From af439cf3af3aa5e72992f17b3adbd301ff4f136d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?kleines=20Filmr=C3=B6llchen?= <filmroellchen@serenityos.org>
Date: Fri, 21 Oct 2022 17:05:20 +0200
Subject: [PATCH] LibGfx: Add Size::match_aspect_ratio

This will create a size that matches the given aspect ratio while
preserving one of the two dimensions.
---
 Userland/Libraries/LibGfx/Size.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Userland/Libraries/LibGfx/Size.h b/Userland/Libraries/LibGfx/Size.h
index 200e764c5e..16f3a623e6 100644
--- a/Userland/Libraries/LibGfx/Size.h
+++ b/Userland/Libraries/LibGfx/Size.h
@@ -93,6 +93,25 @@ public:
         return static_cast<float>(width()) / static_cast<float>(height());
     }
 
+    // Horizontal means preserve the width, Vertical means preserve the height.
+    [[nodiscard]] constexpr Size<T> match_aspect_ratio(float aspect_ratio, Orientation side_to_preserve) const
+    {
+        VERIFY(aspect_ratio != 0.0f);
+        auto matched = *this;
+        auto height_corresponding_to_width = static_cast<T>(static_cast<float>(width()) / aspect_ratio);
+        auto width_corresponding_to_height = static_cast<T>(static_cast<float>(height()) * aspect_ratio);
+
+        switch (side_to_preserve) {
+        case Orientation::Vertical:
+            matched.m_width = width_corresponding_to_height;
+            break;
+        case Orientation::Horizontal:
+            matched.m_height = height_corresponding_to_width;
+            break;
+        }
+        return matched;
+    }
+
     template<typename U>
     [[nodiscard]] constexpr bool contains(Size<U> const& other) const
     {