From 305ff9a261fb24b24f8b011282b30f9fbae49882 Mon Sep 17 00:00:00 2001
From: Guanhua Hou <gaimanjing@gmail.com>
Date: Mon, 23 Oct 2023 17:30:06 +0800
Subject: [PATCH] implemented function getAffineTransform

---
 include/Domain/Layout/Rect.hpp        |  5 +++++
 src/Domain/CMakeLists.txt             |  1 +
 src/Domain/Layout/Rect.cpp            | 17 +++++++++++++++
 test/domain/layout/resizing_tests.cpp | 31 +++++++++++++++++++++++++++
 4 files changed, 54 insertions(+)

diff --git a/include/Domain/Layout/Rect.hpp b/include/Domain/Layout/Rect.hpp
index 32805a8dd..32c2f0779 100644
--- a/include/Domain/Layout/Rect.hpp
+++ b/include/Domain/Layout/Rect.hpp
@@ -15,6 +15,8 @@
  */
 #pragma once
 
+#include <array>
+
 namespace VGG
 {
 
@@ -167,6 +169,9 @@ struct Rect
   }
 };
 
+Matrix getAffineTransform(const std::array<Point, 3>& oldPoints,
+                          const std::array<Point, 3>& newPoints);
+
 } // namespace Layout
 
 } // namespace VGG
diff --git a/src/Domain/CMakeLists.txt b/src/Domain/CMakeLists.txt
index 4f56eec90..e5f11cdf7 100644
--- a/src/Domain/CMakeLists.txt
+++ b/src/Domain/CMakeLists.txt
@@ -32,6 +32,7 @@ target_include_directories(vgg_domain PRIVATE
   ${CMAKE_SOURCE_DIR}/include/Domain/Layout
   ${CMAKE_SOURCE_DIR}/include/Domain/Model
   ${VGG_CONTRIB_BOOST_INCLUDE}
+  ${VGG_CONTRIB_GLM_INCLUDE}
 )
 target_link_libraries(vgg_domain
   flexbox
diff --git a/src/Domain/Layout/Rect.cpp b/src/Domain/Layout/Rect.cpp
index 561fa6651..3abaaf97e 100644
--- a/src/Domain/Layout/Rect.cpp
+++ b/src/Domain/Layout/Rect.cpp
@@ -17,6 +17,8 @@
 
 #include "Utility/VggFloat.hpp"
 
+#include <glm/glm.hpp>
+
 #include <algorithm>
 
 using namespace VGG;
@@ -72,4 +74,19 @@ Rect Rect::makeTransform(const Matrix& matrix, ECoordinateType type) const
   auto maxY = std::max(std::max(p1.y, p2.y), std::max(p3.y, p4.y));
 
   return { { minX, isYAxisDown ? minY : maxY }, { maxX - minX, maxY - minY } };
+}
+
+Matrix Layout::getAffineTransform(const std::array<Point, 3>& oldPoints,
+                                  const std::array<Point, 3>& newPoints)
+{
+  const glm::mat3 oldGlmPoints{ oldPoints[0].x, oldPoints[0].y, 1,
+                                oldPoints[1].x, oldPoints[1].y, 1,
+                                oldPoints[2].x, oldPoints[2].y, 1 };
+  const glm::mat3x2 newGlmPoints{ newPoints[0].x, newPoints[0].y, newPoints[1].x,
+                                  newPoints[1].y, newPoints[2].x, newPoints[2].y };
+
+  const auto gmMatrix = newGlmPoints * glm::inverse(oldGlmPoints);
+  return {
+    gmMatrix[0].x, gmMatrix[0].y, gmMatrix[1].x, gmMatrix[1].y, gmMatrix[2].x, gmMatrix[2].y
+  };
 }
\ No newline at end of file
diff --git a/test/domain/layout/resizing_tests.cpp b/test/domain/layout/resizing_tests.cpp
index 5121d9d98..3942f1bfb 100644
--- a/test/domain/layout/resizing_tests.cpp
+++ b/test/domain/layout/resizing_tests.cpp
@@ -5,6 +5,9 @@
 
 #include <gtest/gtest.h>
 
+#include <glm/ext.hpp>
+#include <glm/glm.hpp>
+
 using namespace VGG;
 
 class VggResizingTestSuite : public ::testing::Test
@@ -245,4 +248,32 @@ TEST_F(VggResizingTestSuite, FigGroupWithRotatedChild)
   EXPECT_TRUE(grandsonFrame(0, 0) == expectedFrames[1]);
   EXPECT_TRUE(grandsonFrame(0, 1) == expectedFrames[2]);
   EXPECT_TRUE(grandsonFrame(0, 2) == expectedFrames[3]);
+}
+
+TEST_F(VggResizingTestSuite, GetAffineTransform)
+{
+  // Given
+  const glm::mat3x2 glmMatrix{ 0.9396926164627075, 0.3420201241970062, -0.3420201241970062,
+                               0.9396926164627075, 177.10513305664062, -228.8557586669922 };
+  const glm::mat3 oldGlmPoints{ 0, 0, 1, 0, 40, 1, 100, 0, 1 };
+  const auto newGlmPoints = glmMatrix * oldGlmPoints;
+
+  const std::array<Layout::Point, 3> oldPoints{
+    Layout::Point{ oldGlmPoints[0].x, oldGlmPoints[0].y },
+    Layout::Point{ oldGlmPoints[1].x, oldGlmPoints[1].y },
+    Layout::Point{ oldGlmPoints[2].x, oldGlmPoints[2].y }
+  };
+  const std::array<Layout::Point, 3> newPoints{
+    Layout::Point{ newGlmPoints[0].x, newGlmPoints[0].y },
+    Layout::Point{ newGlmPoints[1].x, newGlmPoints[1].y },
+    Layout::Point{ newGlmPoints[2].x, newGlmPoints[2].y }
+  };
+
+  // When
+  const auto computedMatrix = Layout::getAffineTransform(oldPoints, newPoints);
+
+  // Then
+  Layout::Matrix layoutMatrix{ glmMatrix[0].x, glmMatrix[0].y, glmMatrix[1].x,
+                               glmMatrix[1].y, glmMatrix[2].x, glmMatrix[2].y };
+  EXPECT_TRUE(layoutMatrix == computedMatrix);
 }
\ No newline at end of file