Clean up AutoLayout wrapper.

- Anchors are now enums, which help in debugging constraint issues.

- Enum types that are acceptable for constraint generation are now
  matched at runtime, and provide better error messages if a constraint
  can't be satisfied and crashes the app.

- `left` and `right` anchors are now supported on all widgets, fixing an
  oversight from early iterations of the framework.

- Reduces `unsafe` usage by a decent amount when setting constraint
  pointers for widget types.

src/button/mod.rs

@@ -38,9 +38,15 @@ pub struct Button {
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -77,14 +83,16 @@ impl Button {
         Button {
             handler: None,
             image: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: unsafe { ShareId::from_ptr(view) },
         }
     }

src/image/mod.rs

@@ -44,16 +44,22 @@ fn allocate_view(registration_fn: fn() -> *const Class) -> id {
 pub struct ImageView {
     /// A pointer to the Objective-C runtime view controller.
     pub objc: ShareId<Object>,
-
+    
     /// A pointer to the Objective-C runtime top layout constraint.
     pub top: LayoutAnchorY,
 
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -82,14 +88,16 @@ impl ImageView {
         let view = allocate_view(register_image_view_class);
 
         ImageView {
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: unsafe { ShareId::from_ptr(view) },
         }
     }

src/input/mod.rs

@@ -89,16 +89,22 @@ pub struct TextField<T = ()> {
 
     /// A pointer to the delegate for this view.
     pub delegate: Option<Box<T>>,
-
+    
     /// A pointer to the Objective-C runtime top layout constraint.
     pub top: LayoutAnchorY,
 
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -128,14 +134,16 @@ impl TextField {
 
         TextField {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: unsafe { ShareId::from_ptr(view) },
         }
     }
@@ -157,14 +165,16 @@ impl<T> TextField<T> where T: TextFieldDelegate + 'static {
 
         let mut label = TextField {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![label, topAnchor] }),
+            top: LayoutAnchorY::top(label),
-            leading: LayoutAnchorX::new(unsafe { msg_send![label, leadingAnchor] }),
+            left: LayoutAnchorX::left(label),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![label, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(label),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![label, bottomAnchor] }),
+            right: LayoutAnchorX::right(label),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![label, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(label),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![label, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(label),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![label, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(label),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![label, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(label),
+            center_x: LayoutAnchorX::center(label),
+            center_y: LayoutAnchorY::center(label),
             objc: unsafe { ShareId::from_ptr(label) },
         };
 
@@ -184,7 +194,9 @@ impl<T> TextField<T> {
             delegate: None,
             top: self.top.clone(),
             leading: self.leading.clone(),
+            left: self.left.clone(),
             trailing: self.trailing.clone(),
+            right: self.right.clone(),
             bottom: self.bottom.clone(),
             width: self.width.clone(),
             height: self.height.clone(),

src/layout/dimension.rs

@@ -1,6 +1,3 @@
-//! A wrapper for `NSLayoutAnchorDimension`, which is typically used to handle `width` and `height`
-//! values for how a given view should layout.
-
 use core_graphics::base::CGFloat;
 
 use objc::{class, msg_send, sel, sel_impl};
@@ -15,82 +12,128 @@ use super::attributes::{LayoutAttribute, LayoutRelation};
 /// A wrapper for `NSLayoutAnchor`. You should never be creating this yourself - it's more of a
 /// factory/helper for creating `LayoutConstraint` objects based on your views.
 #[derive(Clone, Debug, Default)]
-pub struct LayoutAnchorDimension(pub Option<ShareId<Object>>);
+pub struct LayoutAnchorDimension2(pub Option<ShareId<Object>>);
+
+/// A wrapper for `NSLayoutAnchorDimension`, which is typically used to handle `width` and `height`
+/// values for how a given view should layout.
+#[derive(Clone, Debug)]
+pub enum LayoutAnchorDimension {
+    /// Represents an uninitialized anchor (e.g, for a view that's not created yet).
+    Uninitialized,
+
+    /// Represents a Width anchor.
+    Width(ShareId<Object>),
+
+    /// Represents a Height anchor.
+    Height(ShareId<Object>)
+}
+
+impl Default for LayoutAnchorDimension {
+    /// Returns an Uninitialized anchor dimension by default.
+    fn default() -> Self {
+        Self::Uninitialized
+    }
+}
 
 impl LayoutAnchorDimension {
-    /// An internal method for wrapping existing anchors.
+    /// Given a view, returns an anchor for the width anchor.
-    pub(crate) fn new(object: id) -> Self {
+    pub(crate) fn width(view: id) -> Self {
-        LayoutAnchorDimension(Some(unsafe {
+        Self::Width(unsafe {
-            ShareId::from_ptr(object)
+            ShareId::from_ptr(msg_send![view, widthAnchor])
-        }))
+        })
+    }
+
+    /// Given a view, returns an anchor for the height anchor.
+    pub(crate) fn height(view: id) -> Self {
+        Self::Height(unsafe {
+            ShareId::from_ptr(msg_send![view, heightAnchor])
+        })
     }
 
     /// Return a constraint equal to a constant value.
     pub fn constraint_equal_to_constant(&self, constant: f64) -> LayoutConstraint {
-        match &self.0 {
+        if let Self::Width(obj) | Self::Height(obj) = self {
-            Some(from) => LayoutConstraint::new(unsafe {
+            return LayoutConstraint::new(unsafe {
                 let value = constant as CGFloat;
-                msg_send![*from, constraintEqualToConstant:value]
+                msg_send![*obj, constraintEqualToConstant:value]
-            }),
+            });
+        }
+        
+        panic!("Attempted to create a constant constraint with an uninitialized anchor.");
+    }
 
-            _ => { panic!("Attempted to create constraints with an uninitialized anchor!"); }
+    /// Return a constraint greater than or equal to a constant value.
+    pub fn constraint_greater_than_or_equal_to_constant(&self, constant: f64) -> LayoutConstraint {
+        if let Self::Width(obj) | Self::Height(obj) = self {
+            return LayoutConstraint::new(unsafe {
+                let value = constant as CGFloat;
+                msg_send![*obj, constraintGreaterThanOrEqualToConstant:value]
+            });
+        }
+        
+        panic!("Attempted to create a constraint (>=) with an uninitialized anchor.");
+    }
+    
+    /// Return a constraint greater than or equal to a constant value.
+    pub fn constraint_less_than_or_equal_to_constant(&self, constant: f64) -> LayoutConstraint {
+        if let Self::Width(obj) | Self::Height(obj) = self {
+            return LayoutConstraint::new(unsafe {
+                let value = constant as CGFloat;
+                msg_send![*obj, constraintLessThanOrEqualToConstant:value]
+            });
+        }
+        
+        panic!("Attempted to create a constraint (<=) with an uninitialized anchor.");
+    }
+
+    /// Boilerplate for handling constraint construction and panic'ing with some more helpful
+    /// messages. The goal here is to make AutoLayout slightly easier to debug when things go
+    /// wrong.
+    fn constraint_with<F>(&self, anchor_to: &LayoutAnchorDimension, handler: F) -> LayoutConstraint
+    where
+        F: Fn(&ShareId<Object>, &ShareId<Object>) -> id
+    {
+        match (self, anchor_to) {
+            (Self::Width(from), Self::Width(to)) |
+            (Self::Width(from), Self::Height(to)) |
+            (Self::Height(from), Self::Width(to)) |
+            (Self::Height(from), Self::Height(to)) => {
+                LayoutConstraint::new(handler(from, to))
+            },
+            
+            (Self::Uninitialized, Self::Uninitialized) => {
+                panic!("Attempted to create constraints with an uninitialized \"from\" and \"to\" dimension anchor.");
+            },
+
+            (Self::Uninitialized, _) => {
+                panic!("Attempted to create constraints with an uninitialized \"from\" dimension anchor.");
+            },
+
+
+            (_, Self::Uninitialized) => {
+                panic!("Attempted to create constraints with an uninitialized \"to\" dimension anchor.");
+            }
         }
     }
 
     /// Return a constraint equal to another dimension anchor.
     pub fn constraint_equal_to(&self, anchor_to: &LayoutAnchorDimension) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintEqualToAnchor:&**to]
-                msg_send![*from, constraintEqualToAnchor:&**to]
+        })
-            }),
-
-            _ => { panic!("Attempted to create constraints with an uninitialized anchor!"); }
-        }
     }
 
     /// Return a constraint greater than or equal to another dimension anchor.
     pub fn constraint_greater_than_or_equal_to(&self, anchor_to: &LayoutAnchorDimension) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintGreaterThanOrEqualToAnchor:&**to]
-                msg_send![*from, constraintGreaterThanOrEqualToAnchor:&**to]
+        })
-            }),
-
-            _ => { panic!("Attempted to create constraints with an uninitialized anchor!"); }
-        }
-    }
-
-    /// Return a constraint greater than or equal to a constant value.
-    pub fn constraint_greater_than_or_equal_to_constant(&self, constant: f64) -> LayoutConstraint {
-        match &self.0 {
-            Some(from) => LayoutConstraint::new(unsafe {
-                let value = constant as CGFloat;
-                msg_send![*from, constraintGreaterThanOrEqualToConstant:value]
-            }),
-
-            _ => { panic!("Attempted to create constraints with an uninitialized anchor!"); }
-        }
     }
 
     /// Return a constraint less than or equal to another dimension anchor.
     pub fn constraint_less_than_or_equal_to(&self, anchor_to: &LayoutAnchorDimension) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintLessThanOrEqualToAnchor:&**to]
-                msg_send![*from, constraintLessThanOrEqualToAnchor:&**to]
+        })
-            }),
-
-            _ => { panic!("Attempted to create constraints with an uninitialized anchor!"); }
-        }
-    }
-
-    /// Return a constraint greater than or equal to a constant value.
-    pub fn constraint_less_than_or_equal_to_constant(&self, constant: f64) -> LayoutConstraint {
-        match &self.0 {
-            Some(from) => LayoutConstraint::new(unsafe {
-                let value = constant as CGFloat;
-                msg_send![*from, constraintLessThanOrEqualToConstant:value]
-            }),
-
-            _ => { panic!("Attempted to create constraints with an uninitialized anchor!"); }
-        }
     }
 }

src/layout/horizontal.rs

@@ -1,7 +1,3 @@
-//! A wrapper for `NSLayoutAnchorX`, which is typically used to handle values for how a 
-//! given view should layout along the x-axis. Of note: the only thing that can't be protected
-//! against is mixing/matching incorrect left/leading and right/trailing anchors. Be careful!
-
 use objc::{msg_send, sel, sel_impl};
 use objc::runtime::Object;
 use objc_id::ShareId;
@@ -9,49 +5,182 @@ use objc_id::ShareId;
 use crate::foundation::id;
 use crate::layout::constraint::LayoutConstraint;
 
-/// A wrapper for `NSLayoutAnchor`. You should never be creating this yourself - it's more of a
+/// A wrapper for `NSLayoutAnchorX`, used to handle values for how a given view should 
-/// factory/helper for creating `LayoutConstraint` objects based on your views.
+/// layout along the x-axis.
-#[derive(Clone, Debug, Default)]
+///
-pub struct LayoutAnchorX(pub Option<ShareId<Object>>);
+/// Of note: mismatches of incorrect left/leading and right/trailing anchors are detected at
+/// runtime, and will panic - this is by design, as your UI needs to work. Be careful!
+#[derive(Clone, Debug)]
+pub enum LayoutAnchorX {
+    /// Represents an uninitialized anchor (e.g, for a view that's not created yet).
+    Uninitialized,
+
+    /// Represents a leading anchor; side depends on system orientation.
+    Leading(ShareId<Object>),
+
+    /// Represents a left anchor.
+    Left(ShareId<Object>),
+
+    /// Represents a trailing anchor; side depends on system orientation.
+    Trailing(ShareId<Object>),
+
+    /// Represents a right anchor.
+    Right(ShareId<Object>),
+
+    /// Represents a center anchor on the X axis.
+    Center(ShareId<Object>)
+}
+
+impl Default for LayoutAnchorX {
+    /// Returns an uninitialized anchor by default.
+    fn default() -> Self {
+        Self::Uninitialized
+    }
+}
 
 impl LayoutAnchorX {
-    /// An internal method for wrapping existing anchors.
+    /// Given a view, returns an anchor for the leading anchor.
-    pub(crate) fn new(object: id) -> Self {
+    pub(crate) fn leading(view: id) -> Self {
-        LayoutAnchorX(Some(unsafe {
+        Self::Leading(unsafe {
-            ShareId::from_ptr(object)
+            ShareId::from_ptr(msg_send![view, leadingAnchor])
-        }))
+        })
+    }
+
+    /// Given a view, returns an anchor for the left anchor.
+    pub(crate) fn left(view: id) -> Self {
+        Self::Left(unsafe {
+            ShareId::from_ptr(msg_send![view, leftAnchor])
+        })
+    }
+
+    /// Given a view, returns an anchor for the trailing anchor.
+    pub(crate) fn trailing(view: id) -> Self {
+        Self::Trailing(unsafe {
+            ShareId::from_ptr(msg_send![view, trailingAnchor])
+        })
+    }
+
+    /// Given a view, returns an anchor for the right anchor.
+    pub(crate) fn right(view: id) -> Self {
+        Self::Right(unsafe {
+            ShareId::from_ptr(msg_send![view, rightAnchor])
+        })
+    }
+
+    /// Given a view, returns an anchor for the right anchor.
+    pub(crate) fn center(view: id) -> Self {
+        Self::Center(unsafe {
+            ShareId::from_ptr(msg_send![view, centerXAnchor])
+        })
+    }
+
+    /// Boilerplate for handling constraint construction and panic'ing with some more helpful
+    /// messages. The goal here is to make AutoLayout slightly easier to debug when things go
+    /// wrong.
+    fn constraint_with<F>(&self, anchor_to: &LayoutAnchorX, handler: F) -> LayoutConstraint
+    where
+        F: Fn(&ShareId<Object>, &ShareId<Object>) -> id
+    {
+        match (self, anchor_to) {
+            // The anchors that can connect to each other. These blocks could be condensed, but are
+            // kept separate for readability reasons.
+            (Self::Leading(from), Self::Leading(to)) | (Self::Leading(from), Self::Trailing(to)) |
+            (Self::Leading(from), Self::Center(to)) => {
+                LayoutConstraint::new(handler(from, to))
+            },
+
+            (Self::Trailing(from), Self::Trailing(to)) | (Self::Trailing(from), Self::Leading(to)) |
+            (Self::Trailing(from), Self::Center(to)) => {
+                LayoutConstraint::new(handler(from, to))
+            },
+
+            (Self::Left(from), Self::Left(to)) | (Self::Left(from), Self::Right(to)) |
+            (Self::Left(from), Self::Center(to)) => {
+                LayoutConstraint::new(handler(from, to))
+            },
+
+            (Self::Right(from), Self::Right(to)) | (Self::Right(from), Self::Left(to)) |
+            (Self::Right(from), Self::Center(to)) => {
+                LayoutConstraint::new(handler(from, to))
+            },
+
+            (Self::Center(from), Self::Center(to)) | (Self::Center(from), Self::Leading(to)) |
+            (Self::Center(from), Self::Trailing(to)) | (Self::Center(from), Self::Left(to)) |
+            (Self::Center(from), Self::Right(to)) => {
+                LayoutConstraint::new(handler(from, to))
+            },
+
+            // These anchors explicitly cannot be attached to each other, as it results in
+            // undefined/unexpected layout behavior when a system has differing ltr/rtl setups.
+            (Self::Leading(_), Self::Left(_)) | (Self::Left(_), Self::Leading(_)) => {
+                panic!(r#"
+                    Attempted to attach a "leading" constraint to a "left" constraint. This will 
+                    result in undefined behavior for LTR and RTL system settings, and Cacao blocks this.
+                    
+                    Use either left/right or leading/trailing.
+                "#);
+            },
+            
+            (Self::Leading(_), Self::Right(_)) | (Self::Right(_), Self::Leading(_)) => {
+                panic!(r#"
+                    Attempted to attach a "leading" constraint to a "right" constraint. This will 
+                    result in undefined behavior for LTR and RTL system settings, and Cacao blocks this.
+                    
+                    Use either left/right or leading/trailing.
+                "#);
+            },
+
+            (Self::Trailing(_), Self::Left(_)) | (Self::Left(_), Self::Trailing(_)) => {
+                panic!(r#"
+                    Attempted to attach a "trailing" constraint to a "left" constraint. This will 
+                    result in undefined behavior for LTR and RTL system settings, and Cacao blocks this.
+
+                    Use either left/right or leading/trailing.
+                "#);
+            },
+
+            (Self::Trailing(_), Self::Right(_)) | (Self::Right(_), Self::Trailing(_)) => {
+                panic!(r#"
+                    Attempted to attach a "trailing" constraint to a "right" constraint. This will 
+                    result in undefined behavior for LTR and RTL system settings, and Cacao blocks this.
+
+                    Use either left/right or leading/trailing.
+                "#);
+            },
+
+            // If anything is attempted with an uninitialized anchor, then block it.
+            (Self::Uninitialized, Self::Uninitialized) => {
+                panic!("Attempted to create constraints with an uninitialized \"from\" and \"to\" X anchor.");
+            },
+
+            (Self::Uninitialized, _) => {
+                panic!("Attempted to create constraints with an uninitialized \"from\" X anchor.");
+            },
+
+            (_, Self::Uninitialized) => {
+                panic!("Attempted to create constraints with an uninitialized \"to\" X anchor.");
+            }
+        }
     }
 
     /// Return a constraint equal to another horizontal anchor.
     pub fn constraint_equal_to(&self, anchor_to: &LayoutAnchorX) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintEqualToAnchor:&**to]
-                msg_send![*from, constraintEqualToAnchor:&**to]
+        })
-            }),
-
-            _ => { panic!("Attempted to create horizontal constraints with an uninitialized anchor!"); }
-        }
     }
 
     /// Return a constraint greater than or equal to another horizontal anchor.
     pub fn constraint_greater_than_or_equal_to(&self, anchor_to: &LayoutAnchorX) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintGreaterThanOrEqualToAnchor:&**to]
-                msg_send![*from, constraintGreaterThanOrEqualToAnchor:&**to]
+        })
-            }),
-
-            _ => { panic!("Attempted to create horizontal constraints with an uninitialized anchor!"); }
-        }
     }
 
     /// Return a constraint less than or equal to another horizontal anchor.
     pub fn constraint_less_than_or_equal_to(&self, anchor_to: &LayoutAnchorX) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintLessThanOrEqualToAnchor:&**to]
-                msg_send![*from, constraintLessThanOrEqualToAnchor:&**to]
+        })
-            }),
-
-            _ => { panic!("Attempted to create horizontal constraints with an uninitialized anchor!"); }
-        }
     }
 }

src/layout/traits.rs

@@ -1,16 +1,53 @@
 //! Various traits related to controllers opting in to autolayout routines and support for view
 //! heirarchies.
 
+use core_graphics::geometry::{CGRect, CGPoint, CGSize};
+
+use objc::{msg_send, sel, sel_impl};
 use objc::runtime::Object;
 use objc_id::ShareId;
 
+use crate::foundation::{id, YES, NO};
+use crate::geometry::Rect;
+
 /// A trait that view wrappers must conform to. Enables managing the subview tree.
+#[allow(unused_variables)]
 pub trait Layout {
     /// Returns a reference to the backing Objective-C layer. This is optional, as we try to keep
     /// the general lazy-loading approach Cocoa has. This may change in the future, and in general
     /// this shouldn't affect your code too much (if at all).
     fn get_backing_node(&self) -> ShareId<Object>;
 
-    /// This trait should implement adding a view to the subview tree for a given view.
+    /// This trait method should implement adding a view to the subview tree for a given view.
-    fn add_subview<V: Layout>(&self, _view: &V);
+    fn add_subview<V: Layout>(&self, view: &V);
+
+    /// Sets the `frame` for the view this trait is applied to.
+    ///
+    /// Note that Cacao, by default, opts into autolayout - you need to call
+    /// `set_translates_autoresizing_mask_into_constraints` to enable frame-based layout calls (or
+    /// use an appropriate initializer for a given view type).
+    fn set_frame<R: Into<CGRect>>(&self, rect: R) {
+        let backing_node = self.get_backing_node();
+        let frame: CGRect = rect.into();
+
+        unsafe {
+            let _: () = msg_send![&*backing_node, setFrame:frame];
+        }
+    }
+    
+    /// Sets whether the view for this trait should translate autoresizing masks into layout
+    /// constraints.
+    ///
+    /// Cacao defaults this to `false`; if you need to set frame-based layout pieces,
+    /// then you should set this to `true` (or use an appropriate initializer that does it for you).
+    fn set_translates_autoresizing_mask_into_constraints(&self, translates: bool) {
+        let backing_node = self.get_backing_node();
+        
+        unsafe {
+            let _: () = msg_send![&*backing_node, setTranslatesAutoresizingMaskIntoConstraints:match translates {
+                true => YES,
+                false => NO
+            }];
+        }
+    }
 }

src/layout/vertical.rs

@@ -1,7 +1,3 @@
-//! A wrapper for `NSLayoutAnchorX`, which is typically used to handle values for how a 
-//! given view should layout along the x-axis. Of note: the only thing that can't be protected
-//! against is mixing/matching incorrect left/leading and right/trailing anchors. Be careful!
-
 use objc::{msg_send, sel, sel_impl};
 use objc::runtime::Object;
 use objc_id::ShareId;
@@ -9,50 +5,102 @@ use objc_id::ShareId;
 use crate::foundation::id;
 use crate::layout::constraint::LayoutConstraint;
 
-/// A wrapper for `NSLayoutAnchor`. You should never be creating this yourself - it's more of a
+/// A wrapper for `NSLayoutAnchorY`, used to handle values for how a given view should 
-/// factory/helper for creating `LayoutConstraint` objects based on your views.
+/// layout along the y-axis.
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug)]
-pub struct LayoutAnchorY(pub Option<ShareId<Object>>);
+pub enum LayoutAnchorY {
+    /// Represents an uninitialized anchor (e.g, for a view that's not created yet).
+    Uninitialized,
+
+    /// Represents a top anchor.
+    Top(ShareId<Object>),
+
+    /// Represents a bottom anchor.
+    Bottom(ShareId<Object>),
+
+    /// Represents a center anchor for the Y axis.
+    Center(ShareId<Object>)
+}
+
+impl Default for LayoutAnchorY {
+    fn default() -> Self {
+        Self::Uninitialized
+    }
+}
 
 impl LayoutAnchorY {
-    /// An internal method for wrapping existing constraints.
+    /// Given a view, returns an anchor for the top anchor.
-    pub(crate) fn new(object: id) -> Self {
+    pub(crate) fn top(view: id) -> Self {
-        LayoutAnchorY(Some(unsafe {
+        Self::Top(unsafe {
-            ShareId::from_ptr(object)
+            ShareId::from_ptr(msg_send![view, topAnchor])
-        }))
+        })
+    }
+
+    /// Given a view, returns an anchor for the bottom anchor.
+    pub(crate) fn bottom(view: id) -> Self {
+        Self::Bottom(unsafe {
+            ShareId::from_ptr(msg_send![view, bottomAnchor])
+        })
+    }
+
+    /// Given a view, returns an anchor for the center Y anchor.
+    pub(crate) fn center(view: id) -> Self {
+        Self::Center(unsafe {
+            ShareId::from_ptr(msg_send![view, centerYAnchor])
+        })
+    }
+
+    /// Boilerplate for handling constraint construction and panic'ing with some more helpful
+    /// messages. The goal here is to make AutoLayout slightly easier to debug when things go
+    /// wrong.
+    fn constraint_with<F>(&self, anchor_to: &LayoutAnchorY, handler: F) -> LayoutConstraint
+    where
+        F: Fn(&ShareId<Object>, &ShareId<Object>) -> id
+    {
+        match (self, anchor_to) {
+            (Self::Top(from), Self::Top(to)) | (Self::Top(from), Self::Bottom(to)) |
+            (Self::Top(from), Self::Center(to)) | 
+
+            (Self::Bottom(from), Self::Bottom(to)) | (Self::Bottom(from), Self::Top(to)) |
+            (Self::Bottom(from), Self::Center(to)) |
+
+            (Self::Center(from), Self::Center(to)) | (Self::Center(from), Self::Top(to)) |
+            (Self::Center(from), Self::Bottom(to)) => {
+                LayoutConstraint::new(handler(from, to))
+            },
+
+            (Self::Uninitialized, Self::Uninitialized) => {
+                panic!("Attempted to create constraints with uninitialized \"from\" and \"to\" y anchors.");
+            },
+
+            (Self::Uninitialized, _) => {
+                panic!("Attempted to create constraints with an uninitialized \"from\" y anchor.");
+            },
+
+            (_, Self::Uninitialized) => {
+                panic!("Attempted to create constraints with an uninitialized \"to\" y anchor.");
+            }
+        }
     }
 
     /// Return a constraint equal to another vertical anchor.
     pub fn constraint_equal_to(&self, anchor_to: &LayoutAnchorY) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintEqualToAnchor:&**to]
-                let b: id = msg_send![*from, constraintEqualToAnchor:&**to];
+        })
-                b
-            }),
-
-            _ => { panic!("Attempted to create vertical constraints with an uninitialized anchor!"); }
-        }
     }
 
     /// Return a constraint greater than or equal to another vertical anchor.
     pub fn constraint_greater_than_or_equal_to(&self, anchor_to: &LayoutAnchorY) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintGreaterThanOrEqualToAnchor:&**to]
-                msg_send![*from, constraintGreaterThanOrEqualToAnchor:&**to]
+        })
-            }),
-
-            _ => { panic!("Attempted to create vertical constraints with an uninitialized anchor!"); }
-        }
     }
 
     /// Return a constraint less than or equal to another vertical anchor.
     pub fn constraint_less_than_or_equal_to(&self, anchor_to: &LayoutAnchorY) -> LayoutConstraint {
-        match (&self.0, &anchor_to.0) {
+        self.constraint_with(anchor_to, |from, to| unsafe {
-            (Some(from), Some(to)) => LayoutConstraint::new(unsafe {
+            msg_send![*from, constraintLessThanOrEqualToAnchor:&**to]
-                msg_send![*from, constraintLessThanOrEqualToAnchor:&**to]
+        })
-            }),
-
-            _ => { panic!("Attempted to create vertical constraints with an uninitialized anchor!"); }
-        }
     }
 }

src/listview/mod.rs

@@ -200,9 +200,15 @@ pub struct ListView<T = ()> {
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -243,24 +249,27 @@ impl ListView {
         };
 
         // For macOS, we need to use the NSScrollView anchor points, not the NSTableView.
+        // @TODO: Fix this with proper mutable access.
         #[cfg(target_os = "macos")]
-        let anchor_view = &*scrollview.objc;
+        let anchor_view: id = unsafe { msg_send![&*scrollview.objc, self] };
         
         #[cfg(target_os = "ios")]
-        let anchor_view = view;
+        let anchor_view: id = view;
 
         ListView {
             cell_factory: CellFactory::new(),
             menu: PropertyNullable::default(),
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![anchor_view, topAnchor] }),
+            top: LayoutAnchorY::top(anchor_view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![anchor_view, leadingAnchor] }),
+            left: LayoutAnchorX::left(anchor_view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![anchor_view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(anchor_view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![anchor_view, bottomAnchor] }),
+            right: LayoutAnchorX::right(anchor_view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![anchor_view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(anchor_view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![anchor_view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(anchor_view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![anchor_view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(anchor_view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![anchor_view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(anchor_view),
+            center_x: LayoutAnchorX::center(anchor_view),
+            center_y: LayoutAnchorY::center(anchor_view),
             objc: unsafe { ShareId::from_ptr(view) },
 
             #[cfg(target_os = "macos")]
@@ -300,7 +309,7 @@ impl<T> ListView<T> where T: ListViewDelegate + 'static {
 
         // For macOS, we need to use the NSScrollView anchor points, not the NSTableView.
         #[cfg(target_os = "macos")]
-        let anchor_view = &*scrollview.objc;
+        let anchor_view: id = unsafe { msg_send![&*scrollview.objc, self] };
         
         #[cfg(target_os = "ios")]
         let anchor_view = view;
@@ -309,14 +318,16 @@ impl<T> ListView<T> where T: ListViewDelegate + 'static {
             cell_factory: cell,
             menu: PropertyNullable::default(),
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![anchor_view, topAnchor] }),
+            top: LayoutAnchorY::top(anchor_view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![anchor_view, leadingAnchor] }),
+            left: LayoutAnchorX::left(anchor_view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![anchor_view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(anchor_view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![anchor_view, bottomAnchor] }),
+            right: LayoutAnchorX::right(anchor_view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![anchor_view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(anchor_view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![anchor_view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(anchor_view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![anchor_view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(anchor_view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![anchor_view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(anchor_view),
+            center_x: LayoutAnchorX::center(anchor_view),
+            center_y: LayoutAnchorY::center(anchor_view),
             objc: unsafe { ShareId::from_ptr(view) },
             
             #[cfg(target_os = "macos")]
@@ -341,7 +352,9 @@ impl<T> ListView<T> {
             delegate: None,
             top: self.top.clone(),
             leading: self.leading.clone(),
+            left: self.left.clone(),
             trailing: self.trailing.clone(),
+            right: self.right.clone(),
             bottom: self.bottom.clone(),
             width: self.width.clone(),
             height: self.height.clone(),

src/listview/row/mod.rs

@@ -92,16 +92,22 @@ pub struct ListViewRow<T = ()> {
 
     /// A pointer to the delegate for this view.
     pub delegate: Option<Box<T>>,
-
+    
     /// A pointer to the Objective-C runtime top layout constraint.
     pub top: LayoutAnchorY,
 
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -131,14 +137,16 @@ impl ListViewRow {
 
         ListViewRow {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: Rc::new(RefCell::new(unsafe { Id::from_ptr(view) })),
         }
     }
@@ -166,14 +174,16 @@ impl<T> ListViewRow<T> where T: ViewDelegate + 'static {
 
         let view = ListViewRow {
             delegate: Some(delegate),
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: Rc::new(RefCell::new(unsafe { Id::from_ptr(view) })),
         };
 
@@ -198,14 +208,16 @@ impl<T> ListViewRow<T> where T: ViewDelegate + 'static {
 
         let mut view = ListViewRow {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: Rc::new(RefCell::new(unsafe { Id::from_ptr(view) })),
         };
 
@@ -226,7 +238,9 @@ impl<T> ListViewRow<T> where T: ViewDelegate + 'static {
             delegate: None,
             top: self.top.clone(),
             leading: self.leading.clone(),
+            left: self.left.clone(),
             trailing: self.trailing.clone(),
+            right: self.right.clone(),
             bottom: self.bottom.clone(),
             width: self.width.clone(),
             height: self.height.clone(),
@@ -253,7 +267,9 @@ impl<T> ListViewRow<T> {
             delegate: None,
             top: self.top.clone(),
             leading: self.leading.clone(),
+            left: self.left.clone(),
             trailing: self.trailing.clone(),
+            right: self.right.clone(),
             bottom: self.bottom.clone(),
             width: self.width.clone(),
             height: self.height.clone(),

src/progress/mod.rs

@@ -35,29 +35,35 @@ pub use enums::ProgressIndicatorStyle;
 pub struct ProgressIndicator {
     /// A pointer to the Objective-C Object.
     pub objc: ShareId<Object>,
-
+    
-    /// A pointer to the Objective-C top layout constraint.
+    /// A pointer to the Objective-C runtime top layout constraint.
     pub top: LayoutAnchorY,
 
-    /// A pointer to the Objective-C leading layout constraint.
+    /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
-    /// A pointer to the Objective-C trailing layout constraint.
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
+    /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
-    /// A pointer to the Objective-C bottom layout constraint.
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
+    /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
-    /// A pointer to the Objective-C width layout constraint.
+    /// A pointer to the Objective-C runtime width layout constraint.
     pub width: LayoutAnchorDimension,
 
-    /// A pointer to the Objective-C height layout constraint.
+    /// A pointer to the Objective-C runtime height layout constraint.
     pub height: LayoutAnchorDimension,
 
-    /// A pointer to the Objective-C center X layout constraint.
+    /// A pointer to the Objective-C runtime center X layout constraint.
     pub center_x: LayoutAnchorX,
 
-    /// A pointer to the Objective-C center Y layout constraint.
+    /// A pointer to the Objective-C runtime center Y layout constraint.
     pub center_y: LayoutAnchorY
 }
 
@@ -83,14 +89,16 @@ impl ProgressIndicator {
         };
 
         ProgressIndicator {
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: unsafe { ShareId::from_ptr(view) },
         }
     }

src/scrollview/mod.rs

@@ -94,16 +94,22 @@ pub struct ScrollView<T = ()> {
 
     /// A pointer to the delegate for this view.
     pub delegate: Option<Box<T>>,
-
+    
     /// A pointer to the Objective-C runtime top layout constraint.
     pub top: LayoutAnchorY,
 
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -133,14 +139,16 @@ impl ScrollView {
 
         ScrollView {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: unsafe { ShareId::from_ptr(view) },
         }
     }
@@ -160,14 +168,16 @@ impl<T> ScrollView<T> where T: ScrollViewDelegate + 'static {
 
         let mut view = ScrollView {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: unsafe { ShareId::from_ptr(view) },
         };
 
@@ -187,7 +197,9 @@ impl<T> ScrollView<T> {
             delegate: None,
             top: self.top.clone(),
             leading: self.leading.clone(),
+            left: self.left.clone(),
             trailing: self.trailing.clone(),
+            right: self.right.clone(),
             bottom: self.bottom.clone(),
             width: self.width.clone(),
             height: self.height.clone(),

src/switch.rs

@@ -28,9 +28,15 @@ pub struct Switch {
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -45,6 +51,7 @@ pub struct Switch {
 
     /// A pointer to the Objective-C runtime center Y layout constraint.
     pub center_y: LayoutAnchorY
+   
 }
 
 impl Switch {
@@ -62,14 +69,16 @@ impl Switch {
         
         Switch {
             handler: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: unsafe { ShareId::from_ptr(view) },
         }
     }

src/text/label/mod.rs

@@ -97,16 +97,22 @@ pub struct Label<T = ()> {
 
     /// A pointer to the delegate for this view.
     pub delegate: Option<Box<T>>,
-
+    
     /// A pointer to the Objective-C runtime top layout constraint.
     pub top: LayoutAnchorY,
 
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -136,14 +142,16 @@ impl Label {
 
         Label {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: unsafe { ShareId::from_ptr(view) },
         }
     }
@@ -165,14 +173,16 @@ impl<T> Label<T> where T: LabelDelegate + 'static {
 
         let mut label = Label {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![label, topAnchor] }),
+            top: LayoutAnchorY::top(label),
-            leading: LayoutAnchorX::new(unsafe { msg_send![label, leadingAnchor] }),
+            left: LayoutAnchorX::left(label),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![label, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(label),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![label, bottomAnchor] }),
+            right: LayoutAnchorX::right(label),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![label, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(label),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![label, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(label),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![label, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(label),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![label, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(label),
+            center_x: LayoutAnchorX::center(label),
+            center_y: LayoutAnchorY::center(label),
             objc: unsafe { ShareId::from_ptr(label) },
         };
 
@@ -192,7 +202,9 @@ impl<T> Label<T> {
             delegate: None,
             top: self.top.clone(),
             leading: self.leading.clone(),
+            left: self.left.clone(),
             trailing: self.trailing.clone(),
+            right: self.right.clone(),
             bottom: self.bottom.clone(),
             width: self.width.clone(),
             height: self.height.clone(),

src/view/mod.rs

@@ -107,9 +107,15 @@ pub struct View<T = ()> {
     /// A pointer to the Objective-C runtime leading layout constraint.
     pub leading: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime left layout constraint.
+    pub left: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime trailing layout constraint.
     pub trailing: LayoutAnchorX,
 
+    /// A pointer to the Objective-C runtime right layout constraint.
+    pub right: LayoutAnchorX,
+
     /// A pointer to the Objective-C runtime bottom layout constraint.
     pub bottom: LayoutAnchorY,
 
@@ -139,14 +145,16 @@ impl View {
 
         View {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: Rc::new(RefCell::new(unsafe { Id::from_ptr(view) })),
         }
     }
@@ -169,14 +177,16 @@ impl<T> View<T> where T: ViewDelegate + 'static {
 
         let mut view = View {
             delegate: None,
-            top: LayoutAnchorY::new(unsafe { msg_send![view, topAnchor] }),
+            top: LayoutAnchorY::top(view),
-            leading: LayoutAnchorX::new(unsafe { msg_send![view, leadingAnchor] }),
+            left: LayoutAnchorX::left(view),
-            trailing: LayoutAnchorX::new(unsafe { msg_send![view, trailingAnchor] }),
+            leading: LayoutAnchorX::leading(view),
-            bottom: LayoutAnchorY::new(unsafe { msg_send![view, bottomAnchor] }),
+            right: LayoutAnchorX::right(view),
-            width: LayoutAnchorDimension::new(unsafe { msg_send![view, widthAnchor] }),
+            trailing: LayoutAnchorX::trailing(view),
-            height: LayoutAnchorDimension::new(unsafe { msg_send![view, heightAnchor] }),
+            bottom: LayoutAnchorY::bottom(view),
-            center_x: LayoutAnchorX::new(unsafe { msg_send![view, centerXAnchor] }),
+            width: LayoutAnchorDimension::width(view),
-            center_y: LayoutAnchorY::new(unsafe { msg_send![view, centerYAnchor] }),
+            height: LayoutAnchorDimension::height(view),
+            center_x: LayoutAnchorX::center(view),
+            center_y: LayoutAnchorY::center(view),
             objc: Rc::new(RefCell::new(unsafe { Id::from_ptr(view) })),
         };
 
@@ -196,7 +206,9 @@ impl<T> View<T> {
             delegate: None,
             top: self.top.clone(),
             leading: self.leading.clone(),
+            left: self.left.clone(),
             trailing: self.trailing.clone(),
+            right: self.right.clone(),
             bottom: self.bottom.clone(),
             width: self.width.clone(),
             height: self.height.clone(),