Merge pull request #52 from hecrj/custom-layout-engine

Custom layout engine

6 files changed, 112 insertions, 111 deletions

diff --git a/core/src/widget/button.rs b/core/src/widget/button.rs
index a57f2dd8..9cf20071 100644
--- a/core/src/widget/button.rs
+++ b/core/src/widget/button.rs
@@ -5,7 +5,7 @@
 //! [`Button`]: struct.Button.html
 //! [`State`]: struct.State.html
 
-use crate::{Align, Background, Length};
+use crate::{Background, Length};
 
 /// A generic widget that produces a message when clicked.
 pub struct Button<'a, Message, Element> {
@@ -24,8 +24,6 @@ pub struct Button<'a, Message, Element> {
     pub background: Option<Background>,
 
     pub border_radius: u16,
-
-    pub align_self: Option<Align>,
 }
 
 impl<'a, Message, Element> std::fmt::Debug for Button<'a, Message, Element>
@@ -57,7 +55,6 @@ impl<'a, Message, Element> Button<'a, Message, Element> {
             padding: 0,
             background: None,
             border_radius: 0,
-            align_self: None,
         }
     }
 
@@ -84,17 +81,6 @@ impl<'a, Message, Element> Button<'a, Message, Element> {
         self
     }
 
-    /// Sets the alignment of the [`Button`] itself.
-    ///
-    /// This is useful if you want to override the default alignment given by
-    /// the parent container.
-    ///
-    /// [`Button`]: struct.Button.html
-    pub fn align_self(mut self, align: Align) -> Self {
-        self.align_self = Some(align);
-        self
-    }
-
     /// Sets the message that will be produced when the [`Button`] is pressed.
     ///
     /// [`Button`]: struct.Button.html
diff --git a/core/src/widget/column.rs b/core/src/widget/column.rs
index 2df327a0..4a97ad98 100644
--- a/core/src/widget/column.rs
+++ b/core/src/widget/column.rs
@@ -1,4 +1,6 @@
-use crate::{Align, Justify, Length};
+use crate::{Align, Length};
+
+use std::u32;
 
 /// A container that distributes its contents vertically.
 ///
@@ -10,11 +12,9 @@ pub struct Column<Element> {
     pub padding: u16,
     pub width: Length,
     pub height: Length,
-    pub max_width: Length,
-    pub max_height: Length,
-    pub align_self: Option<Align>,
+    pub max_width: u32,
+    pub max_height: u32,
     pub align_items: Align,
-    pub justify_content: Justify,
     pub children: Vec<Element>,
 }
 
@@ -28,11 +28,9 @@ impl<Element> Column<Element> {
             padding: 0,
             width: Length::Fill,
             height: Length::Shrink,
-            max_width: Length::Shrink,
-            max_height: Length::Shrink,
-            align_self: None,
+            max_width: u32::MAX,
+            max_height: u32::MAX,
             align_items: Align::Start,
-            justify_content: Justify::Start,
             children: Vec::new(),
         }
     }
@@ -74,7 +72,7 @@ impl<Element> Column<Element> {
     /// Sets the maximum width of the [`Column`].
     ///
     /// [`Column`]: struct.Column.html
-    pub fn max_width(mut self, max_width: Length) -> Self {
+    pub fn max_width(mut self, max_width: u32) -> Self {
         self.max_width = max_width;
         self
     }
@@ -82,22 +80,11 @@ impl<Element> Column<Element> {
     /// Sets the maximum height of the [`Column`] in pixels.
     ///
     /// [`Column`]: struct.Column.html
-    pub fn max_height(mut self, max_height: Length) -> Self {
+    pub fn max_height(mut self, max_height: u32) -> Self {
         self.max_height = max_height;
         self
     }
 
-    /// Sets the alignment of the [`Column`] itself.
-    ///
-    /// This is useful if you want to override the default alignment given by
-    /// the parent container.
-    ///
-    /// [`Column`]: struct.Column.html
-    pub fn align_self(mut self, align: Align) -> Self {
-        self.align_self = Some(align);
-        self
-    }
-
     /// Sets the horizontal alignment of the contents of the [`Column`] .
     ///
     /// [`Column`]: struct.Column.html
@@ -106,15 +93,6 @@ impl<Element> Column<Element> {
         self
     }
 
-    /// Sets the vertical distribution strategy for the contents of the
-    /// [`Column`] .
-    ///
-    /// [`Column`]: struct.Column.html
-    pub fn justify_content(mut self, justify: Justify) -> Self {
-        self.justify_content = justify;
-        self
-    }
-
     /// Adds an element to the [`Column`].
     ///
     /// [`Column`]: struct.Column.html
diff --git a/core/src/widget/container.rs b/core/src/widget/container.rs
new file mode 100644
index 00000000..9bc92fe0
--- /dev/null
+++ b/core/src/widget/container.rs
@@ -0,0 +1,84 @@
+use crate::{Align, Length};
+
+use std::u32;
+
+#[derive(Debug)]
+pub struct Container<Element> {
+    pub width: Length,
+    pub height: Length,
+    pub max_width: u32,
+    pub max_height: u32,
+    pub horizontal_alignment: Align,
+    pub vertical_alignment: Align,
+    pub content: Element,
+}
+
+impl<Element> Container<Element> {
+    /// Creates an empty [`Container`].
+    ///
+    /// [`Container`]: struct.Container.html
+    pub fn new<T>(content: T) -> Self
+    where
+        T: Into<Element>,
+    {
+        Container {
+            width: Length::Shrink,
+            height: Length::Shrink,
+            max_width: u32::MAX,
+            max_height: u32::MAX,
+            horizontal_alignment: Align::Start,
+            vertical_alignment: Align::Start,
+            content: content.into(),
+        }
+    }
+
+    /// Sets the width of the [`Container`].
+    ///
+    /// [`Container`]: struct.Container.html
+    pub fn width(mut self, width: Length) -> Self {
+        self.width = width;
+        self
+    }
+
+    /// Sets the height of the [`Container`].
+    ///
+    /// [`Container`]: struct.Container.html
+    pub fn height(mut self, height: Length) -> Self {
+        self.height = height;
+        self
+    }
+
+    /// Sets the maximum width of the [`Container`].
+    ///
+    /// [`Container`]: struct.Container.html
+    pub fn max_width(mut self, max_width: u32) -> Self {
+        self.max_width = max_width;
+        self
+    }
+
+    /// Sets the maximum height of the [`Container`] in pixels.
+    ///
+    /// [`Container`]: struct.Container.html
+    pub fn max_height(mut self, max_height: u32) -> Self {
+        self.max_height = max_height;
+        self
+    }
+
+    /// Centers the contents in the horizontal axis of the [`Container`].
+    ///
+    /// [`Container`]: struct.Container.html
+    pub fn center_x(mut self) -> Self {
+        self.horizontal_alignment = Align::Center;
+
+        self
+    }
+
+    /// Centers the contents in the vertical axis of the [`Container`].
+    ///
+    /// [`Container`]: struct.Container.html
+    pub fn center_y(mut self) -> Self {
+        self.vertical_alignment = Align::Center;
+
+        self
+    }
+}
diff --git a/core/src/widget/image.rs b/core/src/widget/image.rs
index 6e410dce..996ab5e1 100644
--- a/core/src/widget/image.rs
+++ b/core/src/widget/image.rs
@@ -1,6 +1,6 @@
 //! Display images in your user interface.
 
-use crate::{Align, Length, Rectangle};
+use crate::{Length, Rectangle};
 
 /// A frame that displays an image while keeping aspect ratio.
 ///
@@ -24,8 +24,6 @@ pub struct Image {
 
     /// The height of the image
     pub height: Length,
-
-    pub align_self: Option<Align>,
 }
 
 impl Image {
@@ -38,7 +36,6 @@ impl Image {
             clip: None,
             width: Length::Shrink,
             height: Length::Shrink,
-            align_self: None,
         }
     }
 
@@ -65,15 +62,4 @@ impl Image {
         self.height = height;
         self
     }
-
-    /// Sets the alignment of the [`Image`] itself.
-    ///
-    /// This is useful if you want to override the default alignment given by
-    /// the parent container.
-    ///
-    /// [`Image`]: struct.Image.html
-    pub fn align_self(mut self, align: Align) -> Self {
-        self.align_self = Some(align);
-        self
-    }
 }
diff --git a/core/src/widget/row.rs b/core/src/widget/row.rs
index 6bdb4ed2..3d882b47 100644
--- a/core/src/widget/row.rs
+++ b/core/src/widget/row.rs
@@ -1,4 +1,6 @@
-use crate::{Align, Justify, Length};
+use crate::{Align, Length};
+
+use std::u32;
 
 /// A container that distributes its contents horizontally.
 ///
@@ -10,11 +12,9 @@ pub struct Row<Element> {
     pub padding: u16,
     pub width: Length,
     pub height: Length,
-    pub max_width: Length,
-    pub max_height: Length,
-    pub align_self: Option<Align>,
+    pub max_width: u32,
+    pub max_height: u32,
     pub align_items: Align,
-    pub justify_content: Justify,
     pub children: Vec<Element>,
 }
 
@@ -28,11 +28,9 @@ impl<Element> Row<Element> {
             padding: 0,
             width: Length::Fill,
             height: Length::Shrink,
-            max_width: Length::Shrink,
-            max_height: Length::Shrink,
-            align_self: None,
+            max_width: u32::MAX,
+            max_height: u32::MAX,
             align_items: Align::Start,
-            justify_content: Justify::Start,
             children: Vec::new(),
         }
     }
@@ -74,7 +72,7 @@ impl<Element> Row<Element> {
     /// Sets the maximum width of the [`Row`].
     ///
     /// [`Row`]: struct.Row.html
-    pub fn max_width(mut self, max_width: Length) -> Self {
+    pub fn max_width(mut self, max_width: u32) -> Self {
         self.max_width = max_width;
         self
     }
@@ -82,22 +80,11 @@ impl<Element> Row<Element> {
     /// Sets the maximum height of the [`Row`].
     ///
     /// [`Row`]: struct.Row.html
-    pub fn max_height(mut self, max_height: Length) -> Self {
+    pub fn max_height(mut self, max_height: u32) -> Self {
         self.max_height = max_height;
         self
     }
 
-    /// Sets the alignment of the [`Row`] itself.
-    ///
-    /// This is useful if you want to override the default alignment given by
-    /// the parent container.
-    ///
-    /// [`Row`]: struct.Row.html
-    pub fn align_self(mut self, align: Align) -> Self {
-        self.align_self = Some(align);
-        self
-    }
-
     /// Sets the vertical alignment of the contents of the [`Row`] .
     ///
     /// [`Row`]: struct.Row.html
@@ -106,15 +93,6 @@ impl<Element> Row<Element> {
         self
     }
 
-    /// Sets the horizontal distribution strategy for the contents of the
-    /// [`Row`] .
-    ///
-    /// [`Row`]: struct.Row.html
-    pub fn justify_content(mut self, justify: Justify) -> Self {
-        self.justify_content = justify;
-        self
-    }
-
     /// Adds an [`Element`] to the [`Row`].
     ///
     /// [`Element`]: ../struct.Element.html
diff --git a/core/src/widget/scrollable.rs b/core/src/widget/scrollable.rs
index 31a5abed..7f2f0e99 100644
--- a/core/src/widget/scrollable.rs
+++ b/core/src/widget/scrollable.rs
@@ -1,11 +1,12 @@
 use crate::{Align, Column, Length, Point, Rectangle};
 
+use std::u32;
+
 #[derive(Debug)]
 pub struct Scrollable<'a, Element> {
     pub state: &'a mut State,
     pub height: Length,
-    pub max_height: Length,
-    pub align_self: Option<Align>,
+    pub max_height: u32,
     pub content: Column<Element>,
 }
 
@@ -14,8 +15,7 @@ impl<'a, Element> Scrollable<'a, Element> {
         Scrollable {
             state,
             height: Length::Shrink,
-            max_height: Length::Shrink,
-            align_self: None,
+            max_height: u32::MAX,
             content: Column::new(),
         }
     }
@@ -57,7 +57,7 @@ impl<'a, Element> Scrollable<'a, Element> {
     /// Sets the maximum width of the [`Scrollable`].
     ///
     /// [`Scrollable`]: struct.Scrollable.html
-    pub fn max_width(mut self, max_width: Length) -> Self {
+    pub fn max_width(mut self, max_width: u32) -> Self {
         self.content = self.content.max_width(max_width);
         self
     }
@@ -65,22 +65,11 @@ impl<'a, Element> Scrollable<'a, Element> {
     /// Sets the maximum height of the [`Scrollable`] in pixels.
     ///
     /// [`Scrollable`]: struct.Scrollable.html
-    pub fn max_height(mut self, max_height: Length) -> Self {
+    pub fn max_height(mut self, max_height: u32) -> Self {
         self.max_height = max_height;
         self
     }
 
-    /// Sets the alignment of the [`Scrollable`] itself.
-    ///
-    /// This is useful if you want to override the default alignment given by
-    /// the parent container.
-    ///
-    /// [`Scrollable`]: struct.Scrollable.html
-    pub fn align_self(mut self, align: Align) -> Self {
-        self.align_self = Some(align);
-        self
-    }
-
     /// Sets the horizontal alignment of the contents of the [`Scrollable`] .
     ///
     /// [`Scrollable`]: struct.Scrollable.html
@@ -140,9 +129,9 @@ impl State {
 
     pub fn offset(&self, bounds: Rectangle, content_bounds: Rectangle) -> u32 {
         let hidden_content =
-            (content_bounds.height - bounds.height).round() as u32;
+            (content_bounds.height - bounds.height).max(0.0).round() as u32;
 
-        self.offset.min(hidden_content).max(0)
+        self.offset.min(hidden_content)
     }
 
     pub fn is_scrollbar_grabbed(&self) -> bool {