Works a lot better now

src/dusk/layout.cpp

@@ -0,0 +1,25 @@
+#include "dusk/layout.hpp"
+
+using namespace dusk;
+
+LayoutRect LayoutRect::FitRectInRect(
+    const f32 widthOuter,
+    const f32 heightOuter,
+    const f32 widthInner,
+    const f32 heightInner) {
+
+    // Try as if constrained vertically first.
+    auto width = widthInner * (heightOuter / heightInner);
+    auto height = heightOuter;
+    if (width > widthOuter) {
+        // Otherwise, constrained horizontally.
+        width = widthOuter;
+        height = heightOuter * (widthOuter / widthInner);
+    }
+
+    // Center it
+    const auto posX = (widthOuter - width) / 2;
+    const auto posY = (heightOuter - height) / 2;
+
+    return {posX, posY, posX + width, posY + height};
+}