1 files changed, 35 insertions, 1 deletions

diff --git a/src/core/frontend/framebuffer_layout.cpp b/src/core/frontend/framebuffer_layout.cpp
index d2d02f9ff..e9f778fcb 100644
--- a/src/core/frontend/framebuffer_layout.cpp
+++ b/src/core/frontend/framebuffer_layout.cpp
@@ -141,6 +141,40 @@ FramebufferLayout LargeFrameLayout(unsigned width, unsigned height, bool swapped
     return res;
 }
 
+FramebufferLayout SideFrameLayout(unsigned width, unsigned height, bool swapped) {
+    ASSERT(width > 0);
+    ASSERT(height > 0);
+
+    FramebufferLayout res{width, height, true, true, {}, {}};
+    // Aspect ratio of both screens side by side
+    const float emulation_aspect_ratio = static_cast<float>(Core::kScreenTopHeight) /
+                                         (Core::kScreenTopWidth + Core::kScreenBottomWidth);
+    float window_aspect_ratio = static_cast<float>(height) / width;
+    MathUtil::Rectangle<unsigned> screen_window_area{0, 0, width, height};
+    // Find largest Rectangle that can fit in the window size with the given aspect ratio
+    MathUtil::Rectangle<unsigned> screen_rect =
+        maxRectangle(screen_window_area, emulation_aspect_ratio);
+    // Find sizes of top and bottom screen
+    MathUtil::Rectangle<unsigned> top_screen = maxRectangle(screen_rect, TOP_SCREEN_ASPECT_RATIO);
+    MathUtil::Rectangle<unsigned> bot_screen = maxRectangle(screen_rect, BOT_SCREEN_ASPECT_RATIO);
+
+    if (window_aspect_ratio < emulation_aspect_ratio) {
+        // Apply borders to the left and right sides of the window.
+        u32 shift_horizontal = (screen_window_area.GetWidth() - screen_rect.GetWidth()) / 2;
+        top_screen = top_screen.TranslateX(shift_horizontal);
+        bot_screen = bot_screen.TranslateX(shift_horizontal);
+    } else {
+        // Window is narrower than the emulation content => apply borders to the top and bottom
+        u32 shift_vertical = (screen_window_area.GetHeight() - screen_rect.GetHeight()) / 2;
+        top_screen = top_screen.TranslateY(shift_vertical);
+        bot_screen = bot_screen.TranslateY(shift_vertical);
+    }
+    // Move the top screen to the right if we are swapped.
+    res.top_screen = swapped ? top_screen.TranslateX(bot_screen.GetWidth()) : top_screen;
+    res.bottom_screen = swapped ? bot_screen : bot_screen.TranslateX(top_screen.GetWidth());
+    return res;
+}
+
 FramebufferLayout CustomFrameLayout(unsigned width, unsigned height) {
     ASSERT(width > 0);
     ASSERT(height > 0);
@@ -158,4 +192,4 @@ FramebufferLayout CustomFrameLayout(unsigned width, unsigned height) {
     res.bottom_screen = bot_screen;
     return res;
 }
-}
+} // namespace Layout