by(1, 1);
-    painter.draw_bitmap(x_location, *m_bitmap, SystemColor::ButtonText);
+    painter.draw_bitmap(x_location, *m_bitmap, palette.button_text());
 }
 
 void WSButton::on_mouse_event(const WSMouseEvent& event)
diff --git a/Servers/WindowServer/WSCompositor.cpp b/Servers/WindowServer/WSCompositor.cpp
index ee166e4df3..29c6fe0f1b 100644
--- a/Servers/WindowServer/WSCompositor.cpp
+++ b/Servers/WindowServer/WSCompositor.cpp
@@ -113,7 +113,7 @@ void WSCompositor::compose()
         if (wm.any_opaque_window_contains_rect(dirty_rect))
             continue;
         // FIXME: If the wallpaper is opaque, no need to fill with color!
-        m_back_painter->fill_rect(dirty_rect, SystemColor::DesktopBackground);
+        m_back_painter->fill_rect(dirty_rect, wm.palette().desktop_background());
         if (m_wallpaper) {
             if (m_wallpaper_mode == WallpaperMode::Simple) {
                 m_back_painter->blit(dirty_rect.location(), *m_wallpaper, dirty_rect);
diff --git a/Servers/WindowServer/WSMenu.cpp b/Servers/WindowServer/WSMenu.cpp
index f1bf900259..7d09933a83 100644
--- a/Servers/WindowServer/WSMenu.cpp
+++ b/Servers/WindowServer/WSMenu.cpp
@@ -126,6 +126,7 @@ WSWindow& WSMenu::ensure_menu_window()
 
 void WSMenu::draw()
 {
+    auto& palette = WSWindowManager::the().palette();
     m_theme_index_at_last_paint = WSWindowManager::the().theme_index();
 
     ASSERT(menu_window());
@@ -133,8 +134,8 @@ void WSMenu::draw()
     Painter painter(*menu_window()->backing_store());
 
     Rect rect { {}, menu_window()->size() };
-    painter.fill_rect(rect.shrunken(6, 6), SystemColor::MenuBase);
-    StylePainter::paint_window_frame(painter, rect);
+    painter.fill_rect(rect.shrunken(6, 6), palette.menu_base());
+    StylePainter::paint_window_frame(painter, rect, palette);
     int width = this->width();
 
     if (!s_checked_bitmap)
@@ -148,15 +149,15 @@ void WSMenu::draw()
     }
 
     Rect stripe_rect { frame_thickness(), frame_thickness(), s_stripe_width, height() - frame_thickness() * 2 };
-    painter.fill_rect(stripe_rect, SystemColor::MenuStripe);
-    painter.draw_line(stripe_rect.top_right(), stripe_rect.bottom_right(), Color(SystemColor::MenuStripe).darkened());
+    painter.fill_rect(stripe_rect, palette.menu_stripe());
+    painter.draw_line(stripe_rect.top_right(), stripe_rect.bottom_right(), palette.menu_stripe().darkened());
 
     for (auto& item : m_items) {
         if (item.type() == WSMenuItem::Text) {
-            Color text_color = SystemColor::WindowText;
+            Color text_color = palette.window_text();
             if (&item == m_hovered_item && item.is_enabled()) {
-                painter.fill_rect(item.rect(), SystemColor::MenuSelection);
-                painter.draw_rect(item.rect(), Color(SystemColor::MenuSelection).darkened());
+                painter.fill_rect(item.rect(), palette.menu_selection());
+                painter.draw_rect(item.rect(), palette.menu_selection().darkened());
                 text_color = Color::White;
             } else if (!item.is_enabled()) {
                 text_color = Color::MidGray;
@@ -166,10 +167,10 @@ void WSMenu::draw()
                 Rect checkmark_rect { item.rect().x() + 7, 0, s_checked_bitmap_width, s_checked_bitmap_height };
                 checkmark_rect.center_vertically_within(text_rect);
                 Rect checkbox_rect = checkmark_rect.inflated(4, 4);
-                painter.fill_rect(checkbox_rect, SystemColor::Base);
-                StylePainter::paint_frame(painter, checkbox_rect, FrameShape::Container, FrameShadow::Sunken, 2);
+                painter.fill_rect(checkbox_rect, palette.base());
+                StylePainter::paint_frame(painter, checkbox_rect, palette, FrameShape::Container, FrameShadow::Sunken, 2);
                 if (item.is_checked()) {
-                    painter.draw_bitmap(checkmark_rect.location(), *s_checked_bitmap, SystemColor::ButtonText);
+                    painter.draw_bitmap(checkmark_rect.location(), *s_checked_bitmap, palette.button_text());
                 }
             } else if (item.icon()) {
                 Rect icon_rect { item.rect().x() + 3, 0, s_item_icon_width, s_item_icon_width };
@@ -189,13 +190,13 @@ void WSMenu::draw()
                     s_submenu_arrow_bitmap_height
                 };
                 submenu_arrow_rect.center_vertically_within(item.rect());
-                painter.draw_bitmap(submenu_arrow_rect.location(), submenu_arrow_bitmap, SystemColor::WindowText);
+                painter.draw_bitmap(submenu_arrow_rect.location(), submenu_arrow_bitmap, palette.window_text());
             }
         } else if (item.type() == WSMenuItem::Separator) {
             Point p1(item.rect().translated(stripe_rect.width() + 4, 0).x(), item.rect().center().y() - 1);
             Point p2(width - 7, item.rect().center().y() - 1);
-            painter.draw_line(p1, p2, SystemColor::ThreedShadow1);
-            painter.draw_line(p1.translated(0, 1), p2.translated(0, 1), SystemColor::ThreedHighlight);
+            painter.draw_line(p1, p2, palette.threed_shadow1());
+            painter.draw_line(p1.translated(0, 1), p2.translated(0, 1), palette.threed_highlight());
         }
     }
 }
diff --git a/Servers/WindowServer/WSMenuManager.cpp b/Servers/WindowServer/WSMenuManager.cpp
index 5db49f1f34..67139e8171 100644
--- a/Servers/WindowServer/WSMenuManager.cpp
+++ b/Servers/WindowServer/WSMenuManager.cpp
@@ -44,6 +44,7 @@ bool WSMenuManager::is_open(const WSMenu& menu) const
 void WSMenuManager::draw()
 {
     auto& wm = WSWindowManager::the();
+    auto& palette = wm.palette();
     auto menubar_rect = this->menubar_rect();
 
     if (m_needs_window_resize) {
@@ -83,14 +84,14 @@ void WSMenuManager::draw()
 
     Painter painter(*window().backing_store());
 
-    painter.fill_rect(menubar_rect, SystemColor::Window);
-    painter.draw_line({ 0, menubar_rect.bottom() }, { menubar_rect.right(), menubar_rect.bottom() }, SystemColor::ThreedShadow1);
+    painter.fill_rect(menubar_rect, palette.window());
+    painter.draw_line({ 0, menubar_rect.bottom() }, { menubar_rect.right(), menubar_rect.bottom() }, palette.threed_shadow1());
     int index = 0;
     wm.for_each_active_menubar_menu([&](WSMenu& menu) {
-        Color text_color = SystemColor::WindowText;
+        Color text_color = palette.window_text();
         if (is_open(menu)) {
-            painter.fill_rect(menu.rect_in_menubar(), SystemColor::MenuSelection);
-            painter.draw_rect(menu.rect_in_menubar(), Color(SystemColor::MenuSelection).darkened());
+            painter.fill_rect(menu.rect_in_menubar(), palette.menu_selection());
+            painter.draw_rect(menu.rect_in_menubar(), palette.menu_selection().darkened());
             text_color = Color::White;
         }
         painter.draw_text(
@@ -103,7 +104,7 @@ void WSMenuManager::draw()
         return IterationDecision::Continue;
     });
 
-    painter.draw_text(m_username_rect, m_username, Font::default_bold_font(), TextAlignment::CenterRight, SystemColor::WindowText);
+    painter.draw_text(m_username_rect, m_username, Font::default_bold_font(), TextAlignment::CenterRight, palette.window_text());
 
     time_t now = time(nullptr);
     auto* tm = localtime(&now);
@@ -115,7 +116,7 @@ void WSMenuManager::draw()
         tm->tm_min,
         tm->tm_sec);
 
-    painter.draw_text(m_time_rect, time_text, wm.font(), TextAlignment::CenterRight, SystemColor::WindowText);
+    painter.draw_text(m_time_rect, time_text, wm.font(), TextAlignment::CenterRight, palette.window_text());
 
     for (auto& applet : m_applets) {
         if (!applet)
diff --git a/Servers/WindowServer/WSWindowFrame.cpp b/Servers/WindowServer/WSWindowFrame.cpp
index 2d8755772f..da968a28a1 100644
--- a/Servers/WindowServer/WSWindowFrame.cpp
+++ b/Servers/WindowServer/WSWindowFrame.cpp
@@ -153,6 +153,7 @@ void WSWindowFrame::paint(Painter& painter)
     if (m_window.type() != WSWindowType::Normal)
         return;
 
+    auto& palette = WSWindowManager::the().palette();
     auto& window = m_window;
 
     auto titlebar_rect = title_bar_rect();
@@ -170,29 +171,29 @@ void WSWindowFrame::paint(Painter& painter)
     auto& wm = WSWindowManager::the();
 
     if (&window == wm.m_highlight_window) {
-        border_color = SystemColor::HighlightWindowBorder1;
-        border_color2 = SystemColor::HighlightWindowBorder2;
-        title_color = SystemColor::HighlightWindowTitle;
+        border_color = palette.highlight_window_border1();
+        border_color2 = palette.highlight_window_border2();
+        title_color = palette.highlight_window_title();
     } else if (&window == wm.m_move_window) {
-        border_color = SystemColor::MovingWindowBorder1;
-        border_color2 = SystemColor::MovingWindowBorder2;
-        title_color = SystemColor::MovingWindowTitle;
+        border_color = palette.moving_window_border1();
+        border_color2 = palette.moving_window_border2();
+        title_color = palette.moving_window_title();
     } else if (&window == wm.m_active_window) {
-        border_color = SystemColor::ActiveWindowBorder1;
-        border_color2 = SystemColor::ActiveWindowBorder2;
-        title_color = SystemColor::ActiveWindowTitle;
+        border_color = palette.active_window_border1();
+        border_color2 = palette.active_window_border2();
+        title_color = palette.active_window_title();
     } else {
-        border_color = SystemColor::InactiveWindowBorder1;
-        border_color2 = SystemColor::InactiveWindowBorder2;
-        title_color = SystemColor::InactiveWindowTitle;
+        border_color = palette.inactive_window_border1();
+        border_color2 = palette.inactive_window_border2();
+        title_color = palette.inactive_window_title();
     }
 
-    StylePainter::paint_window_frame(painter, outer_rect);
+    StylePainter::paint_window_frame(painter, outer_rect, palette);
 
     if (!window.show_titlebar())
         return;
 
-    painter.draw_line(titlebar_rect.bottom_left().translated(0, 1), titlebar_rect.bottom_right().translated(0, 1), SystemColor::Button);
+    painter.draw_line(titlebar_rect.bottom_left().translated(0, 1), titlebar_rect.bottom_right().translated(0, 1), palette.button());
 
     auto leftmost_button_rect = m_buttons.is_empty() ? Rect() : m_buttons.last().relative_rect();
 
diff --git a/Servers/WindowServer/WSWindowManager.cpp b/Servers/WindowServer/WSWindowManager.cpp
index be1f2fb71f..af61885a66 100644
--- a/Servers/WindowServer/WSWindowManager.cpp
+++ b/Servers/WindowServer/WSWindowManager.cpp
@@ -42,7 +42,8 @@ WSWindowManager& WSWindowManager::the()
     return *s_the;
 }
 
-WSWindowManager::WSWindowManager()
+WSWindowManager::WSWindowManager(const Palette& palette)
+    : m_palette(palette)
 {
     s_the = this;
 
@@ -132,6 +133,7 @@ WSWindowManager::WSWindowManager()
         auto new_theme = load_system_theme(theme.path);
         ASSERT(new_theme);
         set_system_theme(*new_theme);
+        m_palette = Palette::create_with_shared_buffer(*new_theme);
         HashTable<WSClientConnection*> notified_clients;
         for_each_window([&](WSWindow& window) {
             if (window.client()) {
diff --git a/Servers/WindowServer/WSWindowManager.h b/Servers/WindowServer/WSWindowManager.h
index 2f19aa9b7d..a7ec2db210 100644
--- a/Servers/WindowServer/WSWindowManager.h
+++ b/Servers/WindowServer/WSWindowManager.h
@@ -9,6 +9,7 @@
 #include <LibDraw/Color.h>
 #include <LibDraw/DisjointRectSet.h>
 #include <LibDraw/Painter.h>
+#include <LibDraw/Palette.h>
 #include <LibDraw/Rect.h>
 #include <WindowServer/WSCursor.h>
 #include <WindowServer/WSEvent.h>
@@ -50,10 +51,15 @@ class WSWindowManager : public CObject {
 public:
     static WSWindowManager& the();
 
-    WSWindowManager();
+    explicit WSWindowManager(const Palette&);
     virtual ~WSWindowManager() override;
 
-    RefPtr<CConfigFile> wm_config() const { return m_wm_config; }
+    const Palette& palette() const { return *m_palette; }
+
+    RefPtr<CConfigFile> wm_config() const
+    {
+        return m_wm_config;
+    }
     void reload_config(bool);
 
     void add_window(WSWindow&);
@@ -276,6 +282,8 @@ private:
     WeakPtr<WSButton> m_cursor_tracking_button;
     WeakPtr<WSButton> m_hovered_button;
 
+    NonnullRefPtr<Palette> m_palette;
+
     RefPtr<CConfigFile> m_wm_config;
 
     struct AppMetadata {
diff --git a/Servers/WindowServer/WSWindowSwitcher.cpp b/Servers/WindowServer/WSWindowSwitcher.cpp
index c88074ea37..f98499a43d 100644
--- a/Servers/WindowServer/WSWindowSwitcher.cpp
+++ b/Servers/WindowServer/WSWindowSwitcher.cpp
@@ -70,9 +70,10 @@ void WSWindowSwitcher::on_key_event(const WSKeyEvent& event)
 
 void WSWindowSwitcher::draw()
 {
+    auto& palette = WSWindowManager::the().palette();
     Painter painter(*m_switcher_window->backing_store());
-    painter.fill_rect({ {}, m_rect.size() }, SystemColor::Window);
-    painter.draw_rect({ {}, m_rect.size() }, SystemColor::ThreedShadow2);
+    painter.fill_rect({ {}, m_rect.size() }, palette.window());
+    painter.draw_rect({ {}, m_rect.size() }, palette.threed_shadow2());
     for (int index = 0; index < m_windows.size(); ++index) {
         auto& window = *m_windows.at(index);
         Rect item_rect {
@@ -84,21 +85,21 @@ void WSWindowSwitcher::draw()
         Color text_color;
         Color rect_text_color;
         if (index == m_selected_index) {
-            painter.fill_rect(item_rect, SystemColor::Selection);
-            text_color = SystemColor::SelectionText;
-            rect_text_color = SystemColor::ThreedShadow1;
+            painter.fill_rect(item_rect, palette.selection());
+            text_color = palette.selection_text();
+            rect_text_color = palette.threed_shadow1();
         } else {
-            text_color = SystemColor::WindowText;
-            rect_text_color = SystemColor::ThreedShadow2;
+            text_color = palette.window_text();
+            rect_text_color = palette.threed_shadow2();
         }
         item_rect.shrink(item_padding(), 0);
         Rect thumbnail_rect = { item_rect.location().translated(0, 5), { thumbnail_width(), thumbnail_height() } };
         if (window.backing_store()) {
             painter.draw_scaled_bitmap(thumbnail_rect, *window.backing_store(), window.backing_store()->rect());
-            StylePainter::paint_frame(painter, thumbnail_rect.inflated(4, 4), FrameShape::Container, FrameShadow::Sunken, 2);
+            StylePainter::paint_frame(painter, thumbnail_rect.inflated(4, 4), palette, FrameShape::Container, FrameShadow::Sunken, 2);
         }
         Rect icon_rect = { thumbnail_rect.bottom_right().translated(-window.icon().width(), -window.icon().height()), { window.icon().width(), window.icon().height() } };
-        painter.fill_rect(icon_rect, SystemColor::Window);
+        painter.fill_rect(icon_rect, palette.window());
         painter.blit(icon_rect.location(), window.icon(), window.icon().rect());
         painter.draw_text(item_rect.translated(thumbnail_width() + 12, 0), window.title(), WSWindowManager::the().window_title_font(), TextAlignment::CenterLeft, text_color);
         painter.draw_text(item_rect, window.rect().to_string(), TextAlignment::CenterRight, rect_text_color);
diff --git a/Servers/WindowServer/main.cpp b/Servers/WindowServer/main.cpp
index c629f9464d..c12a53d496 100644
--- a/Servers/WindowServer/main.cpp
+++ b/Servers/WindowServer/main.cpp
@@ -1,4 +1,5 @@
 #include <LibCore/CConfigFile.h>
+#include <LibDraw/Palette.h>
 #include <LibDraw/SystemTheme.h>
 #include <WindowServer/WSCompositor.h>
 #include <WindowServer/WSEventLoop.h>
@@ -25,13 +26,14 @@ int main(int, char**)
     auto theme = load_system_theme(String::format("/res/themes/%s.ini", theme_name.characters()));
     ASSERT(theme);
     set_system_theme(*theme);
+    auto palette = Palette::create_with_shared_buffer(*theme);
 
     WSEventLoop loop;
 
     WSScreen screen(wm_config->read_num_entry("Screen", "Width", 1024),
         wm_config->read_num_entry("Screen", "Height", 768));
     WSCompositor::the();
-    auto wm = WSWindowManager::construct();
+    auto wm = WSWindowManager::construct(*palette);
 
     dbgprintf("Entering WindowServer main loop.\n");
     loop.exec();