Cleaned up XScreensaver portion of NEDsim.c.

diff --git a/hacks/NEDsim/NEDsim.c b/hacks/NEDsim/NEDsim.c
index 89a2090..71e4b99 100644 (file)
--- a/hacks/NEDsim/NEDsim.c
+++ b/hacks/NEDsim/NEDsim.c
@@ -705,9 +705,11 @@ NEDsim_free(Display * dpy, Window win, void * closure)
 static void *
 NEDsim_init(Display * dpy, Window win)
 {
+    // =========================================================================
+    //  Basic Setup
+    // =========================================================================
+
     struct NEDsim * nedsim;
-    XGCValues gcv;
-    XWindowAttributes xgwa;
 
     nedsim = calloc(1, sizeof(*nedsim));
     if (!nedsim) {
@@ -718,16 +720,25 @@ NEDsim_init(Display * dpy, Window win)
     nedsim->dpy = dpy;
     nedsim->win = win;
 
+    XGCValues gcv;
+    nedsim->gc = XCreateGC(nedsim->dpy, nedsim->win, GCForeground, &gcv);
+
+    XWindowAttributes xgwa;
     XGetWindowAttributes(nedsim->dpy, nedsim->win, &xgwa);
     nedsim->dpy_width = xgwa.width;
     nedsim->dpy_height = xgwa.height;
 
-    // TODO: Explain that this is the delay between each clock cycle of the simulated NED CPU.
+    nedsim->panel = XCreatePixmap(nedsim->dpy, nedsim->win, nedsim->dpy_width, nedsim->dpy_height, xgwa.depth);
+
+    // =========================================================================
+    //  Process User Requests
+    // =========================================================================
+
     nedsim->delay = get_integer_resource(nedsim->dpy, "delay", "Integer");
     nedsim->delay *= 1000; /* Turn milliseconds into microseconds. */
 
-    // Load the program file specified by the user or, if none is specified,
-    // randomly select one of the included programs.
+    // If the user did not supply a program for execution, randomly select one
+    // of the included programs.
     char * input_file = get_string_resource(nedsim->dpy, "binary", "String");
     if (input_file == NULL) {
         // TODO: Need to include some default programs and randomly select one to load into RAM.
@@ -736,11 +747,7 @@ NEDsim_init(Display * dpy, Window win)
         nedsim->nedstate = init_simulator(input_file);
     }
 
-    nedsim->gc = XCreateGC(nedsim->dpy, nedsim->win, GCForeground, &gcv);
-    nedsim->panel = XCreatePixmap(nedsim->dpy, nedsim->win, nedsim->dpy_width, nedsim->dpy_height, xgwa.depth);
-
-    // If the user specified a color, use it. Otherwise, select at random from
-    // the available color schemes.
+    // If the user did not select a color scheme, select one randomly.
     nedsim->color_index = get_integer_resource(nedsim->dpy, "color", "Integer");
     if (nedsim->color_index == -1) {
         nedsim->color_index = random() % sizeof(color_list)/sizeof(color_list[0]);
@@ -749,34 +756,50 @@ NEDsim_init(Display * dpy, Window win)
         nedsim->color_index = 0;
     }
 
-// TODO: Save the GIMP reference diagram somewhere, along with notes about the size/spacing, and that each cell is 10 pixels across in the reference image.
+    // =========================================================================
+    //  Scale Panel To Screen
+    // =========================================================================
 
-    nedsim->cell_size = nedsim->dpy_width / OVERALL_WIDTH_IN_CELLS ; // make panel as wide as it can be while keeping every cell an integer pixel size.
-    // TODO: What is my minimum cell_size? Below that, I should simply paint the window red and print an error in the console. Perform that check here, right after setting cell_size.
-    //       For now, we'll just make it 10 pixels?
+    // We desire to make the panel as wide as possible while also making the
+    // cell size an integer pixel size.
+    nedsim->cell_size = nedsim->dpy_width / OVERALL_WIDTH_IN_CELLS;
+    // Cell sizes below about 10 pixels result in unreadable fonts. For now,
+    // we'll use that as our cutoff. It also works well with a 1:10 border:cell
+    // ratio.
     if (nedsim->cell_size < 10) {
         nedsim->suitable_display = False;
         return nedsim;
     }
-    nedsim->origin_x_offset = (nedsim->dpy_width - (nedsim->cell_size * OVERALL_WIDTH_IN_CELLS)) / 2; // center panel horizontally
-
-    // Determine how many rows for the stack and heap displays. Make it the largest power of two that fits on the display.
-    int available_space_for_data_rows = nedsim->dpy_height - (nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + FOOTER_HEIGHT_IN_CELLS));
+    // Center the panel horizontally.
+    nedsim->origin_x_offset = (nedsim->dpy_width -
+            (nedsim->cell_size * OVERALL_WIDTH_IN_CELLS)) / 2;
+
+    // The stack and heap displays are variable height. Size them to fit the
+    // display window.
+    int available_space_for_data_rows = nedsim->dpy_height -
+            (nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + FOOTER_HEIGHT_IN_CELLS));
     for (int i = 0; ; i++) {
         if ((nedsim->cell_size * (1 << i)) > available_space_for_data_rows) {
             nedsim->num_data_rows = (1 << --i);
             break;
         }
     }
+    // Enforce a minimum vertical size, though '4' is arbitrary.
     if (nedsim->num_data_rows < 4) {
         nedsim->suitable_display = False;
         return nedsim;
     }
-    nedsim->origin_y_offset = (nedsim->dpy_height - (nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + nedsim->num_data_rows + FOOTER_HEIGHT_IN_CELLS))) / 2; // center panel vertically
+    // Center the panel vertically.
+    nedsim->origin_y_offset = (nedsim->dpy_height -
+            (nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + nedsim->num_data_rows + FOOTER_HEIGHT_IN_CELLS))) / 2;
 
     // Scale border relative to cell_size in a 1:10 relationship.
     nedsim->border_size = nedsim->cell_size / 10;
 
+    // =========================================================================
+    //  Draw Initial Panel
+    // =========================================================================
+
     draw_panel(nedsim);
     draw_logo(nedsim);
     draw_halt(nedsim);
@@ -796,6 +819,7 @@ NEDsim_draw(Display * dpy, Window win, void * closure)
 {
     struct NEDsim * nedsim = closure;
 
+    // Update the panel display buffer.
     if (nedsim->suitable_display) {
         nedsim->nedstate = run_simulator(nedsim->nedstate);
         update_display(nedsim);
@@ -804,6 +828,7 @@ NEDsim_draw(Display * dpy, Window win, void * closure)
         XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, 0, 0, nedsim->dpy_width, nedsim->dpy_height);
     }
 
+    // Copy panel buffer to display window.
     XCopyArea(nedsim->dpy, nedsim->panel, nedsim->win, nedsim->gc, 0, 0, nedsim->dpy_width, nedsim->dpy_height, 0, 0);
 
     return nedsim->delay;
@@ -813,10 +838,13 @@ static void
 NEDsim_reshape(Display * dpy, Window win, void * closure, unsigned int w, unsigned int h)
 {
     struct NEDsim * nedsim = closure;
+
+    // Only re-initialize the display if it changed size.
     XWindowAttributes xgwa;
     XGetWindowAttributes(nedsim->dpy, nedsim->win, &xgwa);
-    /* Only restart the simulation if the window changed size.                */
     if (nedsim->dpy_width != xgwa.width || nedsim->dpy_height != xgwa.height) {
+        // Although we are re-initializing the display, we wish to retain the
+        // in-progress NED simulation. Thus, we retain the NEDstate pointer.
         struct NEDstate * original_nedstate = nedsim->nedstate;
         nedsim->nedstate = NULL;
         NEDsim_free(dpy, win, nedsim);