From c69b266e43ca85ed33ae3958823b7c35d7b7ef26 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 2 Mar 2024 10:48:15 +0100
Subject: [PATCH] LibGfx: Add fast path for multiply() with identity transforms

This is a no-op, and exiting early is useful as it cuts time spent in
AffineTransform::multiply() from 3% to 2% when hovering links on
ziglang.org.
---
 Userland/Libraries/LibGfx/AffineTransform.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Userland/Libraries/LibGfx/AffineTransform.cpp b/Userland/Libraries/LibGfx/AffineTransform.cpp
index b32258977e..97787b0f5d 100644
--- a/Userland/Libraries/LibGfx/AffineTransform.cpp
+++ b/Userland/Libraries/LibGfx/AffineTransform.cpp
@@ -108,6 +108,8 @@ AffineTransform& AffineTransform::set_translation(FloatPoint t)
 
 AffineTransform& AffineTransform::multiply(AffineTransform const& other)
 {
+    if (other.is_identity())
+        return *this;
     AffineTransform result;
     result.m_values[0] = other.a() * a() + other.b() * c();
     result.m_values[1] = other.a() * b() + other.b() * d();