diff --git a/rootfs.manifest b/rootfs.manifest
index f3881fd..bd034fc 100644
--- a/rootfs.manifest
+++ b/rootfs.manifest
@@ -1024,9 +1024,25 @@ file /share/examples/c/tetris.c
 # Files: /share/examples/gpanel
 #
 dir /share/examples/gpanel
+dir /share/examples/gpanel/fonts
 file /share/examples/gpanel/Makefile
+file /share/examples/gpanel/circle.c
+file /share/examples/gpanel/fill.c
+file /share/examples/gpanel/font.c
+file /share/examples/gpanel/line.c
+file /share/examples/gpanel/pixel.c
+file /share/examples/gpanel/rect.c
 file /share/examples/gpanel/tft.c
 file /share/examples/gpanel/tftetris.c
+file /share/examples/gpanel/fonts/5x7.c
+file /share/examples/gpanel/fonts/6x9.c
+file /share/examples/gpanel/fonts/digits20.c
+file /share/examples/gpanel/fonts/digits32.c
+file /share/examples/gpanel/fonts/lucidasans11.c
+file /share/examples/gpanel/fonts/lucidasans15.c
+file /share/examples/gpanel/fonts/lucidasans7.c
+file /share/examples/gpanel/fonts/lucidasans9.c
+file /share/examples/gpanel/fonts/verdana7.c
 
 #
 # Files: /share/examples/smallc
diff --git a/share/examples/gpanel/Makefile b/share/examples/gpanel/Makefile
index 6e44238..38876c0 100644
--- a/share/examples/gpanel/Makefile
+++ b/share/examples/gpanel/Makefile
@@ -1,5 +1,9 @@
 CC      = cc
-PROG    = tft tftetris
+LIBS    = -lgpanel
+PROG    = tft tftetris pixel line rect fill circle font
+
+FONTS   = 5x7.o 6x9.o digits20.o digits32.o lucidasans11.o lucidasans15.o \
+          lucidasans7.o lucidasans9.o verdana7.o
 
 all:    $(PROG)
 
@@ -11,3 +15,48 @@ tft:	tft.c
 
 tftetris: tftetris.c
 	$(CC) $(CFLAGS) -o $@ $(LDFLAGS) $?
+
+pixel:  pixel.c
+	$(CC) $(CFLAGS) -o $@ $(LDFLAGS) $? $(LIBS)
+
+line:   line.c
+	$(CC) $(CFLAGS) -o $@ $(LDFLAGS) $? $(LIBS)
+
+rect:   rect.c
+	$(CC) $(CFLAGS) -o $@ $(LDFLAGS) $? $(LIBS)
+
+fill:   fill.c
+	$(CC) $(CFLAGS) -o $@ $(LDFLAGS) $? $(LIBS)
+
+circle: circle.c
+	$(CC) $(CFLAGS) -o $@ $(LDFLAGS) $? $(LIBS)
+
+font:   font.c $(FONTS)
+	$(CC) $(CFLAGS) -o $@ $(LDFLAGS) font.c $(FONTS) $(LIBS)
+
+5x7.o:  fonts/5x7.c
+	$(CC) $(CFLAGS) -o $@ -c $?
+
+6x9.o:  fonts/6x9.c
+	$(CC) $(CFLAGS) -o $@ -c $?
+
+digits20.o: fonts/digits20.c
+	$(CC) $(CFLAGS) -o $@ -c $?
+
+digits32.o: fonts/digits32.c
+	$(CC) $(CFLAGS) -o $@ -c $?
+
+lucidasans11.o: fonts/lucidasans11.c
+	$(CC) $(CFLAGS) -o $@ -c $?
+
+lucidasans15.o: fonts/lucidasans15.c
+	$(CC) $(CFLAGS) -o $@ -c $?
+
+lucidasans7.o: fonts/lucidasans7.c
+	$(CC) $(CFLAGS) -o $@ -c $?
+
+lucidasans9.o: fonts/lucidasans9.c
+	$(CC) $(CFLAGS) -o $@ -c $?
+
+verdana7.o: fonts/verdana7.c
+	$(CC) $(CFLAGS) -o $@ -c $?
diff --git a/share/examples/gpanel/circle.c b/share/examples/gpanel/circle.c
new file mode 100644
index 0000000..997e9d2
--- /dev/null
+++ b/share/examples/gpanel/circle.c
@@ -0,0 +1,33 @@
+/*
+ * Draw random circles.
+ */
+#include <stdio.h>
+#include <sys/gpanel.h>
+
+int xsize, ysize;
+
+int main()
+{
+    char *devname = "/dev/tft0";
+    int x, y, r, color;
+
+    if (gpanel_open(devname) < 0) {
+        printf("Cannot open %s\n", devname);
+        exit(-1);
+    }
+    gpanel_clear(0, &xsize, &ysize);
+    printf("Screen size %u x %u.\n", xsize, ysize);
+
+    srandom(time(0));
+    printf("Draw random circles.\n");
+    printf("Press ^C to stop.\n");
+
+    for (;;) {
+        x = random() % xsize;
+        y = random() % ysize;
+        r = random() % ysize;
+        color = random();
+        gpanel_circle(color, x, y, r);
+    }
+    return 0;
+}
diff --git a/share/examples/gpanel/fill.c b/share/examples/gpanel/fill.c
new file mode 100644
index 0000000..678f0df
--- /dev/null
+++ b/share/examples/gpanel/fill.c
@@ -0,0 +1,34 @@
+/*
+ * Draw random filled rectangles.
+ */
+#include <stdio.h>
+#include <sys/gpanel.h>
+
+int xsize, ysize;
+
+int main()
+{
+    char *devname = "/dev/tft0";
+    int x0, y0, x1, y1, color;
+
+    if (gpanel_open(devname) < 0) {
+        printf("Cannot open %s\n", devname);
+        exit(-1);
+    }
+    gpanel_clear(0, &xsize, &ysize);
+    printf("Screen size %u x %u.\n", xsize, ysize);
+
+    srandom(time(0));
+    printf("Draw random filled rectangles.\n");
+    printf("Press ^C to stop.\n");
+
+    for (;;) {
+        x0 = random() % xsize;
+        y0 = random() % ysize;
+        x1 = random() % xsize;
+        y1 = random() % ysize;
+        color = random();
+        gpanel_fill(color, x0, y0, x1, y1);
+    }
+    return 0;
+}
diff --git a/share/examples/gpanel/font.c b/share/examples/gpanel/font.c
new file mode 100644
index 0000000..b868eab
--- /dev/null
+++ b/share/examples/gpanel/font.c
@@ -0,0 +1,90 @@
+/*
+ * Draw samples of various fonts.
+ */
+#include <stdio.h>
+#include <sys/gpanel.h>
+
+/*
+ * Data from external font files.
+ */
+extern const struct gpanel_font_t font_lucidasans15;
+extern const struct gpanel_font_t font_lucidasans11;
+extern const struct gpanel_font_t font_lucidasans9;
+extern const struct gpanel_font_t font_lucidasans7;
+extern const struct gpanel_font_t font_verdana7;
+extern const struct gpanel_font_t font_6x9;
+extern const struct gpanel_font_t font_5x7;
+extern const struct gpanel_font_t font_digits32;
+extern const struct gpanel_font_t font_digits20;
+
+/*
+ * Color constants.
+ */
+#define COLOR_RGB(r,g,b)    ((r)<<11 | (g)<<5 | (b))
+#define COLOR_BLACK         0
+#define COLOR_WHITE         COLOR_RGB(31, 63, 31)
+#define COLOR_YELLOW        COLOR_RGB(31, 63, 0)
+#define COLOR_MAGENTA       COLOR_RGB(31, 0,  31)
+#define COLOR_CYAN          COLOR_RGB(0,  63, 31)
+
+/*
+ * Screen size.
+ */
+int xsize, ysize;
+
+void show(const struct gpanel_font_t *font, const char *title, int digits_only)
+{
+    char line[100];
+    int x = 10;
+    int y = 10;
+
+    gpanel_clear(COLOR_BLACK, 0, 0);
+    gpanel_text(&font_lucidasans15, COLOR_WHITE, COLOR_BLACK, x, y, title);
+    y += font_lucidasans15.height;
+
+    gpanel_text(font, COLOR_YELLOW, COLOR_BLACK, x, y,
+        digits_only ? "0123456789"
+                    : "The quick brown fox");
+    y += font->height;
+
+    gpanel_text(font, COLOR_CYAN, COLOR_BLACK, x, y,
+        digits_only ? "3456789012"
+                    : "jumps over");
+    y += font->height;
+
+    gpanel_text(font, COLOR_MAGENTA, COLOR_BLACK, x, y,
+        digits_only ? "6789012345"
+                    : "the lazy dog.");
+
+    printf("Font %s: press Enter...", title);
+    fflush(stdout);
+    fgets(line, sizeof(line), stdin);
+}
+
+int main()
+{
+    char *devname = "/dev/tft0";
+    int x, y, color;
+
+    if (gpanel_open(devname) < 0) {
+        printf("Cannot open %s\n", devname);
+        exit(-1);
+    }
+    gpanel_clear(0, &xsize, &ysize);
+    printf("Screen size %u x %u.\n", xsize, ysize);
+    printf("Draw fonts.\n");
+    printf("Press ^C to stop.\n");
+
+    for (;;) {
+        show(&font_lucidasans15, "Lucida Sans 15", 0);
+        show(&font_lucidasans11, "Lucida Sans 11", 0);
+        show(&font_lucidasans9, "Lucida Sans 9", 0);
+        show(&font_lucidasans7, "Lucida Sans 7", 0);
+        show(&font_verdana7, "Verdana 7", 0);
+        show(&font_6x9, "Fixed 6x9", 0);
+        show(&font_5x7, "Fixed 5x7", 0);
+        show(&font_digits32, "Digits 32", 1);
+        show(&font_digits20, "Digits 20", 1);
+    }
+    return 0;
+}
diff --git a/share/examples/gpanel/fonts/5x7.c b/share/examples/gpanel/fonts/5x7.c
index 9720d9f..0a72bd9 100644
--- a/share/examples/gpanel/fonts/5x7.c
+++ b/share/examples/gpanel/fonts/5x7.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:55 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:35 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: 5x7
@@ -4168,7 +4168,7 @@ static const unsigned short _5x7_offset[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_5x7 = {
+const struct gpanel_font_t font_5x7 = {
   "5x7",
   5,
   7,
diff --git a/share/examples/gpanel/fonts/6x9.c b/share/examples/gpanel/fonts/6x9.c
index 0e5e6a9..135b37e 100644
--- a/share/examples/gpanel/fonts/6x9.c
+++ b/share/examples/gpanel/fonts/6x9.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:55 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:35 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: 6x9
@@ -4808,7 +4808,7 @@ static const unsigned short _6x9_offset[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_6x9 = {
+const struct gpanel_font_t font_6x9 = {
   "6x9",
   6,
   9,
diff --git a/share/examples/gpanel/fonts/convbdf.c b/share/examples/gpanel/fonts/convbdf.c
index c14fefc..f622593 100644
--- a/share/examples/gpanel/fonts/convbdf.c
+++ b/share/examples/gpanel/fonts/convbdf.c
@@ -733,7 +733,7 @@ gen_c_source(font_t *pf, char *path)
     char obuf[256];
     char hdr1[] = {
         "/* Generated by convbdf on %s. */\n"
-        "#include \"gpanel.h\"\n"
+        "#include <sys/gpanel.h>\n"
         "\n"
         "/* Font information:\n"
         "   name: %s\n"
@@ -894,7 +894,7 @@ gen_c_source(font_t *pf, char *path)
         sprintf(buf, "_%s_width,", pf->name);
     else sprintf(buf, "0,  /* fixed width*/");
     fprintf(ofp,    "/* Exported structure definition. */\n"
-        "const gpanel_font_t font_%s = {\n"
+        "const struct gpanel_font_t font_%s = {\n"
         "  \"%s\",\n"
         "  %d,\n"
         "  %d,\n"
diff --git a/share/examples/gpanel/fonts/digits20.c b/share/examples/gpanel/fonts/digits20.c
index 457662e..92ddf07 100644
--- a/share/examples/gpanel/fonts/digits20.c
+++ b/share/examples/gpanel/fonts/digits20.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:54 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:34 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: digits20
@@ -670,7 +670,7 @@ static const unsigned char _digits20_width[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_digits20 = {
+const struct gpanel_font_t font_digits20 = {
   "digits20",
   18,
   22,
diff --git a/share/examples/gpanel/fonts/digits32.c b/share/examples/gpanel/fonts/digits32.c
index 93422f8..95edf3e 100644
--- a/share/examples/gpanel/fonts/digits32.c
+++ b/share/examples/gpanel/fonts/digits32.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:54 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:34 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: digits32
@@ -1102,7 +1102,7 @@ static const unsigned char _digits32_width[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_digits32 = {
+const struct gpanel_font_t font_digits32 = {
   "digits32",
   28,
   40,
diff --git a/share/examples/gpanel/fonts/lucidasans11.c b/share/examples/gpanel/fonts/lucidasans11.c
index 6fb8ae0..4cb5c62 100644
--- a/share/examples/gpanel/fonts/lucidasans11.c
+++ b/share/examples/gpanel/fonts/lucidasans11.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:55 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:34 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: lucidasans11
@@ -4038,7 +4038,7 @@ static const unsigned char _lucidasans11_width[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_lucidasans11 = {
+const struct gpanel_font_t font_lucidasans11 = {
   "lucidasans11",
   14,
   17,
diff --git a/share/examples/gpanel/fonts/lucidasans15.c b/share/examples/gpanel/fonts/lucidasans15.c
index 012b5ea..b669203 100644
--- a/share/examples/gpanel/fonts/lucidasans15.c
+++ b/share/examples/gpanel/fonts/lucidasans15.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:55 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:34 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: lucidasans15
@@ -4998,7 +4998,7 @@ static const unsigned char _lucidasans15_width[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_lucidasans15 = {
+const struct gpanel_font_t font_lucidasans15 = {
   "lucidasans15",
   20,
   22,
diff --git a/share/examples/gpanel/fonts/lucidasans7.c b/share/examples/gpanel/fonts/lucidasans7.c
index 3ff6494..2bd27b3 100644
--- a/share/examples/gpanel/fonts/lucidasans7.c
+++ b/share/examples/gpanel/fonts/lucidasans7.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:55 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:35 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: lucidasans7
@@ -2502,7 +2502,7 @@ static const unsigned char _lucidasans7_width[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_lucidasans7 = {
+const struct gpanel_font_t font_lucidasans7 = {
   "lucidasans7",
   9,
   9,
diff --git a/share/examples/gpanel/fonts/lucidasans9.c b/share/examples/gpanel/fonts/lucidasans9.c
index 40b223f..6ea1c2f 100644
--- a/share/examples/gpanel/fonts/lucidasans9.c
+++ b/share/examples/gpanel/fonts/lucidasans9.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:55 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:35 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: lucidasans9
@@ -3462,7 +3462,7 @@ static const unsigned char _lucidasans9_width[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_lucidasans9 = {
+const struct gpanel_font_t font_lucidasans9 = {
   "lucidasans9",
   12,
   14,
diff --git a/share/examples/gpanel/fonts/verdana7.c b/share/examples/gpanel/fonts/verdana7.c
index b37e3b0..2a3b7f5 100644
--- a/share/examples/gpanel/fonts/verdana7.c
+++ b/share/examples/gpanel/fonts/verdana7.c
@@ -1,5 +1,5 @@
-/* Generated by convbdf on Mon Oct  5 14:07:55 2015. */
-#include "gpanel.h"
+/* Generated by convbdf on Thu Oct  8 21:26:35 2015. */
+#include <sys/gpanel.h>
 
 /* Font information:
    name: verdana7
@@ -2694,7 +2694,7 @@ static const unsigned char _verdana7_width[] = {
 };
 
 /* Exported structure definition. */
-const gpanel_font_t font_verdana7 = {
+const struct gpanel_font_t font_verdana7 = {
   "verdana7",
   11,
   10,
diff --git a/share/examples/gpanel/line.c b/share/examples/gpanel/line.c
new file mode 100644
index 0000000..1a87a51
--- /dev/null
+++ b/share/examples/gpanel/line.c
@@ -0,0 +1,34 @@
+/*
+ * Draw random lines.
+ */
+#include <stdio.h>
+#include <sys/gpanel.h>
+
+int xsize, ysize;
+
+int main()
+{
+    char *devname = "/dev/tft0";
+    int x0, y0, x1, y1, color;
+
+    if (gpanel_open(devname) < 0) {
+        printf("Cannot open %s\n", devname);
+        exit(-1);
+    }
+    gpanel_clear(0, &xsize, &ysize);
+    printf("Screen size %u x %u.\n", xsize, ysize);
+
+    srandom(time(0));
+    printf("Draw random lines.\n");
+    printf("Press ^C to stop.\n");
+
+    for (;;) {
+        x0 = random() % xsize;
+        y0 = random() % ysize;
+        x1 = random() % xsize;
+        y1 = random() % ysize;
+        color = random();
+        gpanel_line(color, x0, y0, x1, y1);
+    }
+    return 0;
+}
diff --git a/share/examples/gpanel/pixel.c b/share/examples/gpanel/pixel.c
new file mode 100644
index 0000000..33c5e0f
--- /dev/null
+++ b/share/examples/gpanel/pixel.c
@@ -0,0 +1,32 @@
+/*
+ * Draw random pixels.
+ */
+#include <stdio.h>
+#include <sys/gpanel.h>
+
+int xsize, ysize;
+
+int main()
+{
+    char *devname = "/dev/tft0";
+    int x, y, color;
+
+    if (gpanel_open(devname) < 0) {
+        printf("Cannot open %s\n", devname);
+        exit(-1);
+    }
+    gpanel_clear(0, &xsize, &ysize);
+    printf("Screen size %u x %u.\n", xsize, ysize);
+
+    srandom(time(0));
+    printf("Draw random pixels.\n");
+    printf("Press ^C to stop.\n");
+
+    for (;;) {
+        x = random() % xsize;
+        y = random() % ysize;
+        color = random();
+        gpanel_pixel(color, x, y);
+    }
+    return 0;
+}
diff --git a/share/examples/gpanel/rect.c b/share/examples/gpanel/rect.c
new file mode 100644
index 0000000..433e54d
--- /dev/null
+++ b/share/examples/gpanel/rect.c
@@ -0,0 +1,34 @@
+/*
+ * Draw random rectangles.
+ */
+#include <stdio.h>
+#include <sys/gpanel.h>
+
+int xsize, ysize;
+
+int main()
+{
+    char *devname = "/dev/tft0";
+    int x0, y0, x1, y1, color;
+
+    if (gpanel_open(devname) < 0) {
+        printf("Cannot open %s\n", devname);
+        exit(-1);
+    }
+    gpanel_clear(0, &xsize, &ysize);
+    printf("Screen size %u x %u.\n", xsize, ysize);
+
+    srandom(time(0));
+    printf("Draw random rectangles.\n");
+    printf("Press ^C to stop.\n");
+
+    for (;;) {
+        x0 = random() % xsize;
+        y0 = random() % ysize;
+        x1 = random() % xsize;
+        y1 = random() % ysize;
+        color = random();
+        gpanel_rect(color, x0, y0, x1, y1);
+    }
+    return 0;
+}
diff --git a/src/libc/compat/rand.c b/src/libc/compat/rand.c
index 383fce3..5b51eac 100644
--- a/src/libc/compat/rand.c
+++ b/src/libc/compat/rand.c
@@ -15,9 +15,6 @@ srand(x)
 int
 rand()
 {
-#ifdef pdp11
-	return(((randx = randx * 1103515245 + 12345)>>16) & 0x7fff);
-#else
-	return((randx = randx * 1103515245 + 12345) & 0x7fffffff);
-#endif
+        randx = randx * 1103515245 + 12345;
+	return (randx >> 16) & 0x7fff;
 }
diff --git a/sys/pic32/hx8357.c b/sys/pic32/hx8357.c
index fcf7ed6..2bf6f3e 100644
--- a/sys/pic32/hx8357.c
+++ b/sys/pic32/hx8357.c
@@ -254,6 +254,15 @@ static void fillRectangle(int x0, int y0, int x1, int y1, int color)
 {
     int x, y;
 
+    if (x0 < 0) x0 = 0;
+    if (y0 < 0) x0 = 0;
+    if (x1 < 0) x1 = 0;
+    if (y1 < 0) x1 = 0;
+    if (x0 >= _width) x0 = _width-1;
+    if (x1 >= _width) x1 = _width-1;
+    if (y0 >= _height) y0 = _height-1;
+    if (y1 >= _height) y1 = _height-1;
+
     if (x1 < x0) {
         int t = x0;
         x0 = x1;
@@ -264,12 +273,12 @@ static void fillRectangle(int x0, int y0, int x1, int y1, int color)
         y0 = y1;
         y1 = t;
     }
-    setAddrWindow(x0, y0, x1-1, y1-1);
+    setAddrWindow(x0, y0, x1, y1);
 
     while (PMMODE & PIC32_PMMODE_BUSY);
     PMADDR = 0x0001;
-    for (y=y0; y<y1; y++) {
-        for (x=x0; x<x1; x++) {
+    for (y=y0; y<=y1; y++) {
+        for (x=x0; x<=x1; x++) {
             while (PMMODE & PIC32_PMMODE_BUSY);
             PMDIN = color;
         }