diff --git a/libee/ee.c b/libee/ee.c
index 7b69f20..a9185a4 100644
--- a/libee/ee.c
+++ b/libee/ee.c
@@ -46,7 +46,7 @@
 #include "ee_internals.h"
 
 /* Global array with color names */
-char *ee_color_names[16] =
+const char *ee_color_names[16] =
 {
     "black",
     "blue",
@@ -66,8 +66,10 @@ char *ee_color_names[16] =
     "white",
 };
 
-static int _ee_delay;
+static unsigned int _ee_delay;
+static unsigned int _ee_rendertime;
 char *_ee_empty_line;
+char *_ee_scratch_line;
 
 #if defined(USE_NCURSES)
 int _ee_attr[16];
@@ -185,12 +187,15 @@ int ee_init(void)
     memset(_ee_empty_line, ' ', ee_get_width());
     _ee_empty_line[ee_get_width()] = '\0';
 
+    _ee_scratch_line = malloc(ee_get_width() + 1);
+
     _ee_delay = 0;
+    _ee_rendertime = 0;
 
     return 0;
 }
 
-int ee_get_width(void)
+unsigned int ee_get_width(void)
 {
 #if defined(USE_SLANG)
     return SLtt_Screen_Cols;
@@ -201,7 +206,7 @@ int ee_get_width(void)
 #endif
 }
 
-int ee_get_height(void)
+unsigned int ee_get_height(void)
 {
 #if defined(USE_SLANG)
     return SLtt_Screen_Rows;
@@ -212,11 +217,16 @@ int ee_get_height(void)
 #endif
 }
 
-void ee_set_delay(int usec)
+void ee_set_delay(unsigned int usec)
 {
     _ee_delay = usec;
 }
 
+unsigned int ee_get_rendertime(void)
+{
+    return _ee_rendertime;
+}
+
 static unsigned int _ee_getticks(void)
 {
     static unsigned int last_sec = 0, last_usec = 0;
@@ -239,7 +249,7 @@ static unsigned int _ee_getticks(void)
 
 void ee_refresh(void)
 {
-    static int lastticks = 0;
+    static unsigned int lastticks = 0;
     unsigned int ticks = lastticks + _ee_getticks();
 
 #if defined(USE_SLANG)
@@ -258,6 +268,9 @@ void ee_refresh(void)
     for(ticks += _ee_getticks(); ticks < _ee_delay; ticks += _ee_getticks())
         usleep(10000);
 
+    /* Update the sliding mean of the render time */
+    _ee_rendertime = (7 * _ee_rendertime + ticks) / 8;
+
     lastticks = ticks - _ee_delay;
 
     /* If we drifted too much, it's bad, bad, bad. */
diff --git a/libee/ee.h b/libee/ee.h
index 4da5944..5481568 100644
--- a/libee/ee.h
+++ b/libee/ee.h
@@ -51,7 +51,7 @@ enum ee_colors
     EE_WHITE = 15
 };
 
-extern char *ee_color_names[16];
+extern const char *ee_color_names[16];
 
 /*
  * Types
@@ -62,9 +62,10 @@ struct ee_sprite;
  * Prototypes
  */
 int ee_init(void);
-void ee_set_delay(int);
-int ee_get_width(void);
-int ee_get_height(void);
+void ee_set_delay(unsigned int);
+unsigned int ee_get_rendertime(void);
+unsigned int ee_get_width(void);
+unsigned int ee_get_height(void);
 void ee_refresh(void);
 void ee_end(void);
 
@@ -73,13 +74,13 @@ char ee_get_key(void);
 void ee_set_color(int);
 int ee_get_color(void);
 void ee_putchar(int, int, char);
-void ee_putstr(int, int, char *);
+void ee_putstr(int, int, const char *);
 void ee_clear(void);
 
 void ee_draw_line(int, int, int, int, char);
-void ee_draw_polyline(int[], int[], int, char);
+void ee_draw_polyline(const int[], const int[], int, char);
 void ee_draw_thin_line(int, int, int, int);
-void ee_draw_thin_polyline(int[], int[], int);
+void ee_draw_thin_polyline(const int[], const int[], int);
 
 void ee_draw_circle(int, int, int, char);
 void ee_draw_ellipse(int, int, int, int, char);
diff --git a/libee/ee_internals.h b/libee/ee_internals.h
index 7bb8b7e..6148fa2 100644
--- a/libee/ee_internals.h
+++ b/libee/ee_internals.h
@@ -32,5 +32,6 @@ extern char *_ee_screen;
 #endif
 
 extern char *_ee_empty_line;
+extern char *_ee_scratch_line;
 
 #endif /* __EE_INTERNALS_H__ */
diff --git a/libee/graphics.c b/libee/graphics.c
index b930bc5..ef0399e 100644
--- a/libee/graphics.c
+++ b/libee/graphics.c
@@ -79,11 +79,11 @@ void ee_putchar(int x, int y, char c)
 #endif
 }
 
-void ee_putstr(int x, int y, char *s)
+void ee_putstr(int x, int y, const char *s)
 {
     int len;
 
-    if(y < 0 || y >= ee_get_height())
+    if(y < 0 || y >= ee_get_height() || x >= ee_get_width())
         return;
 
     len = strlen(s);
@@ -97,6 +97,13 @@ void ee_putstr(int x, int y, char *s)
         x = 0;
     }
 
+    if(x + len >= ee_get_width())
+    {
+        memcpy(_ee_scratch_line, s, ee_get_width() - x);
+        _ee_scratch_line[ee_get_width() - x] = '\0';
+        s = _ee_scratch_line;
+    }
+
 #if defined(USE_SLANG)
     SLsmg_gotorc(y, x);
     SLsmg_write_string(s);
diff --git a/libee/line.c b/libee/line.c
index 4f4ee60..598bfb7 100644
--- a/libee/line.c
+++ b/libee/line.c
@@ -68,7 +68,7 @@ void ee_draw_line(int x1, int y1, int x2, int y2, char c)
     clip_line(&s);
 }
 
-void ee_draw_polyline(int x[], int y[], int n, char c)
+void ee_draw_polyline(const int x[], const int y[], int n, char c)
 {
     int i;
     struct line s;
@@ -105,7 +105,7 @@ void ee_draw_thin_line(int x1, int y1, int x2, int y2)
     clip_line(&s);
 }
 
-void ee_draw_thin_polyline(int x[], int y[], int n)
+void ee_draw_thin_polyline(const int x[], const int y[], int n)
 {
     int i;
     struct line s;