sized widgets!

src/core/span.rs

@@ -6,8 +6,8 @@ pub struct Span {
 }
 
 impl Widget for Span {
-    fn draw(&self, painter: &mut Painter) {
-        let total = self.sums();
+    fn draw(&mut self, painter: &mut Painter) {
+        let total = self.setup(painter);
         let mut start = UIScalar::min();
         for (child, length) in &self.children {
             let mut child_region = UiRegion::full();
@@ -29,6 +29,14 @@ impl Widget for Span {
                     start.anchor += rel;
                     axis.bot_right.set(start);
                 }
+                SpanLen::Sized(size) => {
+                    let offset = size.axis(self.dir.axis);
+                    start.offset += offset;
+                    *axis.bot_right.offset = start.offset;
+                    child_region.bot_right.anchor = child_region.top_left.anchor;
+                    let opposite = !self.dir.axis;
+                    *child_region.bot_right.offset.axis_mut(opposite) += size.axis(opposite);
+                }
             }
             if self.dir.sign == Sign::Neg {
                 child_region.flip();
@@ -53,18 +61,23 @@ impl Span {
         }
     }
 
-    pub fn sums(&self) -> SpanLenSums {
-        self.lengths().fold(SpanLenSums::default(), |mut s, l| {
-            match l {
-                SpanLen::Fixed(v) => s.fixed += v,
-                SpanLen::Ratio(v) => s.ratio += v,
-                SpanLen::Relative(v) => s.relative += v,
-            }
-            s
-        })
-    }
-    pub fn lengths(&self) -> impl ExactSizeIterator<Item = &SpanLen> {
-        self.children.iter().map(|(_, s)| s)
+    fn setup(&mut self, painter: &mut Painter) -> SpanLenSums {
+        self.children
+            .iter_mut()
+            .fold(SpanLenSums::default(), |mut s, (id, l)| {
+                match l {
+                    SpanLen::Fixed(v) => s.fixed += *v,
+                    SpanLen::Ratio(v) => s.ratio += *v,
+                    SpanLen::Relative(v) => s.relative += *v,
+                    SpanLen::Sized(v) => {
+                        let size = painter.size(id);
+                        let len = size.axis(self.dir.axis);
+                        *v = size;
+                        s.fixed += len;
+                    }
+                }
+                s
+            })
     }
 }
 
@@ -78,6 +91,10 @@ pub enum SpanLen {
     /// relative to the total space (of the entire span)
     /// eg. 0.5 means 1/2 of the total space
     Relative(f32),
+    /// size determined by the child widget itself
+    /// the value is not used externally, I just don't wanna make a duplicate enum
+    /// there are util functions instead so
+    Sized(Vec2),
 }
 
 pub fn fixed<N: UiNum>(x: N) -> SpanLen {
@@ -92,6 +109,10 @@ pub fn relative<N: UiNum>(x: N) -> SpanLen {
     SpanLen::Relative(x.to_f32())
 }
 
+pub fn sized() -> SpanLen {
+    SpanLen::Sized(Vec2::ZERO)
+}
+
 impl<N: UiNum> From<N> for SpanLen {
     fn from(value: N) -> Self {
         Self::Ratio(value.to_f32())