[gui] Support for setting the initial position of GGUI window (#6156)

Issue: #6107

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

docs/lang/articles/visualization/ggui.md

@@ -25,8 +25,9 @@ It is recommended that you familiarize yourself with GGUI through the examples i
 `ti.ui.Window(name, res)` creates a window.
 
 ```python
-window = ti.ui.Window('Window Title', (640, 360))
+window = ti.ui.Window('Window Title', res = (640, 360), pos = (150, 150))
 ```
+The argument `res` means resulotion(width and height) of the window, `pos` means the position of the window which origins from the left-top of your main screen.
 
 The following three types of objects can be displayed on a `ti.ui.Window`:
 

python/taichi/ui/window.py

@@ -25,15 +25,21 @@ class Window:
         res (tuple[int]): resolution (width, height) of the window, in pixels.
         vsync (bool): whether or not vertical sync should be enabled.
         show_window (bool): where or not display the window after initialization.
+        pos (tuple[int]): position (left to right, up to bottom) of the window which origins from the left-top of your main screen, in pixels.
     """
-    def __init__(self, name, res, vsync=False, show_window=True):
+    def __init__(self,
+                 name,
+                 res,
+                 vsync=False,
+                 show_window=True,
+                 pos=(100, 100)):
         check_ggui_availability()
         package_path = str(pathlib.Path(__file__).parent.parent)
         ti_arch = default_cfg().arch
         is_packed = default_cfg().packed
-        self.window = _ti_core.PyWindow(get_runtime().prog, name, res, vsync,
-                                        show_window, package_path, ti_arch,
-                                        is_packed)
+        self.window = _ti_core.PyWindow(get_runtime().prog, name, res, pos,
+                                        vsync, show_window, package_path,
+                                        ti_arch, is_packed)
 
     @property
     def running(self):

taichi/python/export_ggui.cpp

@@ -355,14 +355,22 @@ struct PyWindow {
   PyWindow(Program *prog,
            std::string name,
            py::tuple res,
+           py::tuple pos,
            bool vsync,
            bool show_window,
            std::string package_path,
            Arch ti_arch,
            bool is_packed_mode) {
-    AppConfig config = {name,    res[0].cast<int>(), res[1].cast<int>(),
-                        vsync,   show_window,        package_path,
-                        ti_arch, is_packed_mode};
+    AppConfig config = {name,
+                        res[0].cast<int>(),
+                        res[1].cast<int>(),
+                        pos[0].cast<int>(),
+                        pos[1].cast<int>(),
+                        vsync,
+                        show_window,
+                        package_path,
+                        ti_arch,
+                        is_packed_mode};
     // todo: support other ggui backends
     if (!(taichi::arch_is_cpu(ti_arch) || ti_arch == Arch::vulkan ||
           ti_arch == Arch::cuda)) {
@@ -480,8 +488,8 @@ void export_ggui(py::module &m) {
   m.attr("GGUI_AVAILABLE") = py::bool_(true);
 
   py::class_<PyWindow>(m, "PyWindow")
-      .def(py::init<Program *, std::string, py::tuple, bool, bool, std::string,
-                    Arch, bool>())
+      .def(py::init<Program *, std::string, py::tuple, py::tuple, bool, bool,
+                    std::string, Arch, bool>())
       .def("get_canvas", &PyWindow::get_canvas)
       .def("show", &PyWindow::show)
       .def("get_window_shape", &PyWindow::get_window_shape)

taichi/ui/common/app_config.h

@@ -11,6 +11,8 @@ struct AppConfig {
   std::string name;
   int width{0};
   int height{0};
+  int window_pos_x{0};
+  int window_pos_y{0};
   bool vsync{false};
   bool show_window{true};
   std::string package_path;

taichi/ui/common/window_base.cpp

@@ -9,7 +9,8 @@ namespace taichi::ui {
 WindowBase ::WindowBase(AppConfig config) : config_(config) {
   if (config_.show_window) {
     glfw_window_ = create_glfw_window_(config_.name, config_.width,
-                                       config_.height, config_.vsync);
+                                       config_.height, config_.window_pos_x,
+                                       config_.window_pos_y, config_.vsync);
     glfwSetWindowUserPointer(glfw_window_, this);
     set_callbacks();
     last_record_time_ = glfwGetTime();

taichi/ui/utils/utils.h

@@ -61,13 +61,15 @@ static void glfw_error_callback(int code, const char *description) {
 inline GLFWwindow *create_glfw_window_(const std::string &name,
                                        int screenWidth,
                                        int screenHeight,
+                                       int window_pos_x,
+                                       int window_pos_y,
                                        bool vsync) {
   initGLFW();
   GLFWwindow *window;
 
   glfwSetErrorCallback(glfw_error_callback);
 
-  glfwWindowHint(GLFW_VISIBLE, GLFW_TRUE);
+  glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
   glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
 
   window = glfwCreateWindow(screenWidth, screenHeight, name.c_str(), nullptr,
@@ -82,6 +84,12 @@ inline GLFWwindow *create_glfw_window_(const std::string &name,
     printf("GLFW reports no Vulkan support\n");
   }
 
+  // Reset the window hints to default
+  glfwDefaultWindowHints();
+
+  glfwSetWindowPos(window, window_pos_x, window_pos_y);
+
+  glfwShowWindow(window);
   // Invalid for Vulkan
   /*
   if (vsync) {