Made NEDsim double-buffered.

[screensavers] / hacks / NEDsim / NEDsim.c

diff --git a/hacks/NEDsim/NEDsim.c b/hacks/NEDsim/NEDsim.c
index bee5e3b..8bd2f29 100644 (file)
--- a/hacks/NEDsim/NEDsim.c
+++ b/hacks/NEDsim/NEDsim.c
@@ -1,24 +1,9 @@
 /* (c) 2021 Aaron Taylor <ataylor at subgeniuskitty dot com>                  */
 /* See LICENSE.txt file for copyright and license details.                    */
 
 /* (c) 2021 Aaron Taylor <ataylor at subgeniuskitty dot com>                  */
 /* See LICENSE.txt file for copyright and license details.                    */
 

-// TODO:
-//      - Write a brief description of the machine being simulated. Only one thread, reduced RAM, no meaningful console when running as screensaver, etc.
-
-// CLI Flags:
-//      -path-to-aout-binary
-//      -path-to-font-file
-//      -speed
-
-// Ideas for sample programs to include:
-//      - Build list of integers on the stack (DUP, IM_1, ADD).
-//      - Calculate prime numbers, placing them on the stack.
-//      - Lights sliding back and forth, like PDP-11 front panel with some OSes.
-

 #include "screenhack.h"
 #include "simulator.h"
 
 #include "screenhack.h"
 #include "simulator.h"
 

-/* Keep this source code C89 compliant per XScreensaver's instructions.       */
-

 /* -------------------------------------------------------------------------- */
 /* Data Structures                                                            */
 /* -------------------------------------------------------------------------- */
 /* -------------------------------------------------------------------------- */
 /* Data Structures                                                            */
 /* -------------------------------------------------------------------------- */


@@ -74,25 +59,6 @@ struct color_scheme {
         text;
 };
 
         text;
 };
 

-//static struct color_scheme color_list[] = {
-//    // TODO: Explain all this.
-//    // TODO: Add other color schemes, like purple PDP-11/70.
-//    // TODO: http://www.chdickman.com/pdp8/DECcolors/
-//    {
-//        {63479,63479,63479}, // 092-XXXX-123
-//        { 5140, 2056, 5654}, // 092-XXXX-152
-//        {40092,11051,15677}, // 092-XXXX-139
-//        {30326,13107,12850}, // 092-XXXX-154
-//        {65535,13107,12850}, // homemade
-//        {30326,13107,12850}, // 092-XXXX-154
-//        { 4112,12850,20046}, // 092-XXXX-145
-//        {12336,29555,37008}, // 092-XXXX-151
-//        {30326,24158, 6425}, // 092-XXXX-157
-//        {63479,63479,63479}, // 092-XXXX-123
-//        {63479,63479,63479}  // 092-XXXX-123
-//    }
-//};
-

 static struct color_scheme color_list[] = {
     // TODO: Explain all this.
     // TODO: Add other color schemes, like purple PDP-11/70.
 static struct color_scheme color_list[] = {
     // TODO: Explain all this.
     // TODO: Add other color schemes, like purple PDP-11/70.


@@ -215,20 +181,20 @@ draw_rect_area(struct NEDsim * nedsim, size_t x_origin, size_t y_origin, size_t
     y_origin += nedsim->origin_y_offset;
     x_size *= nedsim->cell_size;
     y_size *= nedsim->cell_size;
     y_origin += nedsim->origin_y_offset;
     x_size *= nedsim->cell_size;
     y_size *= nedsim->cell_size;

-    XFillRectangle(nedsim->dpy, nedsim->win, nedsim->gc, x_origin, y_origin, x_size, y_size);
+    XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, x_origin, y_origin, x_size, y_size);

 
     set_color(nedsim, &color_list[nedsim->color_index].border);
     if (bord_top) {
 
     set_color(nedsim, &color_list[nedsim->color_index].border);
     if (bord_top) {

-        XFillRectangle(nedsim->dpy, nedsim->win, nedsim->gc, x_origin, y_origin, x_size, nedsim->border_size);
+        XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, x_origin, y_origin, x_size, nedsim->border_size);

     }
     if (bord_bottom) {
     }
     if (bord_bottom) {

-        XFillRectangle(nedsim->dpy, nedsim->win, nedsim->gc, x_origin, (y_origin + y_size - nedsim->border_size), x_size, nedsim->border_size);
+        XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, x_origin, (y_origin + y_size - nedsim->border_size), x_size, nedsim->border_size);

     }
     if (bord_left) {
     }
     if (bord_left) {

-        XFillRectangle(nedsim->dpy, nedsim->win, nedsim->gc, x_origin, y_origin, nedsim->border_size, y_size);
+        XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, x_origin, y_origin, nedsim->border_size, y_size);

     }
     if (bord_right) {
     }
     if (bord_right) {

-        XFillRectangle(nedsim->dpy, nedsim->win, nedsim->gc, (x_origin + x_size - nedsim->border_size), y_origin, nedsim->border_size, y_size);
+        XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, (x_origin + x_size - nedsim->border_size), y_origin, nedsim->border_size, y_size);

     }
 }
 
     }
 }
 


@@ -260,7 +226,7 @@ draw_circular_area(struct NEDsim * nedsim, size_t x, size_t y, double diameter)
     y -= (0.5 * nedsim->border_size);
 
     // Start angle 0 and ending angle 360*64 is one full circle in Xlib units.
     y -= (0.5 * nedsim->border_size);
 
     // Start angle 0 and ending angle 360*64 is one full circle in Xlib units.

-    XFillArc(nedsim->dpy, nedsim->win, nedsim->gc, x, y, diameter, diameter, 0, 360*64);
+    XFillArc(nedsim->dpy, nedsim->panel, nedsim->gc, x, y, diameter, diameter, 0, 360*64);

 }
 
 // TODO: Explain
 }
 
 // TODO: Explain


@@ -274,16 +240,69 @@ draw_panel(struct NEDsim * nedsim)
 
     // Draw background color over entire window.
     set_color(nedsim, &color_list[nedsim->color_index].panel_bg);
 
     // Draw background color over entire window.
     set_color(nedsim, &color_list[nedsim->color_index].panel_bg);

-    XFillRectangle(nedsim->dpy, nedsim->win, nedsim->gc, 0, 0, nedsim->dpy_width, nedsim->dpy_height);
+    XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, 0, 0, nedsim->dpy_width, nedsim->dpy_height);

 
     // Draw NED panel in foreground color.
     set_color(nedsim, &color_list[nedsim->color_index].panel_fg);
 
     // Draw NED panel in foreground color.
     set_color(nedsim, &color_list[nedsim->color_index].panel_fg);

-    XFillRectangle(nedsim->dpy, nedsim->win, nedsim->gc,
+    XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,

             nedsim->origin_x_offset,
             nedsim->origin_y_offset,
             nedsim->cell_size * OVERALL_WIDTH_IN_CELLS,
             nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + nedsim->num_data_rows + FOOTER_HEIGHT_IN_CELLS)
     );
             nedsim->origin_x_offset,
             nedsim->origin_y_offset,
             nedsim->cell_size * OVERALL_WIDTH_IN_CELLS,
             nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + nedsim->num_data_rows + FOOTER_HEIGHT_IN_CELLS)
     );

+
+    // Give the panel rounded corners by first deleting the four right-angle corners...
+    set_color(nedsim, &color_list[nedsim->color_index].panel_bg);
+    XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,
+            nedsim->origin_x_offset,
+            nedsim->origin_y_offset,
+            nedsim->cell_size,
+            nedsim->cell_size
+    );
+    XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,
+            nedsim->origin_x_offset + (nedsim->cell_size * (OVERALL_WIDTH_IN_CELLS-1)),
+            nedsim->origin_y_offset,
+            nedsim->cell_size,
+            nedsim->cell_size
+    );
+    XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,
+            nedsim->origin_x_offset,
+            nedsim->origin_y_offset + (nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + nedsim->num_data_rows + FOOTER_HEIGHT_IN_CELLS - 1)),
+            nedsim->cell_size,
+            nedsim->cell_size
+    );
+    XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,
+            nedsim->origin_x_offset + (nedsim->cell_size * (OVERALL_WIDTH_IN_CELLS-1)),
+            nedsim->origin_y_offset + (nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + nedsim->num_data_rows + FOOTER_HEIGHT_IN_CELLS - 1)),
+            nedsim->cell_size,
+            nedsim->cell_size
+    );
+    // ...and then replacing them with filled arcs, forming rounded corners.
+    set_color(nedsim, &color_list[nedsim->color_index].panel_fg);
+    XFillArc(nedsim->dpy, nedsim->panel, nedsim->gc,
+            nedsim->origin_x_offset,
+            nedsim->origin_y_offset,
+            nedsim->cell_size * 2, nedsim->cell_size * 2,
+            180*64, -90*64
+    );
+    XFillArc(nedsim->dpy, nedsim->panel, nedsim->gc,
+            nedsim->origin_x_offset + (nedsim->cell_size * (OVERALL_WIDTH_IN_CELLS-2)),
+            nedsim->origin_y_offset,
+            nedsim->cell_size * 2, nedsim->cell_size * 2,
+            0, 90*64
+    );
+    XFillArc(nedsim->dpy, nedsim->panel, nedsim->gc,
+            nedsim->origin_x_offset,
+            nedsim->origin_y_offset + (nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + nedsim->num_data_rows + FOOTER_HEIGHT_IN_CELLS - 2)),
+            nedsim->cell_size * 2, nedsim->cell_size * 2,
+            180*64, 90*64
+    );
+    XFillArc(nedsim->dpy, nedsim->panel, nedsim->gc,
+            nedsim->origin_x_offset + (nedsim->cell_size * (OVERALL_WIDTH_IN_CELLS-2)),
+            nedsim->origin_y_offset + (nedsim->cell_size * (HEADER_HEIGHT_IN_CELLS + nedsim->num_data_rows + FOOTER_HEIGHT_IN_CELLS - 2)),
+            nedsim->cell_size * 2, nedsim->cell_size * 2,
+            0, -90*64
+    );

 }
 
 // TODO: Explain
 }
 
 // TODO: Explain


@@ -309,7 +328,7 @@ draw_logo(struct NEDsim * nedsim)
     get_text_size(nedsim, "NED", &text_x_size, &text_y_size);
     int local_x_offset = ((LOGO_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((LOGO_NAME_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     get_text_size(nedsim, "NED", &text_x_size, &text_y_size);
     int local_x_offset = ((LOGO_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((LOGO_NAME_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, (LOGO_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, (LOGO_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),

             ((LOGO_Y_OFFSET+LOGO_NAME_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "NED", 3);
 
     // And draw the 'subgeniuskitty.com' text in the bottom box.
             ((LOGO_Y_OFFSET+LOGO_NAME_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "NED", 3);
 
     // And draw the 'subgeniuskitty.com' text in the bottom box.


@@ -317,7 +336,7 @@ draw_logo(struct NEDsim * nedsim)
     get_text_size(nedsim, "subgeniuskitty.com", &text_x_size, &text_y_size);
     local_x_offset = ((LOGO_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     local_y_offset = ((LOGO_WEBSITE_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     get_text_size(nedsim, "subgeniuskitty.com", &text_x_size, &text_y_size);
     local_x_offset = ((LOGO_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     local_y_offset = ((LOGO_WEBSITE_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, (LOGO_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, (LOGO_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),

             ((LOGO_Y_OFFSET+LOGO_NAME_HEIGHT+LOGO_WEBSITE_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "subgeniuskitty.com", 18);
 }
 
             ((LOGO_Y_OFFSET+LOGO_NAME_HEIGHT+LOGO_WEBSITE_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "subgeniuskitty.com", 18);
 }
 


@@ -343,7 +362,7 @@ draw_halt(struct NEDsim * nedsim)
     get_text_size(nedsim, "HALT", &text_x_size, &text_y_size);
     int local_x_offset = ((HALT_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((HALT_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     get_text_size(nedsim, "HALT", &text_x_size, &text_y_size);
     int local_x_offset = ((HALT_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((HALT_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, (HALT_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, (HALT_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),

             ((HALT_Y_OFFSET+HALT_LIGHT_HEIGHT+HALT_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "HALT", 4);
 }
 
             ((HALT_Y_OFFSET+HALT_LIGHT_HEIGHT+HALT_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "HALT", 4);
 }
 


@@ -407,7 +426,7 @@ draw_pc(struct NEDsim * nedsim)
     get_text_size(nedsim, "PC", &text_x_size, &text_y_size);
     int local_x_offset = ((PC_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((PC_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     get_text_size(nedsim, "PC", &text_x_size, &text_y_size);
     int local_x_offset = ((PC_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((PC_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, (PC_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, (PC_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),

             ((PC_Y_OFFSET+PC_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "PC", 2);
 }
 
             ((PC_Y_OFFSET+PC_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "PC", 2);
 }
 


@@ -433,7 +452,7 @@ draw_sc(struct NEDsim * nedsim)
     get_text_size(nedsim, "SC", &text_x_size, &text_y_size);
     int local_x_offset = ((SC_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((SC_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     get_text_size(nedsim, "SC", &text_x_size, &text_y_size);
     int local_x_offset = ((SC_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((SC_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, (SC_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, (SC_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),

             ((SC_Y_OFFSET+SC_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "SC", 2);
 }
 
             ((SC_Y_OFFSET+SC_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "SC", 2);
 }
 


@@ -465,7 +484,7 @@ draw_psw(struct NEDsim * nedsim)
     get_text_size(nedsim, "N", &text_x_size, &text_y_size);
     int local_x_offset = ((PSW_LABEL_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((PSW_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     get_text_size(nedsim, "N", &text_x_size, &text_y_size);
     int local_x_offset = ((PSW_LABEL_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     int local_y_offset = ((PSW_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, (PSW_N_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, (PSW_N_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),

             ((PSW_Y_OFFSET+PSW_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "N", 1);
 
     // Now draw the label text "Z".
             ((PSW_Y_OFFSET+PSW_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "N", 1);
 
     // Now draw the label text "Z".


@@ -473,7 +492,7 @@ draw_psw(struct NEDsim * nedsim)
     get_text_size(nedsim, "Z", &text_x_size, &text_y_size);
     local_x_offset = ((PSW_LABEL_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     local_y_offset = ((PSW_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     get_text_size(nedsim, "Z", &text_x_size, &text_y_size);
     local_x_offset = ((PSW_LABEL_WIDTH * nedsim->cell_size) - text_x_size) / 2;
     local_y_offset = ((PSW_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, (PSW_Z_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, (PSW_Z_X_OFFSET * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),

             ((PSW_Y_OFFSET+PSW_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "Z", 1);
 }
 
             ((PSW_Y_OFFSET+PSW_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "Z", 1);
 }
 


@@ -499,7 +518,7 @@ draw_stack(struct NEDsim * nedsim)
     int text_x_size, text_y_size;
     get_text_size(nedsim, "Stack Size:", &text_x_size, &text_y_size);
     int local_y_offset = ((STACK_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     int text_x_size, text_y_size;
     get_text_size(nedsim, "Stack Size:", &text_x_size, &text_y_size);
     int local_y_offset = ((STACK_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, ((STACK_X_OFFSET + 1) * nedsim->cell_size + nedsim->origin_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, ((STACK_X_OFFSET + 1) * nedsim->cell_size + nedsim->origin_x_offset),

             ((STACK_Y_OFFSET+STACK_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "Stack Size:", 11);
 }
 
             ((STACK_Y_OFFSET+STACK_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "Stack Size:", 11);
 }
 


@@ -527,7 +546,7 @@ draw_heap(struct NEDsim * nedsim)
     int text_x_size, text_y_size;
     get_text_size(nedsim, "RAM Base:", &text_x_size, &text_y_size);
     int local_y_offset = ((HEAP_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     int text_x_size, text_y_size;
     get_text_size(nedsim, "RAM Base:", &text_x_size, &text_y_size);
     int local_y_offset = ((HEAP_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, ((HEAP_X_OFFSET + 1) * nedsim->cell_size + nedsim->origin_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, ((HEAP_X_OFFSET + 1) * nedsim->cell_size + nedsim->origin_x_offset),

             ((HEAP_Y_OFFSET+HEAP_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "RAM Base:", 9);
 
     // Now draw the address text.
             ((HEAP_Y_OFFSET+HEAP_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), "RAM Base:", 9);
 
     // Now draw the address text.


@@ -536,7 +555,7 @@ draw_heap(struct NEDsim * nedsim)
     snprintf(address, sizeof(address), "0x%08X", HEAP_START_ADDRESS);
     get_text_size(nedsim, address, &text_x_size, &text_y_size);
     local_y_offset = ((HEAP_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     snprintf(address, sizeof(address), "0x%08X", HEAP_START_ADDRESS);
     get_text_size(nedsim, address, &text_x_size, &text_y_size);
     local_y_offset = ((HEAP_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, ((HEAP_X_OFFSET + 1 + (HEAP_WIDTH / 2)) * nedsim->cell_size + nedsim->origin_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, ((HEAP_X_OFFSET + 1 + (HEAP_WIDTH / 2)) * nedsim->cell_size + nedsim->origin_x_offset),

             ((HEAP_Y_OFFSET+HEAP_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), address, strlen(address));
 }
 
             ((HEAP_Y_OFFSET+HEAP_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), address, strlen(address));
 }
 


@@ -602,7 +621,7 @@ update_display(struct NEDsim * nedsim)
     int text_x_size, text_y_size;
     get_text_size(nedsim, stack_size, &text_x_size, &text_y_size);
     int local_y_offset = ((STACK_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;
     int text_x_size, text_y_size;
     get_text_size(nedsim, stack_size, &text_x_size, &text_y_size);
     int local_y_offset = ((STACK_LABEL_HEIGHT * nedsim->cell_size) - text_y_size) / 2;

-    XDrawString(nedsim->dpy, nedsim->win, nedsim->gc, ((STACK_X_OFFSET + 1 + (STACK_WIDTH / 2)) * nedsim->cell_size + nedsim->origin_x_offset),
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, ((STACK_X_OFFSET + 1 + (STACK_WIDTH / 2)) * nedsim->cell_size + nedsim->origin_x_offset),

             ((STACK_Y_OFFSET+STACK_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), stack_size, strlen(stack_size));
 
     // Draw the heap lights.
             ((STACK_Y_OFFSET+STACK_LABEL_HEIGHT) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), stack_size, strlen(stack_size));
 
     // Draw the heap lights.


@@ -624,9 +643,18 @@ NEDsim_event(Display * dpy, Window win, void * closure, XEvent * event)
 static void
 NEDsim_free(Display * dpy, Window win, void * closure)
 {
 static void
 NEDsim_free(Display * dpy, Window win, void * closure)
 {

-    // TODO: Replace all this with proper code to free everything.

     struct NEDsim * nedsim = closure;
     struct NEDsim * nedsim = closure;

+
+    if (nedsim->nedstate != NULL) {
+        free(nedsim->nedstate->active_thread->psw);
+        free(nedsim->nedstate->active_thread);
+        free(nedsim->nedstate->hack);
+        free(nedsim->nedstate);
+    }
+
+    // TODO: Replace all this with proper code to free everything related to the screensaver itself.

     XFreeGC(nedsim->dpy, nedsim->gc);
     XFreeGC(nedsim->dpy, nedsim->gc);

+    XFreePixmap(nedsim->dpy, nedsim->panel);

     free(nedsim);
 }
 
     free(nedsim);
 }
 


@@ -654,10 +682,18 @@ NEDsim_init(Display * dpy, Window win)
     nedsim->delay = get_integer_resource(nedsim->dpy, "delay", "Integer");
     nedsim->delay *= 1000; /* Turn milliseconds into microseconds. */
 
     nedsim->delay = get_integer_resource(nedsim->dpy, "delay", "Integer");
     nedsim->delay *= 1000; /* Turn milliseconds into microseconds. */
 

-    // TODO: Read in the a.out file. This should be done in the simulator's init function call?
-    nedsim->nedstate = init_simulator();
+    // Load the program file specified by the user or, if none is specified,
+    // 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.
+        nedsim->nedstate = init_simulator("./test.out");
+    } else {
+        nedsim->nedstate = init_simulator(input_file);
+    }

 
     nedsim->gc = XCreateGC(nedsim->dpy, nedsim->win, GCForeground, &gcv);
 
     nedsim->gc = XCreateGC(nedsim->dpy, nedsim->win, GCForeground, &gcv);

+    nedsim->panel = XCreatePixmap(nedsim->dpy, nedsim->win, nedsim->dpy_width, nedsim->dpy_height, xgwa.depth);

 
     // TODO: Do this properly.
     nedsim->color_index = 0;
 
     // TODO: Do this properly.
     nedsim->color_index = 0;


@@ -714,9 +750,11 @@ NEDsim_draw(Display * dpy, Window win, void * closure)
         update_display(nedsim);
     } else {
         set_color(nedsim, &color_list[nedsim->color_index].error_on);
         update_display(nedsim);
     } else {
         set_color(nedsim, &color_list[nedsim->color_index].error_on);

-        XFillRectangle(nedsim->dpy, nedsim->win, nedsim->gc, 0, 0, nedsim->dpy_width, nedsim->dpy_height);
+        XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, 0, 0, nedsim->dpy_width, nedsim->dpy_height);

     }
 
     }
 

+    XCopyArea(nedsim->dpy, nedsim->panel, nedsim->win, nedsim->gc, 0, 0, nedsim->dpy_width, nedsim->dpy_height, 0, 0);
+

     return nedsim->delay;
 }
 
     return nedsim->delay;
 }
 


@@ -728,8 +766,12 @@ NEDsim_reshape(Display * dpy, Window win, void * closure, unsigned int w, unsign
     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) {
     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) {

-        NEDsim_free(dpy, win, closure);
-        closure = NEDsim_init(dpy, win);
+        struct NEDstate * original_nedstate = nedsim->nedstate;
+        nedsim->nedstate = NULL;
+        NEDsim_free(dpy, win, nedsim);
+        struct NEDsim * new_nedsim = NEDsim_init(dpy, win);
+        new_nedsim->nedstate = original_nedstate;
+        closure = new_nedsim;

     }
 }
 
     }
 }
 


@@ -740,6 +782,7 @@ static const char * NEDsim_defaults[] = {
 
 static XrmOptionDescRec NEDsim_options[] = {
     { "-delay",              ".delay",                  XrmoptionSepArg, 0      },
 
 static XrmOptionDescRec NEDsim_options[] = {
     { "-delay",              ".delay",                  XrmoptionSepArg, 0      },

+    { "-binary",             ".binary",                 XrmoptionSepArg, 0      },

     { 0, 0, 0, 0 }
 };
 
     { 0, 0, 0, 0 }
 };