section: Move properties into Row

eek/eek-keyboard.c

@@ -432,9 +432,9 @@ EekKeyboard *level_keyboard_current(LevelKeyboard *keyboard)
 }
 
 struct GetSectionData {
-    const struct squeek_button *button;
+    struct squeek_button *button;
     EekSection *section;
-    const struct squeek_key *needle;
+    struct squeek_key *needle;
 };
 
 void find_button_in_section(EekElement *element, gpointer user_data) {
@@ -449,7 +449,7 @@ void find_button_in_section(EekElement *element, gpointer user_data) {
 }
 
 EekSection *eek_keyboard_get_section(EekKeyboard *keyboard,
-                                     const struct squeek_button *button) {
+                                     struct squeek_button *button) {
     struct GetSectionData data = {
         .button = button,
         .section = NULL,
@@ -473,7 +473,7 @@ void find_key_in_section(EekElement *element, gpointer user_data) {
 
 // TODO: return multiple
 struct button_place eek_keyboard_get_button_by_state(EekKeyboard *keyboard,
-                                             const struct squeek_key *key) {
+                                             struct squeek_key *key) {
     struct GetSectionData data = {
         .section = NULL,
         .button = NULL,
@@ -482,7 +482,7 @@ struct button_place eek_keyboard_get_button_by_state(EekKeyboard *keyboard,
     eek_container_foreach_child(EEK_CONTAINER(keyboard), find_key_in_section, &data);
     struct button_place ret = {
         .section = data.section,
-        .button = (struct squeek_button*)data.button,
+        .button = data.button,
     };
     return ret;
 }

eek/eek-keyboard.h

@@ -158,7 +158,7 @@ EekSection         *eek_keyboard_create_section
                                      (EekKeyboard        *keyboard);
 EekSection         *eek_keyboard_get_section
                                      (EekKeyboard *keyboard,
-                                      const struct squeek_button *button);
+                                      struct squeek_button *button);
 struct squeek_button *eek_keyboard_find_button_by_name(LevelKeyboard *keyboard,
                                       const gchar        *name);
 
@@ -169,7 +169,7 @@ struct button_place {
 };
 
 struct button_place eek_keyboard_get_button_by_state(EekKeyboard *keyboard,
-                                             const struct squeek_key *key);
+                                             struct squeek_key *key);
 
 EekOutline         *level_keyboard_get_outline
                                      (LevelKeyboard        *keyboard,
@@ -196,5 +196,9 @@ void level_keyboard_free(LevelKeyboard *self);
 EekSection *
 eek_keyboard_real_create_section (EekKeyboard *self);
 
+struct squeek_row *
+eek_keyboard_real_create_row (EekKeyboard *self);
+
+
 G_END_DECLS
 #endif  /* EEK_KEYBOARD_H */

eek/eek-renderer.c

@@ -93,10 +93,9 @@ struct _CreateKeyboardSurfaceCallbackData {
 typedef struct _CreateKeyboardSurfaceCallbackData CreateKeyboardSurfaceCallbackData;
 
 static void
-create_keyboard_surface_button_callback (gpointer item,
+create_keyboard_surface_button_callback (struct squeek_button *button,
                                       gpointer    user_data)
 {
-    struct squeek_button *button = item;
     CreateKeyboardSurfaceCallbackData *data = user_data;
     EekBounds bounds = squeek_button_get_bounds(button);
 
@@ -978,10 +977,9 @@ sign (EekPoint *p1, EekPoint *p2, EekPoint *p3)
 }
 
 static void
-find_button_by_position_key_callback (gpointer item,
+find_button_by_position_key_callback (struct squeek_button *button,
                                    gpointer user_data)
 {
-    struct squeek_button *button = item;
     FindKeyByPositionCallbackData *data = user_data;
     if (data->button) {
         return;

eek/eek-section.c

@@ -44,36 +44,11 @@ enum {
 
 typedef struct _EekSectionPrivate
 {
-    gint angle;
+    struct squeek_row *row;
-    EekModifierType modifiers;
-    GPtrArray *buttons; // struct squeek_button*
 } EekSectionPrivate;
 
 G_DEFINE_TYPE_WITH_PRIVATE (EekSection, eek_section, EEK_TYPE_ELEMENT)
 
-struct squeek_button*
-eek_section_create_button (EekSection *self,
-                             const gchar *name,
-                             guint        keycode,
-                             guint oref)
-{
-    struct squeek_button *button = squeek_button_new(keycode, oref);
-    g_return_val_if_fail (button, NULL);
-    EekSectionPrivate *priv = eek_section_get_instance_private (self);
-    g_ptr_array_add(priv->buttons, button);
-    return button;
-}
-
-struct squeek_button *eek_section_create_button_with_state(EekSection *self,
-                                  const gchar *name,
-                                    struct squeek_button *source) {
-    struct squeek_button *button = squeek_button_new_with_state(source);
-    g_return_val_if_fail (button, NULL);
-    EekSectionPrivate *priv = eek_section_get_instance_private (self);
-    g_ptr_array_add(priv->buttons, button);
-    return button;
-}
-
 static void
 eek_section_finalize (GObject *object)
 {
@@ -143,7 +118,7 @@ static void
 eek_section_init (EekSection *self)
 {
     EekSectionPrivate *priv = eek_section_get_instance_private (self);
-    priv->buttons = g_ptr_array_new();
+    priv->row = squeek_row_new(0);
 }
 
 /**
@@ -161,10 +136,7 @@ eek_section_set_angle (EekSection  *section,
 
     EekSectionPrivate *priv = eek_section_get_instance_private (section);
 
-    if (priv->angle != angle) {
+    squeek_row_set_angle(priv->row, angle);
-        priv->angle = angle;
-        g_object_notify (G_OBJECT(section), "angle");
-    }
 }
 
 /**
@@ -180,7 +152,16 @@ eek_section_get_angle (EekSection *section)
 
     EekSectionPrivate *priv = eek_section_get_instance_private (section);
 
-    return priv->angle;
+    return squeek_row_get_angle(priv->row);
+}
+
+struct squeek_row *
+eek_section_get_row (EekSection *section)
+{
+    g_return_val_if_fail (EEK_IS_SECTION(section), NULL);
+
+    EekSectionPrivate *priv = eek_section_get_instance_private (section);
+    return priv->row;
 }
 
 const double keyspacing = 4.0;
@@ -191,14 +172,7 @@ struct keys_info {
     double biggest_height;
 };
 
-/// Set button size to match the outline. Reset position
+EekBounds eek_get_outline_size(LevelKeyboard *keyboard, uint32_t oref) {
-static void
-buttonsizer(gpointer item, gpointer user_data)
-{
-    struct squeek_button *button = item;
-
-    LevelKeyboard *keyboard = user_data;
-    uint oref = squeek_button_get_oref(button);
     EekOutline *outline = level_keyboard_get_outline (keyboard, oref);
     if (outline && outline->num_points > 0) {
         double minx = outline->points[0].x;
@@ -225,81 +199,47 @@ buttonsizer(gpointer item, gpointer user_data)
             .x = 0,
             .y = 0,
         };
-        squeek_button_set_bounds(button, key_bounds);
+        return key_bounds;
     }
+    EekBounds bounds = {0, 0, 0, 0};
+    return bounds;
 }
 
-static void
+void eek_section_set_bounds(EekSection *section, EekBounds bounds) {
-buttoncounter (gpointer item, gpointer user_data)
+    eek_element_set_bounds(EEK_ELEMENT(section), &bounds);
-{
-    struct squeek_button *button = item;
-    struct keys_info *data = user_data;
-    data->count++;
-    EekBounds key_bounds = squeek_button_get_bounds(button);
-    data->total_width += key_bounds.width;
-    if (key_bounds.height > data->biggest_height) {
-        data->biggest_height = key_bounds.height;
-    }
-}
-
-static void
-buttonplacer(gpointer item, gpointer user_data)
-{
-    struct squeek_button *button = item;
-    double *current_offset = user_data;
-    EekBounds key_bounds = squeek_button_get_bounds(button);
-    key_bounds.x = *current_offset;
-    key_bounds.y = 0;
-    squeek_button_set_bounds(button, key_bounds);
-    *current_offset += key_bounds.width + keyspacing;
 }
 
 void
 eek_section_place_keys(EekSection *section, LevelKeyboard *keyboard)
 {
     EekSectionPrivate *priv = eek_section_get_instance_private (section);
-
+    EekBounds section_size = squeek_row_place_keys(priv->row, keyboard);
-    g_ptr_array_foreach(priv->buttons, buttonsizer, keyboard);
-
-    struct keys_info keyinfo = {0};
-    g_ptr_array_foreach(priv->buttons, buttoncounter, &keyinfo);
-
     EekBounds section_bounds = {0};
     eek_element_get_bounds(EEK_ELEMENT(section), &section_bounds);
-
+    // FIXME: do centering of each section based on keyboard dimensions,
-    double key_offset = (section_bounds.width - (keyinfo.total_width + (keyinfo.count - 1) * keyspacing)) / 2;
+    // one level up the iterators
-    g_ptr_array_foreach(priv->buttons, buttonplacer, &key_offset);
+    // now centering by comparing previous width to the new, calculated one
-
+    section_bounds.x = (section_bounds.width - section_size.width) / 2;
-    section_bounds.height = keyinfo.biggest_height;
+    section_bounds.width = section_size.width;
+    section_bounds.height = section_size.height;
     eek_element_set_bounds(EEK_ELEMENT(section), &section_bounds);
 }
 
 void eek_section_foreach (EekSection *section,
-                     GFunc      func,
+                          ButtonCallback func,
                           gpointer   user_data) {
     EekSectionPrivate *priv = eek_section_get_instance_private (section);
-    g_ptr_array_foreach(priv->buttons, func, user_data);
+    squeek_row_foreach(priv->row, func, user_data);
 }
 
 gboolean eek_section_find(EekSection *section,
-                          const struct squeek_button *button) {
+                          struct squeek_button *button) {
     EekSectionPrivate *priv = eek_section_get_instance_private (section);
-    return g_ptr_array_find(priv->buttons, button, NULL);
+    return squeek_row_contains(priv->row, button) != 0;
-}
-
-static gboolean button_has_key(gconstpointer buttonptr, gconstpointer keyptr) {
-    const struct squeek_button *button = buttonptr;
-    const struct squeek_key *key = keyptr;
-    return squeek_button_has_key((struct squeek_button*)button, key) != 0;
 }
 
 struct squeek_button *eek_section_find_key(EekSection *section,
-                                           const struct squeek_key *key) {
+                                           struct squeek_key *key) {
     EekSectionPrivate *priv = eek_section_get_instance_private (section);
-    guint index;
+    return squeek_row_find_key(priv->row, key);
-    gboolean ret = g_ptr_array_find_with_equal_func(priv->buttons, key, button_has_key, &index);
-    if (ret) {
-        return g_ptr_array_index(priv->buttons, index);
-    }
-    return NULL;// TODO: store keys in locked_keys, pressed_keys
 }

eek/eek-section.h

@@ -64,6 +64,8 @@ GType   eek_section_get_type             (void) G_GNUC_CONST;
 void    eek_section_set_angle            (EekSection     *section,
                                           gint            angle);
 gint    eek_section_get_angle            (EekSection     *section);
+struct squeek_row *
+eek_section_get_row (EekSection *section);
 
 struct squeek_button *eek_section_create_button (EekSection     *section,
                                           const gchar    *name,
@@ -73,13 +75,13 @@ struct squeek_button *eek_section_create_button_with_state(EekSection *self,
                                     struct squeek_button *source);
 void eek_section_place_keys              (EekSection     *section, LevelKeyboard *keyboard);
 void eek_section_foreach (EekSection *section,
-                     GFunc      func,
+                     ButtonCallback func,
                      gpointer   user_data);
 
 gboolean eek_section_find(EekSection *section,
-                     const struct squeek_button *button);
+                     struct squeek_button *button);
 
 struct squeek_button *eek_section_find_key(EekSection *section,
-                                           const struct squeek_key *key);
+                                           struct squeek_key *key);
 G_END_DECLS
 #endif  /* EEK_SECTION_H */

eek/eek-xml-layout.c

@@ -235,6 +235,7 @@ struct _GeometryParseData {
     EekKeyboard **views;
     guint view_idx;
     EekSection *section;
+    struct squeek_row *row;
     gint num_rows;
     EekOrientation orientation;
     gdouble corner_radius;
@@ -375,6 +376,7 @@ geometry_start_element_callback (GMarkupParseContext *pcontext,
 
     if (g_strcmp0 (element_name, "section") == 0) {
         data->section = eek_keyboard_real_create_section (data->views[data->view_idx]);
+        data->row = eek_section_get_row(data->section);
         attribute = get_attribute (attribute_names, attribute_values,
                                    "id");
         if (attribute != NULL)
@@ -384,7 +386,7 @@ geometry_start_element_callback (GMarkupParseContext *pcontext,
         if (attribute != NULL) {
             gint angle;
             angle = strtol (attribute, NULL, 10);
-            eek_section_set_angle (data->section, angle);
+            squeek_row_set_angle (data->row, angle);
         }
 
         goto out;
@@ -566,15 +568,12 @@ geometry_end_element_callback (GMarkupParseContext *pcontext,
 
                 guint oref = GPOINTER_TO_UINT(g_hash_table_lookup(data->keyname_oref_hash, name));
                 // default value gives idx 0, which is guaranteed to be occupied
-                button = eek_section_create_button (data->section,
+                button = squeek_row_create_button (data->row, keycode, oref);
-                                                    name,
-                                                    keycode,
-                                              oref);
                 g_hash_table_insert (data->name_button_hash,
                                      g_strdup(name),
                                      button);
             } else {
-                struct squeek_button *new_button = eek_section_create_button_with_state(data->section, name, button);
+                struct squeek_button *new_button = squeek_row_create_button_with_state(data->row, button);
                 if (!new_button) {
                     g_set_error (error,
                                  G_MARKUP_ERROR,
@@ -586,6 +585,7 @@ geometry_end_element_callback (GMarkupParseContext *pcontext,
         }
 
         data->section = NULL;
+        data->row = NULL;
         data->num_rows = 0;
         return;
     }

src/float_ord.rs

@@ -0,0 +1,141 @@
+//! Order floating point numbers, into this ordering:
+//!
+//!    NaN | -Infinity | x < 0 | -0 | +0 | x > 0 | +Infinity | NaN
+
+/* Adapted from https://github.com/notriddle/rust-float-ord revision e995165f
+ * maintained by Michael Howell <michael@notriddle.com>
+ * licensed under MIT / Apache-2.0 licenses
+ */
+
+extern crate core;
+
+use ::float_ord::core::cmp::{Eq, Ord, Ordering, PartialEq, PartialOrd};
+use ::float_ord::core::hash::{Hash, Hasher};
+use ::float_ord::core::mem::transmute;
+
+/// A wrapper for floats, that implements total equality and ordering
+/// and hashing.
+#[derive(Clone, Copy)]
+pub struct FloatOrd<T>(pub T);
+
+macro_rules! float_ord_impl {
+    ($f:ident, $i:ident, $n:expr) => {
+        impl FloatOrd<$f> {
+            fn convert(self) -> $i {
+                let u = unsafe { transmute::<$f, $i>(self.0) };
+                let bit = 1 << ($n - 1);
+                if u & bit == 0 {
+                    u | bit
+                } else {
+                    !u
+                }
+            }
+        }
+        impl PartialEq for FloatOrd<$f> {
+            fn eq(&self, other: &Self) -> bool {
+                self.convert() == other.convert()
+            }
+        }
+        impl Eq for FloatOrd<$f> {}
+        impl PartialOrd for FloatOrd<$f> {
+            fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+                self.convert().partial_cmp(&other.convert())
+            }
+        }
+        impl Ord for FloatOrd<$f> {
+            fn cmp(&self, other: &Self) -> Ordering {
+                self.convert().cmp(&other.convert())
+            }
+        }
+        impl Hash for FloatOrd<$f> {
+            fn hash<H: Hasher>(&self, state: &mut H) {
+                self.convert().hash(state);
+            }
+        }
+    }
+}
+
+float_ord_impl!(f32, u32, 32);
+float_ord_impl!(f64, u64, 64);
+
+/// Sort a slice of floats.
+///
+/// # Allocation behavior
+///
+/// This routine uses a quicksort implementation that does not heap allocate.
+///
+/// # Example
+///
+/// ```
+/// let mut v = [-5.0, 4.0, 1.0, -3.0, 2.0];
+///
+/// float_ord::sort(&mut v);
+/// assert!(v == [-5.0, -3.0, 1.0, 2.0, 4.0]);
+/// ```
+#[allow(dead_code)]
+pub fn sort<T>(v: &mut [T]) where FloatOrd<T>: Ord {
+    let v_: &mut [FloatOrd<T>] = unsafe { transmute(v) };
+    v_.sort_unstable();
+}
+
+#[cfg(test)]
+mod tests {
+    extern crate std;
+
+    use self::std::collections::hash_map::DefaultHasher;
+    use self::std::hash::{Hash, Hasher};
+    use super::FloatOrd;
+
+    #[test]
+    fn test_ord() {
+        assert!(FloatOrd(1.0f64) < FloatOrd(2.0f64));
+        assert!(FloatOrd(2.0f32) > FloatOrd(1.0f32));
+        assert!(FloatOrd(1.0f64) == FloatOrd(1.0f64));
+        assert!(FloatOrd(1.0f32) == FloatOrd(1.0f32));
+        assert!(FloatOrd(0.0f64) > FloatOrd(-0.0f64));
+        assert!(FloatOrd(0.0f32) > FloatOrd(-0.0f32));
+        assert!(FloatOrd(::float_ord::core::f64::NAN) == FloatOrd(::float_ord::core::f64::NAN));
+        assert!(FloatOrd(::float_ord::core::f32::NAN) == FloatOrd(::float_ord::core::f32::NAN));
+        assert!(FloatOrd(-::float_ord::core::f64::NAN) < FloatOrd(::float_ord::core::f64::NAN));
+        assert!(FloatOrd(-::float_ord::core::f32::NAN) < FloatOrd(::float_ord::core::f32::NAN));
+        assert!(FloatOrd(-::float_ord::core::f64::INFINITY) < FloatOrd(::float_ord::core::f64::INFINITY));
+        assert!(FloatOrd(-::float_ord::core::f32::INFINITY) < FloatOrd(::float_ord::core::f32::INFINITY));
+        assert!(FloatOrd(::float_ord::core::f64::INFINITY) < FloatOrd(::float_ord::core::f64::NAN));
+        assert!(FloatOrd(::float_ord::core::f32::INFINITY) < FloatOrd(::float_ord::core::f32::NAN));
+        assert!(FloatOrd(-::float_ord::core::f64::NAN) < FloatOrd(::float_ord::core::f64::INFINITY));
+        assert!(FloatOrd(-::float_ord::core::f32::NAN) < FloatOrd(::float_ord::core::f32::INFINITY));
+    }
+
+    fn hash<F: Hash>(f: F) -> u64 {
+        let mut hasher = DefaultHasher::new();
+        f.hash(&mut hasher);
+        hasher.finish()
+    }
+
+    #[test]
+    fn test_hash() {
+        assert_ne!(hash(FloatOrd(0.0f64)), hash(FloatOrd(-0.0f64)));
+        assert_ne!(hash(FloatOrd(0.0f32)), hash(FloatOrd(-0.0f32)));
+        assert_eq!(hash(FloatOrd(-0.0f64)), hash(FloatOrd(-0.0f64)));
+        assert_eq!(hash(FloatOrd(0.0f32)), hash(FloatOrd(0.0f32)));
+        assert_ne!(hash(FloatOrd(::float_ord::core::f64::NAN)), hash(FloatOrd(-::float_ord::core::f64::NAN)));
+        assert_ne!(hash(FloatOrd(::float_ord::core::f32::NAN)), hash(FloatOrd(-::float_ord::core::f32::NAN)));
+        assert_eq!(hash(FloatOrd(::float_ord::core::f64::NAN)), hash(FloatOrd(::float_ord::core::f64::NAN)));
+        assert_eq!(hash(FloatOrd(-::float_ord::core::f32::NAN)), hash(FloatOrd(-::float_ord::core::f32::NAN)));
+    }
+
+    #[test]
+    fn test_sort_nan() {
+        let nan = ::float_ord::core::f64::NAN;
+        let mut v = [-1.0, 5.0, 0.0, -0.0, nan, 1.5, nan, 3.7];
+        super::sort(&mut v);
+        assert!(v[0] == -1.0);
+        assert!(v[1] == 0.0 && v[1].is_sign_negative());
+        assert!(v[2] == 0.0 && !v[2].is_sign_negative());
+        assert!(v[3] == 1.5);
+        assert!(v[4] == 3.7);
+        assert!(v[5] == 5.0);
+        assert!(v[6].is_nan());
+        assert!(v[7].is_nan());
+    }
+}

src/layout.h

@@ -7,17 +7,28 @@
 #include "src/keyboard.h"
 
 struct squeek_button;
+struct squeek_row;
 
-/*
+struct squeek_row *squeek_row_new(int32_t angle);
-struct squeek_buttons;
+struct squeek_button *squeek_row_create_button (struct squeek_row *row,
+                                          guint keycode, guint oref);
+struct squeek_button *squeek_row_create_button_with_state(struct squeek_row *row,
+                                    struct squeek_button *source);
+void squeek_row_set_angle(struct squeek_row *row, int32_t angle);
+int32_t squeek_row_get_angle(struct squeek_row*);
+
+uint32_t squeek_row_contains(struct squeek_row*, struct squeek_button *button);
+
+struct squeek_button* squeek_row_find_key(struct squeek_row*, struct squeek_key *state);
 
 typedef void (*ButtonCallback) (struct squeek_button *button, gpointer user_data);
-
+void squeek_row_foreach(struct squeek_row*,
-struct squeek_buttons *squeek_buttons_new();
-void squeek_buttons_free(struct squeek_buttons*);
-void squeek_buttons_foreach(const struct squeek_buttons*,
                             ButtonCallback   callback,
                             gpointer      user_data);
+
+void squeek_row_free(struct squeek_row*);
+
+/*
 struct squeek_button *squeek_buttons_find_by_position(
     const struct squeek_buttons *buttons,
     double x, double y,
@@ -26,6 +37,7 @@ struct squeek_button *squeek_buttons_find_by_position(
 void squeek_buttons_add(struct squeek_buttons*, const struct squeek_button* button);
 void squeek_buttons_remove_key(struct squeek_buttons*, const struct squeek_key* key);
 */
+
 struct squeek_button *squeek_button_new(uint32_t keycode, uint32_t oref);
 struct squeek_button *squeek_button_new_with_state(const struct squeek_button* source);
 uint32_t squeek_button_get_oref(const struct squeek_button*);
@@ -37,4 +49,8 @@ struct squeek_symbol *squeek_button_get_symbol (
 struct squeek_key *squeek_button_get_key(struct squeek_button*);
 uint32_t *squeek_button_has_key(const struct squeek_button* button,
                                 const struct squeek_key *key);
+void squeek_button_print(const struct squeek_button* button);
+
+
+EekBounds squeek_row_place_keys(struct squeek_row *row, LevelKeyboard *keyboard);
 #endif

src/layout.rs

@@ -1,25 +1,31 @@
 use std::cell::RefCell;
 use std::rc::Rc;
+use std::vec::Vec;
 
-use ::symbol::*;
 use ::keyboard::*;
+use ::float_ord::FloatOrd;
+use ::symbol::*;
 
 /// Gathers stuff defined in C or called by C
 pub mod c {
     use super::*;
 
+    use std::os::raw::c_void;
     use std::ptr;
 
     // The following defined in C
 
+    #[repr(transparent)]
+    pub struct UserData(*const c_void);
+    
     /// The index in the relevant outline table
     #[repr(C)]
-    #[derive(Clone)]
+    #[derive(Clone, Debug)]
     pub struct OutlineRef(u32);
 
     /// Defined in eek-types.h
     #[repr(C)]
-    #[derive(Clone)]
+    #[derive(Clone, Debug)]
     pub struct Bounds {
         x: f64,
         y: f64,
@@ -27,6 +33,114 @@ pub mod c {
         height: f64
     }
     
+    type ButtonCallback = unsafe extern "C" fn(button: *mut ::layout::Button, data: *mut UserData);
+
+    // The following defined in Rust. TODO: wrap naked pointers to Rust data inside RefCells to prevent multiple writers
+    
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_row_new(angle: i32) -> *mut ::layout::Row {
+        Box::into_raw(Box::new(::layout::Row {
+            buttons: Vec::new(),
+            angle: angle,
+        }))
+    }
+    
+    /// Places a button into the row and returns a reference to it
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_row_create_button(
+        row: *mut ::layout::Row,
+        keycode: u32, oref: u32
+    ) -> *mut ::layout::Button {
+        let row = unsafe { &mut *row };
+        let state: Rc<RefCell<::keyboard::KeyState>> = Rc::new(RefCell::new(
+            ::keyboard::KeyState {
+                pressed: false,
+                locked: false,
+                keycode: keycode,
+                symbol: None,
+            }
+        ));
+        row.buttons.push(Box::new(::layout::Button {
+            oref: OutlineRef(oref),
+            bounds: None,
+            state: state,
+        }));
+        // Return the reference directly instead of a Box, it's not on the stack
+        // It will live as long as the Vec
+        let last_idx = row.buttons.len() - 1;
+        // Caution: Box can't be returned directly,
+        // so returning a reference to its innards
+        row.buttons[last_idx].as_mut() as *mut ::layout::Button
+    }
+    
+    /// Places a button into the row, copying its state,
+    /// and returns a reference to it
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_row_create_button_with_state(
+        row: *mut ::layout::Row,
+        button: *const ::layout::Button,
+    ) -> *mut ::layout::Button {
+        let row = unsafe { &mut *row };
+        let source = unsafe { &*button };
+        row.buttons.push(Box::new(source.clone()));
+        // Return the reference directly instead of a Box, it's not on the stack
+        // It will live as long as the Vec
+        let last_idx = row.buttons.len() - 1;
+        // Caution: Box can't be returned directly,
+        // so returning a reference to its innards directly
+        row.buttons[last_idx].as_mut() as *mut ::layout::Button
+    }
+    
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_row_set_angle(row: *mut ::layout::Row, angle: i32) {
+        let row = unsafe { &mut *row };
+        row.angle = angle;
+    }
+    
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_row_get_angle(row: *const ::layout::Row) -> i32 {
+        let row = unsafe { &*row };
+        row.angle
+    }
+    
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_row_contains(
+        row: *mut ::layout::Row,
+        needle: *const ::layout::Button,
+    ) -> u32 {
+        let row = unsafe { &mut *row };
+        row.buttons.iter().position(
+            // TODO: wrap Button properly in Rc; this comparison is unreliable
+            |button| button.as_ref() as *const ::layout::Button == needle
+        ).is_some() as u32
+    }
+    
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_row_foreach(
+        row: *mut ::layout::Row,
+        callback: ButtonCallback,
+        data: *mut UserData,
+    ) {
+        let row = unsafe { &mut *row };
+        for button in row.buttons.iter_mut() {
+            let button = button.as_mut() as *mut ::layout::Button;
+            unsafe { callback(button, data) };
+        }
+    }
+    
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_row_free(row: *mut ::layout::Row) {
+        unsafe { Box::from_raw(row) }; // gets dropped
+    }
+
     #[no_mangle]
     pub extern "C"
     fn squeek_button_new(keycode: u32, oref: u32) -> *mut ::layout::Button {
@@ -117,6 +231,108 @@ pub mod c {
         equal as u32
     }
     
+    #[no_mangle]
+    pub extern "C"
+    fn squeek_button_print(button: *const ::layout::Button) {
+        let button = unsafe { &*button };
+        println!("{:?}", button);
+    }
+    
+    /// More complex procedures and algoithms which span multiple modules
+    mod procedures {
+        use super::*;
+        
+        use std::convert::TryFrom;
+
+        #[repr(transparent)]
+        pub struct LevelKeyboard(*const c_void);
+
+        #[no_mangle]
+        extern "C" {
+            fn eek_get_outline_size(
+                keyboard: *const LevelKeyboard,
+                outline: u32
+            ) -> Bounds;
+        }
+        
+        const BUTTON_SPACING: f64 = 4.0;
+        
+        /// Places each button in order, starting from 0 on the left,
+        /// keeping the spacing.
+        /// Sizes each button according to outline dimensions.
+        /// Returns the width and height of the resulting row.
+        #[no_mangle]
+        pub extern "C"
+        fn squeek_row_place_keys(
+            row: *mut ::layout::Row,
+            keyboard: *const LevelKeyboard,
+        ) -> Bounds {
+            let row = unsafe { &mut *row };
+
+            // Size buttons
+            for mut button in &mut row.buttons {
+                button.bounds = Some(
+                    unsafe { eek_get_outline_size(keyboard, button.oref.0) }
+                );
+            }
+
+            // Place buttons
+            let cumulative_width: f64 = row.buttons.iter().map(
+                |button| button.bounds.as_ref().unwrap().width
+            ).sum();
+
+            let max_height = row.buttons.iter().map(
+                |button| FloatOrd(
+                    button.bounds.as_ref().unwrap().height
+                )
+            ).max()
+                .unwrap_or(FloatOrd(0f64))
+                .0;
+
+            row.buttons.iter_mut().fold(0f64, |acc, button| {
+                let mut bounds = button.bounds.as_mut().unwrap();
+                bounds.x = acc;
+                acc + bounds.width + BUTTON_SPACING
+            });
+            
+            // Total size
+            let total_width = match row.buttons.is_empty() {
+                true => 0f64,
+                false => {
+                    let last_button = &row.buttons[row.buttons.len() - 1];
+                    let bounds = last_button.bounds.as_ref().unwrap();
+                    bounds.x + bounds.width
+                },
+            };
+
+            Bounds {
+                x: 0f64,
+                y: 0f64,
+                width: total_width,
+                height: max_height,
+            }
+        }
+
+        /// Finds a button sharing this state
+        #[no_mangle]
+        pub extern "C"
+        fn squeek_row_find_key(
+            row: *mut ::layout::Row,
+            state: ::keyboard::c::CKeyState,
+        ) -> *mut Button {
+            let row = unsafe { &mut *row };
+            let needle = state.unwrap();
+            let found = row.buttons.iter_mut().find(
+                |button| Rc::ptr_eq(&button.state, &needle)
+            );
+            Rc::into_raw(needle); // Prevent dropping
+            match found {
+                Some(button) => button.as_mut() as *mut Button,
+                None => ptr::null_mut(),
+            }
+        }
+    }
+    
     #[cfg(test)]
     mod test {
         use super::*;
@@ -133,11 +349,22 @@ pub mod c {
             let shared_button = squeek_button_new_with_state(button);
             assert_eq!(squeek_button_has_key(shared_button, state), 1);
         }
+        
+        #[test]
+        fn row_has_button() {
+            let row = squeek_row_new(0);
+            let button = squeek_row_create_button(row, 0, 0);
+            assert_eq!(squeek_row_contains(row, button), 1);
+            let shared_button = squeek_row_create_button_with_state(row, button);
+            assert_eq!(squeek_row_contains(row, shared_button), 1);
+            let row = squeek_row_new(0);
+            assert_eq!(squeek_row_contains(row, button), 0);
+        }
     }
 }
 
 /// The graphical representation of a button
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Button {
     oref: c::OutlineRef,
     /// TODO: abolish Option, buttons should be created with bounds fully formed
@@ -145,3 +372,8 @@ pub struct Button {
     /// current state, shared with other buttons
     pub state: Rc<RefCell<KeyState>>,
 }
+
+pub struct Row {
+    buttons: Vec<Box<Button>>,
+    angle: i32,
+}

src/lib.rs

@@ -1,6 +1,7 @@
 #[macro_use]
 mod bitflags;
 
+mod float_ord;
 mod imservice;
 mod keyboard;
 mod layout;

src/util.rs

@@ -3,6 +3,7 @@ pub mod c {
     use std::os::raw::c_char;
     use std::str::Utf8Error;
     
+    #[allow(dead_code)]
     pub fn as_str(s: &*const c_char) -> Result<Option<&str>, Utf8Error> {
         if s.is_null() {
             Ok(None)

tests/eek-simple-test.c

@@ -31,9 +31,11 @@ test_create (void)
     keyboard = g_object_new (EEK_TYPE_KEYBOARD, NULL);
     section = eek_keyboard_real_create_section (keyboard);
     g_assert (EEK_IS_SECTION(section));
-    button0 = eek_section_create_button (section, "key0", 1, 0);
+    struct squeek_row *row = eek_section_get_row(section);
+    g_assert (row);
+    button0 = squeek_row_create_button (row, 1, 0);
     g_assert (button0);
-    button1 = eek_section_create_button (section, "key1", 2, 0);
+    button1 = squeek_row_create_button (row, 2, 0);
     g_assert (button1);
 }