1 files changed, 262 insertions, 0 deletions
diff --git a/core/src/style.rs b/core/src/style.rs
new file mode 100644
index 00000000..575ea366
--- /dev/null
+++ b/core/src/style.rs
@@ -0,0 +1,262 @@
+use std::hash::{Hash, Hasher};
+use stretch::{geometry, style};
+
+/// The appearance of a [`Node`].
+///
+/// [`Node`]: struct.Node.html
+#[derive(Debug, Clone, Copy)]
+pub struct Style(pub(crate) style::Style);
+
+impl Style {
+    /// Defines the width of a [`Node`] in pixels.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn width(mut self, width: u16) -> Self {
+        self.0.size.width = style::Dimension::Points(width as f32);
+        self
+    }
+
+    /// Defines the height of a [`Node`] in pixels.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn height(mut self, height: u16) -> Self {
+        self.0.size.height = style::Dimension::Points(height as f32);
+        self
+    }
+
+    /// Defines the minimum width of a [`Node`] in pixels.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn min_width(mut self, min_width: u16) -> Self {
+        self.0.min_size.width = style::Dimension::Points(min_width as f32);
+        self
+    }
+
+    /// Defines the maximum width of a [`Node`] in pixels.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn max_width(mut self, max_width: u16) -> Self {
+        self.0.max_size.width = style::Dimension::Points(max_width as f32);
+        self.fill_width()
+    }
+
+    /// Defines the minimum height of a [`Node`] in pixels.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn min_height(mut self, min_height: u16) -> Self {
+        self.0.min_size.height =
+            style::Dimension::Points(f32::from(min_height));
+        self
+    }
+
+    /// Defines the maximum height of a [`Node`] in pixels.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn max_height(mut self, max_height: u16) -> Self {
+        self.0.max_size.height =
+            style::Dimension::Points(f32::from(max_height));
+        self.fill_height()
+    }
+
+    /// Makes a [`Node`] fill all the horizontal available space.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn fill_width(mut self) -> Self {
+        self.0.size.width = stretch::style::Dimension::Percent(1.0);
+        self
+    }
+
+    /// Makes a [`Node`] fill all the vertical available space.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn fill_height(mut self) -> Self {
+        self.0.size.height = stretch::style::Dimension::Percent(1.0);
+        self
+    }
+
+    pub(crate) fn align_items(mut self, align: Align) -> Self {
+        self.0.align_items = align.into();
+        self
+    }
+
+    pub(crate) fn justify_content(mut self, justify: Justify) -> Self {
+        self.0.justify_content = justify.into();
+        self
+    }
+
+    /// Sets the alignment of a [`Node`].
+    ///
+    /// If the [`Node`] is inside a...
+    ///
+    ///   * [`Column`], this setting will affect its __horizontal__ alignment.
+    ///   * [`Row`], this setting will affect its __vertical__ alignment.
+    ///
+    /// [`Node`]: struct.Node.html
+    /// [`Column`]: widget/struct.Column.html
+    /// [`Row`]: widget/struct.Row.html
+    pub fn align_self(mut self, align: Align) -> Self {
+        self.0.align_self = align.into();
+        self
+    }
+
+    /// Sets the padding of a [`Node`] in pixels.
+    ///
+    /// [`Node`]: struct.Node.html
+    pub fn padding(mut self, px: u16) -> Self {
+        self.0.padding = stretch::geometry::Rect {
+            start: style::Dimension::Points(px as f32),
+            end: style::Dimension::Points(px as f32),
+            top: style::Dimension::Points(px as f32),
+            bottom: style::Dimension::Points(px as f32),
+        };
+
+        self
+    }
+}
+
+impl Default for Style {
+    fn default() -> Style {
+        Style(style::Style {
+            align_items: style::AlignItems::FlexStart,
+            justify_content: style::JustifyContent::FlexStart,
+            ..style::Style::default()
+        })
+    }
+}
+
+impl Hash for Style {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        hash_size(&self.0.size, state);
+        hash_size(&self.0.min_size, state);
+        hash_size(&self.0.max_size, state);
+
+        hash_rect(&self.0.margin, state);
+
+        (self.0.flex_direction as u8).hash(state);
+        (self.0.align_items as u8).hash(state);
+        (self.0.justify_content as u8).hash(state);
+        (self.0.align_self as u8).hash(state);
+        (self.0.flex_grow as u32).hash(state);
+    }
+}
+
+fn hash_size<H: Hasher>(
+    size: &geometry::Size<style::Dimension>,
+    state: &mut H,
+) {
+    hash_dimension(size.width, state);
+    hash_dimension(size.height, state);
+}
+
+fn hash_rect<H: Hasher>(
+    rect: &geometry::Rect<style::Dimension>,
+    state: &mut H,
+) {
+    hash_dimension(rect.start, state);
+    hash_dimension(rect.end, state);
+    hash_dimension(rect.top, state);
+    hash_dimension(rect.bottom, state);
+}
+
+fn hash_dimension<H: Hasher>(dimension: style::Dimension, state: &mut H) {
+    match dimension {
+        style::Dimension::Undefined => state.write_u8(0),
+        style::Dimension::Auto => state.write_u8(1),
+        style::Dimension::Points(points) => {
+            state.write_u8(2);
+            (points as u32).hash(state);
+        }
+        style::Dimension::Percent(percent) => {
+            state.write_u8(3);
+            (percent as u32).hash(state);
+        }
+    }
+}
+
+/// Alignment on the cross axis of a container.
+///
+///   * On a [`Column`], it describes __horizontal__ alignment.
+///   * On a [`Row`], it describes __vertical__ alignment.
+///
+/// [`Column`]: widget/struct.Column.html
+/// [`Row`]: widget/struct.Row.html
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Align {
+    /// Align at the start of the cross axis.
+    Start,
+
+    /// Align at the center of the cross axis.
+    Center,
+
+    /// Align at the end of the cross axis.
+    End,
+
+    /// Stretch over the cross axis.
+    Stretch,
+}
+
+#[doc(hidden)]
+impl From<Align> for style::AlignItems {
+    fn from(align: Align) -> Self {
+        match align {
+            Align::Start => style::AlignItems::FlexStart,
+            Align::Center => style::AlignItems::Center,
+            Align::End => style::AlignItems::FlexEnd,
+            Align::Stretch => style::AlignItems::Stretch,
+        }
+    }
+}
+
+#[doc(hidden)]
+impl From<Align> for style::AlignSelf {
+    fn from(align: Align) -> Self {
+        match align {
+            Align::Start => style::AlignSelf::FlexStart,
+            Align::Center => style::AlignSelf::Center,
+            Align::End => style::AlignSelf::FlexEnd,
+            Align::Stretch => style::AlignSelf::Stretch,
+        }
+    }
+}
+
+/// Distribution on the main axis of a container.
+///
+///   * On a [`Column`], it describes __vertical__ distribution.
+///   * On a [`Row`], it describes __horizontal__ distribution.
+///
+/// [`Column`]: widget/struct.Column.html
+/// [`Row`]: widget/struct.Row.html
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Justify {
+    /// Place items at the start of the main axis.
+    Start,
+
+    /// Place items at the center of the main axis.
+    Center,
+
+    /// Place items at the end of the main axis.
+    End,
+
+    /// Place items with space between.
+    SpaceBetween,
+
+    /// Place items with space around.
+    SpaceAround,
+
+    /// Place items with evenly distributed space.
+    SpaceEvenly,
+}
+
+#[doc(hidden)]
+impl From<Justify> for style::JustifyContent {
+    fn from(justify: Justify) -> Self {
+        match justify {
+            Justify::Start => style::JustifyContent::FlexStart,
+            Justify::Center => style::JustifyContent::Center,
+            Justify::End => style::JustifyContent::FlexEnd,
+            Justify::SpaceBetween => style::JustifyContent::SpaceBetween,
+            Justify::SpaceAround => style::JustifyContent::SpaceAround,
+            Justify::SpaceEvenly => style::JustifyContent::SpaceEvenly,
+        }
+    }
+}