Check for button position more in Rust

The check against fitting inside the Layout was removed: as an optimization it is unneeded, as the actual search must be optimized to be quick. In addition, the view bounds don't correspond to anything physical as long as negative offsets are allowed.

src/layout.h

@@ -25,7 +25,6 @@ uint32_t squeek_row_contains(struct squeek_row*, struct squeek_button *button);
 
 struct button_place squeek_view_find_key(struct squeek_view*, struct squeek_key *state);
 
-struct squeek_button *squeek_row_find_button_by_position(struct squeek_row *row, EekPoint point, EekPoint origin);
 
 typedef void (*ButtonCallback) (struct squeek_button *button, gpointer user_data);
 void squeek_row_foreach(struct squeek_row*,
@@ -74,4 +73,6 @@ struct squeek_row *squeek_view_get_row(struct squeek_view *view,
 
 void
 squeek_view_place_contents(struct squeek_view *view, LevelKeyboard *keyboard);
+
+struct squeek_button *squeek_view_find_button_by_position(struct squeek_view *view, EekPoint point);
 #endif

src/layout.rs

@@ -1,3 +1,22 @@
+/**
+ * Layout-related data.
+ * 
+ * The `View` contains `Row`s and each `Row` contains `Button`s.
+ * They carry data relevant to their positioning only,
+ * except the Button, which also carries some data
+ * about its appearance and function.
+ * 
+ * The layout is determined bottom-up, by measuring `Button` sizes,
+ * deriving `Row` sizes from them, and then centering them within the `View`.
+ * 
+ * That makes the `View` position immutable,
+ * and therefore different than the other positions.
+ * 
+ * Note that it might be a better idea
+ * to make `View` position depend on its contents,
+ * and let the renderer scale and center it within the widget.
+ */
+
 use std::cell::RefCell;
 use std::rc::Rc;
 use std::vec::Vec;
@@ -310,7 +329,7 @@ pub mod c {
     }
     
     /// Entry points for more complex procedures and algoithms which span multiple modules
-    mod procedures {
+    pub mod procedures {
         use super::*;
         
         #[repr(transparent)]
@@ -332,7 +351,7 @@ pub mod c {
 
             /// Checks if point falls within bounds,
             /// which are relative to origin and rotated by angle (I think)
-            fn eek_are_bounds_inside (bounds: Bounds,
+            pub fn eek_are_bounds_inside (bounds: Bounds,
                 point: Point,
                 origin: Point,
                 angle: i32
@@ -369,36 +388,6 @@ pub mod c {
             view.place_buttons_with_sizes(sizes);
         }
 
-        #[no_mangle]
-        pub extern "C"
-        fn squeek_row_find_button_by_position(
-            row: *mut Row, point: Point, origin: Point
-        ) -> *mut Button {
-            let row = unsafe { &mut *row };
-            let row_bounds = row.bounds
-                .as_ref().expect("Missing bounds on row");
-            let origin = Point {
-                x: origin.x + row_bounds.x,
-                y: origin.y + row_bounds.y,
-            };
-            let angle = row.angle;
-            let result = row.buttons.iter_mut().find(|button| {
-                let bounds = button.bounds
-                    .as_ref().expect("Missing bounds on button")
-                    .clone();
-                let point = point.clone();
-                let origin = origin.clone();
-                unsafe {
-                    eek_are_bounds_inside(bounds, point, origin, angle) == 1
-                }
-            });
-            
-            match result {
-                Some(button) => button.as_mut() as *mut Button,
-                None => ptr::null_mut(),
-            }
-        }
-        
         fn squeek_row_contains(row: &Row, needle: *const Button) -> bool {
             row.buttons.iter().position(
                 // TODO: wrap Button properly in Rc; this comparison is unreliable
@@ -446,6 +435,20 @@ pub mod c {
             };
             ButtonPlace { row, button }
         }
+
+
+        #[no_mangle]
+        pub extern "C"
+        fn squeek_view_find_button_by_position(
+            view: *mut View, point: Point
+        ) -> *mut Button {
+            let view = unsafe { &mut *view };
+            let result = view.find_button_by_position(point);
+            match result {
+                Some(button) => button.as_mut() as *mut Button,
+                None => ptr::null_mut(),
+            }
+        }
         
         #[cfg(test)]
         mod test {
@@ -559,12 +562,13 @@ pub struct Size {
 pub struct Button {
     oref: c::OutlineRef,
     /// TODO: abolish Option, buttons should be created with bounds fully formed
+    /// Position relative to some origin (i.e. parent/row)
     bounds: Option<c::Bounds>,
     /// current state, shared with other buttons
     pub state: Rc<RefCell<KeyState>>,
 }
 
-
+// FIXME: derive from the style/margin/padding
 const BUTTON_SPACING: f64 = 4.0;
 const ROW_SPACING: f64 = 7.0;
 
@@ -573,6 +577,7 @@ pub struct Row {
     buttons: Vec<Box<Button>>,
     /// Angle is not really used anywhere...
     angle: i32,
+    /// Position relative to some origin (i.e. parent/view origin)
     bounds: Option<c::Bounds>,
 }
 
@@ -621,6 +626,27 @@ impl Row {
         };
         Size { width: total_width, height: max_height }
     }
+
+    /// Finds the first button that covers the specified point
+    /// relative to row's position's origin
+    fn find_button_by_position(&mut self, point: c::Point)
+        -> Option<&mut Box<Button>>
+    {
+        let row_bounds = self.bounds.as_ref().expect("Missing bounds on row");
+        let origin = c::Point {
+            x: row_bounds.x,
+            y: row_bounds.y,
+        };
+        let angle = self.angle;
+        self.buttons.iter_mut().find(|button| {
+            let bounds = button.bounds
+                .as_ref().expect("Missing bounds on button")
+                .clone();
+            let point = point.clone();
+            let origin = origin.clone();
+            procedures::is_point_inside(bounds, point, origin, angle)
+        })
+    }
 }
 
 pub struct View {
@@ -633,8 +659,10 @@ impl View {
     /// Determines the positions of rows based on their sizes
     /// Each row will be centered horizontally
     /// The collection of rows will not be altered vertically
-    /// (TODO: make view bounds a constraint,
+    /// (TODO: maybe make view bounds a constraint,
     /// and derive a scaling factor that lets contents fit into view)
+    /// (or TODO: blow up view bounds to match contents
+    /// and then scale the entire thing)
     fn calculate_row_positions(&self, sizes: Vec<Size>) -> Vec<c::Bounds> {
         let mut y_offset = self.bounds.y;
         sizes.into_iter().map(|size| {
@@ -680,6 +708,23 @@ impl View {
             }
         }
     }
+
+    /// Finds the first button that covers the specified point
+    /// relative to view's position's origin
+    fn find_button_by_position(&mut self, point: c::Point)
+        -> Option<&mut Box<Button>>
+    {
+        // make point relative to the inside of the view,
+        // which is the origin of all rows
+        let point = c::Point {
+            x: point.x - self.bounds.x,
+            y: point.y - self.bounds.y,
+        };
+
+        self.rows.iter_mut().find_map(
+            |row| row.find_button_by_position(point.clone())
+        )
+    }
 }
 
 mod procedures {
@@ -703,4 +748,17 @@ mod procedures {
             row_paths.into_iter()
         }).collect()
     }
+    
+    /// Checks if point is inside bounds which are rotated by angle.
+    /// FIXME: what's origin about?
+    pub fn is_point_inside(
+        bounds: c::Bounds,
+        point: c::Point,
+        origin: c::Point,
+        angle: i32
+    ) -> bool {
+        (unsafe {
+            c::procedures::eek_are_bounds_inside(bounds, point, origin, angle)
+        }) == 1
+    }
 }