games: auto-size windows to available screen; dmenu shows Sys menu from any app

src/games/tetris.cpp

@@ -23,8 +23,7 @@
 #include <X11/keysym.h>
 #include <X11/Xatom.h>
 
-static const int WIN_W = 224;
-static const int WIN_H = 292;
+static const int TOPBAR = 24;
 static const int PCOLS = 10;
 static const int PROWS = 20;
 static const int CELL = 14;
@@ -87,7 +86,7 @@ static Window win;
 static GC gc;
 static Pixmap back;
 static int screen;
-static int winW = WIN_W, winH = WIN_H;
+static int winW = 240, winH = 296;  // overridden at runtime from the actual screen
 static unsigned long C_BG, C_FG, C_HEAD, C_FOOD, C_DIM;
 
 // ---- tetromino definitions (state 0 within a 4x4 box) ----
@@ -328,6 +327,12 @@ static void setup_window() {
   dpy = XOpenDisplay(nullptr);
   if (!dpy) { fprintf(stderr, "tetris: cannot open display\n"); exit(1); }
   screen = DefaultScreen(dpy);
+  int sw = DisplayWidth(dpy, screen);
+  int scrH = DisplayHeight(dpy, screen);
+  winW = sw;
+  winH = scrH - TOPBAR;          // fill the area below the status bar
+  if (winW < 96) winW = 96;
+  if (winH < 96) winH = 96;
   win = XCreateWindow(dpy, RootWindow(dpy, screen), 0, 0, winW, winH, 0,
                        CopyFromParent, InputOutput, CopyFromParent, 0, nullptr);
   XStoreName(dpy, win, "Tetris");