drawing: Generalized foreach_visible_button

src/drawing.rs

@@ -47,22 +47,17 @@ mod c {
         let layout = unsafe { &mut *layout };
         let cr = unsafe { cairo::Context::from_raw_none(cr) };
 
-        let (view_offset, view) = layout.get_current_view_position();
-        for (row_offset, row) in &view.get_rows() {
-            for (x_offset, button) in &row.buttons {
+        layout.foreach_visible_button(|offset, button| {
             let state = RefCell::borrow(&button.state).clone();
             if state.pressed == keyboard::PressType::Pressed || state.locked {
                 render_button_at_position(
                     renderer, &cr,
-                        view_offset
-                            + row_offset.clone()
-                            + Point { x: *x_offset, y: 0.0 },
+                    offset,
                     button.as_ref(),
                     state.pressed, state.locked,
                 );
             }
-            }
-        }
+        })
     }
     
     #[no_mangle]
@@ -74,19 +69,15 @@ mod c {
     ) {
         let layout = unsafe { &mut *layout };
         let cr = unsafe { cairo::Context::from_raw_none(cr) };
-        let (view_offset, view) = layout.get_current_view_position();
-        for (row_offset, row) in &view.get_rows() {
-            for (x_offset, button) in &row.buttons {
+        
+        layout.foreach_visible_button(|offset, button| {
             render_button_at_position(
                 renderer, &cr,
-                    view_offset
-                            + row_offset.clone()
-                            + Point { x: *x_offset, y: 0.0 },
+                offset,
                 button.as_ref(),
                 keyboard::PressType::Released, false,
             );
-            }
-        }
+        })
     }
 }
 

src/layout.rs

@@ -728,6 +728,20 @@ impl Layout {
         let (offset, layout) = self.get_current_view_position();
         layout.find_button_by_position(point - offset)
     }
+
+    pub fn foreach_visible_button<F>(&self, mut f: F)
+        where F: FnMut(c::Point, &Box<Button>)
+    {
+        let (view_offset, view) = self.get_current_view_position();
+        for (row_offset, row) in &view.get_rows() {
+            for (x_offset, button) in &row.buttons {
+                let offset = view_offset
+                    + row_offset.clone()
+                    + c::Point { x: *x_offset, y: 0.0 };
+                f(offset, button);
+            }
+        }
+    }
 }
 
 mod procedures {