Added COLOR() macro to NEDsim for ease of reading.

[screensavers] / hacks / NEDsim / NEDsim.c

diff --git a/hacks/NEDsim/NEDsim.c b/hacks/NEDsim/NEDsim.c
index 71e4b99..01733f1 100644 (file)
--- a/hacks/NEDsim/NEDsim.c
+++ b/hacks/NEDsim/NEDsim.c
@@ -4,6 +4,66 @@
 #include "screenhack.h"
 #include "simulator.h"
 
 #include "screenhack.h"
 #include "simulator.h"
 

+/* -------------------------------------------------------------------------- */
+/* Front Panel Layout                                                         */
+/* -------------------------------------------------------------------------- */
+
+// All of these values are in units of 'cells', not 'pixels'. Where applicable,
+// coordinates refer to the upper-left corner of a cell. See the files
+// `layout_reference.*` for details.
+
+#define OVERALL_WIDTH_IN_CELLS      70
+#define HEADER_HEIGHT_IN_CELLS      14
+#define FOOTER_HEIGHT_IN_CELLS      2
+
+#define LOGO_X_OFFSET               2
+#define LOGO_Y_OFFSET               2
+#define LOGO_WIDTH                  20
+#define LOGO_NAME_HEIGHT            6
+#define LOGO_WEBSITE_HEIGHT         2
+
+#define HALT_X_OFFSET               26
+#define HALT_Y_OFFSET               2
+#define HALT_WIDTH                  6
+#define HALT_LIGHT_HEIGHT           6
+#define HALT_LABEL_HEIGHT           2
+
+#define WORDLINE_BITS_PER_STRIPE    4
+#define WORDLINE_WIDTH              32
+#define WORDLINE_HEIGHT             1
+
+#define PC_X_OFFSET                 36
+#define PC_Y_OFFSET                 7
+#define PC_WIDTH                    32
+#define PC_LABEL_HEIGHT             2
+#define PC_LIGHT_HEIGHT             1
+
+#define SC_X_OFFSET                 42
+#define SC_Y_OFFSET                 2
+#define SC_WIDTH                    5
+#define SC_LABEL_HEIGHT             2
+#define SC_LIGHT_HEIGHT             1
+
+#define PSW_N_X_OFFSET              51
+#define PSW_Z_X_OFFSET              58
+#define PSW_Y_OFFSET                2
+#define PSW_LABEL_WIDTH             3
+#define PSW_LABEL_HEIGHT            2
+#define PSW_LIGHT_WIDTH             1
+#define PSW_LIGHT_HEIGHT            1
+
+#define STACK_X_OFFSET              2
+#define STACK_Y_OFFSET              12
+#define STACK_WIDTH                 32
+#define STACK_LABEL_HEIGHT          2
+#define STACK_LIGHT_HEIGHT          1
+
+#define HEAP_X_OFFSET               36
+#define HEAP_Y_OFFSET               12
+#define HEAP_WIDTH                  32
+#define HEAP_LABEL_HEIGHT           2
+#define HEAP_LIGHT_HEIGHT           1
+

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


@@ -126,7 +186,10 @@ static struct color_scheme color_list[] = {
 /* Helper Functions                                                           */
 /* -------------------------------------------------------------------------- */
 
 /* Helper Functions                                                           */
 /* -------------------------------------------------------------------------- */
 

-// TODO: Explain
+// Fill in boilerplate when selecting colors.
+#define COLOR(X) &color_list[nedsim->color_index].X
+
+// Set foreground color for the current graphics context.

 static void
 set_color(struct NEDsim * nedsim, struct color_rgb * color)
 {
 static void
 set_color(struct NEDsim * nedsim, struct color_rgb * color)
 {


@@ -143,9 +206,8 @@ set_color(struct NEDsim * nedsim, struct color_rgb * color)
     XSetForeground(nedsim->dpy, nedsim->gc, temp.pixel);
 }
 
     XSetForeground(nedsim->dpy, nedsim->gc, temp.pixel);
 }
 

-// TODO: Explain

 // TODO: Make this a lot faster.
 // TODO: Make this a lot faster.

-// Input: size in 'cells', and sets font to fill that size, minus border and padding room.
+// Set font size to fill 'size' cells vertically, minus space for border and padding.

 static void
 set_font_size(struct NEDsim * nedsim, int size)
 {
 static void
 set_font_size(struct NEDsim * nedsim, int size)
 {


@@ -199,8 +261,9 @@ set_font_size(struct NEDsim * nedsim, int size)
     nedsim->current_font = font_full_name;
 }
 
     nedsim->current_font = font_full_name;
 }
 

-// TODO: Explain
-// TODO: Explain that this returns result in pixels so we can track fractional cell usage.
+// Unlike most functions in this program that input/output in units of 'cells',
+// this function uses units of 'pixels' so the caller can track fractional cell
+// usage (e.g. for centering the text).

 static void
 get_text_size(struct NEDsim * nedsim, const char * text, int * x_size, int * y_size)
 {
 static void
 get_text_size(struct NEDsim * nedsim, const char * text, int * x_size, int * y_size)
 {


@@ -212,13 +275,14 @@ get_text_size(struct NEDsim * nedsim, const char * text, int * x_size, int * y_s
     *y_size = overall.ascent - overall.descent;
 }
 
     *y_size = overall.ascent - overall.descent;
 }
 

-// TODO: Explain
-// TODO: Note that this might leave the foreground color changed.
-// Argument coordinates are in 'cells', not pixels.
+// When specifying the rectangular area to draw, all coordinates and sizes are
+// in units of 'cells'.  Also, be aware that this function alters the
+// foreground color.

 static void
 draw_rect_area(struct NEDsim * nedsim, size_t x_origin, size_t y_origin, size_t x_size, size_t y_size,
                Bool bord_top, Bool bord_bottom, Bool bord_left, Bool bord_right)
 {
 static void
 draw_rect_area(struct NEDsim * nedsim, size_t x_origin, size_t y_origin, size_t x_size, size_t y_size,
                Bool bord_top, Bool bord_bottom, Bool bord_left, Bool bord_right)
 {

+    // First fill in the rectangular area...

     x_origin *= nedsim->cell_size;
     x_origin += nedsim->origin_x_offset;
     y_origin *= nedsim->cell_size;
     x_origin *= nedsim->cell_size;
     x_origin += nedsim->origin_x_offset;
     y_origin *= nedsim->cell_size;


@@ -227,25 +291,29 @@ draw_rect_area(struct NEDsim * nedsim, size_t x_origin, size_t y_origin, size_t
     y_size *= nedsim->cell_size;
     XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, x_origin, y_origin, x_size, y_size);
 
     y_size *= nedsim->cell_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);
+    // ...then give it a border, if requested.
+    set_color(nedsim, COLOR(border));

     if (bord_top) {
     if (bord_top) {

-        XFillRectangle(nedsim->dpy, nedsim->panel, 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->panel, 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->panel, 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->panel, 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);

     }
 }
 
     }
 }
 

-// TODO: Explain
-// Arguments are in units of 'cells', not pixels.
-// Will leave foreground color changed.
-// Draws filled circle with upper left corner at x,y.
+// Draws filled circle in a square area with upper left corner at x,y.  When
+// specifying the location and size to draw, all values are in units of
+// 'cells'.  Also, be aware that this function alters the foreground color.

 static void
 draw_circular_area(struct NEDsim * nedsim, size_t x, size_t y, double diameter)
 {
 static void
 draw_circular_area(struct NEDsim * nedsim, size_t x, size_t y, double diameter)
 {


@@ -273,21 +341,36 @@ draw_circular_area(struct NEDsim * nedsim, size_t x, size_t y, double diameter)
     XFillArc(nedsim->dpy, nedsim->panel, 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
+// Draws text in a square area with upper left corner at (x_origin,y_origin).
+// Requires that set_font_size() has been run at least once. All values are in
+// units of 'cells'.

 static void
 static void

-draw_panel(struct NEDsim * nedsim)
+draw_text(struct NEDsim * nedsim, const char * text, int x_origin, int y_origin, int x_size, int y_size, Bool horizontally_center)

 {
 {

-// TODO: Collect all relevant #defines somewhere.
-#define OVERALL_WIDTH_IN_CELLS 70 
-#define HEADER_HEIGHT_IN_CELLS 14
-#define FOOTER_HEIGHT_IN_CELLS 2
+    set_color(nedsim, COLOR(text));
+
+    int text_x_size, text_y_size;
+    get_text_size(nedsim, text, &text_x_size, &text_y_size);

 
 

+    int local_y_offset = ((y_size * nedsim->cell_size) - text_y_size) / 2;
+    int local_x_offset = 0;
+    if (horizontally_center) local_x_offset = ((x_size * nedsim->cell_size) - text_x_size) / 2;
+
+    XDrawString(nedsim->dpy, nedsim->panel, nedsim->gc, (x_origin * nedsim->cell_size + nedsim->origin_x_offset + local_x_offset),
+            ((y_origin + y_size) * nedsim->cell_size + nedsim->origin_y_offset - local_y_offset), text, strlen(text));
+}
+
+// Draws the panel itself. Not the lights/labels/etc, but the flat sheet of
+// metal that is the front panel.
+static void
+draw_panel(struct NEDsim * nedsim)
+{

     // Draw background color over entire window.
     // Draw background color over entire window.

-    set_color(nedsim, &color_list[nedsim->color_index].panel_bg);
+    set_color(nedsim, COLOR(panel_bg));

     XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc, 0, 0, nedsim->dpy_width, nedsim->dpy_height);
 
     // Draw NED panel in foreground color.
     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);
+    set_color(nedsim, COLOR(panel_fg));

     XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,
             nedsim->origin_x_offset,
             nedsim->origin_y_offset,
     XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,
             nedsim->origin_x_offset,
             nedsim->origin_y_offset,


@@ -296,7 +379,7 @@ draw_panel(struct NEDsim * nedsim)
     );
 
     // Give the panel rounded corners by first deleting the four right-angle corners...
     );
 
     // Give the panel rounded corners by first deleting the four right-angle corners...

-    set_color(nedsim, &color_list[nedsim->color_index].panel_bg);
+    set_color(nedsim, COLOR(panel_bg));

     XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,
             nedsim->origin_x_offset,
             nedsim->origin_y_offset,
     XFillRectangle(nedsim->dpy, nedsim->panel, nedsim->gc,
             nedsim->origin_x_offset,
             nedsim->origin_y_offset,


@@ -322,7 +405,7 @@ draw_panel(struct NEDsim * nedsim)
             nedsim->cell_size
     );
     // ...and then replacing them with filled arcs, forming rounded corners.
             nedsim->cell_size
     );
     // ...and then replacing them with filled arcs, forming rounded corners.

-    set_color(nedsim, &color_list[nedsim->color_index].panel_fg);
+    set_color(nedsim, COLOR(panel_fg));

     XFillArc(nedsim->dpy, nedsim->panel, nedsim->gc,
             nedsim->origin_x_offset,
             nedsim->origin_y_offset,
     XFillArc(nedsim->dpy, nedsim->panel, nedsim->gc,
             nedsim->origin_x_offset,
             nedsim->origin_y_offset,


@@ -349,97 +432,70 @@ draw_panel(struct NEDsim * nedsim)
     );
 }
 
     );
 }
 

-// TODO: Explain
+// Draw the "NED" and "subgeniuskitty.com" logos on the front panel.

 static void
 draw_logo(struct NEDsim * nedsim)
 {
 static void
 draw_logo(struct NEDsim * nedsim)
 {

-#define LOGO_X_OFFSET       2
-#define LOGO_Y_OFFSET       2
-#define LOGO_WIDTH          20
-#define LOGO_NAME_HEIGHT    6
-#define LOGO_WEBSITE_HEIGHT 2
-

     // First draw the two colored boxes that comprise the logo area.
     // First draw the two colored boxes that comprise the logo area.

-    set_color(nedsim, &color_list[nedsim->color_index].primary);
+    set_color(nedsim, COLOR(primary));

     draw_rect_area(nedsim, LOGO_X_OFFSET, LOGO_Y_OFFSET, LOGO_WIDTH, LOGO_NAME_HEIGHT, True, True, False, False);
     draw_rect_area(nedsim, LOGO_X_OFFSET, LOGO_Y_OFFSET, LOGO_WIDTH, LOGO_NAME_HEIGHT, True, True, False, False);

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, LOGO_X_OFFSET, LOGO_Y_OFFSET+LOGO_NAME_HEIGHT, LOGO_WIDTH, LOGO_WEBSITE_HEIGHT, False, True, False, False);
 
     // Now draw the 'NED' text in the top box.
     draw_rect_area(nedsim, LOGO_X_OFFSET, LOGO_Y_OFFSET+LOGO_NAME_HEIGHT, LOGO_WIDTH, LOGO_WEBSITE_HEIGHT, False, True, False, False);
 
     // Now draw the 'NED' text in the top box.

-    set_color(nedsim, &color_list[nedsim->color_index].text);

     set_font_size(nedsim, LOGO_NAME_HEIGHT);
     set_font_size(nedsim, LOGO_NAME_HEIGHT);

-    int text_x_size, text_y_size;
-    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->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);
+    draw_text(nedsim, "NED", LOGO_X_OFFSET, LOGO_Y_OFFSET, LOGO_WIDTH, LOGO_NAME_HEIGHT, True);

 
     // And draw the 'subgeniuskitty.com' text in the bottom box.
     set_font_size(nedsim, LOGO_WEBSITE_HEIGHT);
 
     // And draw the 'subgeniuskitty.com' text in the bottom box.
     set_font_size(nedsim, LOGO_WEBSITE_HEIGHT);

-    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->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);
+    draw_text(nedsim, "subgeniuskitty.com", LOGO_X_OFFSET, LOGO_Y_OFFSET+LOGO_NAME_HEIGHT, LOGO_WIDTH, LOGO_WEBSITE_HEIGHT, True);

 }
 
 }
 

-// TODO: Explain
+// Draw the HALT indicator area on the front panel.

 static void
 draw_halt(struct NEDsim * nedsim)
 {
 static void
 draw_halt(struct NEDsim * nedsim)
 {

-#define HALT_X_OFFSET     26
-#define HALT_Y_OFFSET     2
-#define HALT_WIDTH        6
-#define HALT_LIGHT_HEIGHT 6
-#define HALT_LABEL_HEIGHT 2
-

     // First draw the two colored boxes that comprise the halt area.
     // First draw the two colored boxes that comprise the halt area.

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, HALT_X_OFFSET, HALT_Y_OFFSET, HALT_WIDTH, HALT_LIGHT_HEIGHT, True, True, False, False);
     draw_rect_area(nedsim, HALT_X_OFFSET, HALT_Y_OFFSET, HALT_WIDTH, HALT_LIGHT_HEIGHT, True, True, False, False);

-    set_color(nedsim, &color_list[nedsim->color_index].secondary);
+    set_color(nedsim, COLOR(secondary));

     draw_rect_area(nedsim, HALT_X_OFFSET, HALT_Y_OFFSET+HALT_LIGHT_HEIGHT, HALT_WIDTH, HALT_LABEL_HEIGHT, False, True, False, False);
 
     // And finally, draw the label.
     draw_rect_area(nedsim, HALT_X_OFFSET, HALT_Y_OFFSET+HALT_LIGHT_HEIGHT, HALT_WIDTH, HALT_LABEL_HEIGHT, False, True, False, False);
 
     // And finally, draw the label.

-    set_color(nedsim, &color_list[nedsim->color_index].text);
-    int text_x_size, text_y_size;
-    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->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);
+    draw_text(nedsim, "HALT", HALT_X_OFFSET, HALT_Y_OFFSET+HALT_LIGHT_HEIGHT, HALT_WIDTH, HALT_LABEL_HEIGHT, True);

 }
 
 }
 

-// TODO: Explain
+// Draw the 32 lights corresponding to 'word' at coordinates ('x','y').
+// Note that this function ONLY draws the lights and is used each frame for
+// updating the panel. To draw the wordline area itself, use draw_wordline().

 static void
 draw_wordline_lights(struct NEDsim * nedsim, uint32_t word, int x, int y)
 {
 static void
 draw_wordline_lights(struct NEDsim * nedsim, uint32_t word, int x, int y)
 {

-#define WORDLINE_BITS_PER_STRIPE 4
-#define WORDLINE_WIDTH           32
-#define WORDLINE_HEIGHT          1
-

     for (int i = 0; i < WORDLINE_WIDTH; i++) {
         if (word & (1<<(WORDLINE_WIDTH-1-i))) {
     for (int i = 0; i < WORDLINE_WIDTH; i++) {
         if (word & (1<<(WORDLINE_WIDTH-1-i))) {

-            set_color(nedsim, &color_list[nedsim->color_index].light_on);
+            set_color(nedsim, COLOR(light_on));

         } else {
         } else {

-            set_color(nedsim, &color_list[nedsim->color_index].light_off);
+            set_color(nedsim, COLOR(light_off));

         }
         draw_circular_area(nedsim, x+i, y, WORDLINE_HEIGHT);
     }
 }
 
         }
         draw_circular_area(nedsim, x+i, y, WORDLINE_HEIGHT);
     }
 }
 

-// TODO: Explain
+// Draw a single 32-bit NED word line at coordinates ('x','y').
+// Note that this draws a wordline with value 0. To update with a specific
+// value, call draw_wordline_lights() after drawing the wordline area at least
+// once.

 static void
 draw_wordline(struct NEDsim * nedsim, int x, int y)
 {
     // First, draw a solid box in the primary color over the entire wordline area.
 static void
 draw_wordline(struct NEDsim * nedsim, int x, int y)
 {
     // First, draw a solid box in the primary color over the entire wordline area.

-    set_color(nedsim, &color_list[nedsim->color_index].primary);
+    set_color(nedsim, COLOR(primary));

     draw_rect_area(nedsim, x, y, WORDLINE_WIDTH, WORDLINE_HEIGHT, False, True, False, False);
 
     // Now, draw stripes in the secondary color.
     int i;
     for (i = 0; i < (WORDLINE_WIDTH/(2*WORDLINE_BITS_PER_STRIPE)); i++) {
     draw_rect_area(nedsim, x, y, WORDLINE_WIDTH, WORDLINE_HEIGHT, False, True, False, False);
 
     // Now, draw stripes in the secondary color.
     int i;
     for (i = 0; i < (WORDLINE_WIDTH/(2*WORDLINE_BITS_PER_STRIPE)); i++) {

-        set_color(nedsim, &color_list[nedsim->color_index].secondary);
+        set_color(nedsim, COLOR(secondary));

         draw_rect_area(nedsim, (x+(i*(WORDLINE_WIDTH/WORDLINE_BITS_PER_STRIPE))), y,
                 WORDLINE_BITS_PER_STRIPE, WORDLINE_HEIGHT, False, True, False, False);
     }
         draw_rect_area(nedsim, (x+(i*(WORDLINE_WIDTH/WORDLINE_BITS_PER_STRIPE))), y,
                 WORDLINE_BITS_PER_STRIPE, WORDLINE_HEIGHT, False, True, False, False);
     }


@@ -448,186 +504,117 @@ draw_wordline(struct NEDsim * nedsim, int x, int y)
     draw_wordline_lights(nedsim, 0, x, y);
 }
 
     draw_wordline_lights(nedsim, 0, x, y);
 }
 

-// TODO: Explain
+// Draw the Program Counter area (but don't populate it yet).

 static void
 draw_pc(struct NEDsim * nedsim)
 {
 static void
 draw_pc(struct NEDsim * nedsim)
 {

-// TODO: Note that all #defines use units of 'cells', not 'pixels', etc.
-#define PC_X_OFFSET     36
-#define PC_Y_OFFSET     7
-#define PC_WIDTH        32
-#define PC_LABEL_HEIGHT 2
-#define PC_LIGHT_HEIGHT 1
-

     // First draw the two colored boxes that comprise the PC area.
     // First draw the two colored boxes that comprise the PC area.

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, PC_X_OFFSET, PC_Y_OFFSET, PC_WIDTH, PC_LABEL_HEIGHT, True, True, False, False);
     draw_wordline(nedsim, PC_X_OFFSET, PC_Y_OFFSET+PC_LABEL_HEIGHT);
 
     // Now draw the label text "PC".
     draw_rect_area(nedsim, PC_X_OFFSET, PC_Y_OFFSET, PC_WIDTH, PC_LABEL_HEIGHT, True, True, False, False);
     draw_wordline(nedsim, PC_X_OFFSET, PC_Y_OFFSET+PC_LABEL_HEIGHT);
 
     // Now draw the label text "PC".

-    set_color(nedsim, &color_list[nedsim->color_index].text);
-    int text_x_size, text_y_size;
-    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->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);
+    draw_text(nedsim, "PC", PC_X_OFFSET, PC_Y_OFFSET, PC_WIDTH, PC_LABEL_HEIGHT, True);

 }
 
 }
 

-// TODO: Explain
+// Draw the Stack Counter area (but don't populate it yet).

 static void
 draw_sc(struct NEDsim * nedsim)
 {
 static void
 draw_sc(struct NEDsim * nedsim)
 {

-#define SC_X_OFFSET     42
-#define SC_Y_OFFSET     2
-#define SC_WIDTH        5
-#define SC_LABEL_HEIGHT 2
-#define SC_LIGHT_HEIGHT 1
-

     // First draw the two colored boxes that comprise the SC area.
     // First draw the two colored boxes that comprise the SC area.

-    set_color(nedsim, &color_list[nedsim->color_index].secondary);
+    set_color(nedsim, COLOR(secondary));

     draw_rect_area(nedsim, SC_X_OFFSET, SC_Y_OFFSET, SC_WIDTH, SC_LABEL_HEIGHT, True, True, False, False);
     draw_rect_area(nedsim, SC_X_OFFSET, SC_Y_OFFSET, SC_WIDTH, SC_LABEL_HEIGHT, True, True, False, False);

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, SC_X_OFFSET, SC_Y_OFFSET+SC_LABEL_HEIGHT, SC_WIDTH, SC_LIGHT_HEIGHT, False, True, False, False);
 
     // Now draw the label text "SC".
     draw_rect_area(nedsim, SC_X_OFFSET, SC_Y_OFFSET+SC_LABEL_HEIGHT, SC_WIDTH, SC_LIGHT_HEIGHT, False, True, False, False);
 
     // Now draw the label text "SC".

-    set_color(nedsim, &color_list[nedsim->color_index].text);
-    int text_x_size, text_y_size;
-    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->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);
+    draw_text(nedsim, "SC", SC_X_OFFSET, SC_Y_OFFSET, SC_WIDTH, SC_LABEL_HEIGHT, True);

 }
 
 }
 

-// TODO: Explain
+// Draw areas for the two PSW flags, 'Z'ero and 'N'egative.

 static void
 draw_psw(struct NEDsim * nedsim)
 {
 static void
 draw_psw(struct NEDsim * nedsim)
 {

-#define PSW_N_X_OFFSET   51
-#define PSW_Z_X_OFFSET   58
-#define PSW_Y_OFFSET     2
-#define PSW_LABEL_WIDTH  3
-#define PSW_LABEL_HEIGHT 2
-#define PSW_LIGHT_WIDTH  1
-#define PSW_LIGHT_HEIGHT 1
-

     // First draw the four colored boxes that comprise the two PSW areas.
     // First draw the four colored boxes that comprise the two PSW areas.

-    set_color(nedsim, &color_list[nedsim->color_index].secondary);
+    set_color(nedsim, COLOR(secondary));

     draw_rect_area(nedsim, PSW_N_X_OFFSET, PSW_Y_OFFSET, PSW_LABEL_WIDTH, PSW_LABEL_HEIGHT, True, True, False, False);
     draw_rect_area(nedsim, PSW_N_X_OFFSET, PSW_Y_OFFSET, PSW_LABEL_WIDTH, PSW_LABEL_HEIGHT, True, True, False, False);

-    set_color(nedsim, &color_list[nedsim->color_index].secondary);
+    set_color(nedsim, COLOR(secondary));

     draw_rect_area(nedsim, PSW_Z_X_OFFSET, PSW_Y_OFFSET, PSW_LABEL_WIDTH, PSW_LABEL_HEIGHT, True, True, False, False);
     draw_rect_area(nedsim, PSW_Z_X_OFFSET, PSW_Y_OFFSET, PSW_LABEL_WIDTH, PSW_LABEL_HEIGHT, True, True, False, False);

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, (PSW_N_X_OFFSET + 1), PSW_Y_OFFSET+PSW_LABEL_HEIGHT, PSW_LIGHT_WIDTH, PSW_LIGHT_HEIGHT, False, True, False, False);
     draw_rect_area(nedsim, (PSW_N_X_OFFSET + 1), PSW_Y_OFFSET+PSW_LABEL_HEIGHT, PSW_LIGHT_WIDTH, PSW_LIGHT_HEIGHT, False, True, False, False);

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, (PSW_Z_X_OFFSET + 1), PSW_Y_OFFSET+PSW_LABEL_HEIGHT, PSW_LIGHT_WIDTH, PSW_LIGHT_HEIGHT, False, True, False, False);
 
     draw_rect_area(nedsim, (PSW_Z_X_OFFSET + 1), PSW_Y_OFFSET+PSW_LABEL_HEIGHT, PSW_LIGHT_WIDTH, PSW_LIGHT_HEIGHT, False, True, False, False);
 

-    // Now draw the label text "N".
-    set_color(nedsim, &color_list[nedsim->color_index].text);
-    int text_x_size, text_y_size;
-    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->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".
-    set_color(nedsim, &color_list[nedsim->color_index].text);
-    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->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);
+    // Now draw the label text.
+    draw_text(nedsim, "N", PSW_N_X_OFFSET, PSW_Y_OFFSET, PSW_LABEL_WIDTH, PSW_LABEL_HEIGHT, True);
+    draw_text(nedsim, "Z", PSW_Z_X_OFFSET, PSW_Y_OFFSET, PSW_LABEL_WIDTH, PSW_LABEL_HEIGHT, True);

 }
 
 }
 

-// TODO: Explain
+// Draw the stack area (but don't populate it yet).

 static void
 draw_stack(struct NEDsim * nedsim)
 {
 static void
 draw_stack(struct NEDsim * nedsim)
 {

-#define STACK_X_OFFSET     2
-#define STACK_Y_OFFSET     12
-#define STACK_WIDTH        32
-#define STACK_LABEL_HEIGHT 2
-#define STACK_LIGHT_HEIGHT 1
-

     // First draw the two colored boxes that comprise the stack area.
     // First draw the two colored boxes that comprise the stack area.

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, STACK_X_OFFSET, STACK_Y_OFFSET, STACK_WIDTH, STACK_LABEL_HEIGHT, True, True, False, False);
     for (int i = 0; i < nedsim->num_data_rows; i++) {
         draw_wordline(nedsim, STACK_X_OFFSET, STACK_Y_OFFSET+STACK_LABEL_HEIGHT+i);
     }
 
     // Now draw the label text "Stack Size:".
     draw_rect_area(nedsim, STACK_X_OFFSET, STACK_Y_OFFSET, STACK_WIDTH, STACK_LABEL_HEIGHT, True, True, False, False);
     for (int i = 0; i < nedsim->num_data_rows; i++) {
         draw_wordline(nedsim, STACK_X_OFFSET, STACK_Y_OFFSET+STACK_LABEL_HEIGHT+i);
     }
 
     // Now draw the label text "Stack Size:".

-    set_color(nedsim, &color_list[nedsim->color_index].text);
-    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->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);
+    draw_text(nedsim, "Stack Size:", STACK_X_OFFSET+1, STACK_Y_OFFSET, STACK_WIDTH, STACK_LABEL_HEIGHT, False);

 }
 
 }
 

-// TODO: Explain
+// Draw the heap area (but don't populate it yet).

 static void
 draw_heap(struct NEDsim * nedsim)
 {
 static void
 draw_heap(struct NEDsim * nedsim)
 {

-#define HEAP_X_OFFSET     36
-#define HEAP_Y_OFFSET     12
-#define HEAP_WIDTH        32
-#define HEAP_LABEL_HEIGHT 2
-#define HEAP_LIGHT_HEIGHT 1

 // TODO: What should I do about this define? I would like to be able to specify the address so I can do things like display the code itself if nothign interesting happens in RAM.
 #define HEAP_START_ADDRESS 0x20000000
 
     // First draw the two colored boxes that comprise the heap area.
 // TODO: What should I do about this define? I would like to be able to specify the address so I can do things like display the code itself if nothign interesting happens in RAM.
 #define HEAP_START_ADDRESS 0x20000000
 
     // First draw the two colored boxes that comprise the heap area.

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, HEAP_X_OFFSET, HEAP_Y_OFFSET, HEAP_WIDTH, HEAP_LABEL_HEIGHT, True, True, False, False);
     for (int i = 0; i < nedsim->num_data_rows; i++) {
         draw_wordline(nedsim, HEAP_X_OFFSET, HEAP_Y_OFFSET+HEAP_LABEL_HEIGHT+i);
     }
 
     draw_rect_area(nedsim, HEAP_X_OFFSET, HEAP_Y_OFFSET, HEAP_WIDTH, HEAP_LABEL_HEIGHT, True, True, False, False);
     for (int i = 0; i < nedsim->num_data_rows; i++) {
         draw_wordline(nedsim, HEAP_X_OFFSET, HEAP_Y_OFFSET+HEAP_LABEL_HEIGHT+i);
     }
 

-    // Now draw the label text "RAM Base:".
-    set_color(nedsim, &color_list[nedsim->color_index].text);
-    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->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 text label "RAM Base:".
+    draw_text(nedsim, "RAM Base:", HEAP_X_OFFSET+1, HEAP_Y_OFFSET, HEAP_WIDTH, HEAP_LABEL_HEIGHT, False);

 
     // Now draw the address text.
 
     // Now draw the address text.

-    set_color(nedsim, &color_list[nedsim->color_index].text);

     char address[11];
     snprintf(address, sizeof(address), "0x%08X", HEAP_START_ADDRESS);
     char address[11];
     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->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));
+    draw_text(nedsim, address, (HEAP_X_OFFSET+(HEAP_WIDTH/2)+1), HEAP_Y_OFFSET, HEAP_WIDTH, HEAP_LABEL_HEIGHT, False);

 }
 
 }
 

-// TODO: Explain
+// After the static front panel has been drawn at least once, this function
+// updates all the dynamic parts of the panel (lights + text values) and is
+// called every frame.

 static void
 update_display(struct NEDsim * nedsim)
 {
     // Draw the halt indicator.
     if (nedsim->nedstate->halted) {
 static void
 update_display(struct NEDsim * nedsim)
 {
     // Draw the halt indicator.
     if (nedsim->nedstate->halted) {

-        set_color(nedsim, &color_list[nedsim->color_index].error_on);
+        set_color(nedsim, COLOR(error_on));

     } else {
     } else {

-        set_color(nedsim, &color_list[nedsim->color_index].error_off);
+        set_color(nedsim, COLOR(error_off));

     }
     draw_circular_area(nedsim, HALT_X_OFFSET, HALT_Y_OFFSET, HALT_WIDTH);
 
     // Draw the PSW "N" light.
     if (nedsim->nedstate->active_thread->psw->negative) {
     }
     draw_circular_area(nedsim, HALT_X_OFFSET, HALT_Y_OFFSET, HALT_WIDTH);
 
     // Draw the PSW "N" light.
     if (nedsim->nedstate->active_thread->psw->negative) {

-        set_color(nedsim, &color_list[nedsim->color_index].light_on);
+        set_color(nedsim, COLOR(light_on));

     } else {
     } else {

-        set_color(nedsim, &color_list[nedsim->color_index].light_off);
+        set_color(nedsim, COLOR(light_off));

     }
     draw_circular_area(nedsim, PSW_N_X_OFFSET+1, PSW_Y_OFFSET+PSW_LABEL_HEIGHT, PSW_LIGHT_HEIGHT);
 
     // Draw the PSW "Z" light.
     if (nedsim->nedstate->active_thread->psw->zero) {
     }
     draw_circular_area(nedsim, PSW_N_X_OFFSET+1, PSW_Y_OFFSET+PSW_LABEL_HEIGHT, PSW_LIGHT_HEIGHT);
 
     // Draw the PSW "Z" light.
     if (nedsim->nedstate->active_thread->psw->zero) {

-        set_color(nedsim, &color_list[nedsim->color_index].light_on);
+        set_color(nedsim, COLOR(light_on));

     } else {
     } else {

-        set_color(nedsim, &color_list[nedsim->color_index].light_off);
+        set_color(nedsim, COLOR(light_off));

     }
     draw_circular_area(nedsim, PSW_Z_X_OFFSET+1, PSW_Y_OFFSET+PSW_LABEL_HEIGHT, PSW_LIGHT_HEIGHT);
 
     }
     draw_circular_area(nedsim, PSW_Z_X_OFFSET+1, PSW_Y_OFFSET+PSW_LABEL_HEIGHT, PSW_LIGHT_HEIGHT);
 


@@ -636,9 +623,9 @@ update_display(struct NEDsim * nedsim)
     int i;
     for (i = 0; i < SC_WIDTH; i++) {
         if ((SC_WIDTH-1-i) == nedsim->nedstate->active_thread->sc) {
     int i;
     for (i = 0; i < SC_WIDTH; i++) {
         if ((SC_WIDTH-1-i) == nedsim->nedstate->active_thread->sc) {

-            set_color(nedsim, &color_list[nedsim->color_index].light_on);
+            set_color(nedsim, COLOR(light_on));

         } else {
         } else {

-            set_color(nedsim, &color_list[nedsim->color_index].light_off);
+            set_color(nedsim, COLOR(light_off));

         }
         draw_circular_area(nedsim, SC_X_OFFSET+i, SC_Y_OFFSET+SC_LABEL_HEIGHT, SC_LIGHT_HEIGHT);
     }
         }
         draw_circular_area(nedsim, SC_X_OFFSET+i, SC_Y_OFFSET+SC_LABEL_HEIGHT, SC_LIGHT_HEIGHT);
     }


@@ -657,16 +644,11 @@ update_display(struct NEDsim * nedsim)
     }
 
     // Draw the stack size in text.
     }
 
     // Draw the stack size in text.

-    set_color(nedsim, &color_list[nedsim->color_index].tertiary);
+    set_color(nedsim, COLOR(tertiary));

     draw_rect_area(nedsim, STACK_X_OFFSET+(STACK_WIDTH/2), STACK_Y_OFFSET, STACK_WIDTH/2, STACK_LABEL_HEIGHT, True, True, False, False);
     draw_rect_area(nedsim, STACK_X_OFFSET+(STACK_WIDTH/2), STACK_Y_OFFSET, STACK_WIDTH/2, STACK_LABEL_HEIGHT, True, True, False, False);

-    set_color(nedsim, &color_list[nedsim->color_index].text);

     char stack_size[11];
     snprintf(stack_size, sizeof(stack_size), "0x%08X", nedsim->nedstate->active_thread->sp);
     char stack_size[11];
     snprintf(stack_size, sizeof(stack_size), "0x%08X", nedsim->nedstate->active_thread->sp);

-    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->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_text(nedsim, stack_size, (STACK_X_OFFSET+(STACK_WIDTH/2)+1), STACK_Y_OFFSET, STACK_WIDTH, STACK_LABEL_HEIGHT, False);

 
     // Draw the heap lights.
     for (i = 0; i < nedsim->num_data_rows; i++) {
 
     // Draw the heap lights.
     for (i = 0; i < nedsim->num_data_rows; i++) {


@@ -779,8 +761,8 @@ NEDsim_init(Display * dpy, Window win)
     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++) {
     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);
+        if ((nedsim->cell_size * i) > available_space_for_data_rows) {
+            nedsim->num_data_rows = --i;

             break;
         }
     }
             break;
         }
     }


@@ -824,7 +806,7 @@ NEDsim_draw(Display * dpy, Window win, void * closure)
         nedsim->nedstate = run_simulator(nedsim->nedstate);
         update_display(nedsim);
     } else {
         nedsim->nedstate = run_simulator(nedsim->nedstate);
         update_display(nedsim);
     } else {

-        set_color(nedsim, &color_list[nedsim->color_index].error_on);
+        set_color(nedsim, COLOR(error_on));

         XFillRectangle(nedsim->dpy, nedsim->panel, 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);
     }