From 4ea785f81826f8103182e9b461e02ac7128c68f8 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Sat, 19 Apr 2008 19:25:52 +0000
Subject: [PATCH]   * Remove all unsigned ints from exported functions. Signed
 arithmetic is     far better for error checking.

---
 caca/caca.h             | 40 ++++++++++++------------
 caca/caca_internals.h   | 26 ++++++++--------
 caca/driver_cocoa.m     | 32 ++++++++++----------
 caca/driver_conio.c     | 10 +++---
 caca/driver_gl.c        | 20 ++++++------
 caca/driver_ncurses.c   | 14 ++++-----
 caca/driver_raw.c       | 10 +++---
 caca/driver_slang.c     | 15 +++++----
 caca/driver_vga.c       |  8 ++---
 caca/driver_win32.c     | 17 +++++------
 caca/driver_x11.c       | 30 +++++++++---------
 caca/event.c            | 24 +++++++--------
 caca/graphics.c         | 19 ++++++++----
 caca/time.c             |  8 ++---
 cucul/canvas.c          | 25 +++++++++------
 cucul/cucul.c           | 37 ++++++++++++++++-------
 cucul/cucul.h           | 45 ++++++++++++---------------
 cucul/cucul_internals.h | 12 ++++----
 cucul/dither.c          | 67 ++++++++++++++++++++---------------------
 cucul/export.c          | 24 +++++++--------
 cucul/figfont.c         | 22 +++++++-------
 cucul/font.c            | 37 +++++++++++++----------
 cucul/frame.c           | 25 ++++++++-------
 cucul/transform.c       | 16 +++++-----
 examples/text.c         |  4 +--
 25 files changed, 304 insertions(+), 283 deletions(-)

diff --git a/caca/caca.h b/caca/caca.h
index b147fd1..80b9851 100644
--- a/caca/caca.h
+++ b/caca/caca.h
@@ -27,7 +27,8 @@
 #include <cucul.h>
 
 #undef __extern
-#if defined(_WIN32) && defined(__LIBCACA__)
+#if defined(_DOXYGEN_SKIP_ME)
+#elif defined(_WIN32) && defined(__LIBCACA__)
 #   define __extern extern __declspec(dllexport)
 #else
 #   define __extern extern
@@ -79,9 +80,9 @@ struct caca_event
     enum caca_event_type type;
     union
     {
-        struct { unsigned int x, y, button; } mouse;
-        struct { unsigned int w, h; } resize;
-        struct { unsigned int ch; uint32_t utf32; char utf8[8]; } key;
+        struct { int x, y, button; } mouse;
+        struct { int w, h; } resize;
+        struct { int ch; uint32_t utf32; char utf8[8]; } key;
     } data;
     uint8_t padding[16];
 };
@@ -170,10 +171,10 @@ __extern int caca_set_display_driver(caca_display_t *, char const *);
 __extern int caca_free_display(caca_display_t *);
 __extern cucul_canvas_t * caca_get_canvas(caca_display_t *);
 __extern int caca_refresh_display(caca_display_t *);
-__extern int caca_set_display_time(caca_display_t *, unsigned int);
-__extern unsigned int caca_get_display_time(caca_display_t const *);
-__extern unsigned int caca_get_display_width(caca_display_t const *);
-__extern unsigned int caca_get_display_height(caca_display_t const *);
+__extern int caca_set_display_time(caca_display_t *, int);
+__extern int caca_get_display_time(caca_display_t const *);
+__extern int caca_get_display_width(caca_display_t const *);
+__extern int caca_get_display_height(caca_display_t const *);
 __extern int caca_set_display_title(caca_display_t *, char const *);
 __extern int caca_set_mouse(caca_display_t *, int);
 __extern int caca_set_cursor(caca_display_t *, int);
@@ -186,27 +187,24 @@ __extern char const * caca_get_version(void);
  *  clicks.
  *
  *  @{ */
-__extern int caca_get_event(caca_display_t *, unsigned int,
-                            caca_event_t *, int);
-__extern unsigned int caca_get_mouse_x(caca_display_t const *);
-__extern unsigned int caca_get_mouse_y(caca_display_t const *);
+__extern int caca_get_event(caca_display_t *, int, caca_event_t *, int);
+__extern int caca_get_mouse_x(caca_display_t const *);
+__extern int caca_get_mouse_y(caca_display_t const *);
 __extern enum caca_event_type caca_get_event_type(caca_event_t const *);
-__extern unsigned int caca_get_event_key_ch(caca_event_t const *);
+__extern int caca_get_event_key_ch(caca_event_t const *);
 __extern uint32_t caca_get_event_key_utf32(caca_event_t const *);
 __extern int caca_get_event_key_utf8(caca_event_t const *, char *);
-__extern unsigned int caca_get_event_mouse_button(caca_event_t const *);
-__extern unsigned int caca_get_event_mouse_x(caca_event_t const *);
-__extern unsigned int caca_get_event_mouse_y(caca_event_t const *);
-__extern unsigned int caca_get_event_resize_width(caca_event_t const *);
-__extern unsigned int caca_get_event_resize_height(caca_event_t const *);
+__extern int caca_get_event_mouse_button(caca_event_t const *);
+__extern int caca_get_event_mouse_x(caca_event_t const *);
+__extern int caca_get_event_mouse_y(caca_event_t const *);
+__extern int caca_get_event_resize_width(caca_event_t const *);
+__extern int caca_get_event_resize_height(caca_event_t const *);
 /*  @} */
 
 #ifdef __cplusplus
 }
 #endif
 
-#if !defined(_DOXYGEN_SKIP_ME)
-#   undef __extern
-#endif
+#undef __extern
 
 #endif /* __CACA_H__ */
diff --git a/caca/caca_internals.h b/caca/caca_internals.h
index 4248018..751d6c1 100644
--- a/caca/caca_internals.h
+++ b/caca/caca_internals.h
@@ -95,9 +95,9 @@ struct caca_privevent
 
     union
     {
-        struct { unsigned int x, y, button; } mouse;
-        struct { unsigned int w, h; } resize;
-        struct { unsigned int ch; unsigned long int utf32; char utf8[8]; } key;
+        struct { int x, y, button; } mouse;
+        struct { int w, h; } resize;
+        struct { int ch; uint32_t utf32; char utf8[8]; } key;
     } data;
 };
 
@@ -122,8 +122,8 @@ struct caca_display
         int (* init_graphics) (caca_display_t *);
         int (* end_graphics) (caca_display_t *);
         int (* set_display_title) (caca_display_t *, char const *);
-        unsigned int (* get_display_width) (caca_display_t const *);
-        unsigned int (* get_display_height) (caca_display_t const *);
+        int (* get_display_width) (caca_display_t const *);
+        int (* get_display_height) (caca_display_t const *);
         void (* display) (caca_display_t *);
         void (* handle_resize) (caca_display_t *);
         int (* get_event) (caca_display_t *, caca_privevent_t *);
@@ -134,7 +134,7 @@ struct caca_display
     /* Mouse position */
     struct mouse
     {
-        unsigned int x, y;
+        int x, y;
     } mouse;
 
     /* Window resize handling */
@@ -142,11 +142,11 @@ struct caca_display
     {
         int resized;   /* A resize event was requested */
         int allow;     /* The display driver allows resizing */
-        unsigned w, h; /* Requested width and height */
+        int w, h; /* Requested width and height */
     } resize;
 
     /* Framerate handling */
-    unsigned int delay, rendertime;
+    int delay, rendertime;
     caca_timer_t timer;
     int lastticks;
 
@@ -158,19 +158,19 @@ struct caca_display
 #endif
 #if defined(USE_SLANG) || defined(USE_NCURSES)
         caca_timer_t key_timer;
-        unsigned int last_key_ticks;
-        unsigned int autorepeat_ticks;
+        int last_key_ticks;
+        int autorepeat_ticks;
         caca_privevent_t last_key_event;
 #endif
 #if defined(USE_WIN32)
-        unsigned char not_empty_struct;
+        uint8_t not_empty_struct;
 #endif
     } events;
 };
 
 /* Internal timer functions */
-extern void _caca_sleep(unsigned int);
-extern unsigned int _caca_getticks(caca_timer_t *);
+extern void _caca_sleep(int);
+extern int _caca_getticks(caca_timer_t *);
 
 /* Internal event functions */
 extern void _caca_handle_resize(caca_display_t *);
diff --git a/caca/driver_cocoa.m b/caca/driver_cocoa.m
index c651374..e899872 100644
--- a/caca/driver_cocoa.m
+++ b/caca/driver_cocoa.m
@@ -62,7 +62,7 @@ static BOOL s_quitting = NO;
 {
     //NSFont* _font;
     NSRect _font_rect;
-    unsigned int _h, _w;
+    int _h, _w;
     uint32_t* _attrs;
     uint32_t* _chars;
     NSRect*   _bkg_rects;
@@ -99,7 +99,7 @@ static BOOL s_quitting = NO;
     [[self window] makeFirstResponder:self];
 
 #ifdef PRECACHE_WHOLE_COLOR_TABLE
-    unsigned int i;
+    int i;
     for(i = 0; i < NCOLORS; i++)
         _colorCache[i] = [[NSColor colorFromRgb12:i] retain];
 #else
@@ -125,7 +125,7 @@ static BOOL s_quitting = NO;
 {
     //[_font release];
 #ifdef PRECACHE_WHOLE_COLOR_TABLE
-    unsigned short i;
+    short i;
     for(i = 0; i < NCOLORS; i++)
         [_colorCache[i] release];
 #else
@@ -248,7 +248,7 @@ static BOOL s_quitting = NO;
         return;
     }
 
-    unsigned int x, y;
+    int x, y;
     float fw = _font_rect.size.width;
     float fh = _font_rect.size.height;
     uint32_t* attrs;
@@ -258,10 +258,10 @@ static BOOL s_quitting = NO;
     [[NSColor blackColor] set];
     NSRectFill(rect);
 
-    unsigned int arrayLength = 0;
+    int arrayLength = 0;
     for(y = 0; y < _h; y++)
     {
-        unsigned int yoff = y * fh;
+        int yoff = y * fh;
         for(x = 0; x < _w; x++)
         {
             NSRect r = NSMakeRect(x * fw, yoff, fw, fh);
@@ -307,7 +307,7 @@ static BOOL s_quitting = NO;
     /* Then print the foreground characters */
     for(y = 0; y < _h; y++)
     {
-        unsigned int yoff = y * fh;
+        int yoff = y * fh;
         for(x = 0; x < _w; x++, chars++)
         {
             attrs = _attrs + x + y * _w;
@@ -597,9 +597,9 @@ static void create_first_window(caca_display_t *dp)
     dp->drv.p->view = view;
 }
 
-static unsigned int get_caca_keycode(NSEvent* event)
+static int get_caca_keycode(NSEvent* event)
 {
-    unsigned int caca_keycode = 0;
+    int caca_keycode = 0;
     /*
     unsigned short mac_keycode = [event keyCode];
     debug_log(@"keycode %u (%x)", mac_keycode, mac_keycode);
@@ -747,7 +747,7 @@ static BOOL handle_key_event(caca_privevent_t *ev, NSEvent* event)
             ;
     }
 
-    unsigned int caca_keycode = get_caca_keycode(event);
+    int caca_keycode = get_caca_keycode(event);
     if(caca_keycode)
     {
         ev->data.key.ch = caca_keycode;
@@ -800,8 +800,8 @@ static BOOL handle_mouse_event(caca_display_t *dp, caca_privevent_t *ev,
         case NSMouseMoved:
         {
             NSPoint mouseLoc = [NSEvent mouseLocation];
-            unsigned int mouse_x = round(mouseLoc.x);
-            unsigned int mouse_y = round(mouseLoc.y);
+            int mouse_x = round(mouseLoc.x);
+            int mouse_y = round(mouseLoc.y);
             if(dp->mouse.x == mouse_x && dp->mouse.y == mouse_y)
                 break;
 
@@ -826,8 +826,8 @@ static BOOL handle_mouse_event(caca_display_t *dp, caca_privevent_t *ev,
 
 static int cocoa_init_graphics(caca_display_t *dp)
 {
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
 
     debug_log(@"%s dp->cv: %ux%u", __PRETTY_FUNCTION__, width, height);
 
@@ -970,12 +970,12 @@ static int cocoa_set_display_title(caca_display_t *dp, char const *title)
     return 0;
 }
 
-static unsigned int cocoa_get_display_width(caca_display_t const *dp)
+static int cocoa_get_display_width(caca_display_t const *dp)
 {
     return [dp->drv.p->window frame].size.width;
 }
 
-static unsigned int cocoa_get_display_height(caca_display_t const *dp)
+static int cocoa_get_display_height(caca_display_t const *dp)
 {
     return [dp->drv.p->window frame].size.height;
 }
diff --git a/caca/driver_conio.c b/caca/driver_conio.c
index 4462e2b..2d42a61 100644
--- a/caca/driver_conio.c
+++ b/caca/driver_conio.c
@@ -84,13 +84,13 @@ static int conio_set_display_title(caca_display_t *dp, char const *title)
     return -1;
 }
 
-static unsigned int conio_get_display_width(caca_display_t const *dp)
+static int conio_get_display_width(caca_display_t const *dp)
 {
     /* Fallback to a 6x10 font */
     return cucul_get_canvas_width(dp->cv) * 6;
 }
 
-static unsigned int conio_get_display_height(caca_display_t const *dp)
+static int conio_get_display_height(caca_display_t const *dp)
 {
     /* Fallback to a 6x10 font */
     return cucul_get_canvas_height(dp->cv) * 10;
@@ -101,9 +101,9 @@ static void conio_display(caca_display_t *dp)
     char *screen = dp->drv.p->screen;
     uint32_t const *chars = (uint32_t const *)cucul_get_canvas_chars(dp->cv);
     uint32_t const *attrs = (uint32_t const *)cucul_get_canvas_attrs(dp->cv);
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
-    unsigned int n;
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
+    int n;
 
     for(n = height * width; n--; )
     {
diff --git a/caca/driver_gl.c b/caca/driver_gl.c
index 050a274..2e10d51 100644
--- a/caca/driver_gl.c
+++ b/caca/driver_gl.c
@@ -63,8 +63,8 @@ static void gl_compute_font(caca_display_t *);
 struct driver_private
 {
     int window;
-    unsigned int width, height;
-    unsigned int new_width, new_height;
+    int width, height;
+    int new_width, new_height;
     cucul_font_t *f;
     float font_width, font_height;
     float incx, incy;
@@ -73,8 +73,8 @@ struct driver_private
     uint8_t close;
     uint8_t bit;
     uint8_t mouse_changed, mouse_clicked;
-    unsigned int mouse_x, mouse_y;
-    unsigned int mouse_button, mouse_state;
+    int mouse_x, mouse_y;
+    int mouse_button, mouse_state;
 
     uint8_t key;
     int special_key;
@@ -87,8 +87,8 @@ static int gl_init_graphics(caca_display_t *dp)
     char const *geometry;
     char *argv[2] = { "", NULL };
     char const * const * fonts;
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
     int argc = 1;
 
     dp->drv.p = malloc(sizeof(struct driver_private));
@@ -204,12 +204,12 @@ static int gl_set_display_title(caca_display_t *dp, char const *title)
     return 0;
 }
 
-static unsigned int gl_get_display_width(caca_display_t const *dp)
+static int gl_get_display_width(caca_display_t const *dp)
 {
     return dp->drv.p->width;
 }
 
-static unsigned int gl_get_display_height(caca_display_t const *dp)
+static int gl_get_display_height(caca_display_t const *dp)
 {
     return dp->drv.p->height;
 }
@@ -218,8 +218,8 @@ static void gl_display(caca_display_t *dp)
 {
     uint32_t const *cvchars = (uint32_t const *)cucul_get_canvas_chars(dp->cv);
     uint32_t const *cvattrs = (uint32_t const *)cucul_get_canvas_attrs(dp->cv);
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int x, y, line;
+    int width = cucul_get_canvas_width(dp->cv);
+    int x, y, line;
 
     glClear(GL_COLOR_BUFFER_BIT);
     glDisable(GL_TEXTURE_2D);
diff --git a/caca/driver_ncurses.c b/caca/driver_ncurses.c
index 85931c1..1f8cbfc 100644
--- a/caca/driver_ncurses.c
+++ b/caca/driver_ncurses.c
@@ -332,13 +332,13 @@ static int ncurses_set_display_title(caca_display_t *dp, char const *title)
     return 0;
 }
 
-static unsigned int ncurses_get_display_width(caca_display_t const *dp)
+static int ncurses_get_display_width(caca_display_t const *dp)
 {
     /* Fallback to a 6x10 font */
     return cucul_get_canvas_width(dp->cv) * 6;
 }
 
-static unsigned int ncurses_get_display_height(caca_display_t const *dp)
+static int ncurses_get_display_height(caca_display_t const *dp)
 {
     /* Fallback to a 6x10 font */
     return cucul_get_canvas_height(dp->cv) * 10;
@@ -348,8 +348,8 @@ static void ncurses_display(caca_display_t *dp)
 {
     uint32_t const *cvchars = (uint32_t const *)cucul_get_canvas_chars(dp->cv);
     uint32_t const *cvattrs = (uint32_t const *)cucul_get_canvas_attrs(dp->cv);
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
     int x, y;
 
     for(y = 0; y < (int)height; y++)
@@ -420,8 +420,7 @@ static int ncurses_get_event(caca_display_t *dp, caca_privevent_t *ev)
         int keys[7]; /* Necessary for ungetch(); */
         char utf8[7];
         uint32_t utf32;
-        unsigned int i;
-        size_t bytes = 0;
+        size_t i, bytes = 0;
 
         keys[0] = intkey;
         utf8[0] = intkey;
@@ -495,8 +494,7 @@ static int ncurses_get_event(caca_display_t *dp, caca_privevent_t *ev)
 #undef CLICK
         }
 
-        if(dp->mouse.x == (unsigned int)mevent.x &&
-           dp->mouse.y == (unsigned int)mevent.y)
+        if(dp->mouse.x == mevent.x && dp->mouse.y == mevent.y)
             return _pop_event(dp, ev);
 
         dp->mouse.x = mevent.x;
diff --git a/caca/driver_raw.c b/caca/driver_raw.c
index 7938464..144a2f8 100644
--- a/caca/driver_raw.c
+++ b/caca/driver_raw.c
@@ -29,8 +29,8 @@
 
 static int raw_init_graphics(caca_display_t *dp)
 {
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
     char const *geometry;
 
 #if defined(HAVE_GETENV)
@@ -56,12 +56,12 @@ static int raw_set_display_title(caca_display_t *dp, char const *title)
     return -1;
 }
 
-static unsigned int raw_get_display_width(caca_display_t const *dp)
+static int raw_get_display_width(caca_display_t const *dp)
 {
     return 0;
 }
 
-static unsigned int raw_get_display_height(caca_display_t const *dp)
+static int raw_get_display_height(caca_display_t const *dp)
 {
     return 0;
 }
@@ -69,7 +69,7 @@ static unsigned int raw_get_display_height(caca_display_t const *dp)
 static void raw_display(caca_display_t *dp)
 {
     void *buffer;
-    unsigned long int len;
+    size_t len;
 
     buffer = cucul_export_memory(dp->cv, "caca", &len);
     if(!buffer)
diff --git a/caca/driver_slang.c b/caca/driver_slang.c
index 8e0fc2d..3195fdd 100644
--- a/caca/driver_slang.c
+++ b/caca/driver_slang.c
@@ -207,13 +207,13 @@ static int slang_set_display_title(caca_display_t *dp, char const *title)
     return 0;
 }
 
-static unsigned int slang_get_display_width(caca_display_t const *dp)
+static int slang_get_display_width(caca_display_t const *dp)
 {
     /* Fallback to a 6x10 font */
     return cucul_get_canvas_width(dp->cv) * 6;
 }
 
-static unsigned int slang_get_display_height(caca_display_t const *dp)
+static int slang_get_display_height(caca_display_t const *dp)
 {
     /* Fallback to a 6x10 font */
     return cucul_get_canvas_height(dp->cv) * 10;
@@ -223,8 +223,8 @@ static void slang_display(caca_display_t *dp)
 {
     uint32_t const *cvchars = (uint32_t const *)cucul_get_canvas_chars(dp->cv);
     uint32_t const *cvattrs = (uint32_t const *)cucul_get_canvas_attrs(dp->cv);
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
     int x, y;
 
     for(y = 0; y < (int)height; y++)
@@ -328,8 +328,7 @@ static int slang_get_event(caca_display_t *dp, caca_privevent_t *ev)
         int keys[7]; /* Necessary for ungetkey(); */
         char utf8[7];
         uint32_t utf32;
-        unsigned int i;
-        size_t bytes = 0;
+        size_t i, bytes = 0;
 
         keys[0] = intkey;
         utf8[0] = intkey;
@@ -361,8 +360,8 @@ static int slang_get_event(caca_display_t *dp, caca_privevent_t *ev)
     if(intkey == 0x3e9)
     {
         int button = (SLang_getkey() - ' ' + 1) & 0xf;
-        unsigned int x = SLang_getkey() - '!';
-        unsigned int y = SLang_getkey() - '!';
+        int x = SLang_getkey() - '!';
+        int y = SLang_getkey() - '!';
 
         ev->data.mouse.button = button;
         ev->type = CACA_EVENT_MOUSE_PRESS;
diff --git a/caca/driver_vga.c b/caca/driver_vga.c
index c604629..a8ed5e6 100644
--- a/caca/driver_vga.c
+++ b/caca/driver_vga.c
@@ -101,13 +101,13 @@ static int vga_set_display_title(caca_display_t *dp, char const *title)
     return -1;
 }
 
-static unsigned int vga_get_display_width(caca_display_t const *dp)
+static int vga_get_display_width(caca_display_t const *dp)
 {
     /* Fallback to a 320x200 screen */
     return 320;
 }
 
-static unsigned int vga_get_display_height(caca_display_t const *dp)
+static int vga_get_display_height(caca_display_t const *dp)
 {
     /* Fallback to a 320x200 screen */
     return 200;
@@ -118,8 +118,8 @@ static void vga_display(caca_display_t *dp)
     char *screen = (char *)(intptr_t)0x000b8000;
     uint32_t const *cvchars = (uint32_t const *)cucul_get_canvas_chars(dp->cv);
     uint32_t const *cvattrs = (uint32_t const *)cucul_get_canvas_attrs(dp->cv);
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
     int n;
 
     for(n = height * width; n--; )
diff --git a/caca/driver_win32.c b/caca/driver_win32.c
index 14a9f77..33db626 100644
--- a/caca/driver_win32.c
+++ b/caca/driver_win32.c
@@ -82,8 +82,8 @@ struct driver_private
 
 static int win32_init_graphics(caca_display_t *dp)
 {
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
     CONSOLE_SCREEN_BUFFER_INFO csbi;
     SMALL_RECT rect;
     COORD size;
@@ -175,7 +175,7 @@ static int win32_set_display_title(caca_display_t *dp, char const *title)
     return 0;
 }
 
-static unsigned int win32_get_display_width(caca_display_t const *dp)
+static int win32_get_display_width(caca_display_t const *dp)
 {
     /* FIXME */
 
@@ -183,7 +183,7 @@ static unsigned int win32_get_display_width(caca_display_t const *dp)
     return cucul_get_canvas_width(dp->cv) * 6;
 }
 
-static unsigned int win32_get_display_height(caca_display_t const *dp)
+static int win32_get_display_height(caca_display_t const *dp)
 {
     /* FIXME */
 
@@ -198,9 +198,9 @@ static void win32_display(caca_display_t *dp)
     CHAR_INFO *buffer = dp->drv.p->buffer;
     uint32_t const *cvchars = (uint32_t const *)cucul_get_canvas_chars(dp->cv);
     uint32_t const *cvattrs = (uint32_t const *)cucul_get_canvas_attrs(dp->cv);
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
-    unsigned int n;
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
+    int n;
 
     /* Render everything to our screen buffer */
     for(n = height * width; n--; )
@@ -302,8 +302,7 @@ static int win32_get_event(caca_display_t *dp, caca_privevent_t *ev)
             {
                 COORD pos = rec.Event.MouseEvent.dwMousePosition;
 
-                if(dp->mouse.x == (unsigned int)pos.X &&
-                   dp->mouse.y == (unsigned int)pos.Y)
+                if(dp->mouse.x == pos.X && dp->mouse.y == pos.Y)
                     continue;
 
                 dp->mouse.x = pos.X;
diff --git a/caca/driver_x11.c b/caca/driver_x11.c
index 6d70850..27d157d 100644
--- a/caca/driver_x11.c
+++ b/caca/driver_x11.c
@@ -75,8 +75,8 @@ static int x11_init_graphics(caca_display_t *dp)
     int (*old_error_handler)(Display *, XErrorEvent *);
     char const *fonts[] = { NULL, "8x13bold", "fixed" }, **parser;
     char const *geometry;
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
     int i;
 
     dp->drv.p = malloc(sizeof(struct driver_private));
@@ -111,7 +111,7 @@ static int x11_init_graphics(caca_display_t *dp)
     /* Parse our font list */
     for( ; ; parser++)
     {
-        unsigned int font_max_char;
+        uint32_t font_max_char;
 
         if(!*parser)
         {
@@ -143,7 +143,7 @@ static int x11_init_graphics(caca_display_t *dp)
             dp->drv.p->max_char = 0x7f;
 
         font_max_char = 
-            (((unsigned int)dp->drv.p->font_struct->max_byte1) << 8)
+            (dp->drv.p->font_struct->max_byte1 << 8)
              | dp->drv.p->font_struct->max_char_or_byte2;
         if(font_max_char && (font_max_char < dp->drv.p->max_char))
             dp->drv.p->max_char = font_max_char;
@@ -277,12 +277,12 @@ static int x11_set_display_title(caca_display_t *dp, char const *title)
     return 0;
 }
 
-static unsigned int x11_get_display_width(caca_display_t const *dp)
+static int x11_get_display_width(caca_display_t const *dp)
 {
     return cucul_get_canvas_width(dp->cv) * dp->drv.p->font_width;
 }
 
-static unsigned int x11_get_display_height(caca_display_t const *dp)
+static int x11_get_display_height(caca_display_t const *dp)
 {
     return cucul_get_canvas_height(dp->cv) * dp->drv.p->font_height;
 }
@@ -291,9 +291,9 @@ static void x11_display(caca_display_t *dp)
 {
     uint32_t const *cvchars = (uint32_t const *)cucul_get_canvas_chars(dp->cv);
     uint32_t const *cvattrs = (uint32_t const *)cucul_get_canvas_attrs(dp->cv);
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
-    unsigned int x, y, len;
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
+    int x, y, len;
 
     /* First draw the background colours. Splitting the process in two
      * loops like this is actually slightly faster. */
@@ -322,7 +322,7 @@ static void x11_display(caca_display_t *dp)
     /* Then print the foreground characters */
     for(y = 0; y < height; y++)
     {
-        unsigned int yoff = (y + 1) * dp->drv.p->font_height
+        int yoff = (y + 1) * dp->drv.p->font_height
                                     - dp->drv.p->font_offset;
         uint32_t const *chars = cvchars + y * width;
         uint32_t const *attrs = cvattrs + y * width;
@@ -378,8 +378,8 @@ static void x11_handle_resize(caca_display_t *dp)
 
 static int x11_get_event(caca_display_t *dp, caca_privevent_t *ev)
 {
-    unsigned int width = cucul_get_canvas_width(dp->cv);
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
     XEvent xevent;
     char key;
 
@@ -401,7 +401,7 @@ static int x11_get_event(caca_display_t *dp, caca_privevent_t *ev)
         /* Resize event */
         if(xevent.type == ConfigureNotify)
         {
-            unsigned int w, h;
+            int w, h;
 
             w = (xevent.xconfigure.width + dp->drv.p->font_width / 3)
                   / dp->drv.p->font_width;
@@ -421,8 +421,8 @@ static int x11_get_event(caca_display_t *dp, caca_privevent_t *ev)
         /* Check for mouse motion events */
         if(xevent.type == MotionNotify)
         {
-            unsigned int newx = xevent.xmotion.x / dp->drv.p->font_width;
-            unsigned int newy = xevent.xmotion.y / dp->drv.p->font_height;
+            int newx = xevent.xmotion.x / dp->drv.p->font_width;
+            int newy = xevent.xmotion.y / dp->drv.p->font_height;
 
             if(newx >= width)
                 newx = width - 1;
diff --git a/caca/event.c b/caca/event.c
index f212c23..00b6d8a 100644
--- a/caca/event.c
+++ b/caca/event.c
@@ -63,7 +63,7 @@ static int _lowlevel_event(caca_display_t *, caca_privevent_t *);
  *  \param ev A pointer to a caca_event structure, or NULL.
  *  \return 1 if a matching event was received, or 0 if the wait timeouted.
  */
-int caca_get_event(caca_display_t *dp, unsigned int event_mask,
+int caca_get_event(caca_display_t *dp, int event_mask,
                    caca_event_t *ev, int timeout)
 {
     caca_privevent_t privevent;
@@ -127,9 +127,9 @@ int caca_get_event(caca_display_t *dp, unsigned int event_mask,
  *  \param dp The libcaca graphical context.
  *  \return The X mouse coordinate.
  */
-unsigned int caca_get_mouse_x(caca_display_t const *dp)
+int caca_get_mouse_x(caca_display_t const *dp)
 {
-    unsigned int width = cucul_get_canvas_width(dp->cv);
+    int width = cucul_get_canvas_width(dp->cv);
 
     if(dp->mouse.x >= width)
         return width - 1;
@@ -149,9 +149,9 @@ unsigned int caca_get_mouse_x(caca_display_t const *dp)
  *  \param dp The libcaca graphical context.
  *  \return The Y mouse coordinate.
  */
-unsigned int caca_get_mouse_y(caca_display_t const *dp)
+int caca_get_mouse_y(caca_display_t const *dp)
 {
-    unsigned int height = cucul_get_canvas_height(dp->cv);
+    int height = cucul_get_canvas_height(dp->cv);
 
     if(dp->mouse.y >= height)
         return height - 1;
@@ -198,7 +198,7 @@ enum caca_event_type caca_get_event_type(caca_event_t const *ev)
  *  \param ev The libcaca event.
  *  \return The key value.
  */
-unsigned int caca_get_event_key_ch(caca_event_t const *ev)
+int caca_get_event_key_ch(caca_event_t const *ev)
 {
     return ((caca_privevent_t const *)ev)->data.key.ch;
 }
@@ -249,7 +249,7 @@ int caca_get_event_key_utf8(caca_event_t const *ev, char *utf8)
  *  \param ev The libcaca event.
  *  \return The event's mouse button.
  */
-unsigned int caca_get_event_mouse_button(caca_event_t const *ev)
+int caca_get_event_mouse_button(caca_event_t const *ev)
 {
     return ((caca_privevent_t const *)ev)->data.mouse.button;
 }
@@ -265,7 +265,7 @@ unsigned int caca_get_event_mouse_button(caca_event_t const *ev)
  *  \param ev The libcaca event.
  *  \return The event's X mouse coordinate.
  */
-unsigned int caca_get_event_mouse_x(caca_event_t const *ev)
+int caca_get_event_mouse_x(caca_event_t const *ev)
 {
     return ((caca_privevent_t const *)ev)->data.mouse.x;
 }
@@ -281,7 +281,7 @@ unsigned int caca_get_event_mouse_x(caca_event_t const *ev)
  *  \param ev The libcaca event.
  *  \return The event's Y mouse coordinate.
  */
-unsigned int caca_get_event_mouse_y(caca_event_t const *ev)
+int caca_get_event_mouse_y(caca_event_t const *ev)
 {
     return ((caca_privevent_t const *)ev)->data.mouse.y;
 }
@@ -297,7 +297,7 @@ unsigned int caca_get_event_mouse_y(caca_event_t const *ev)
  *  \param ev The libcaca event.
  *  \return The event's new display width value.
  */
-unsigned int caca_get_event_resize_width(caca_event_t const *ev)
+int caca_get_event_resize_width(caca_event_t const *ev)
 {
     return ((caca_privevent_t const *)ev)->data.resize.w;
 }
@@ -313,7 +313,7 @@ unsigned int caca_get_event_resize_width(caca_event_t const *ev)
  *  \param ev The libcaca event.
  *  \return The event's new display height value.
  */
-unsigned int caca_get_event_resize_height(caca_event_t const *ev)
+int caca_get_event_resize_height(caca_event_t const *ev)
 {
     return ((caca_privevent_t const *)ev)->data.resize.h;
 }
@@ -325,7 +325,7 @@ unsigned int caca_get_event_resize_height(caca_event_t const *ev)
 static int _get_next_event(caca_display_t *dp, caca_privevent_t *ev)
 {
 #if defined(USE_SLANG) || defined(USE_NCURSES)
-    unsigned int ticks;
+    int ticks;
 #endif
     int ret;
 
diff --git a/caca/graphics.c b/caca/graphics.c
index 458fc34..0599d76 100644
--- a/caca/graphics.c
+++ b/caca/graphics.c
@@ -62,7 +62,7 @@ int caca_set_display_title(caca_display_t *dp, char const *title)
  *  \param dp The libcaca display context.
  *  \return The display width.
  */
-unsigned int caca_get_display_width(caca_display_t const *dp)
+int caca_get_display_width(caca_display_t const *dp)
 {
     return dp->drv.get_display_width(dp);
 }
@@ -79,7 +79,7 @@ unsigned int caca_get_display_width(caca_display_t const *dp)
  *  \param dp The libcaca display context.
  *  \return The display height.
  */
-unsigned int caca_get_display_height(caca_display_t const *dp)
+int caca_get_display_height(caca_display_t const *dp)
 {
     return dp->drv.get_display_height(dp);
 }
@@ -93,14 +93,21 @@ unsigned int caca_get_display_height(caca_display_t const *dp)
  *  If the argument is zero, constant framerate is disabled. This is the
  *  default behaviour.
  *
- *  This function never fails.
+ *  If an error occurs, -1 is returned and \b errno is set accordingly:
+ *  - \c EINVAL Refresh delay value is invalid.
  *
  *  \param dp The libcaca display context.
  *  \param usec The refresh delay in microseconds.
- *  \return This function always returns 0.
+ *  \return 0 upon success, -1 if an error occurred.
  */
-int caca_set_display_time(caca_display_t *dp, unsigned int usec)
+int caca_set_display_time(caca_display_t *dp, int usec)
 {
+    if(usec < 0)
+    {
+        seterrno(EINVAL);
+        return -1;
+    }
+
     dp->delay = usec;
     return 0;
 }
@@ -118,7 +125,7 @@ int caca_set_display_time(caca_display_t *dp, unsigned int usec)
  *  \param dp The libcaca display context.
  *  \return The render time in microseconds.
  */
-unsigned int caca_get_display_time(caca_display_t const *dp)
+int caca_get_display_time(caca_display_t const *dp)
 {
     return dp->rendertime;
 }
diff --git a/caca/time.c b/caca/time.c
index 23639ea..9c9f33f 100644
--- a/caca/time.c
+++ b/caca/time.c
@@ -35,7 +35,7 @@
 #include "caca.h"
 #include "caca_internals.h"
 
-void _caca_sleep(unsigned int usec)
+void _caca_sleep(int usec)
 {
 #if defined(HAVE_USLEEP)
         usleep(usec);
@@ -46,15 +46,15 @@ void _caca_sleep(unsigned int usec)
 #endif
 }
 
-unsigned int _caca_getticks(caca_timer_t *timer)
+int _caca_getticks(caca_timer_t *timer)
 {
 #if defined(HAVE_GETTIMEOFDAY)
     struct timeval tv;
 #elif defined(USE_WIN32)
     static __int64 freq = -1; /* FIXME: can this move to caca_context? */
-    unsigned __int64 usec;
+    __int64 usec;
 #endif
-    unsigned int ticks = 0;
+    int ticks = 0;
     int new_sec, new_usec;
 
 #if defined(HAVE_GETTIMEOFDAY)
diff --git a/cucul/canvas.c b/cucul/canvas.c
index 8cff78d..683f77b 100644
--- a/cucul/canvas.c
+++ b/cucul/canvas.c
@@ -299,7 +299,7 @@ int cucul_printf(cucul_canvas_t *cv, int x, int y, char const *format, ...)
 int cucul_clear_canvas(cucul_canvas_t *cv)
 {
     uint32_t attr = cv->curattr;
-    unsigned int n;
+    int n;
 
     for(n = cv->width * cv->height; n--; )
     {
@@ -393,21 +393,21 @@ int cucul_blit(cucul_canvas_t *dst, int x, int y,
     endi = (x + src->width >= dst->width) ? dst->width - x : src->width;
     endj = (y + src->height >= dst->height) ? dst->height - y : src->height;
 
-    if((unsigned int)starti > src->width || (unsigned int)startj > src->height
+    if(starti > src->width || startj > src->height
         || starti >= endi || startj >= endj)
         return 0;
 
     for(j = startj; j < endj; j++)
     {
-        unsigned int dstix = (j + y) * dst->width + starti + x;
-        unsigned int srcix = j * src->width + starti;
+        int dstix = (j + y) * dst->width + starti + x;
+        int srcix = j * src->width + starti;
         int stride = endi - starti;
 
         /* FIXME: we are ignoring the mask here */
         if((starti + x) && dst->chars[dstix] == CUCUL_MAGIC_FULLWIDTH)
             dst->chars[dstix - 1] = ' ';
 
-        if((unsigned int)(endi + x) < dst->width
+        if(endi + x < dst->width
                 && dst->chars[dstix + stride] == CUCUL_MAGIC_FULLWIDTH)
             dst->chars[dstix + stride] = ' ';
 
@@ -432,8 +432,7 @@ int cucul_blit(cucul_canvas_t *dst, int x, int y,
         if(src->chars[srcix] == CUCUL_MAGIC_FULLWIDTH)
             dst->chars[dstix] = ' ';
 
-        if((unsigned int)endi < src->width
-                && src->chars[endi] == CUCUL_MAGIC_FULLWIDTH)
+        if(endi < src->width && src->chars[endi] == CUCUL_MAGIC_FULLWIDTH)
             dst->chars[dstix + stride - 1] = ' ';
     }
 
@@ -447,6 +446,7 @@ int cucul_blit(cucul_canvas_t *dst, int x, int y,
  *  are affected by this function.
  *
  *  If an error occurs, -1 is returned and \b errno is set accordingly:
+ *  - \c EINVAL Specified width or height is invalid.
  *  - \c EBUSY The canvas is in use by a display driver and cannot be resized.
  *  - \c ENOMEM Not enough memory for the requested canvas size. If this
  *    happens, the canvas handle becomes invalid and should not be used.
@@ -458,11 +458,10 @@ int cucul_blit(cucul_canvas_t *dst, int x, int y,
  *  \param h The height of the cropped area.
  *  \return 0 in case of success, -1 if an error occurred.
  */
-int cucul_set_canvas_boundaries(cucul_canvas_t *cv, int x, int y,
-                                unsigned int w, unsigned int h)
+int cucul_set_canvas_boundaries(cucul_canvas_t *cv, int x, int y, int w, int h)
 {
     cucul_canvas_t *new;
-    unsigned int f, saved_f, framecount;
+    int f, saved_f, framecount;
 
     if(cv->refcount)
     {
@@ -470,6 +469,12 @@ int cucul_set_canvas_boundaries(cucul_canvas_t *cv, int x, int y,
         return -1;
     }
 
+    if(w < 0 || h < 0)
+    {
+        seterrno(EINVAL);
+        return -1;
+    }
+
     new = cucul_create_canvas(w, h);
 
     framecount = cucul_get_frame_count(cv);
diff --git a/cucul/cucul.c b/cucul/cucul.c
index fb2c55b..3a22eb8 100644
--- a/cucul/cucul.c
+++ b/cucul/cucul.c
@@ -33,7 +33,7 @@
 #include "cucul.h"
 #include "cucul_internals.h"
 
-static int cucul_resize(cucul_canvas_t *, unsigned int, unsigned int);
+static int cucul_resize(cucul_canvas_t *, int, int);
 
 /** \brief Initialise a \e libcucul canvas.
  *
@@ -46,15 +46,24 @@ static int cucul_resize(cucul_canvas_t *, unsigned int, unsigned int);
  *  corner.
  *
  *  If an error occurs, NULL is returned and \b errno is set accordingly:
+ *  - \c EINVAL Specified width or height is invalid.
  *  - \c ENOMEM Not enough memory for the requested canvas size.
  *
  *  \param width The desired canvas width
  *  \param height The desired canvas height
  *  \return A libcucul canvas handle upon success, NULL if an error occurred.
  */
-cucul_canvas_t * cucul_create_canvas(unsigned int width, unsigned int height)
+cucul_canvas_t * cucul_create_canvas(int width, int height)
 {
-    cucul_canvas_t *cv = malloc(sizeof(cucul_canvas_t));
+    cucul_canvas_t *cv;
+
+    if(width < 0 || height < 0)
+    {
+        seterrno(EINVAL);
+        return NULL;
+    }
+
+    cv = malloc(sizeof(cucul_canvas_t));
 
     if(!cv)
         goto nomem;
@@ -190,6 +199,7 @@ int cucul_unmanage_canvas(cucul_canvas_t *cv, int (*callback)(void *), void *p)
  *  for more about this.
  *
  *  If an error occurs, -1 is returned and \b errno is set accordingly:
+ *  - \c EINVAL Specified width or height is invalid.
  *  - \c EBUSY The canvas is in use by a display driver and cannot be resized.
  *  - \c ENOMEM Not enough memory for the requested canvas size. If this
  *    happens, the canvas handle becomes invalid and should not be used.
@@ -199,9 +209,14 @@ int cucul_unmanage_canvas(cucul_canvas_t *cv, int (*callback)(void *), void *p)
  *  \param height The desired canvas height.
  *  \return 0 in case of success, -1 if an error occurred.
  */
-int cucul_set_canvas_size(cucul_canvas_t *cv, unsigned int width,
-                                              unsigned int height)
+int cucul_set_canvas_size(cucul_canvas_t *cv, int width, int height)
 {
+    if(width < 0 || height < 0)
+    {
+        seterrno(EINVAL);
+        return -1;
+    }
+
     if(cv->refcount && cv->resize_callback
         && !cv->resize_callback(cv->resize_data))
     {
@@ -221,7 +236,7 @@ int cucul_set_canvas_size(cucul_canvas_t *cv, unsigned int width,
  *  \param cv A libcucul canvas.
  *  \return The canvas width.
  */
-unsigned int cucul_get_canvas_width(cucul_canvas_t const *cv)
+int cucul_get_canvas_width(cucul_canvas_t const *cv)
 {
     return cv->width;
 }
@@ -235,7 +250,7 @@ unsigned int cucul_get_canvas_width(cucul_canvas_t const *cv)
  *  \param cv A libcucul canvas.
  *  \return The canvas height.
  */
-unsigned int cucul_get_canvas_height(cucul_canvas_t const *cv)
+int cucul_get_canvas_height(cucul_canvas_t const *cv)
 {
     return cv->height;
 }
@@ -292,7 +307,7 @@ uint8_t const * cucul_get_canvas_attrs(cucul_canvas_t const *cv)
  */
 int cucul_free_canvas(cucul_canvas_t *cv)
 {
-    unsigned int f;
+    int f;
 
     if(cv->refcount)
     {
@@ -356,9 +371,9 @@ char const * cucul_get_version(void)
  * XXX: The following functions are local.
  */
 
-int cucul_resize(cucul_canvas_t *cv, unsigned int width, unsigned int height)
+int cucul_resize(cucul_canvas_t *cv, int width, int height)
 {
-    unsigned int x, y, f, old_width, old_height, new_size, old_size;
+    int x, y, f, old_width, old_height, new_size, old_size;
 
     old_width = cv->width;
     old_height = cv->height;
@@ -426,7 +441,7 @@ int cucul_resize(cucul_canvas_t *cv, unsigned int width, unsigned int height)
     {
         /* New width is smaller. Copy as many lines as possible. Ignore
          * the first line, it is already in place. */
-        unsigned int lines = height < old_height ? height : old_height;
+        int lines = height < old_height ? height : old_height;
 
         for(f = 0; f < cv->framecount; f++)
         {
diff --git a/cucul/cucul.h b/cucul/cucul.h
index c5c63eb..e8378b8 100644
--- a/cucul/cucul.h
+++ b/cucul/cucul.h
@@ -27,7 +27,8 @@
 #include <cucul_types.h>
 
 #undef __extern
-#if defined(_WIN32) && defined(__LIBCUCUL__)
+#if defined(_DOXYGEN_SKIP_ME)
+#elif defined(_WIN32) && defined(__LIBCUCUL__)
 #   define __extern extern __declspec(dllexport)
 #else
 #   define __extern extern
@@ -86,13 +87,12 @@ typedef struct cucul_file cucul_file_t;
  *  initialisation, system information retrieval and configuration.
  *
  *  @{ */
-__extern cucul_canvas_t * cucul_create_canvas(unsigned int, unsigned int);
+__extern cucul_canvas_t * cucul_create_canvas(int, int);
 __extern int cucul_manage_canvas(cucul_canvas_t *, int (*)(void *), void *);
 __extern int cucul_unmanage_canvas(cucul_canvas_t *, int (*)(void *), void *);
-__extern int cucul_set_canvas_size(cucul_canvas_t *, unsigned int,
-                                   unsigned int);
-__extern unsigned int cucul_get_canvas_width(cucul_canvas_t const *);
-__extern unsigned int cucul_get_canvas_height(cucul_canvas_t const *);
+__extern int cucul_set_canvas_size(cucul_canvas_t *, int, int);
+__extern int cucul_get_canvas_width(cucul_canvas_t const *);
+__extern int cucul_get_canvas_height(cucul_canvas_t const *);
 __extern uint8_t const * cucul_get_canvas_chars(cucul_canvas_t const *);
 __extern uint8_t const * cucul_get_canvas_attrs(cucul_canvas_t const *);
 __extern int cucul_free_canvas(cucul_canvas_t *);
@@ -125,8 +125,7 @@ __extern int cucul_get_canvas_handle_x(cucul_canvas_t const *);
 __extern int cucul_get_canvas_handle_y(cucul_canvas_t const *);
 __extern int cucul_blit(cucul_canvas_t *, int, int, cucul_canvas_t const *,
                         cucul_canvas_t const *);
-__extern int cucul_set_canvas_boundaries(cucul_canvas_t *, int, int,
-                                         unsigned int, unsigned int);
+__extern int cucul_set_canvas_boundaries(cucul_canvas_t *, int, int, int, int);
 /*  @} */
 
 /** \defgroup cucul_transform libcucul canvas transformation
@@ -207,12 +206,12 @@ __extern int cucul_fill_triangle(cucul_canvas_t *, int, int, int, int, int,
  *  removal, copying etc.
  *
  *  @{ */
-__extern unsigned int cucul_get_frame_count(cucul_canvas_t const *);
-__extern int cucul_set_frame(cucul_canvas_t *, unsigned int);
+__extern int cucul_get_frame_count(cucul_canvas_t const *);
+__extern int cucul_set_frame(cucul_canvas_t *, int);
 __extern char const *cucul_get_frame_name(cucul_canvas_t const *);
 __extern int cucul_set_frame_name(cucul_canvas_t *, char const *);
-__extern int cucul_create_frame(cucul_canvas_t *, unsigned int);
-__extern int cucul_free_frame(cucul_canvas_t *, unsigned int);
+__extern int cucul_create_frame(cucul_canvas_t *, int);
+__extern int cucul_free_frame(cucul_canvas_t *, int);
 /*  @} */
 
 /** \defgroup cucul_dither libcucul bitmap dithering
@@ -221,13 +220,12 @@ __extern int cucul_free_frame(cucul_canvas_t *, unsigned int);
  *  rendering.
  *
  *  @{ */
-__extern cucul_dither_t *cucul_create_dither(unsigned int, unsigned int,
-                                             unsigned int, unsigned int,
+__extern cucul_dither_t *cucul_create_dither(int, int, int, int,
                                              uint32_t, uint32_t,
                                              uint32_t, uint32_t);
 __extern int cucul_set_dither_palette(cucul_dither_t *,
-                                      unsigned int r[], unsigned int g[],
-                                      unsigned int b[], unsigned int a[]);
+                                      uint32_t r[], uint32_t g[],
+                                      uint32_t b[], uint32_t a[]);
 __extern int cucul_set_dither_brightness(cucul_dither_t *, float);
 __extern float cucul_get_dither_brightness(cucul_dither_t const *);
 __extern int cucul_set_dither_gamma(cucul_dither_t *, float);
@@ -261,14 +259,13 @@ __extern int cucul_free_dither(cucul_dither_t *);
  *  canvas to bitmap rendering.
  *
  *  @{ */
-__extern cucul_font_t *cucul_load_font(void const *, unsigned int);
+__extern cucul_font_t *cucul_load_font(void const *, size_t);
 __extern char const * const * cucul_get_font_list(void);
-__extern unsigned int cucul_get_font_width(cucul_font_t const *);
-__extern unsigned int cucul_get_font_height(cucul_font_t const *);
-__extern unsigned int const *cucul_get_font_blocks(cucul_font_t const *);
+__extern int cucul_get_font_width(cucul_font_t const *);
+__extern int cucul_get_font_height(cucul_font_t const *);
+__extern uint32_t const *cucul_get_font_blocks(cucul_font_t const *);
 __extern int cucul_render_canvas(cucul_canvas_t const *, cucul_font_t const *,
-                                 void *, unsigned int, unsigned int,
-                                 unsigned int);
+                                 void *, int, int, int);
 __extern int cucul_free_font(cucul_font_t *);
 /*  @} */
 
@@ -366,8 +363,6 @@ __extern char const * const * cucul_get_dither_mode_list(cucul_dither_t
 }
 #endif
 
-#if !defined(_DOXYGEN_SKIP_ME)
-#   undef __extern
-#endif
+#undef __extern
 
 #endif /* __CUCUL_H__ */
diff --git a/cucul/cucul_internals.h b/cucul/cucul_internals.h
index 2413db4..cd34214 100644
--- a/cucul/cucul_internals.h
+++ b/cucul/cucul_internals.h
@@ -22,7 +22,7 @@ typedef struct cucul_figfont cucul_figfont_t;
 struct cucul_frame
 {
     /* Frame size */
-    unsigned int width, height;
+    int width, height;
 
     /* Cell information */
     uint32_t *chars;
@@ -43,17 +43,17 @@ struct cucul_canvas
      * to this structure. The function is quite hacky. */
 
     /* Frame information */
-    unsigned int frame, framecount;
+    int frame, framecount;
     struct cucul_frame *frames;
 
     /* Canvas management */
-    unsigned int refcount;
-    unsigned int autoinc;
+    int refcount;
+    int autoinc;
     int (*resize_callback)(void *);
     void *resize_data;
 
     /* Shortcut to the active frame information */
-    unsigned int width, height;
+    int width, height;
     uint32_t *chars;
     uint32_t *attrs;
     uint32_t curattr;
@@ -64,7 +64,7 @@ struct cucul_canvas
 
 struct cucul_buffer
 {
-    unsigned long int size;
+    size_t size;
     char *data;
     int user_data;
 };
diff --git a/cucul/dither.c b/cucul/dither.c
index 17bef93..dec0e12 100644
--- a/cucul/dither.c
+++ b/cucul/dither.c
@@ -138,12 +138,12 @@ struct cucul_dither
 
     char const *algo_name;
     void (*init_dither) (int);
-    unsigned int (*get_dither) (void);
+    int (*get_dither) (void);
     void (*increment_dither) (void);
 
     char const *glyph_name;
     uint32_t const * glyphs;
-    unsigned glyph_count;
+    int glyph_count;
 
     int invert;
 };
@@ -178,27 +178,27 @@ static int init_lookup(void);
 
 /* Dithering algorithms */
 static void init_no_dither(int);
-static unsigned int get_no_dither(void);
+static int get_no_dither(void);
 static void increment_no_dither(void);
 
 static void init_fstein_dither(int);
-static unsigned int get_fstein_dither(void);
+static int get_fstein_dither(void);
 static void increment_fstein_dither(void);
 
 static void init_ordered2_dither(int);
-static unsigned int get_ordered2_dither(void);
+static int get_ordered2_dither(void);
 static void increment_ordered2_dither(void);
 
 static void init_ordered4_dither(int);
-static unsigned int get_ordered4_dither(void);
+static int get_ordered4_dither(void);
 static void increment_ordered4_dither(void);
 
 static void init_ordered8_dither(int);
-static unsigned int get_ordered8_dither(void);
+static int get_ordered8_dither(void);
 static void increment_ordered8_dither(void);
 
 static void init_random_dither(int);
-static unsigned int get_random_dither(void);
+static int get_random_dither(void);
 static void increment_random_dither(void);
 
 static inline int sq(int x)
@@ -260,8 +260,7 @@ static inline void rgb2hsv_default(int r, int g, int b,
  *  \param amask Bitmask for alpha values.
  *  \return Dither object upon success, NULL if an error occurred.
  */
-cucul_dither_t *cucul_create_dither(unsigned int bpp, unsigned int w,
-                                    unsigned int h, unsigned int pitch,
+cucul_dither_t *cucul_create_dither(int bpp, int w, int h, int pitch,
                                     uint32_t rmask, uint32_t gmask,
                                     uint32_t bmask, uint32_t amask)
 {
@@ -269,7 +268,7 @@ cucul_dither_t *cucul_create_dither(unsigned int bpp, unsigned int w,
     int i;
 
     /* Minor sanity test */
-    if(!w || !h || !pitch || bpp > 32 || bpp < 8)
+    if(w < 0 || h < 0 || pitch < 0 || bpp > 32 || bpp < 8)
     {
         seterrno(EINVAL);
         return NULL;
@@ -373,8 +372,8 @@ cucul_dither_t *cucul_create_dither(unsigned int bpp, unsigned int w,
  *  \return 0 in case of success, -1 if an error occurred.
  */
 int cucul_set_dither_palette(cucul_dither_t *d,
-                             unsigned int red[], unsigned int green[],
-                             unsigned int blue[], unsigned int alpha[])
+                             uint32_t red[], uint32_t green[],
+                             uint32_t blue[], uint32_t alpha[])
 {
     int i, has_alpha = 0;
 
@@ -946,8 +945,7 @@ int cucul_dither_bitmap(cucul_canvas_t *cv, int x, int y, int w, int h,
     int *floyd_steinberg, *fs_r, *fs_g, *fs_b;
     uint32_t savedattr;
     int fs_length;
-    int x1, y1, x2, y2, pitch, deltax, deltay;
-    unsigned int dchmax;
+    int x1, y1, x2, y2, pitch, deltax, deltay, dchmax;
 
     if(!d || !pixels)
         return 0;
@@ -981,14 +979,13 @@ int cucul_dither_bitmap(cucul_canvas_t *cv, int x, int y, int w, int h,
             x <= x2 && x <= (int)cv->width;
             x++)
     {
-        unsigned int i;
-        int ch = 0, distmin;
         unsigned int rgba[4];
+        int error[3];
+        int i, ch = 0, distmin;
         int fg_r = 0, fg_g = 0, fg_b = 0, bg_r, bg_g, bg_b;
         int fromx, fromy, tox, toy, myx, myy, dots, dist;
-        int error[3];
 
-        unsigned int outfg = 0, outbg = 0;
+        int outfg = 0, outbg = 0;
         uint32_t outch;
 
         rgba[0] = rgba[1] = rgba[2] = rgba[3] = 0;
@@ -1362,7 +1359,7 @@ static void init_no_dither(int line)
     ;
 }
 
-static unsigned int get_no_dither(void)
+static int get_no_dither(void)
 {
     return 0x80;
 }
@@ -1380,7 +1377,7 @@ static void init_fstein_dither(int line)
     ;
 }
 
-static unsigned int get_fstein_dither(void)
+static int get_fstein_dither(void)
 {
     return 0x80;
 }
@@ -1393,12 +1390,12 @@ static void increment_fstein_dither(void)
 /*
  * Ordered 2 dithering
  */
-static unsigned int const *ordered2_table;
-static unsigned int ordered2_index;
+static int const *ordered2_table;
+static int ordered2_index;
 
 static void init_ordered2_dither(int line)
 {
-    static unsigned int const dither2x2[] =
+    static int const dither2x2[] =
     {
         0x00, 0x80,
         0xc0, 0x40,
@@ -1408,7 +1405,7 @@ static void init_ordered2_dither(int line)
     ordered2_index = 0;
 }
 
-static unsigned int get_ordered2_dither(void)
+static int get_ordered2_dither(void)
 {
     return ordered2_table[ordered2_index];
 }
@@ -1425,12 +1422,12 @@ static void increment_ordered2_dither(void)
                           -1, -6, -5,  2,
                           -2, -7, -8,  3,
                            4, -3, -4, -7};*/
-static unsigned int const *ordered4_table;
-static unsigned int ordered4_index;
+static int const *ordered4_table;
+static int ordered4_index;
 
 static void init_ordered4_dither(int line)
 {
-    static unsigned int const dither4x4[] =
+    static int const dither4x4[] =
     {
         0x00, 0x80, 0x20, 0xa0,
         0xc0, 0x40, 0xe0, 0x60,
@@ -1442,7 +1439,7 @@ static void init_ordered4_dither(int line)
     ordered4_index = 0;
 }
 
-static unsigned int get_ordered4_dither(void)
+static int get_ordered4_dither(void)
 {
     return ordered4_table[ordered4_index];
 }
@@ -1455,12 +1452,12 @@ static void increment_ordered4_dither(void)
 /*
  * Ordered 8 dithering
  */
-static unsigned int const *ordered8_table;
-static unsigned int ordered8_index;
+static int const *ordered8_table;
+static int ordered8_index;
 
 static void init_ordered8_dither(int line)
 {
-    static unsigned int const dither8x8[] =
+    static int const dither8x8[] =
     {
         0x00, 0x80, 0x20, 0xa0, 0x08, 0x88, 0x28, 0xa8,
         0xc0, 0x40, 0xe0, 0x60, 0xc8, 0x48, 0xe8, 0x68,
@@ -1476,7 +1473,7 @@ static void init_ordered8_dither(int line)
     ordered8_index = 0;
 }
 
-static unsigned int get_ordered8_dither(void)
+static int get_ordered8_dither(void)
 {
     return ordered8_table[ordered8_index];
 }
@@ -1494,7 +1491,7 @@ static void init_random_dither(int line)
     ;
 }
 
-static unsigned int get_random_dither(void)
+static int get_random_dither(void)
 {
     return cucul_rand(0x00, 0x100);
 }
@@ -1509,7 +1506,7 @@ static void increment_random_dither(void)
  */
 static int init_lookup(void)
 {
-    unsigned int v, s, h;
+    int v, s, h;
 
     /* These ones are constant */
     lookup_colors[0] = CUCUL_BLACK;
diff --git a/cucul/export.c b/cucul/export.c
index f845339..ff671a5 100644
--- a/cucul/export.c
+++ b/cucul/export.c
@@ -162,7 +162,7 @@ char const * const * cucul_get_export_list(void)
 static void *export_caca(cucul_canvas_t const *cv, size_t *bytes)
 {
     char *data, *cur;
-    unsigned int f, n;
+    int f, n;
 
     /* 52 bytes for the header:
      *  - 4 bytes for "\xCA\xCA" + "CV"
@@ -222,7 +222,7 @@ static void *export_utf8(cucul_canvas_t const *cv, size_t *bytes,
     };
 
     char *data, *cur;
-    unsigned int x, y;
+    int x, y;
 
     /* 23 bytes assumed for max length per pixel ('\e[5;1;3x;4y;9x;10ym' plus
      * 4 max bytes for a UTF-8 character).
@@ -302,7 +302,7 @@ static void *export_ansi(cucul_canvas_t const *cv, size_t *bytes)
     };
 
     char *data, *cur;
-    unsigned int x, y;
+    int x, y;
 
     uint8_t prevfg = -1;
     uint8_t prevbg = -1;
@@ -376,7 +376,7 @@ static void *export_ansi(cucul_canvas_t const *cv, size_t *bytes)
 static void *export_html(cucul_canvas_t const *cv, size_t *bytes)
 {
     char *data, *cur;
-    unsigned int x, y, len;
+    int x, y, len;
 
     /* The HTML header: less than 1000 bytes
      * A line: 7 chars for "<br />\n"
@@ -458,7 +458,7 @@ static void *export_html(cucul_canvas_t const *cv, size_t *bytes)
 static void *export_html3(cucul_canvas_t const *cv, size_t *bytes)
 {
     char *data, *cur;
-    unsigned int x, y, len;
+    int x, y, len;
 
     /* The HTML table markup: less than 1000 bytes
      * A line: 10 chars for "<tr></tr>\n"
@@ -482,7 +482,7 @@ static void *export_html3(cucul_canvas_t const *cv, size_t *bytes)
 
         for(x = 0; x < cv->width; x += len)
         {
-            unsigned int i, needfont;
+            int i, needfont;
 
             /* Use colspan option to factor cells with same attributes
              * (see below) */
@@ -559,7 +559,7 @@ static void *export_html3(cucul_canvas_t const *cv, size_t *bytes)
 static void *export_bbfr(cucul_canvas_t const *cv, size_t *bytes)
 {
     char *data, *cur;
-    unsigned int x, y, len;
+    int x, y, len;
 
     /* The font markup: less than 100 bytes
      * A line: 1 char for "\n"
@@ -580,7 +580,7 @@ static void *export_bbfr(cucul_canvas_t const *cv, size_t *bytes)
 
         for(x = 0; x < cv->width; x += len)
         {
-            unsigned int i, needback, needfront;
+            int i, needback, needfront;
 
             /* Use colspan option to factor cells with same attributes
              * (see below) */
@@ -666,7 +666,7 @@ static void *export_irc(cucul_canvas_t const *cv, size_t *bytes)
     };
 
     char *data, *cur;
-    unsigned int x, y;
+    int x, y;
 
     /* 14 bytes assumed for max length per pixel. Worst case scenario:
      * ^Cxx,yy   6 bytes
@@ -792,7 +792,7 @@ static void *export_ps(cucul_canvas_t const *cv, size_t *bytes)
         "6 10 scale\n";
 
     char *data, *cur;
-    unsigned int x, y;
+    int x, y;
 
     /* 200 is arbitrary but should be ok */
     *bytes = strlen(ps_header) + 100 + cv->height * (32 + cv->width * 200);
@@ -883,7 +883,7 @@ static void *export_svg(cucul_canvas_t const *cv, size_t *bytes)
         " xml:space=\"preserve\" version=\"1.1\"  baseProfile=\"full\">\n";
 
     char *data, *cur;
-    unsigned int x, y;
+    int x, y;
 
     /* 200 is arbitrary but should be ok */
     *bytes = strlen(svg_header) + 128 + cv->width * cv->height * 200;
@@ -964,7 +964,7 @@ static void *export_tga(cucul_canvas_t const *cv, size_t *bytes)
     char const * const *fontlist;
     char *data, *cur;
     cucul_font_t *f;
-    unsigned int i, w, h;
+    int i, w, h;
 
     fontlist = cucul_get_font_list();
     if(!fontlist[0])
diff --git a/cucul/figfont.c b/cucul/figfont.c
index c8329a7..81873a7 100644
--- a/cucul/figfont.c
+++ b/cucul/figfont.c
@@ -33,22 +33,22 @@
 
 struct cucul_figfont
 {
-    unsigned int term_width;
+    int term_width;
     int x, y, w, h, lines;
 
     enum { H_DEFAULT, H_KERN, H_SMUSH, H_NONE, H_OVERLAP } hmode;
-    unsigned int hsmushrule;
+    int hsmushrule;
     uint32_t hardblank;
-    unsigned int height, baseline, max_length;
+    int height, baseline, max_length;
     int old_layout;
-    unsigned int print_direction, full_layout, codetag_count;
-    unsigned int glyphs;
+    int print_direction, full_layout, codetag_count;
+    int glyphs;
     cucul_canvas_t *fontcv, *charcv;
     int *left, *right; /* Unused yet */
-    unsigned int *lookup;
+    uint32_t *lookup;
 };
 
-static uint32_t hsmush(uint32_t ch1, uint32_t ch2, unsigned int rule);
+static uint32_t hsmush(uint32_t ch1, uint32_t ch2, int rule);
 static cucul_figfont_t * open_figfont(char const *);
 static int free_figfont(cucul_figfont_t *);
 
@@ -130,7 +130,7 @@ int cucul_canvas_set_figfont(cucul_canvas_t *cv, char const *path)
 int cucul_put_figchar(cucul_canvas_t *cv, uint32_t ch)
 {
     cucul_figfont_t *ff = cv->ff;
-    unsigned int c, w, h, x, y, overlap, extra, xleft, xright;
+    int c, w, h, x, y, overlap, extra, xleft, xright;
 
     switch(ch)
     {
@@ -253,7 +253,7 @@ int cucul_put_figchar(cucul_canvas_t *cv, uint32_t ch)
 static int flush_figlet(cucul_canvas_t *cv)
 {
     cucul_figfont_t *ff = cv->ff;
-    unsigned int x, y;
+    int x, y;
 
     //ff->torender = cv;
     //cucul_set_canvas_size(ff->torender, ff->w, ff->h);
@@ -291,7 +291,7 @@ cucul_figfont_t * open_figfont(char const *path)
     cucul_figfont_t *ff;
     char *data = NULL;
     cucul_file_t *f;
-    unsigned int i, j, size, comment_lines;
+    int i, j, size, comment_lines;
 
     ff = malloc(sizeof(cucul_figfont_t));
     if(!ff)
@@ -487,7 +487,7 @@ int free_figfont(cucul_figfont_t *ff)
     return 0;
 }
 
-static uint32_t hsmush(uint32_t ch1, uint32_t ch2, unsigned int rule)
+static uint32_t hsmush(uint32_t ch1, uint32_t ch2, int rule)
 {
     /* Rule 1 */
     if((rule & 0x01) && ch1 == ch2 && ch1 != 0xa0)
diff --git a/cucul/font.c b/cucul/font.c
index bca9a71..a0321f0 100644
--- a/cucul/font.c
+++ b/cucul/font.c
@@ -70,10 +70,9 @@ struct cucul_font
 
 #define DECLARE_UNPACKGLYPH(bpp) \
     static inline void \
-      unpack_glyph ## bpp(uint8_t *glyph, uint8_t *packed_data, \
-                          unsigned int n) \
+      unpack_glyph ## bpp(uint8_t *glyph, uint8_t *packed_data, int n) \
 { \
-    unsigned int i; \
+    int i; \
     \
     for(i = 0; i < n; i++) \
     { \
@@ -111,10 +110,10 @@ DECLARE_UNPACKGLYPH(1)
  *  \param size The size of the memory area, or 0 if the font name is given.
  *  \return A font handle or NULL in case of error.
  */
-cucul_font_t *cucul_load_font(void const *data, unsigned int size)
+cucul_font_t *cucul_load_font(void const *data, size_t size)
 {
     cucul_font_t *f;
-    unsigned int i;
+    int i;
 
     if(size == 0)
     {
@@ -247,7 +246,7 @@ cucul_font_t *cucul_load_font(void const *data, unsigned int size)
            f->private + 4 + sizeof(struct font_header)
                 + f->header.blocks * sizeof(struct block_info),
            f->header.glyphs * sizeof(struct glyph_info));
-    for(i = 0; i < f->header.glyphs; i++)
+    for(i = 0; i < (int)f->header.glyphs; i++)
     {
         f->glyph_list[i].width = hton16(f->glyph_list[i].width);
         f->glyph_list[i].height = hton16(f->glyph_list[i].height);
@@ -324,7 +323,7 @@ char const * const * cucul_get_font_list(void)
  *  \param f The font, as returned by cucul_load_font()
  *  \return The standard glyph width.
  */
-unsigned int cucul_get_font_width(cucul_font_t const *f)
+int cucul_get_font_width(cucul_font_t const *f)
 {
     return f->header.width;
 }
@@ -339,7 +338,7 @@ unsigned int cucul_get_font_width(cucul_font_t const *f)
  *  \param f The font, as returned by cucul_load_font()
  *  \return The standard glyph height.
  */
-unsigned int cucul_get_font_height(cucul_font_t const *f)
+int cucul_get_font_height(cucul_font_t const *f)
 {
     return f->header.height;
 }
@@ -404,7 +403,8 @@ int cucul_free_font(cucul_font_t *f)
  *  Glyphs that do not fit in the image buffer are currently not rendered at
  *  all. They may be cropped instead in future versions.
  *
- *  This function never fails.
+ *  If an error occurs, -1 is returned and \b errno is set accordingly:
+ *  - \c EINVAL Specified width, height or pitch is invalid.
  *
  *  \param cv The canvas to render
  *  \param f The font, as returned by cucul_load_font()
@@ -412,14 +412,19 @@ int cucul_free_font(cucul_font_t *f)
  *  \param width The width (in pixels) of the image buffer
  *  \param height The height (in pixels) of the image buffer
  *  \param pitch The pitch (in bytes) of an image buffer line.
- *  \return This function always returns 0.
+ *  \return 0 in case of success, -1 if an error occurred.
  */
 int cucul_render_canvas(cucul_canvas_t const *cv, cucul_font_t const *f,
-                        void *buf, unsigned int width,
-                        unsigned int height, unsigned int pitch)
+                        void *buf, int width, int height, int pitch)
 {
     uint8_t *glyph = NULL;
-    unsigned int x, y, xmax, ymax;
+    int x, y, xmax, ymax;
+
+    if(width < 0 || height < 0 || pitch < 0)
+    {
+        seterrno(EINVAL);
+        return -1;
+    }
 
     if(f->header.bpp != 8)
         glyph = malloc(f->header.width * 2 * f->header.height);
@@ -439,11 +444,11 @@ int cucul_render_canvas(cucul_canvas_t const *cv, cucul_font_t const *f,
         for(x = 0; x < xmax; x++)
         {
             uint8_t argb[8];
-            unsigned int starty = y * f->header.height;
-            unsigned int startx = x * f->header.width;
+            int starty = y * f->header.height;
+            int startx = x * f->header.width;
             uint32_t ch = cv->chars[y * cv->width + x];
             uint32_t attr = cv->attrs[y * cv->width + x];
-            unsigned int b, i, j;
+            int b, i, j;
             struct glyph_info *g;
 
             /* Find the Unicode block where our glyph lies */
diff --git a/cucul/frame.c b/cucul/frame.c
index 3b3141d..49fcba1 100644
--- a/cucul/frame.c
+++ b/cucul/frame.c
@@ -36,7 +36,7 @@
  *  \param cv A libcucul canvas
  *  \return The frame count
  */
-unsigned int cucul_get_frame_count(cucul_canvas_t const *cv)
+int cucul_get_frame_count(cucul_canvas_t const *cv)
 {
     return cv->framecount;
 }
@@ -56,9 +56,9 @@ unsigned int cucul_get_frame_count(cucul_canvas_t const *cv)
  *  \param id The canvas frame to activate
  *  \return 0 in case of success, -1 if an error occurred.
  */
-int cucul_set_frame(cucul_canvas_t *cv, unsigned int id)
+int cucul_set_frame(cucul_canvas_t *cv, int id)
 {
-    if(id >= cv->framecount)
+    if(id < 0 || id >= cv->framecount)
     {
         seterrno(EINVAL);
         return -1;
@@ -124,7 +124,8 @@ int cucul_set_frame_name(cucul_canvas_t *cv, char const *name)
  *  The frame index indicates where the frame should be inserted. Valid
  *  values range from 0 to the current canvas frame count. If the frame
  *  index is greater than or equals the current canvas frame count, the new
- *  frame is appended at the end of the canvas.
+ *  frame is appended at the end of the canvas. If the frame index is less
+ *  than zero, the new frame is inserted at index 0.
  *
  *  The active frame does not change, but its index may be renumbered due
  *  to the insertion.
@@ -136,12 +137,14 @@ int cucul_set_frame_name(cucul_canvas_t *cv, char const *name)
  *  \param id The index where to insert the new frame
  *  \return 0 in case of success, -1 if an error occurred.
  */
-int cucul_create_frame(cucul_canvas_t *cv, unsigned int id)
+int cucul_create_frame(cucul_canvas_t *cv, int id)
 {
-    unsigned int size = cv->width * cv->height;
-    unsigned int f;
+    int size = cv->width * cv->height;
+    int f;
 
-    if(id > cv->framecount)
+    if(id < 0)
+        id = 0;
+    else if(id > cv->framecount)
         id = cv->framecount;
 
     cv->framecount++;
@@ -194,11 +197,11 @@ int cucul_create_frame(cucul_canvas_t *cv, unsigned int id)
  *  \param id The index of the frame to delete
  *  \return 0 in case of success, -1 if an error occurred.
  */
-int cucul_free_frame(cucul_canvas_t *cv, unsigned int id)
+int cucul_free_frame(cucul_canvas_t *cv, int id)
 {
-    unsigned int f;
+    int f;
 
-    if(id >= cv->framecount)
+    if(id < 0 || id >= cv->framecount)
     {
         seterrno(EINVAL);
         return -1;
diff --git a/cucul/transform.c b/cucul/transform.c
index 69ccb77..a35dac7 100644
--- a/cucul/transform.c
+++ b/cucul/transform.c
@@ -46,7 +46,7 @@ static void rightpair(uint32_t pair[2]);
 int cucul_invert(cucul_canvas_t *cv)
 {
     uint32_t *attrs = cv->attrs;
-    unsigned int i;
+    int i;
 
     for(i = cv->height * cv->width; i--; )
     {
@@ -71,7 +71,7 @@ int cucul_invert(cucul_canvas_t *cv)
  */
 int cucul_flip(cucul_canvas_t *cv)
 {
-    unsigned int y;
+    int y;
 
     for(y = 0; y < cv->height; y++)
     {
@@ -130,7 +130,7 @@ int cucul_flip(cucul_canvas_t *cv)
  */
 int cucul_flop(cucul_canvas_t *cv)
 {
-    unsigned int x;
+    int x;
 
     for(x = 0; x < cv->width; x++)
     {
@@ -180,7 +180,7 @@ int cucul_rotate_180(cucul_canvas_t *cv)
     uint32_t *cend = cbegin + cv->width * cv->height - 1;
     uint32_t *abegin = cv->attrs;
     uint32_t *aend = abegin + cv->width * cv->height - 1;
-    unsigned int y;
+    int y;
 
     while(cbegin < cend)
     {
@@ -242,7 +242,7 @@ int cucul_rotate_180(cucul_canvas_t *cv)
 int cucul_rotate_left(cucul_canvas_t *cv)
 {
     uint32_t *newchars, *newattrs;
-    unsigned int x, y, w2, h2;
+    int x, y, w2, h2;
 
     if(cv->refcount)
     {
@@ -359,7 +359,7 @@ int cucul_rotate_left(cucul_canvas_t *cv)
 int cucul_rotate_right(cucul_canvas_t *cv)
 {
     uint32_t *newchars, *newattrs;
-    unsigned int x, y, w2, h2;
+    int x, y, w2, h2;
 
     if(cv->refcount)
     {
@@ -474,7 +474,7 @@ int cucul_rotate_right(cucul_canvas_t *cv)
 int cucul_stretch_left(cucul_canvas_t *cv)
 {
     uint32_t *newchars, *newattrs;
-    unsigned int x, y;
+    int x, y;
 
     if(cv->refcount)
     {
@@ -565,7 +565,7 @@ int cucul_stretch_left(cucul_canvas_t *cv)
 int cucul_stretch_right(cucul_canvas_t *cv)
 {
     uint32_t *newchars, *newattrs;
-    unsigned int x, y;
+    int x, y;
 
     if(cv->refcount)
     {
diff --git a/examples/text.c b/examples/text.c
index 0f763b2..2569c8d 100644
--- a/examples/text.c
+++ b/examples/text.c
@@ -37,8 +37,8 @@ int main(int argc, char *argv[])
 {
     cucul_canvas_t *cv, *pig;
     void *buffer;
-    unsigned long int len;
-    unsigned int i, j;
+    size_t len;
+    int i, j;
 
     pig = cucul_create_canvas(0, 0);
     cucul_import_memory(pig, STRING, strlen(STRING), "text");