Merge pull request #1753 from jroweboy/frame_layouts

Support additional screen layouts.

src/citra/config.cpp

@@ -72,6 +72,11 @@ void Config::ReadValues() {
     Settings::values.bg_green = (float)sdl2_config->GetReal("Renderer", "bg_green", 1.0);
     Settings::values.bg_blue = (float)sdl2_config->GetReal("Renderer", "bg_blue", 1.0);
 
+    // Layout
+    Settings::values.layout_option =
+        static_cast<Settings::LayoutOption>(sdl2_config->GetInteger("Layout", "layout_option", 0));
+    Settings::values.swap_screen = sdl2_config->GetBoolean("Layout", "swap_screen", false);
+
     // Audio
     Settings::values.sink_id = sdl2_config->Get("Audio", "output_engine", "auto");
     Settings::values.enable_audio_stretching =

src/citra/default_ini.h

@@ -63,6 +63,16 @@ use_scaled_resolution =
 # 0 (default): Off, 1: On
 use_vsync =
 
+[Layout]
+# Layout for the screen inside the render window.
+# 0 (default): Default Top Bottom Screen, 1: Single Screen Only, 2: Large Screen Small Screen
+layout_option =
+
+# Swaps the prominent screen with the other screen.
+# For example, if Single Screen is chosen, setting this to 1 will display the bottom screen instead of the top screen.
+# 0 (default): Top Screen is prominent, 1: Bottom Screen is prominent
+swap_screen =
+
 # The clear color for the renderer. What shows up on the sides of the bottom screen.
 # Must be in range of 0.0-1.0. Defaults to 1.0 for all.
 bg_red =

src/citra/emu_window/emu_window_sdl2.cpp

@@ -46,11 +46,8 @@ bool EmuWindow_SDL2::IsOpen() const {
 
 void EmuWindow_SDL2::OnResize() {
     int width, height;
-
     SDL_GetWindowSize(render_window, &width, &height);
-
-    NotifyFramebufferLayoutChanged(
-        EmuWindow::FramebufferLayout::DefaultScreenLayout(width, height));
+    UpdateCurrentFramebufferLayout(width, height);
 }
 
 EmuWindow_SDL2::EmuWindow_SDL2() {

src/citra_qt/bootmanager.cpp

@@ -161,9 +161,7 @@ void GRenderWindow::OnFramebufferSizeChanged() {
     qreal pixelRatio = windowPixelRatio();
     unsigned width = child->QPaintDevice::width() * pixelRatio;
     unsigned height = child->QPaintDevice::height() * pixelRatio;
-
-    NotifyFramebufferLayoutChanged(
-        EmuWindow::FramebufferLayout::DefaultScreenLayout(width, height));
+    UpdateCurrentFramebufferLayout(width, height);
 }
 
 void GRenderWindow::BackupGeometry() {

src/citra_qt/config.cpp

@@ -54,6 +54,12 @@ void Config::ReadValues() {
     Settings::values.bg_blue = qt_config->value("bg_blue", 1.0).toFloat();
     qt_config->endGroup();
 
+    qt_config->beginGroup("Layout");
+    Settings::values.layout_option =
+        static_cast<Settings::LayoutOption>(qt_config->value("layout_option").toInt());
+    Settings::values.swap_screen = qt_config->value("swap_screen", false).toBool();
+    qt_config->endGroup();
+
     qt_config->beginGroup("Audio");
     Settings::values.sink_id = qt_config->value("output_engine", "auto").toString().toStdString();
     Settings::values.enable_audio_stretching =
@@ -155,6 +161,11 @@ void Config::SaveValues() {
     qt_config->setValue("bg_blue", (double)Settings::values.bg_blue);
     qt_config->endGroup();
 
+    qt_config->beginGroup("Layout");
+    qt_config->setValue("layout_option", static_cast<int>(Settings::values.layout_option));
+    qt_config->setValue("swap_screen", Settings::values.swap_screen);
+    qt_config->endGroup();
+
     qt_config->beginGroup("Audio");
     qt_config->setValue("output_engine", QString::fromStdString(Settings::values.sink_id));
     qt_config->setValue("enable_audio_stretching", Settings::values.enable_audio_stretching);

src/citra_qt/configure_dialog.cpp

@@ -23,4 +23,5 @@ void ConfigureDialog::applyConfiguration() {
     ui->graphicsTab->applyConfiguration();
     ui->audioTab->applyConfiguration();
     ui->debugTab->applyConfiguration();
+    Settings::Apply();
 }

src/citra_qt/configure_graphics.cpp

@@ -23,6 +23,8 @@ void ConfigureGraphics::setConfiguration() {
     ui->toggle_shader_jit->setChecked(Settings::values.use_shader_jit);
     ui->toggle_scaled_resolution->setChecked(Settings::values.use_scaled_resolution);
     ui->toggle_vsync->setChecked(Settings::values.use_vsync);
+    ui->layout_combobox->setCurrentIndex(static_cast<int>(Settings::values.layout_option));
+    ui->swap_screen->setChecked(Settings::values.swap_screen);
 }
 
 void ConfigureGraphics::applyConfiguration() {
@@ -30,5 +32,8 @@ void ConfigureGraphics::applyConfiguration() {
     Settings::values.use_shader_jit = ui->toggle_shader_jit->isChecked();
     Settings::values.use_scaled_resolution = ui->toggle_scaled_resolution->isChecked();
     Settings::values.use_vsync = ui->toggle_vsync->isChecked();
+    Settings::values.layout_option =
+        static_cast<Settings::LayoutOption>(ui->layout_combobox->currentIndex());
+    Settings::values.swap_screen = ui->swap_screen->isChecked();
     Settings::Apply();
 }

src/citra_qt/configure_graphics.ui

@@ -22,38 +22,88 @@
         <string>Graphics</string>
        </property>
        <layout class="QVBoxLayout" name="verticalLayout_2">
-         <item>
-           <widget class="QCheckBox" name="toggle_hw_renderer">
-             <property name="text">
-               <string>Enable hardware renderer</string>
-             </property>
+        <item>
+         <widget class="QCheckBox" name="toggle_hw_renderer">
+          <property name="text">
+           <string>Enable hardware renderer</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QCheckBox" name="toggle_shader_jit">
+          <property name="text">
+           <string>Enable shader JIT</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QCheckBox" name="toggle_scaled_resolution">
+          <property name="text">
+           <string>Enable scaled resolution</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QCheckBox" name="toggle_vsync">
+          <property name="text">
+           <string>Enable V-Sync</string>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </widget>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QGroupBox" name="groupBox2">
+     <property name="title">
+      <string>Layout</string>
+     </property>
+     <layout class="QHBoxLayout" name="horizontalLayout_3">
+      <item>
+       <layout class="QVBoxLayout" name="verticalLayout_2">
+        <item>
+         <layout class="QHBoxLayout" name="horizontalLayout_3">
+          <item>
+           <widget class="QLabel" name="label1">
+            <property name="text">
+             <string>Screen Layout:</string>
+            </property>
            </widget>
-         </item>
-         <item>
-           <widget class="QCheckBox" name="toggle_shader_jit">
+          </item>
+          <item>
+           <widget class="QComboBox" name="layout_combobox">
+            <item>
              <property name="text">
-               <string>Enable shader JIT</string>
+              <string notr="true">Default</string>
              </property>
-           </widget>
-         </item>
-         <item>
-           <widget class="QCheckBox" name="toggle_scaled_resolution">
+            </item>
+            <item>
              <property name="text">
-               <string>Enable scaled resolution</string>
+              <string notr="true">Single Screen</string>
              </property>
-           </widget>
-         </item>
-         <item>
-           <widget class="QCheckBox" name="toggle_vsync">
+            </item>
+            <item>
              <property name="text">
-               <string>Enable V-Sync</string>
+              <string notr="true">Large Screen</string>
              </property>
+            </item>
            </widget>
-         </item>
+          </item>
+         </layout>
+        </item>
+        <item>
+         <widget class="QCheckBox" name="swap_screen">
+          <property name="text">
+           <string>Swap Screens</string>
+          </property>
+         </widget>
+        </item>
        </layout>
-      </widget>
-     </item>
-    </layout>
+      </item>
+     </layout>
+    </widget>
    </item>
    <item>
     <spacer name="verticalSpacer">
@@ -71,22 +121,5 @@
   </layout>
  </widget>
  <resources/>
- <connections>
-  <connection>
-   <sender>toggle_gdbstub</sender>
-   <signal>toggled(bool)</signal>
-   <receiver>gdbport_spinbox</receiver>
-   <slot>setEnabled(bool)</slot>
-   <hints>
-    <hint type="sourcelabel">
-     <x>84</x>
-     <y>157</y>
-    </hint>
-    <hint type="destinationlabel">
-     <x>342</x>
-     <y>158</y>
-    </hint>
-   </hints>
-  </connection>
- </connections>
+ <connections/>
 </ui>

src/citra_qt/main.cpp

@@ -196,6 +196,7 @@ GMainWindow::GMainWindow() : config(new Config()), emu_thread(nullptr) {
 
     // Setup hotkeys
     RegisterHotkey("Main Window", "Load File", QKeySequence::Open);
+    RegisterHotkey("Main Window", "Swap Screens", QKeySequence::NextChild);
     RegisterHotkey("Main Window", "Start Emulation");
     LoadHotkeys();
 
@@ -203,6 +204,8 @@ GMainWindow::GMainWindow() : config(new Config()), emu_thread(nullptr) {
             SLOT(OnMenuLoadFile()));
     connect(GetHotkey("Main Window", "Start Emulation", this), SIGNAL(activated()), this,
             SLOT(OnStartGame()));
+    connect(GetHotkey("Main Window", "Swap Screens", this), SIGNAL(activated()), this,
+            SLOT(OnSwapScreens()));
 
     std::string window_title =
         Common::StringFromFormat("Citra | %s-%s", Common::g_scm_branch, Common::g_scm_desc);
@@ -550,6 +553,11 @@ void GMainWindow::OnConfigure() {
     }
 }
 
+void GMainWindow::OnSwapScreens() {
+    Settings::values.swap_screen = !Settings::values.swap_screen;
+    Settings::Apply();
+}
+
 void GMainWindow::OnCreateGraphicsSurfaceViewer() {
     auto graphicsSurfaceViewerWidget = new GraphicsSurfaceWidget(Pica::g_debug_context, this);
     addDockWidget(Qt::RightDockWidgetArea, graphicsSurfaceViewerWidget);

src/citra_qt/main.h

@@ -105,6 +105,7 @@ private slots:
     /// Called whenever a user selects the "File->Select Game List Root" menu item
     void OnMenuSelectGameListRoot();
     void OnMenuRecentFile();
+    void OnSwapScreens();
     void OnConfigure();
     void OnDisplayTitleBars(bool);
     void ToggleWindowMode();

src/common/CMakeLists.txt

@@ -5,6 +5,7 @@ set(SRCS
             break_points.cpp
             emu_window.cpp
             file_util.cpp
+            framebuffer_layout.cpp
             hash.cpp
             key_map.cpp
             logging/filter.cpp
@@ -35,6 +36,7 @@ set(HEADERS
             common_types.h
             emu_window.h
             file_util.h
+            framebuffer_layout.h
             hash.h
             key_map.h
             linear_disk_cache.h

src/common/emu_window.cpp

@@ -40,7 +40,7 @@ void EmuWindow::CirclePadUpdated(float x, float y) {
  * @param framebuffer_y Framebuffer y-coordinate to check
  * @return True if the coordinates are within the touchpad, otherwise false
  */
-static bool IsWithinTouchscreen(const EmuWindow::FramebufferLayout& layout, unsigned framebuffer_x,
+static bool IsWithinTouchscreen(const Layout::FramebufferLayout& layout, unsigned framebuffer_x,
                                 unsigned framebuffer_y) {
     return (
         framebuffer_y >= layout.bottom_screen.top && framebuffer_y < layout.bottom_screen.bottom &&
@@ -89,57 +89,19 @@ void EmuWindow::TouchMoved(unsigned framebuffer_x, unsigned framebuffer_y) {
     TouchPressed(framebuffer_x, framebuffer_y);
 }
 
-EmuWindow::FramebufferLayout EmuWindow::FramebufferLayout::DefaultScreenLayout(unsigned width,
-                                                                               unsigned height) {
-    // When hiding the widget, the function receives a size of 0
-    if (width == 0)
-        width = 1;
-    if (height == 0)
-        height = 1;
-
-    EmuWindow::FramebufferLayout res = {width, height, {}, {}};
-
-    float window_aspect_ratio = static_cast<float>(height) / width;
-    float emulation_aspect_ratio =
-        static_cast<float>(VideoCore::kScreenTopHeight * 2) / VideoCore::kScreenTopWidth;
-
-    if (window_aspect_ratio > emulation_aspect_ratio) {
-        // Window is narrower than the emulation content => apply borders to the top and bottom
-        int viewport_height = static_cast<int>(std::round(emulation_aspect_ratio * width));
-
-        res.top_screen.left = 0;
-        res.top_screen.right = res.top_screen.left + width;
-        res.top_screen.top = (height - viewport_height) / 2;
-        res.top_screen.bottom = res.top_screen.top + viewport_height / 2;
-
-        int bottom_width = static_cast<int>(
-            (static_cast<float>(VideoCore::kScreenBottomWidth) / VideoCore::kScreenTopWidth) *
-            (res.top_screen.right - res.top_screen.left));
-        int bottom_border = ((res.top_screen.right - res.top_screen.left) - bottom_width) / 2;
-
-        res.bottom_screen.left = bottom_border;
-        res.bottom_screen.right = res.bottom_screen.left + bottom_width;
-        res.bottom_screen.top = res.top_screen.bottom;
-        res.bottom_screen.bottom = res.bottom_screen.top + viewport_height / 2;
-    } else {
-        // Otherwise, apply borders to the left and right sides of the window.
-        int viewport_width = static_cast<int>(std::round(height / emulation_aspect_ratio));
-
-        res.top_screen.left = (width - viewport_width) / 2;
-        res.top_screen.right = res.top_screen.left + viewport_width;
-        res.top_screen.top = 0;
-        res.top_screen.bottom = res.top_screen.top + height / 2;
-
-        int bottom_width = static_cast<int>(
-            (static_cast<float>(VideoCore::kScreenBottomWidth) / VideoCore::kScreenTopWidth) *
-            (res.top_screen.right - res.top_screen.left));
-        int bottom_border = ((res.top_screen.right - res.top_screen.left) - bottom_width) / 2;
-
-        res.bottom_screen.left = res.top_screen.left + bottom_border;
-        res.bottom_screen.right = res.bottom_screen.left + bottom_width;
-        res.bottom_screen.top = res.top_screen.bottom;
-        res.bottom_screen.bottom = res.bottom_screen.top + height / 2;
+void EmuWindow::UpdateCurrentFramebufferLayout(unsigned width, unsigned height) {
+    Layout::FramebufferLayout layout;
+    switch (Settings::values.layout_option) {
+    case Settings::LayoutOption::SingleScreen:
+        layout = Layout::SingleFrameLayout(width, height, Settings::values.swap_screen);
+        break;
+    case Settings::LayoutOption::LargeScreen:
+        layout = Layout::LargeFrameLayout(width, height, Settings::values.swap_screen);
+        break;
+    case Settings::LayoutOption::Default:
+    default:
+        layout = Layout::DefaultFrameLayout(width, height, Settings::values.swap_screen);
+        break;
     }
-
-    return res;
+    NotifyFramebufferLayoutChanged(layout);
 }

src/common/emu_window.h

@@ -7,6 +7,7 @@
 #include <tuple>
 #include <utility>
 #include "common/common_types.h"
+#include "common/framebuffer_layout.h"
 #include "common/math_util.h"
 #include "core/hle/service/hid/hid.h"
 
@@ -38,23 +39,6 @@ public:
         std::pair<unsigned, unsigned> min_client_area_size;
     };
 
-    /// Describes the layout of the window framebuffer (size and top/bottom screen positions)
-    struct FramebufferLayout {
-
-        /**
-         * Factory method for constructing a default FramebufferLayout
-         * @param width Window framebuffer width in pixels
-         * @param height Window framebuffer height in pixels
-         * @return Newly created FramebufferLayout object with default screen regions initialized
-         */
-        static FramebufferLayout DefaultScreenLayout(unsigned width, unsigned height);
-
-        unsigned width;
-        unsigned height;
-        MathUtil::Rectangle<unsigned> top_screen;
-        MathUtil::Rectangle<unsigned> bottom_screen;
-    };
-
     /// Swap buffers to display the next frame
     virtual void SwapBuffers() = 0;
 
@@ -211,10 +195,16 @@ public:
       * Gets the framebuffer layout (width, height, and screen regions)
       * @note This method is thread-safe
       */
-    const FramebufferLayout& GetFramebufferLayout() const {
+    const Layout::FramebufferLayout& GetFramebufferLayout() const {
         return framebuffer_layout;
     }
 
+    /**
+     * Convenience method to update the current frame layout
+     * Read from the current settings to determine which layout to use.
+     */
+    void UpdateCurrentFramebufferLayout(unsigned width, unsigned height);
+
 protected:
     EmuWindow() {
         // TODO: Find a better place to set this.
@@ -250,7 +240,7 @@ protected:
      * Update framebuffer layout with the given parameter.
      * @note EmuWindow implementations will usually use this in window resize event handlers.
      */
-    void NotifyFramebufferLayoutChanged(const FramebufferLayout& layout) {
+    void NotifyFramebufferLayoutChanged(const Layout::FramebufferLayout& layout) {
         framebuffer_layout = layout;
     }
 
@@ -274,7 +264,7 @@ private:
         // By default, ignore this request and do nothing.
     }
 
-    FramebufferLayout framebuffer_layout; ///< Current framebuffer layout
+    Layout::FramebufferLayout framebuffer_layout; ///< Current framebuffer layout
 
     unsigned client_area_width;  ///< Current client width, should be set by window impl.
     unsigned client_area_height; ///< Current client height, should be set by window impl.

src/common/framebuffer_layout.cpp

@@ -0,0 +1,138 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cmath>
+
+#include "common/assert.h"
+#include "common/framebuffer_layout.h"
+#include "video_core/video_core.h"
+
+namespace Layout {
+
+static const float TOP_SCREEN_ASPECT_RATIO =
+    static_cast<float>(VideoCore::kScreenTopHeight) / VideoCore::kScreenTopWidth;
+static const float BOT_SCREEN_ASPECT_RATIO =
+    static_cast<float>(VideoCore::kScreenBottomHeight) / VideoCore::kScreenBottomWidth;
+
+// Finds the largest size subrectangle contained in window area that is confined to the aspect ratio
+template <class T>
+static MathUtil::Rectangle<T> maxRectangle(MathUtil::Rectangle<T> window_area,
+                                           float screen_aspect_ratio) {
+    float scale = std::min(static_cast<float>(window_area.GetWidth()),
+                           window_area.GetHeight() / screen_aspect_ratio);
+    return MathUtil::Rectangle<T>{0, 0, static_cast<T>(std::round(scale)),
+                                  static_cast<T>(std::round(scale * screen_aspect_ratio))};
+}
+
+FramebufferLayout DefaultFrameLayout(unsigned width, unsigned height, bool swapped) {
+    ASSERT(width > 0);
+    ASSERT(height > 0);
+
+    FramebufferLayout res{width, height, true, true, {}, {}};
+    // Default layout gives equal screen sizes to the top and bottom screen
+    MathUtil::Rectangle<unsigned> screen_window_area{0, 0, width, height / 2};
+    MathUtil::Rectangle<unsigned> top_screen =
+        maxRectangle(screen_window_area, TOP_SCREEN_ASPECT_RATIO);
+    MathUtil::Rectangle<unsigned> bot_screen =
+        maxRectangle(screen_window_area, BOT_SCREEN_ASPECT_RATIO);
+
+    float window_aspect_ratio = static_cast<float>(height) / width;
+    // both screens height are taken into account by multiplying by 2
+    float emulation_aspect_ratio = TOP_SCREEN_ASPECT_RATIO * 2;
+
+    if (window_aspect_ratio < emulation_aspect_ratio) {
+        // Apply borders to the left and right sides of the window.
+        top_screen =
+            top_screen.TranslateX((screen_window_area.GetWidth() - top_screen.GetWidth()) / 2);
+        bot_screen =
+            bot_screen.TranslateX((screen_window_area.GetWidth() - bot_screen.GetWidth()) / 2);
+    } else {
+        // Window is narrower than the emulation content => apply borders to the top and bottom
+        // Recalculate the bottom screen to account for the width difference between top and bottom
+        screen_window_area = {0, 0, width, top_screen.GetHeight()};
+        bot_screen = maxRectangle(screen_window_area, BOT_SCREEN_ASPECT_RATIO);
+        bot_screen = bot_screen.TranslateX((top_screen.GetWidth() - bot_screen.GetWidth()) / 2);
+        if (swapped) {
+            bot_screen = bot_screen.TranslateY(height / 2 - bot_screen.GetHeight());
+        } else {
+            top_screen = top_screen.TranslateY(height / 2 - top_screen.GetHeight());
+        }
+    }
+    // Move the top screen to the bottom if we are swapped.
+    res.top_screen = swapped ? top_screen.TranslateY(height / 2) : top_screen;
+    res.bottom_screen = swapped ? bot_screen : bot_screen.TranslateY(height / 2);
+    return res;
+}
+
+FramebufferLayout SingleFrameLayout(unsigned width, unsigned height, bool swapped) {
+    ASSERT(width > 0);
+    ASSERT(height > 0);
+    // The drawing code needs at least somewhat valid values for both screens
+    // so just calculate them both even if the other isn't showing.
+    FramebufferLayout res{width, height, !swapped, swapped, {}, {}};
+
+    MathUtil::Rectangle<unsigned> screen_window_area{0, 0, width, height};
+    MathUtil::Rectangle<unsigned> top_screen =
+        maxRectangle(screen_window_area, TOP_SCREEN_ASPECT_RATIO);
+    MathUtil::Rectangle<unsigned> bot_screen =
+        maxRectangle(screen_window_area, BOT_SCREEN_ASPECT_RATIO);
+
+    float window_aspect_ratio = static_cast<float>(height) / width;
+    float emulation_aspect_ratio = (swapped) ? BOT_SCREEN_ASPECT_RATIO : TOP_SCREEN_ASPECT_RATIO;
+
+    if (window_aspect_ratio < emulation_aspect_ratio) {
+        top_screen =
+            top_screen.TranslateX((screen_window_area.GetWidth() - top_screen.GetWidth()) / 2);
+        bot_screen =
+            bot_screen.TranslateX((screen_window_area.GetWidth() - bot_screen.GetWidth()) / 2);
+    } else {
+        top_screen = top_screen.TranslateY((height - top_screen.GetHeight()) / 2);
+        bot_screen = bot_screen.TranslateY((height - bot_screen.GetHeight()) / 2);
+    }
+    res.top_screen = top_screen;
+    res.bottom_screen = bot_screen;
+    return res;
+}
+
+FramebufferLayout LargeFrameLayout(unsigned width, unsigned height, bool swapped) {
+    ASSERT(width > 0);
+    ASSERT(height > 0);
+
+    FramebufferLayout res{width, height, true, true, {}, {}};
+    // Split the window into two parts. Give 4x width to the main screen and 1x width to the small
+    // To do that, find the total emulation box and maximize that based on window size
+    float window_aspect_ratio = static_cast<float>(height) / width;
+    float emulation_aspect_ratio =
+        swapped
+            ? VideoCore::kScreenBottomHeight * 4 /
+                  (VideoCore::kScreenBottomWidth * 4.0f + VideoCore::kScreenTopWidth)
+            : VideoCore::kScreenTopHeight * 4 /
+                  (VideoCore::kScreenTopWidth * 4.0f + VideoCore::kScreenBottomWidth);
+    float large_screen_aspect_ratio = swapped ? BOT_SCREEN_ASPECT_RATIO : TOP_SCREEN_ASPECT_RATIO;
+    float small_screen_aspect_ratio = swapped ? TOP_SCREEN_ASPECT_RATIO : BOT_SCREEN_ASPECT_RATIO;
+
+    MathUtil::Rectangle<unsigned> screen_window_area{0, 0, width, height};
+    MathUtil::Rectangle<unsigned> total_rect =
+        maxRectangle(screen_window_area, emulation_aspect_ratio);
+    MathUtil::Rectangle<unsigned> large_screen =
+        maxRectangle(total_rect, large_screen_aspect_ratio);
+    MathUtil::Rectangle<unsigned> fourth_size_rect = total_rect.Scale(.25f);
+    MathUtil::Rectangle<unsigned> small_screen =
+        maxRectangle(fourth_size_rect, small_screen_aspect_ratio);
+
+    if (window_aspect_ratio < emulation_aspect_ratio) {
+        large_screen =
+            large_screen.TranslateX((screen_window_area.GetWidth() - total_rect.GetWidth()) / 2);
+    } else {
+        large_screen = large_screen.TranslateY((height - total_rect.GetHeight()) / 2);
+    }
+    // Shift the small screen to the bottom right corner
+    small_screen =
+        small_screen.TranslateX(large_screen.right)
+            .TranslateY(large_screen.GetHeight() + large_screen.top - small_screen.GetHeight());
+    res.top_screen = swapped ? small_screen : large_screen;
+    res.bottom_screen = swapped ? large_screen : small_screen;
+    return res;
+}
+}

src/common/framebuffer_layout.h

@@ -0,0 +1,47 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/math_util.h"
+namespace Layout {
+/// Describes the layout of the window framebuffer (size and top/bottom screen positions)
+struct FramebufferLayout {
+    unsigned width;
+    unsigned height;
+    bool top_screen_enabled;
+    bool bottom_screen_enabled;
+    MathUtil::Rectangle<unsigned> top_screen;
+    MathUtil::Rectangle<unsigned> bottom_screen;
+};
+
+/**
+ * Factory method for constructing a default FramebufferLayout
+ * @param width Window framebuffer width in pixels
+ * @param height Window framebuffer height in pixels
+ * @param is_swapped if true, the bottom screen will be displayed above the top screen
+ * @return Newly created FramebufferLayout object with default screen regions initialized
+ */
+FramebufferLayout DefaultFrameLayout(unsigned width, unsigned height, bool is_swapped);
+
+/**
+ * Factory method for constructing a FramebufferLayout with only the top or bottom screen
+ * @param width Window framebuffer width in pixels
+ * @param height Window framebuffer height in pixels
+ * @param is_swapped if true, the bottom screen will be displayed (and the top won't be displayed)
+ * @return Newly created FramebufferLayout object with default screen regions initialized
+ */
+FramebufferLayout SingleFrameLayout(unsigned width, unsigned height, bool is_swapped);
+
+/**
+ * Factory method for constructing a Frame with the a 4x size Top screen with a 1x size bottom
+ * screen on the right
+ * This is useful in particular because it matches well with a 1920x1080 resolution monitor
+ * @param width Window framebuffer width in pixels
+ * @param height Window framebuffer height in pixels
+ * @param is_swapped if true, the bottom screen will be the large display
+ * @return Newly created FramebufferLayout object with default screen regions initialized
+ */
+FramebufferLayout LargeFrameLayout(unsigned width, unsigned height, bool is_swapped);
+}

src/common/math_util.h

@@ -38,6 +38,16 @@ struct Rectangle {
     T GetHeight() const {
         return std::abs(static_cast<typename std::make_signed<T>::type>(bottom - top));
     }
+    Rectangle<T> TranslateX(const T x) const {
+        return Rectangle{left + x, top, right + x, bottom};
+    }
+    Rectangle<T> TranslateY(const T y) const {
+        return Rectangle{left, top + y, right, bottom + y};
+    }
+    Rectangle<T> Scale(const float s) const {
+        return Rectangle{left, top, static_cast<T>(left + GetWidth() * s),
+                         static_cast<T>(top + GetHeight() * s)};
+    }
 };
 
 } // namespace MathUtil

src/core/settings.cpp

@@ -7,6 +7,8 @@
 #include "settings.h"
 #include "video_core/video_core.h"
 
+#include "common/emu_window.h"
+
 namespace Settings {
 
 Values values = {};
@@ -20,6 +22,11 @@ void Apply() {
     VideoCore::g_shader_jit_enabled = values.use_shader_jit;
     VideoCore::g_scaled_resolution_enabled = values.use_scaled_resolution;
 
+    if (VideoCore::g_emu_window) {
+        auto layout = VideoCore::g_emu_window->GetFramebufferLayout();
+        VideoCore::g_emu_window->UpdateCurrentFramebufferLayout(layout.width, layout.height);
+    }
+
     AudioCore::SelectSink(values.sink_id);
     AudioCore::EnableStretching(values.enable_audio_stretching);
 }

src/core/settings.h

@@ -10,7 +10,15 @@
 
 namespace Settings {
 
+enum class LayoutOption {
+    Default,
+    SingleScreen,
+    LargeScreen,
+    Custom,
+};
+
 namespace NativeInput {
+
 enum Values {
     // directly mapped keys
     A,
@@ -84,6 +92,9 @@ struct Values {
     bool use_scaled_resolution;
     bool use_vsync;
 
+    LayoutOption layout_option;
+    bool swap_screen;
+
     float bg_red;
     float bg_green;
     float bg_blue;

src/video_core/renderer_opengl/renderer_opengl.cpp

@@ -390,6 +390,8 @@ void RendererOpenGL::DrawSingleScreenRotated(const ScreenInfo& screen_info, floa
  */
 void RendererOpenGL::DrawScreens() {
     auto layout = render_window->GetFramebufferLayout();
+    const auto& top_screen = layout.top_screen;
+    const auto& bottom_screen = layout.bottom_screen;
 
     glViewport(0, 0, layout.width, layout.height);
     glClear(GL_COLOR_BUFFER_BIT);
@@ -403,12 +405,15 @@ void RendererOpenGL::DrawScreens() {
     glActiveTexture(GL_TEXTURE0);
     glUniform1i(uniform_color_texture, 0);
 
-    DrawSingleScreenRotated(screen_infos[0], (float)layout.top_screen.left,
-                            (float)layout.top_screen.top, (float)layout.top_screen.GetWidth(),
-                            (float)layout.top_screen.GetHeight());
-    DrawSingleScreenRotated(screen_infos[1], (float)layout.bottom_screen.left,
-                            (float)layout.bottom_screen.top, (float)layout.bottom_screen.GetWidth(),
-                            (float)layout.bottom_screen.GetHeight());
+    if (layout.top_screen_enabled) {
+        DrawSingleScreenRotated(screen_infos[0], (float)top_screen.left, (float)top_screen.top,
+                                (float)top_screen.GetWidth(), (float)top_screen.GetHeight());
+    }
+    if (layout.bottom_screen_enabled) {
+        DrawSingleScreenRotated(screen_infos[1], (float)bottom_screen.left,
+                                (float)bottom_screen.top, (float)bottom_screen.GetWidth(),
+                                (float)bottom_screen.GetHeight());
+    }
 
     m_current_frame++;
 }