[Gui] [doc] Add subwindow dimension control flags to GGUI interface

docs/lang/articles/visualization/ggui.md

@@ -437,6 +437,22 @@ with gui.sub_window("Sub Window", x=10, y=10, width=300, height=100):
     color = gui.color_edit_3("name2", color)
 ```
 
+### Locking a subwindow
+
+You can control whether GGUI subwindows dimensions can be manipulated using these flags.
+They all default to `True`:
+
+- `movable`: Allow users to drag the subwindow. If False, position can be updated programmatically.
+- `resizable`: Allow users to resize the subwindow. If `False`, size can be updated programmatically.
+- `collapsible`: Allow users to collapse the subwindow by clicking its title bar.
+
+```python
+# Window that is fully locked
+with gui.sub_window("Locked subwindow", 0.1, 0.1, 0.3, 0.2,
+                    resizable=False, movable=False, collapsible=False):
+    gui.text("Locked!")
+```
+
 ## Show a window
 
 Call `show()` to show a window.

python/taichi/ui/imgui.py

@@ -13,7 +13,7 @@ def __init__(self, gui) -> None:
         self.gui = gui
 
     @contextmanager
-    def sub_window(self, name, x, y, width, height):
+    def sub_window(self, name, x, y, width, height, movable=True, resizable=True, collapsible=True):
         """Creating a context manager for subwindow.
 
         Note:
@@ -26,19 +26,25 @@ def sub_window(self, name, x, y, width, height):
                 corner of the subwindow, relative to the full window.
             width (float): The width of the subwindow relative to the full window.
             height (float): The height of the subwindow relative to the full window.
+            movable (bool): Whether the window can be moved by the user. \
+                When False, position can only be changed programmatically.
+            resizable (bool): Whether the window can be resized by the user. \
+                When False, size can only be changed programmatically.
+            collapsible (bool): Whether the window can be collapsed by the user. \
+                When False, the collapse button is disabled.
 
         Example::
 
             >>> with gui.sub_window(name, x, y, width, height) as g:
             >>>     g.text("Hello, World!")
         """
-        self.begin(name, x, y, width, height)
+        self.begin(name, x, y, width, height, movable, resizable, collapsible)
         try:
             yield self
         finally:
             self.end()
 
-    def begin(self, name, x, y, width, height):
+    def begin(self, name, x, y, width, height, movable=True, resizable=True, collapsible=True):
         """Creates a subwindow that holds imgui widgets.
 
         All widget function calls (e.g. `text`, `button`) after the `begin`
@@ -51,8 +57,14 @@ def begin(self, name, x, y, width, height):
                 corner of the subwindow, relative to the full window.
             width (float): The width of the subwindow relative to the full window.
             height (float): The height of the subwindow relative to the full window.
+            movable (bool): Whether the window can be moved by the user. \
+                When False, position can only be changed programmatically.
+            resizable (bool): Whether the window can be resized by the user. \
+                When False, size can only be changed programmatically.
+            collapsible (bool): Whether the window can be collapsed by the user. \
+                When False, the collapse button is disabled.
         """
-        self.gui.begin(name, x, y, width, height)
+        self.gui.begin(name, x, y, width, height, movable, resizable, collapsible)
 
     def end(self):
         """End the description of the current subwindow."""

taichi/python/export_ggui.cpp

@@ -60,8 +60,15 @@ py::array_t<float> mat4_to_nparray(glm::mat4 mat) {
 
 struct PyGui {
   GuiBase *gui;  // not owned
-  void begin(std::string name, float x, float y, float width, float height) {
-    gui->begin(name, x, y, width, height);
+  void begin(std::string name,
+             float x,
+             float y,
+             float width,
+             float height,
+             bool movable = true,
+             bool resizable = true,
+             bool collapsible = true) {
+    gui->begin(name, x, y, width, height, movable, resizable, collapsible);
   }
   void end() {
     gui->end();

taichi/ui/common/gui_base.h

@@ -10,7 +10,10 @@ class GuiBase {
                      float x,
                      float y,
                      float width,
-                     float height) = 0;
+                     float height,
+                     bool movable = true,
+                     bool resizable = true,
+                     bool collapsible = true) = 0;
   virtual void end() = 0;
   virtual void text(const std::string &text) = 0;
   virtual void text(const std::string &text, glm::vec3 color) = 0;

taichi/ui/ggui/gui.cpp

@@ -145,13 +145,49 @@ void Gui::begin(const std::string &name,
                 float x,
                 float y,
                 float width,
-                float height) {
+                float height,
+                bool movable,
+                bool resizable,
+                bool collapsible) {
   if (!initialized()) {
     return;
   }
-  ImGui::SetNextWindowPos(ImVec2(abs_x(x), abs_y(y)), ImGuiCond_Once);
-  ImGui::SetNextWindowSize(ImVec2(abs_x(width), abs_y(height)), ImGuiCond_Once);
-  ImGui::Begin(name.c_str());
+
+  // Update window dimensions when locked, so programmatic updates use current
+  // window size
+  if ((!movable || !resizable) && app_context_->config.show_window) {
+#ifdef ANDROID
+    widthBeforeDPIScale =
+        (int)ANativeWindow_getWidth(app_context_->taichi_window());
+    heightBeforeDPIScale =
+        (int)ANativeWindow_getHeight(app_context_->taichi_window());
+#else
+    glfwGetWindowSize(app_context_->taichi_window(), &widthBeforeDPIScale,
+                      &heightBeforeDPIScale);
+#endif
+  }
+
+  // Set position: Always if locked, Once if unlocked
+  ImGuiCond pos_cond = movable ? ImGuiCond_Once : ImGuiCond_Always;
+  ImGui::SetNextWindowPos(ImVec2(abs_x(x), abs_y(y)), pos_cond);
+
+  // Set size: Always if locked, Once if unlocked
+  ImGuiCond size_cond = resizable ? ImGuiCond_Once : ImGuiCond_Always;
+  ImGui::SetNextWindowSize(ImVec2(abs_x(width), abs_y(height)), size_cond);
+
+  // Build window flags
+  ImGuiWindowFlags flags = 0;
+  if (!movable) {
+    flags |= ImGuiWindowFlags_NoMove;
+  }
+  if (!resizable) {
+    flags |= ImGuiWindowFlags_NoResize;
+  }
+  if (!collapsible) {
+    flags |= ImGuiWindowFlags_NoCollapse;
+  }
+
+  ImGui::Begin(name.c_str(), nullptr, flags);
   is_empty_ = false;
 }
 void Gui::end() {

taichi/ui/ggui/gui.h

@@ -33,7 +33,10 @@ class TI_DLL_EXPORT Gui final : public GuiBase {
              float x,
              float y,
              float width,
-             float height) override;
+             float height,
+             bool movable = true,
+             bool resizable = true,
+             bool collapsible = true) override;
   void end() override;
   void text(const std::string &text) override;
   void text(const std::string &text, glm::vec3 color) override;

taichi/ui/ggui/gui_metal.h

@@ -27,7 +27,10 @@ class TI_DLL_EXPORT GuiMetal final : public GuiBase {
              float x,
              float y,
              float width,
-             float height) override;
+             float height,
+             bool movable = true,
+             bool resizable = true,
+             bool collapsible = true) override;
   void end() override;
   void text(const std::string &text) override;
   void text(const std::string &text, glm::vec3 color) override;

taichi/ui/ggui/gui_metal.mm

@@ -55,10 +55,36 @@
 float GuiMetal::abs_y(float y) { return y * heightBeforeDPIScale; }
 
 void GuiMetal::begin(const std::string &name, float x, float y, float width,
-                     float height) {
-  ImGui::SetNextWindowPos(ImVec2(abs_x(x), abs_y(y)), ImGuiCond_Once);
-  ImGui::SetNextWindowSize(ImVec2(abs_x(width), abs_y(height)), ImGuiCond_Once);
-  ImGui::Begin(name.c_str());
+                     float height, bool movable, bool resizable,
+                     bool collapsible) {
+  // Update window dimensions when locked, so programmatic updates use current
+  // window size
+  if ((!movable || !resizable) && app_context_->config.show_window) {
+    glfwGetWindowSize(app_context_->taichi_window(), &widthBeforeDPIScale,
+                      &heightBeforeDPIScale);
+  }
+
+  // Set position: Always if locked, Once if unlocked
+  ImGuiCond pos_cond = movable ? ImGuiCond_Once : ImGuiCond_Always;
+  ImGui::SetNextWindowPos(ImVec2(abs_x(x), abs_y(y)), pos_cond);
+
+  // Set size: Always if locked, Once if unlocked
+  ImGuiCond size_cond = resizable ? ImGuiCond_Once : ImGuiCond_Always;
+  ImGui::SetNextWindowSize(ImVec2(abs_x(width), abs_y(height)), size_cond);
+
+  // Build window flags
+  ImGuiWindowFlags flags = 0;
+  if (!movable) {
+    flags |= ImGuiWindowFlags_NoMove;
+  }
+  if (!resizable) {
+    flags |= ImGuiWindowFlags_NoResize;
+  }
+  if (!collapsible) {
+    flags |= ImGuiWindowFlags_NoCollapse;
+  }
+
+  ImGui::Begin(name.c_str(), nullptr, flags);
   is_empty_ = false;
 }
 void GuiMetal::end() { ImGui::End(); }