Draft custom layout engine based on druid

core/src/length.rs

@@ -1,7 +1,17 @@
 /// The strategy used to fill space in a specific dimension.
-#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Hash)]
 pub enum Length {
     Fill,
     Shrink,
     Units(u16),
 }
+
+impl Length {
+    pub fn fill_factor(&self) -> u16 {
+        match self {
+            Length::Fill => 1,
+            Length::Shrink => 0,
+            Length::Units(_) => 0,
+        }
+    }
+}

core/src/rectangle.rs

@@ -1,7 +1,7 @@
 use crate::Point;
 
 /// A rectangle.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
 pub struct Rectangle<T = f32> {
     /// X coordinate of the top-left corner.
     pub x: T,

core/src/widget/column.rs

@@ -1,5 +1,7 @@
 use crate::{Align, Justify, Length};
 
+use std::u32;
+
 /// A container that distributes its contents vertically.
 ///
 /// A [`Column`] will try to fill the horizontal space of its container.
@@ -10,8 +12,8 @@ pub struct Column<Element> {
     pub padding: u16,
     pub width: Length,
     pub height: Length,
-    pub max_width: Length,
-    pub max_height: Length,
+    pub max_width: u32,
+    pub max_height: u32,
     pub align_self: Option<Align>,
     pub align_items: Align,
     pub justify_content: Justify,
@@ -28,8 +30,8 @@ impl<Element> Column<Element> {
             padding: 0,
             width: Length::Fill,
             height: Length::Shrink,
-            max_width: Length::Shrink,
-            max_height: Length::Shrink,
+            max_width: u32::MAX,
+            max_height: u32::MAX,
             align_self: None,
             align_items: Align::Start,
             justify_content: Justify::Start,
@@ -74,7 +76,7 @@ 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
     }
@@ -82,7 +84,7 @@ 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
     }

core/src/widget/row.rs

@@ -1,5 +1,7 @@
 use crate::{Align, Justify, Length};
 
+use std::u32;
+
 /// A container that distributes its contents horizontally.
 ///
 /// A [`Row`] will try to fill the horizontal space of its container.
@@ -10,8 +12,8 @@ pub struct Row<Element> {
     pub padding: u16,
     pub width: Length,
     pub height: Length,
-    pub max_width: Length,
-    pub max_height: Length,
+    pub max_width: u32,
+    pub max_height: u32,
     pub align_self: Option<Align>,
     pub align_items: Align,
     pub justify_content: Justify,
@@ -28,8 +30,8 @@ impl<Element> Row<Element> {
             padding: 0,
             width: Length::Fill,
             height: Length::Shrink,
-            max_width: Length::Shrink,
-            max_height: Length::Shrink,
+            max_width: u32::MAX,
+            max_height: u32::MAX,
             align_self: None,
             align_items: Align::Start,
             justify_content: Justify::Start,
@@ -74,7 +76,7 @@ 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
     }
@@ -82,7 +84,7 @@ 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
     }

core/src/widget/scrollable.rs

@@ -1,10 +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 max_height: u32,
     pub align_self: Option<Align>,
     pub content: Column<Element>,
 }
@@ -14,7 +16,7 @@ impl<'a, Element> Scrollable<'a, Element> {
         Scrollable {
             state,
             height: Length::Shrink,
-            max_height: Length::Shrink,
+            max_height: u32::MAX,
             align_self: None,
             content: Column::new(),
         }
@@ -57,7 +59,7 @@ 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
     }
@@ -65,7 +67,7 @@ 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
     }