Make many functions const

The point is to set up repeated components or boilerplate before their
use sites.

The majority of these make sense as `const`. However, some functions
such as those regarding state may not make sense as `const`.

native/src/widget/column.rs

@@ -28,7 +28,7 @@ impl<'a, Message, Renderer> Column<'a, Message, Renderer> {
     /// Creates an empty [`Column`].
     ///
     /// [`Column`]: struct.Column.html
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         Column {
             spacing: 0,
             padding: 0,
@@ -46,7 +46,7 @@ impl<'a, Message, Renderer> Column<'a, Message, Renderer> {
     /// Custom margins per element do not exist in Iced. You should use this
     /// method instead! While less flexible, it helps you keep spacing between
     /// elements consistent.
-    pub fn spacing(mut self, units: u16) -> Self {
+    pub const fn spacing(mut self, units: u16) -> Self {
         self.spacing = units;
         self
     }
@@ -54,7 +54,7 @@ impl<'a, Message, Renderer> Column<'a, Message, Renderer> {
     /// Sets the padding of the [`Column`].
     ///
     /// [`Column`]: struct.Column.html
-    pub fn padding(mut self, units: u16) -> Self {
+    pub const fn padding(mut self, units: u16) -> Self {
         self.padding = units;
         self
     }
@@ -62,7 +62,7 @@ impl<'a, Message, Renderer> Column<'a, Message, Renderer> {
     /// Sets the width of the [`Column`].
     ///
     /// [`Column`]: struct.Column.html
-    pub fn width(mut self, width: Length) -> Self {
+    pub const fn width(mut self, width: Length) -> Self {
         self.width = width;
         self
     }
@@ -70,7 +70,7 @@ impl<'a, Message, Renderer> Column<'a, Message, Renderer> {
     /// Sets the height of the [`Column`].
     ///
     /// [`Column`]: struct.Column.html
-    pub fn height(mut self, height: Length) -> Self {
+    pub const fn height(mut self, height: Length) -> Self {
         self.height = height;
         self
     }
@@ -78,7 +78,7 @@ impl<'a, Message, Renderer> Column<'a, Message, Renderer> {
     /// Sets the maximum width of the [`Column`].
     ///
     /// [`Column`]: struct.Column.html
-    pub fn max_width(mut self, max_width: u32) -> Self {
+    pub const fn max_width(mut self, max_width: u32) -> Self {
         self.max_width = max_width;
         self
     }
@@ -86,7 +86,7 @@ impl<'a, Message, Renderer> Column<'a, Message, Renderer> {
     /// Sets the maximum height of the [`Column`] in pixels.
     ///
     /// [`Column`]: struct.Column.html
-    pub fn max_height(mut self, max_height: u32) -> Self {
+    pub const fn max_height(mut self, max_height: u32) -> Self {
         self.max_height = max_height;
         self
     }
@@ -94,7 +94,7 @@ impl<'a, Message, Renderer> Column<'a, Message, Renderer> {
     /// Sets the horizontal alignment of the contents of the [`Column`] .
     ///
     /// [`Column`]: struct.Column.html
-    pub fn align_items(mut self, align: Align) -> Self {
+    pub const fn align_items(mut self, align: Align) -> Self {
         self.align_items = align;
         self
     }

native/src/widget/image.rs

@@ -37,7 +37,7 @@ impl Image {
     /// Sets the width of the [`Image`] boundaries.
     ///
     /// [`Image`]: struct.Image.html
-    pub fn width(mut self, width: Length) -> Self {
+    pub const fn width(mut self, width: Length) -> Self {
         self.width = width;
         self
     }
@@ -45,7 +45,7 @@ impl Image {
     /// Sets the height of the [`Image`] boundaries.
     ///
     /// [`Image`]: struct.Image.html
-    pub fn height(mut self, height: Length) -> Self {
+    pub const fn height(mut self, height: Length) -> Self {
         self.height = height;
         self
     }

native/src/widget/row.rs

@@ -28,7 +28,7 @@ impl<'a, Message, Renderer> Row<'a, Message, Renderer> {
     /// Creates an empty [`Row`].
     ///
     /// [`Row`]: struct.Row.html
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         Row {
             spacing: 0,
             padding: 0,
@@ -46,7 +46,7 @@ impl<'a, Message, Renderer> Row<'a, Message, Renderer> {
     /// Custom margins per element do not exist in Iced. You should use this
     /// method instead! While less flexible, it helps you keep spacing between
     /// elements consistent.
-    pub fn spacing(mut self, units: u16) -> Self {
+    pub const fn spacing(mut self, units: u16) -> Self {
         self.spacing = units;
         self
     }
@@ -54,7 +54,7 @@ impl<'a, Message, Renderer> Row<'a, Message, Renderer> {
     /// Sets the padding of the [`Row`].
     ///
     /// [`Row`]: struct.Row.html
-    pub fn padding(mut self, units: u16) -> Self {
+    pub const fn padding(mut self, units: u16) -> Self {
         self.padding = units;
         self
     }
@@ -62,7 +62,7 @@ impl<'a, Message, Renderer> Row<'a, Message, Renderer> {
     /// Sets the width of the [`Row`].
     ///
     /// [`Row`]: struct.Row.html
-    pub fn width(mut self, width: Length) -> Self {
+    pub const fn width(mut self, width: Length) -> Self {
         self.width = width;
         self
     }
@@ -70,7 +70,7 @@ impl<'a, Message, Renderer> Row<'a, Message, Renderer> {
     /// Sets the height of the [`Row`].
     ///
     /// [`Row`]: struct.Row.html
-    pub fn height(mut self, height: Length) -> Self {
+    pub const fn height(mut self, height: Length) -> Self {
         self.height = height;
         self
     }
@@ -78,7 +78,7 @@ impl<'a, Message, Renderer> Row<'a, Message, Renderer> {
     /// Sets the maximum width of the [`Row`].
     ///
     /// [`Row`]: struct.Row.html
-    pub fn max_width(mut self, max_width: u32) -> Self {
+    pub const fn max_width(mut self, max_width: u32) -> Self {
         self.max_width = max_width;
         self
     }
@@ -86,7 +86,7 @@ impl<'a, Message, Renderer> Row<'a, Message, Renderer> {
     /// Sets the maximum height of the [`Row`].
     ///
     /// [`Row`]: struct.Row.html
-    pub fn max_height(mut self, max_height: u32) -> Self {
+    pub const fn max_height(mut self, max_height: u32) -> Self {
         self.max_height = max_height;
         self
     }
@@ -94,7 +94,7 @@ impl<'a, Message, Renderer> Row<'a, Message, Renderer> {
     /// Sets the vertical alignment of the contents of the [`Row`] .
     ///
     /// [`Row`]: struct.Row.html
-    pub fn align_items(mut self, align: Align) -> Self {
+    pub const fn align_items(mut self, align: Align) -> Self {
         self.align_items = align;
         self
     }

native/src/widget/slider.rs

@@ -95,8 +95,8 @@ impl State {
     /// Creates a new [`State`].
     ///
     /// [`State`]: struct.State.html
-    pub fn new() -> State {
-        State::default()
+    pub const fn new() -> State {
+        State { is_dragging: false }
     }
 }
 

native/src/widget/text_input.rs

@@ -326,14 +326,17 @@ impl State {
     /// Creates a new [`State`], representing an unfocused [`TextInput`].
     ///
     /// [`State`]: struct.State.html
-    pub fn new() -> Self {
-        Self::default()
+    pub const fn new() -> Self {
+        Self {
+            is_focused: false,
+            cursor_position: 0,
+        }
     }
 
     /// Creates a new [`State`], representing a focused [`TextInput`].
     ///
     /// [`State`]: struct.State.html
-    pub fn focused() -> Self {
+    pub const fn focused() -> Self {
         use std::usize;
 
         Self {
@@ -345,7 +348,7 @@ impl State {
     /// Returns whether the [`TextInput`] is currently focused or not.
     ///
     /// [`TextInput`]: struct.TextInput.html
-    pub fn is_focused(&self) -> bool {
+    pub const fn is_focused(&self) -> bool {
         self.is_focused
     }