From ce5ee8f82f70df2d7aaf2d84298f61db28234d6f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C4=B0smail=20Y=C4=B1lmaz?=
 <32938453+ismail-yilmaz@users.noreply.github.com>
Date: Mon, 9 Dec 2024 10:36:27 +0300
Subject: [PATCH] Core: Linear interpolation (Lerp) templates and reference
 example for (numbers, Point Size and Rect) (#215)

---
 .../LinearInterpolation.cpp                   | 19 ++++++++++++
 .../LinearInterpolation.upp                   | 11 +++++++
 uppsrc/Core/Gtypes.h                          | 30 +++++++++++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 reference/LinearInterpolation/LinearInterpolation.cpp
 create mode 100644 reference/LinearInterpolation/LinearInterpolation.upp

diff --git a/reference/LinearInterpolation/LinearInterpolation.cpp b/reference/LinearInterpolation/LinearInterpolation.cpp
new file mode 100644
index 000000000..f0c60bf4b
--- /dev/null
+++ b/reference/LinearInterpolation/LinearInterpolation.cpp
@@ -0,0 +1,19 @@
+#include <Core/Core.h>
+
+using namespace Upp;
+
+// Generic Lerp and specializations
+
+CONSOLE_APP_MAIN
+{
+	StdLogSetup(LOG_COUT);
+	
+    DUMP(Lerp(10, 20, 0.5));
+    DUMP(Lerp(10.0, 20.0, 0.25));
+    DUMP(Lerp(Point(10, 20), Point(30, 40), 0.5));
+    DUMP(Lerp(Size(100, 200), Size(300, 400), 0.5));
+    DUMP(Lerp(Rect(0, 0, 100, 100), Rect(100, 100, 200, 200), 0.5));
+}
+
+
+
diff --git a/reference/LinearInterpolation/LinearInterpolation.upp b/reference/LinearInterpolation/LinearInterpolation.upp
new file mode 100644
index 000000000..f41efe19c
--- /dev/null
+++ b/reference/LinearInterpolation/LinearInterpolation.upp
@@ -0,0 +1,11 @@
+description "Demonstrates the linear interpolation templates.\377";
+
+uses
+	Core;
+
+file
+	LinearInterpolation.cpp;
+
+mainconfig
+	"" = "";
+
diff --git a/uppsrc/Core/Gtypes.h b/uppsrc/Core/Gtypes.h
index d08678c3f..973c1b9a3 100644
--- a/uppsrc/Core/Gtypes.h
+++ b/uppsrc/Core/Gtypes.h
@@ -720,6 +720,36 @@ Pointf Normalize(const Pointf& p);
 Pointf Polar(double a);
 Pointf Polar(const Pointf& p, double r, double a);
 
+// Linear interopolation templates
+
+template <typename T>
+inline T Lerp(T a, T b, double t)
+{
+    return a + t * (b - a);
+}
+
+template <typename T>
+inline Point_<T> Lerp(Point_<T> a, Point_<T> b, double t)
+{
+    return Point_<T>(Lerp(a.x, b.x, t), Lerp(a.y, b.y, t));
+}
+
+template <typename T>
+inline Size_<T> Lerp(Size_<T> a, Size_<T> b, double t)
+{
+    return Size_<T>(Lerp(a.cx, b.cx, t), Lerp(a.cy, b.cy, t));
+}
+
+template <typename T>
+inline Rect_<T> Lerp(Rect_<T> a, Rect_<T> b, double t)
+{
+    return Rect_<T>(
+        Lerp(a.left, b.left, t),
+        Lerp(a.top, b.top, t),
+        Lerp(a.right, b.right, t),
+        Lerp(a.bottom, b.bottom, t)
+    );
+}
 
 // deprecated because of confusing name: