GPU Display: Add minimum window size

Author: davidrohr

GPU/GPUTracking/display/frontend/GPUDisplayFrontend.h

@@ -83,6 +83,7 @@ class GPUDisplayFrontend : public GPUDisplayFrontendInterface
   void waitForFPSLimit(); // Sleep until the next frame is due according to fpsRate (no sleep with maxFPSRate or fpsRate <= 0)
 
   static constexpr int32_t INIT_WIDTH = 1024, INIT_HEIGHT = 768;                        // Initial window size, before maximizing
+  static constexpr int32_t MIN_WIDTH = 200, MIN_HEIGHT = 150;                           // Minimum window size
   static constexpr const char* DISPLAY_WINDOW_NAME = "GPU CA Standalone Event Display"; // Title of event display set by backend
   // Constant key codes for special mKeys (to unify different treatment in X11 / Windows / GLUT / etc.)
   static constexpr int32_t KEY_UP = 1;

GPU/GPUTracking/display/frontend/GPUDisplayFrontendGlfw.cxx

@@ -291,6 +291,7 @@ int32_t GPUDisplayFrontendGlfw::FrontendMain()
   glfwSetWindowSizeCallback(mWindow, resize_callback);
   glfwSetWindowMaximizeCallback(mWindow, maximize_callback);
   glfwSetWindowFocusCallback(mWindow, focus_callback);
+  glfwSetWindowSizeLimits(mWindow, MIN_WIDTH, MIN_HEIGHT, GLFW_DONT_CARE, GLFW_DONT_CARE);
   applyInitialWindowState();
   if (backend()->backendType() == GPUDisplayBackend::TYPE_OPENGL) {
     glfwSwapInterval(1);

GPU/GPUTracking/display/frontend/GPUDisplayFrontendWayland.cxx

@@ -510,8 +510,9 @@ int32_t GPUDisplayFrontendWayland::FrontendMain()
   xdg_toplevel_add_listener(mXdgToplevel, &mXdgToplevelListener, this);
 
   xdg_toplevel_set_title(mXdgToplevel, DISPLAY_WINDOW_NAME);
-  xdg_toplevel_set_app_id(mXdgToplevel, "o2-gpu-event-display"); // Used by the compositor for window grouping, window rules, and matching a .desktop file
-  applyInitialWindowState();                                     // Must be requested before the first commit
+  xdg_toplevel_set_min_size(mXdgToplevel, MIN_WIDTH, MIN_HEIGHT); // Logical size, avoids degenerate swapchains / projections
+  xdg_toplevel_set_app_id(mXdgToplevel, "o2-gpu-event-display");  // Used by the compositor for window grouping, window rules, and matching a .desktop file
+  applyInitialWindowState();                                      // Must be requested before the first commit
 
   if (mDecManager) { // Must be requested before the first commit. Without the protocol (e.g. GNOME), the window has no decorations
     mXdgDecoration = zxdg_decoration_manager_v1_get_toplevel_decoration(mDecManager, mXdgToplevel);

GPU/GPUTracking/display/frontend/GPUDisplayFrontendX11.cxx

@@ -267,6 +267,11 @@ int32_t GPUDisplayFrontendX11::FrontendMain()
   mWindow = XCreateWindow(mXDisplay, win, 50, 50, INIT_WIDTH, INIT_HEIGHT, // Position / Width and height of window
                           0, visualInfo->depth, InputOutput, visualInfo->visual, CWBorderPixel | CWColormap | CWEventMask, &windowAttributes);
   XSetStandardProperties(mXDisplay, mWindow, DISPLAY_WINDOW_NAME, DISPLAY_WINDOW_NAME, None, nullptr, 0, nullptr);
+  XSizeHints sizeHints{};
+  sizeHints.flags = PMinSize;
+  sizeHints.min_width = MIN_WIDTH;
+  sizeHints.min_height = MIN_HEIGHT;
+  XSetWMNormalHints(mXDisplay, mWindow, &sizeHints);
   if (backend()->backendType() == GPUDisplayBackend::TYPE_OPENGL) {
     glXMakeCurrent(mXDisplay, mWindow, glxContext);
   }