libui: Reduce redraw calls by doing them only when events are actually handled

apps/CMakeLists.txt

@@ -42,5 +42,7 @@ luna_app(touch.cpp touch)
 luna_app(free.cpp free)
 luna_app(gclient.cpp gclient)
 target_link_libraries(gclient PUBLIC ui)
+luna_app(about.cpp about)
+target_link_libraries(about PUBLIC ui)
 luna_app(taskbar.cpp taskbar)
 target_link_libraries(taskbar PUBLIC ui)

apps/about.cpp

@@ -0,0 +1,46 @@
+#include <luna/String.h>
+#include <sys/utsname.h>
+#include <ui/App.h>
+#include <ui/Button.h>
+#include <ui/Label.h>
+#include <ui/Layout.h>
+
+Result<int> luna_main(int argc, char** argv)
+{
+    ui::App app;
+    TRY(app.init(argc, argv));
+
+    auto* window = TRY(ui::Window::create(ui::Rect { 300, 300, 400, 300 }));
+    app.set_main_window(window);
+
+    window->set_title("About");
+    window->set_background(ui::CYAN);
+
+    utsname info;
+    uname(&info);
+
+    ui::VerticalLayout main_layout;
+    window->set_main_widget(main_layout);
+
+    ui::Label title("About Luna", ui::VerticalAlignment::Center, ui::HorizontalAlignment::Center,
+                    ui::Font::default_bold_font());
+    main_layout.add_widget(title);
+
+    ui::VerticalLayout version_info;
+    main_layout.add_widget(version_info);
+
+    ui::Label license("Licensed under the BSD-2-Clause license.");
+    main_layout.add_widget(license);
+
+    String os_release_text = TRY(String::format("OS release: %s"_sv, info.release));
+    ui::Label os_release(os_release_text.view());
+    version_info.add_widget(os_release);
+
+    String kernel_version_text = TRY(String::format("Kernel version: %s"_sv, info.version));
+    ui::Label kernel_version(kernel_version_text.view());
+    version_info.add_widget(kernel_version);
+
+    window->draw();
+
+    return app.run();
+}

apps/gclient.cpp

@@ -10,14 +10,16 @@ struct ColorWidget : public ui::Widget
 
     Result<ui::EventResult> handle_mouse_move(ui::Point) override
     {
+        auto old_color = m_color;
         m_color = m_second_color;
-        return ui::EventResult::DidHandle;
+        return old_color.raw == m_second_color.raw ? ui::EventResult::DidNotHandle : ui::EventResult::DidHandle;
     }
 
     Result<ui::EventResult> handle_mouse_leave() override
     {
+        auto old_color = m_color;
         m_color = m_first_color;
-        return ui::EventResult::DidHandle;
+        return old_color.raw == m_first_color.raw ? ui::EventResult::DidNotHandle : ui::EventResult::DidHandle;
     }
 
     Result<void> draw(ui::Canvas& canvas) override
@@ -40,7 +42,7 @@ Result<int> luna_main(int argc, char** argv)
     auto* window = TRY(ui::Window::create(ui::Rect { 200, 200, 400, 300 }));
     app.set_main_window(window);
 
-    window->set_title("Main Window");
+    window->set_title("Test Window");
     window->set_background(ui::CYAN);
 
     ui::HorizontalLayout layout;

apps/taskbar.cpp

@@ -1,3 +1,4 @@
+#include <os/File.h>
 #include <os/Process.h>
 #include <signal.h>
 #include <sys/wait.h>
@@ -30,18 +31,31 @@ Result<int> luna_main(int argc, char** argv)
     ui::HorizontalLayout layout(ui::AdjustHeight::Yes, ui::AdjustWidth::No);
     window->set_main_widget(layout);
 
-    ui::Button button({ 0, 0, 50, 50 });
+    ui::Button start_button({ 0, 0, 50, 50 });
-    layout.add_widget(button);
+    layout.add_widget(start_button);
 
-    ui::Container container({ 0, 0, 50, 50 }, ui::VerticalAlignment::Center, ui::HorizontalAlignment::Center);
+    ui::Container start_container({ 0, 0, 50, 50 }, ui::VerticalAlignment::Center, ui::HorizontalAlignment::Center);
-    button.set_widget(container);
+    start_button.set_widget(start_container);
-    button.set_action([] {
+    start_button.set_action([] {
         StringView args[] = { "/usr/bin/gclient" };
         os::Process::spawn("/usr/bin/gclient", Slice<StringView> { args, 1 }, false);
     });
 
-    auto image = TRY(ui::ImageWidget::load("/usr/share/icons/32x32/start-icon.tga"));
+    auto start_image = TRY(ui::ImageWidget::load("/usr/share/icons/32x32/start-icon.tga"));
-    container.set_widget(*image);
+    start_container.set_widget(*start_image);
+
+    ui::Button about_button({ 0, 0, 50, 50 });
+    layout.add_widget(about_button);
+
+    ui::Container about_container({ 0, 0, 50, 50 }, ui::VerticalAlignment::Center, ui::HorizontalAlignment::Center);
+    about_button.set_widget(about_container);
+    about_button.set_action([] {
+        StringView args[] = { "/usr/bin/about" };
+        os::Process::spawn("/usr/bin/about", Slice<StringView> { args, 1 }, false);
+    });
+
+    auto about_image = TRY(ui::ImageWidget::load("/usr/share/icons/32x32/app-about.tga"));
+    about_container.set_widget(*about_image);
 
     window->draw();
 

libui/CMakeLists.txt

@@ -16,6 +16,7 @@ set(SOURCES
     src/Alignment.cpp
     src/Container.cpp
     src/Button.cpp
+    src/Label.cpp
 )
 
 add_library(ui ${SOURCES})

libui/include/ui/Font.h

@@ -18,7 +18,10 @@
 namespace ui
 {
     /**
-     * @brief A class holding PSF font data, used for direct rendering of glyphs into a canvas.
+     * @brief A class holding PSF font data, used for low-level direct rendering of glyphs into a canvas.
+     *
+     * This class does not handle special characters such as tabs or newlines. For those, you should be using a more
+     * high-level component such as ui::Label instead.
      */
     class Font : public Shareable
     {

libui/include/ui/Label.h

@@ -0,0 +1,41 @@
+/**
+ * @file Label.h
+ * @author apio (cloudapio.eu)
+ * @brief A simple one-line text widget.
+ *
+ * @copyright Copyright (c) 2023, the Luna authors.
+ *
+ */
+
+#pragma once
+#include <ui/Alignment.h>
+#include <ui/Font.h>
+#include <ui/Widget.h>
+
+namespace ui
+{
+    /**
+     * @brief Displays one line of text.
+     *
+     * This component does not handle newlines.
+     */
+    class Label final : public Widget
+    {
+      public:
+        Label(StringView text, VerticalAlignment valign = VerticalAlignment::Center,
+              HorizontalAlignment halign = HorizontalAlignment::Center, SharedPtr<Font> font = Font::default_font());
+
+        void set_text(StringView text)
+        {
+            m_text = text;
+        }
+
+        Result<void> draw(Canvas& canvas) override;
+
+      private:
+        StringView m_text;
+        VerticalAlignment m_valign;
+        HorizontalAlignment m_halign;
+        SharedPtr<Font> m_font;
+    };
+}

libui/include/ui/Layout.h

@@ -43,7 +43,7 @@ namespace ui
         Vector<Widget*> m_widgets;
         AdjustHeight m_adjust_height;
         AdjustWidth m_adjust_width;
-        int m_used_width;
+        int m_used_width { 0 };
     };
 
     class VerticalLayout final : public Widget
@@ -64,6 +64,6 @@ namespace ui
         Vector<Widget*> m_widgets;
         AdjustHeight m_adjust_height;
         AdjustWidth m_adjust_width;
-        int m_used_height;
+        int m_used_height { 0 };
     };
 }

libui/include/ui/Window.h

@@ -46,9 +46,9 @@ namespace ui
         void close();
 
         Result<void> draw();
-        Result<void> handle_mouse_leave();
+        Result<ui::EventResult> handle_mouse_leave();
-        Result<void> handle_mouse_move(ui::Point position);
+        Result<ui::EventResult> handle_mouse_move(ui::Point position);
-        Result<void> handle_mouse_buttons(ui::Point position, int buttons);
+        Result<ui::EventResult> handle_mouse_buttons(ui::Point position, int buttons);
 
         int id() const
         {

libui/src/App.cpp

@@ -117,17 +117,19 @@ namespace ui
             MouseEventRequest request;
             READ_MESSAGE(request);
             auto* window = find_window(request.window);
-            window->handle_mouse_move(request.position);
+            auto move_result = window->handle_mouse_move(request.position).value_or(ui::EventResult::DidNotHandle);
-            window->handle_mouse_buttons(request.position, request.buttons);
+            auto button_result =
-            window->draw();
+                window->handle_mouse_buttons(request.position, request.buttons).value_or(ui::EventResult::DidNotHandle);
+            if (move_result == ui::EventResult::DidHandle || button_result == ui::EventResult::DidHandle)
+                window->draw();
             return {};
         }
         case MOUSE_LEAVE_REQUEST_ID: {
             MouseLeaveRequest request;
             READ_MESSAGE(request);
             auto* window = find_window(request.window);
-            window->handle_mouse_leave();
+            if (window->handle_mouse_leave().value_or(ui::EventResult::DidNotHandle) == ui::EventResult::DidHandle)
-            window->draw();
+                window->draw();
             return {};
         }
         default: fail("Unexpected IPC request from server!");

libui/src/Label.cpp

@@ -0,0 +1,36 @@
+/**
+ * @file Label.cpp
+ * @author apio (cloudapio.eu)
+ * @brief A simple one-line text widget.
+ *
+ * @copyright Copyright (c) 2023, the Luna authors.
+ *
+ */
+
+#include <luna/Utf8.h>
+#include <ui/Label.h>
+
+namespace ui
+{
+    Label::Label(StringView text, VerticalAlignment valign, HorizontalAlignment halign, SharedPtr<Font> font)
+        : m_text(text), m_valign(valign), m_halign(halign), m_font(font)
+    {
+    }
+
+    Result<void> Label::draw(Canvas& canvas)
+    {
+        ui::Rect contained;
+        contained.pos = { 0, 0 };
+        contained.width = static_cast<int>(m_text.length() * m_font->width());
+        contained.height = m_font->height();
+        auto subcanvas =
+            canvas.subcanvas(ui::align({ 0, 0, m_rect.width, m_rect.height }, contained, m_valign, m_halign));
+
+        Utf8StringDecoder decoder(m_text.chars());
+        wchar_t buf[4096];
+        TRY(decoder.decode(buf, sizeof(buf)));
+
+        m_font->render(buf, ui::BLACK, subcanvas);
+        return {};
+    }
+}

libui/src/Layout.cpp

@@ -33,9 +33,15 @@ namespace ui
 
     Result<EventResult> HorizontalLayout::handle_mouse_leave()
     {
-        for (auto widget : m_widgets) TRY(widget->handle_mouse_leave());
+        EventResult result = ui::EventResult::DidNotHandle;
 
-        return ui::EventResult::DidNotHandle;
+        for (auto widget : m_widgets)
+        {
+            auto rc = TRY(widget->handle_mouse_leave());
+            if (rc == ui::EventResult::DidHandle) result = rc;
+        }
+
+        return result;
     }
 
     Result<EventResult> HorizontalLayout::handle_mouse_up(Point position, int buttons)
@@ -122,9 +128,15 @@ namespace ui
 
     Result<EventResult> VerticalLayout::handle_mouse_leave()
     {
-        for (auto widget : m_widgets) TRY(widget->handle_mouse_leave());
+        EventResult result = ui::EventResult::DidNotHandle;
 
-        return ui::EventResult::DidNotHandle;
+        for (auto widget : m_widgets)
+        {
+            auto rc = TRY(widget->handle_mouse_leave());
+            if (rc == ui::EventResult::DidHandle) result = rc;
+        }
+
+        return result;
     }
 
     Result<EventResult> VerticalLayout::handle_mouse_up(Point position, int buttons)

libui/src/Window.cpp

@@ -80,31 +80,38 @@ namespace ui
         return {};
     }
 
-    Result<void> Window::handle_mouse_leave()
+    Result<ui::EventResult> Window::handle_mouse_leave()
     {
-        if (!m_main_widget) return {};
+        if (!m_main_widget) return ui::EventResult::DidNotHandle;
-        TRY(m_main_widget->handle_mouse_leave());
+        return m_main_widget->handle_mouse_leave();
-        return {};
     }
 
-    Result<void> Window::handle_mouse_move(ui::Point position)
+    Result<ui::EventResult> Window::handle_mouse_move(ui::Point position)
     {
-        if (!m_main_widget) return {};
+        if (!m_main_widget) return ui::EventResult::DidNotHandle;
-        TRY(m_main_widget->handle_mouse_move(position));
+        return m_main_widget->handle_mouse_move(position);
-        return {};
     }
 
-    Result<void> Window::handle_mouse_buttons(ui::Point position, int buttons)
+    Result<ui::EventResult> Window::handle_mouse_buttons(ui::Point position, int buttons)
     {
-        if (!m_main_widget) return {};
+        if (!m_main_widget) return ui::EventResult::DidNotHandle;
-        if (buttons) TRY(m_main_widget->handle_mouse_down(position, buttons));
+        auto result = ui::EventResult::DidNotHandle;
+        if (buttons)
+        {
+            auto rc = TRY(m_main_widget->handle_mouse_down(position, buttons));
+            if (rc == ui::EventResult::DidHandle) result = rc;
+        }
         if (m_old_mouse_buttons.has_value())
         {
             int old_buttons = m_old_mouse_buttons.value();
             int diff = old_buttons & ~buttons;
-            if (diff) TRY(m_main_widget->handle_mouse_up(position, diff));
+            if (diff)
+            {
+                auto rc = TRY(m_main_widget->handle_mouse_up(position, diff));
+                if (rc == ui::EventResult::DidHandle) result = rc;
+            }
         }
         m_old_mouse_buttons = buttons;
-        return {};
+        return result;
     }
 }