Round the rectangle size to prevent float to int casting issues

And other minor style changes

src/common/framebuffer_layout.cpp

@@ -14,8 +14,6 @@ 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;
-static const float BOT_TO_TOP_SCREEN_RATIO_DIFFERENCE =
-    BOT_SCREEN_ASPECT_RATIO - TOP_SCREEN_ASPECT_RATIO;
 
 // Finds the largest size subrectangle contained in window area that is confined to the aspect ratio
 template <class T>
@@ -23,8 +21,8 @@ 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>(scale),
+    return MathUtil::Rectangle<T>{0, 0, static_cast<T>(std::round(scale)),
-                                  static_cast<T>(scale * screen_aspect_ratio)};
+                                  static_cast<T>(std::round(scale * screen_aspect_ratio))};
 }
 
 FramebufferLayout DefaultFrameLayout(unsigned width, unsigned height, bool swapped) {

src/common/framebuffer_layout.h

@@ -20,14 +20,16 @@ struct FramebufferLayout {
  * 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 screen
+ * 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);
@@ -38,6 +40,7 @@ FramebufferLayout SingleFrameLayout(unsigned width, unsigned height, bool is_swa
  * 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

@@ -45,8 +45,8 @@ struct Rectangle {
         return Rectangle{left, top + y, right, bottom + y};
     }
     Rectangle<T> Scale(const float s) const {
-        return Rectangle{left, top, static_cast<T>((right + left) * s),
+        return Rectangle{left, top, static_cast<T>(left + GetWidth() * s),
-                         static_cast<T>((top + bottom) * s)};
+                         static_cast<T>(top + GetHeight() * s)};
     }
 };