WIP flexbox-ish layout

crates/sao-ui-rs/src/widgets/flex.rs

@@ -0,0 +1,132 @@
+#[derive(Clone, Debug)]
+pub enum Unit {
+    Fixed(f32),
+    Percentage(f32),
+    Stretch(f32),
+}
+
+impl Unit {
+    pub fn as_fixed(&self, parent_size: f32) -> Option<f32> {
+        match self {
+            Unit::Fixed(u) => Some(*u),
+            Unit::Percentage(u) => Some(u * parent_size),
+            Unit::Stretch(_) => None,
+        }
+    }
+
+    pub fn as_stretch(&self) -> f32 {
+        if let Unit::Stretch(stretch) = self {
+            *stretch
+        } else {
+            0.0
+        }
+    }
+
+    pub fn calc_stretched(&self, parent_size: f32, stretch_factor: f32) -> f32 {
+        match self {
+            Unit::Fixed(u) => *u,
+            Unit::Percentage(u) => u * parent_size,
+            Unit::Stretch(u) => u * stretch_factor,
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct Constraint {
+    pub desired: Unit,
+    pub min: Option<Unit>,
+    pub max: Option<Unit>,
+}
+
+impl Constraint {
+    pub fn calc_minimum_size(&self, parent_size: f32) -> f32 {
+        let desired = self.desired.as_fixed(parent_size).unwrap_or(0.0);
+
+        if let Some(min) = self.min.as_ref() {
+            let min = min.as_fixed(parent_size).unwrap_or(0.0);
+            min.max(desired)
+        } else {
+            desired
+        }
+    }
+
+    pub fn calc_stretch(&self) -> f32 {
+        self.desired.as_stretch()
+            + self.min.as_ref().map(|u| u.as_stretch()).unwrap_or(0.0)
+            + self.max.as_ref().map(|u| u.as_stretch()).unwrap_or(0.0)
+    }
+
+    pub fn calc_stretched(&self, parent_size: f32, stretch_factor: f32) -> f32 {
+        self.desired
+            .calc_stretched(parent_size, stretch_factor)
+            .max(
+                self.min
+                    .as_ref()
+                    .map(|u| u.calc_stretched(parent_size, stretch_factor))
+                    .unwrap_or(0.0),
+            )
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct Metrics {
+    pub margin_before: Constraint,
+    pub content: Constraint,
+    pub margin_after: Constraint,
+}
+
+impl Metrics {
+    pub fn calc_minimum_size(&self, parent_size: f32) -> f32 {
+        self.margin_before.calc_minimum_size(parent_size)
+            + self.content.calc_minimum_size(parent_size)
+            + self.margin_after.calc_minimum_size(parent_size)
+    }
+
+    pub fn calc_stretch(&self) -> f32 {
+        self.margin_before.calc_stretch()
+            + self.content.calc_stretch()
+            + self.margin_after.calc_stretch()
+    }
+}
+
+pub trait Node {
+    fn get_flex_hori(&self) -> Metrics;
+    fn get_flex_vert(&self) -> Metrics;
+}
+
+#[derive(Clone, Debug)]
+pub enum AbsoluteConstraint {}
+
+#[derive(Clone, Debug)]
+pub struct AbsoluteMetrics {}
+
+#[derive(Clone, Debug)]
+pub struct Position {
+    pub start: f32,
+    pub end: f32,
+}
+
+pub fn compute_layout(size: f32, nodes: &[Metrics]) -> Vec<Position> {
+    let mut minimum_size = 0.0;
+    let mut stretch_total = 0.0;
+    for node in nodes.iter() {
+        minimum_size += node.calc_minimum_size(size);
+        stretch_total += stretch_total;
+    }
+
+    let remaining = (size - minimum_size).max(0.0);
+    let stretch = remaining / stretch_total;
+
+    let mut cursor = 0.0;
+    let mut positions = Vec::new();
+    for node in nodes.iter() {
+        cursor += node.margin_before.calc_stretched(size, stretch);
+        let start = cursor;
+        cursor += node.content.calc_stretched(size, stretch);
+        let end = cursor;
+        cursor += node.margin_after.calc_stretched(size, stretch);
+        positions.push(Position { start, end });
+    }
+
+    positions
+}

crates/sao-ui-rs/src/widgets/mod.rs

@@ -6,6 +6,7 @@ use keyframe::functions::*;
 
 pub mod button;
 pub mod dialog;
+pub mod flex;
 pub mod menu;
 pub mod scroll;
 pub mod shell;
@@ -44,10 +45,6 @@ impl<T: Widget> Widget for Option<T> {
     }
 }
 
-pub trait FixedWidth {
-    fn get_width(&self) -> f32;
-}
-
 pub struct MainMenu {
     pub menu: Offset<SlotMenu<RoundButton>>,
     pub inventory: Reveal<Offset<TabMenu>>,

crates/script/src/draw.rs

@@ -23,6 +23,14 @@ bitflags! {
     }
 }
 
+#[derive(Copy, Clone, Debug)]
+pub enum Side {
+    Top,
+    Right,
+    Bottom,
+    Left,
+}
+
 #[derive(Copy, Clone)]
 pub struct ColoredTriangle {
     pub v1: Vec2,