From 977d50cabd35cf1e034dd15f1891f15c7e2b8a06 Mon Sep 17 00:00:00 2001
From: Yixing Lao <yixing.lao@gmail.com>
Date: Fri, 30 Jun 2023 22:44:14 +0800
Subject: [PATCH] allow setting view status

---
 .../visualization/visualizer/Visualizer.h     | 11 ++++-
 .../visualizer/VisualizerRender.cpp           | 44 +++++++++++--------
 cpp/pybind/visualization/visualizer.cpp       |  9 +++-
 3 files changed, 43 insertions(+), 21 deletions(-)

diff --git a/cpp/open3d/visualization/visualizer/Visualizer.h b/cpp/open3d/visualization/visualizer/Visualizer.h
index a253b753f32..02126229bc3 100644
--- a/cpp/open3d/visualization/visualizer/Visualizer.h
+++ b/cpp/open3d/visualization/visualizer/Visualizer.h
@@ -209,11 +209,18 @@ class Visualizer {
                                 bool do_render = true,
                                 bool convert_to_world_coordinate = false);
     void CaptureRenderOption(const std::string &filename = "");
+
     /// Function to reset view point.
     void ResetViewPoint(bool reset_bounding_box = false);
 
     const std::string &GetWindowName() const { return window_name_; }
 
+    /// Get the current view status as a json string of ViewTrajectory.
+    std::string GetViewStatus();
+
+    /// Set the current view status from a json string of ViewTrajectory.
+    void SetViewStatus(const std::string &view_status_str);
+
 protected:
     /// Function to initialize OpenGL
     virtual bool InitOpenGL();
@@ -229,11 +236,13 @@ class Visualizer {
     /// meshes individually).
     virtual void Render(bool render_screen = false);
 
+    /// Copy the current view status to clipboard.
     void CopyViewStatusToClipboard();
 
+    /// Apply the view point from clipboard.
     void CopyViewStatusFromClipboard();
 
-    // callback functions
+    /// Callback functions
     virtual void WindowRefreshCallback(GLFWwindow *window);
     virtual void WindowResizeCallback(GLFWwindow *window, int w, int h);
     virtual void MouseMoveCallback(GLFWwindow *window, double x, double y);
diff --git a/cpp/open3d/visualization/visualizer/VisualizerRender.cpp b/cpp/open3d/visualization/visualizer/VisualizerRender.cpp
index 9669f995249..175d11f99f8 100644
--- a/cpp/open3d/visualization/visualizer/VisualizerRender.cpp
+++ b/cpp/open3d/visualization/visualizer/VisualizerRender.cpp
@@ -143,34 +143,40 @@ void Visualizer::ResetViewPoint(bool reset_bounding_box /* = false*/) {
 }
 
 void Visualizer::CopyViewStatusToClipboard() {
+    glfwSetClipboardString(window_, GetViewStatus().c_str());
+}
+
+void Visualizer::CopyViewStatusFromClipboard() {
+    const char *clipboard_string_buffer = glfwGetClipboardString(window_);
+    if (clipboard_string_buffer != nullptr) {
+        std::string clipboard_string(clipboard_string_buffer);
+        SetViewStatus(clipboard_string);
+    }
+}
+
+std::string Visualizer::GetViewStatus() {
     ViewParameters current_status;
     if (!view_control_ptr_->ConvertToViewParameters(current_status)) {
-        utility::LogWarning("Something is wrong copying view status.");
+        utility::LogWarning("Cannot convert to view parameters.");
     }
     ViewTrajectory trajectory;
     trajectory.view_status_.push_back(current_status);
-    std::string clipboard_string;
-    if (!io::WriteIJsonConvertibleToJSONString(clipboard_string, trajectory)) {
-        utility::LogWarning("Something is wrong copying view status.");
+    std::string view_status_str;
+    if (!io::WriteIJsonConvertibleToJSONString(view_status_str, trajectory)) {
+        utility::LogWarning("Cannot convert ViewTrajectory to json string.");
     }
-    glfwSetClipboardString(window_, clipboard_string.c_str());
+    return view_status_str;
 }
 
-void Visualizer::CopyViewStatusFromClipboard() {
-    const char *clipboard_string_buffer = glfwGetClipboardString(window_);
-    if (clipboard_string_buffer != NULL) {
-        std::string clipboard_string(clipboard_string_buffer);
-        ViewTrajectory trajectory;
-        if (!io::ReadIJsonConvertibleFromJSONString(clipboard_string,
-                                                    trajectory)) {
-            utility::LogWarning("Something is wrong copying view status.");
-        }
-        if (trajectory.view_status_.size() != 1) {
-            utility::LogWarning("Something is wrong copying view status.");
-        }
-        view_control_ptr_->ConvertFromViewParameters(
-                trajectory.view_status_[0]);
+void Visualizer::SetViewStatus(const std::string &view_status_str) {
+    ViewTrajectory trajectory;
+    if (!io::ReadIJsonConvertibleFromJSONString(view_status_str, trajectory)) {
+        utility::LogWarning("Cannot convert string to view status.");
+    }
+    if (trajectory.view_status_.size() != 1) {
+        utility::LogWarning("Cannot convert string to view status.");
     }
+    view_control_ptr_->ConvertFromViewParameters(trajectory.view_status_[0]);
 }
 
 std::shared_ptr<geometry::Image> Visualizer::CaptureScreenFloatBuffer(
diff --git a/cpp/pybind/visualization/visualizer.cpp b/cpp/pybind/visualization/visualizer.cpp
index 8d2521a4d7b..7b76396c7c3 100644
--- a/cpp/pybind/visualization/visualizer.cpp
+++ b/cpp/pybind/visualization/visualizer.cpp
@@ -117,7 +117,14 @@ void pybind_visualizer(py::module &m) {
                  &Visualizer::CaptureDepthPointCloud,
                  "Function to capture and save local point cloud", "filename"_a,
                  "do_render"_a = false, "convert_to_world_coordinate"_a = false)
-            .def("get_window_name", &Visualizer::GetWindowName);
+            .def("get_window_name", &Visualizer::GetWindowName)
+            .def("get_view_status", &Visualizer::GetViewStatus,
+                 "Get the current view status as a json string of "
+                 "ViewTrajectory.")
+            .def("set_view_status", &Visualizer::SetViewStatus,
+                 "Set the current view status from a json string of "
+                 "ViewTrajectory.",
+                 "view_status_str"_a);
 
     py::class_<VisualizerWithKeyCallback,
                PyVisualizer<VisualizerWithKeyCallback>,