TMP

masonry/src/box_constraints.rs

@@ -8,9 +8,10 @@ use vello::kurbo::Size;
 /// The layout strategy for Masonry is strongly inspired by Flutter,
 /// and this struct is similar to the [Flutter BoxConstraints] class.
 ///
-/// At the moment, it represents simply a minimum and maximum size.
+/// At the moment, it represents only a maximum size.
 /// A widget's [`layout`] method should choose an appropriate size that
-/// meets these constraints.
+/// meets that constraint.
+/// The algorithm is supposed to use a minimum constraint, but we're phasing that out.
 ///
 /// Further, a container widget should compute appropriate constraints
 /// for each of its child widgets, and pass those down when recursing.
@@ -23,7 +24,6 @@ use vello::kurbo::Size;
 /// [rounded away from zero]: Size::expand
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct BoxConstraints {
-    min: Size,
     max: Size,
 }
 
@@ -32,7 +32,6 @@ impl BoxConstraints {
     ///
     /// Can be satisfied by any nonnegative size.
     pub const UNBOUNDED: BoxConstraints = BoxConstraints {
-        min: Size::ZERO,
         max: Size::new(f64::INFINITY, f64::INFINITY),
     };
 
@@ -44,37 +43,8 @@ impl BoxConstraints {
     /// so that the layout is aligned to integers.
     ///
     /// [rounded away from zero]: Size::expand
-    pub fn new(min: Size, max: Size) -> BoxConstraints {
-        BoxConstraints {
-            min: min.expand(),
-            max: max.expand(),
-        }
-    }
-
-    /// Create a "tight" box constraints object.
-    ///
-    /// A "tight" constraint can only be satisfied by a single size.
-    ///
-    /// The given size is also [rounded away from zero],
-    /// so that the layout is aligned to integers.
-    ///
-    /// [rounded away from zero]: Size::expand
-    pub fn tight(size: Size) -> BoxConstraints {
-        let size = size.expand();
-        BoxConstraints {
-            min: size,
-            max: size,
-        }
-    }
-
-    /// Create a "loose" version of the constraints.
-    ///
-    /// Make a version with zero minimum size, but the same maximum size.
-    pub fn loosen(&self) -> BoxConstraints {
-        BoxConstraints {
-            min: Size::ZERO,
-            max: self.max,
-        }
+    pub fn new(max: Size) -> BoxConstraints {
+        BoxConstraints { max: max.expand() }
     }
 
     /// Clamp a given size so that it fits within the constraints.
@@ -84,19 +54,14 @@ impl BoxConstraints {
     ///
     /// [rounded away from zero]: Size::expand
     pub fn constrain(&self, size: impl Into<Size>) -> Size {
-        size.into().expand().clamp(self.min, self.max)
+        size.into().expand().clamp(Size::ZERO, self.max)
     }
 
     /// Returns the max size of these constraints.
     pub fn max(&self) -> Size {
         self.max
     }
 
-    /// Returns the min size of these constraints.
-    pub fn min(&self) -> Size {
-        self.min
-    }
-
     /// Whether there is an upper bound on the width.
     pub fn is_width_bounded(&self) -> bool {
         self.max.width.is_finite()
@@ -115,51 +80,32 @@ impl BoxConstraints {
             return;
         }
 
-        if !(0.0 <= self.min.width
-            && self.min.width <= self.max.width
-            && 0.0 <= self.min.height
-            && self.min.height <= self.max.height
-            && self.min.expand() == self.min
-            && self.max.expand() == self.max)
-        {
+        if !(0.0 <= self.max.width && 0.0 <= self.max.height && self.max.expand() == self.max) {
             tracing::warn!("Bad BoxConstraints passed to {}:", name);
             tracing::warn!("{:?}", self);
         }
-
-        if self.min.width.is_infinite() {
-            tracing::warn!("Infinite minimum width constraint passed to {}:", name);
-        }
-
-        if self.min.height.is_infinite() {
-            tracing::warn!("Infinite minimum height constraint passed to {}:", name);
-        }
     }
 
-    /// Shrink min and max constraints by size
+    /// Shrink max constraint by size
     ///
     /// The given size is also [rounded away from zero],
     /// so that the layout is aligned to integers.
     ///
     /// [rounded away from zero]: Size::expand
     pub fn shrink(&self, diff: impl Into<Size>) -> BoxConstraints {
         let diff = diff.into().expand();
-        let min = Size::new(
-            (self.min().width - diff.width).max(0.),
-            (self.min().height - diff.height).max(0.),
-        );
         let max = Size::new(
             (self.max().width - diff.width).max(0.),
             (self.max().height - diff.height).max(0.),
         );
 
-        BoxConstraints::new(min, max)
+        BoxConstraints::new(max)
     }
 
     /// Test whether these constraints contain the given `Size`.
     pub fn contains(&self, size: impl Into<Size>) -> bool {
         let size = size.into();
-        (self.min.width <= size.width && size.width <= self.max.width)
-            && (self.min.height <= size.height && size.height <= self.max.height)
+        (size.width <= self.max.width) && (size.height <= self.max.height)
     }
 
     /// Find the `Size` within these `BoxConstraint`s that minimises the difference between the
@@ -192,9 +138,9 @@ impl BoxConstraints {
 
         // Then we check if any `Size`s with our desired aspect ratio are inside the constraints.
         // TODO this currently outputs garbage when things are < 0 - See https://github.com/linebender/xilem/issues/377
-        let min_w_min_h = self.min.height / self.min.width;
-        let max_w_min_h = self.min.height / self.max.width;
-        let min_w_max_h = self.max.height / self.min.width;
+        let min_w_min_h = 0.0 / 0.0;
+        let max_w_min_h = 0.0 / self.max.width;
+        let min_w_max_h = self.max.height / 0.0;
         let max_w_max_h = self.max.height / self.max.width;
 
         // When the aspect ratio line crosses the constraints, the closest point must be one of the
@@ -208,22 +154,22 @@ impl BoxConstraints {
         if aspect_ratio > min_w_max_h {
             // outside max height min width
             Size {
-                width: self.min.width,
+                width: 0.0,
                 height: self.max.height,
             }
         } else if aspect_ratio < max_w_min_h {
             // outside min height max width
             Size {
                 width: self.max.width,
-                height: self.min.height,
+                height: 0.0,
             }
         } else if aspect_ratio > min_w_min_h {
             // hits the constraints on the min width line
-            if width < self.min.width {
+            if width < 0.0 {
                 // we take the point on the min width
                 Size {
-                    width: self.min.width,
-                    height: self.min.width * aspect_ratio,
+                    width: 0.0,
+                    height: 0.0 * aspect_ratio,
                 }
             } else if aspect_ratio < max_w_max_h {
                 // exits through max.width
@@ -240,11 +186,11 @@ impl BoxConstraints {
             }
         } else {
             // final case is where we hit constraints on the min height line
-            if width < self.min.width {
+            if width < 0.0 {
                 // take the point on the min height
                 Size {
-                    width: self.min.height * aspect_ratio.recip(),
-                    height: self.min.height,
+                    width: 0.0 * aspect_ratio.recip(),
+                    height: 0.0,
                 }
             } else if aspect_ratio > max_w_max_h {
                 // exit thru max height
@@ -268,10 +214,7 @@ mod tests {
     use super::*;
 
     fn bc(min_width: f64, min_height: f64, max_width: f64, max_height: f64) -> BoxConstraints {
-        BoxConstraints::new(
-            Size::new(min_width, min_height),
-            Size::new(max_width, max_height),
-        )
+        BoxConstraints::new(Size::new(max_width, max_height))
     }
 
     #[test]
@@ -362,7 +305,5 @@ mod tests {
     fn unbounded() {
         assert!(!BoxConstraints::UNBOUNDED.is_width_bounded());
         assert!(!BoxConstraints::UNBOUNDED.is_height_bounded());
-
-        assert_eq!(BoxConstraints::UNBOUNDED.min(), Size::ZERO);
     }
 }

masonry/src/render_root.rs

@@ -455,7 +455,7 @@ impl RenderRoot {
     pub(crate) fn root_layout(&mut self) {
         let window_size = self.get_kurbo_size();
         let bc = match self.size_policy {
-            WindowSizePolicy::User => BoxConstraints::tight(window_size),
+            WindowSizePolicy::User => BoxConstraints::new(window_size),
             WindowSizePolicy::Content => BoxConstraints::UNBOUNDED,
         };
 

masonry/src/widget/align.rs

@@ -98,7 +98,7 @@ impl Widget for Align {
     fn on_status_change(&mut self, _ctx: &mut LifeCycleCtx, _event: &StatusChange) {}
 
     fn layout(&mut self, ctx: &mut LayoutCtx, bc: &BoxConstraints) -> Size {
-        let size = ctx.run_layout(&mut self.child, &bc.loosen());
+        let size = ctx.run_layout(&mut self.child, &bc);
 
         log_size_warnings(size);
 

masonry/src/widget/button.rs

@@ -121,7 +121,7 @@ impl Widget for Button {
 
     fn layout(&mut self, ctx: &mut LayoutCtx, bc: &BoxConstraints) -> Size {
         let padding = Size::new(LABEL_INSETS.x_value(), LABEL_INSETS.y_value());
-        let label_bc = bc.shrink(padding).loosen();
+        let label_bc = bc.shrink(padding);
 
         let label_size = ctx.run_layout(&mut self.label, &label_bc);
 

masonry/src/widget/flex.rs

@@ -127,7 +127,7 @@ impl Flex {
             cross_alignment: CrossAxisAlignment::Center,
             main_alignment: MainAxisAlignment::Start,
             fill_major_axis: false,
-            old_bc: BoxConstraints::tight(Size::ZERO),
+            old_bc: BoxConstraints::new(Size::ZERO),
             gap: None,
         }
     }
@@ -687,21 +687,10 @@ impl Axis {
     }
 
     /// Generate constraints with new values on the major axis.
-    pub(crate) fn constraints(
-        self,
-        bc: &BoxConstraints,
-        min_major: f64,
-        major: f64,
-    ) -> BoxConstraints {
+    pub(crate) fn constraints(self, bc: &BoxConstraints, major: f64) -> BoxConstraints {
         match self {
-            Axis::Horizontal => BoxConstraints::new(
-                Size::new(min_major, bc.min().height),
-                Size::new(major, bc.max().height),
-            ),
-            Axis::Vertical => BoxConstraints::new(
-                Size::new(bc.min().width, min_major),
-                Size::new(bc.max().width, major),
-            ),
+            Axis::Horizontal => BoxConstraints::new(Size::new(major, bc.max().height)),
+            Axis::Vertical => BoxConstraints::new(Size::new(bc.max().width, major)),
         }
     }
 }
@@ -911,10 +900,10 @@ impl Widget for Flex {
 
     fn layout(&mut self, ctx: &mut LayoutCtx, bc: &BoxConstraints) -> Size {
         // we loosen our constraints when passing to children.
-        let loosened_bc = bc.loosen();
+        let loosened_bc = bc;
 
         // minor-axis values for all children
-        let mut minor = self.direction.minor(bc.min());
+        let mut minor = 0_f64;
         // these two are calculated but only used if we're baseline aligned
         let mut max_above_baseline = 0_f64;
         let mut max_below_baseline = 0_f64;
@@ -1007,7 +996,7 @@ impl Widget for Flex {
                         remainder = desired_major - actual_major;
 
                         let old_size = ctx.widget_state.layout_rect().size();
-                        let child_bc = self.direction.constraints(&loosened_bc, 0.0, actual_major);
+                        let child_bc = self.direction.constraints(&loosened_bc, actual_major);
                         let child_size = ctx.run_layout(widget, &child_bc);
 
                         if old_size != child_size {
@@ -1043,8 +1032,8 @@ impl Widget for Flex {
             (remaining - major_flex).max(0.0)
         } else {
             // if we are *not* expected to fill our available space this usually
-            // means we don't have any extra, unless dictated by our constraints.
-            (self.direction.major(bc.min()) - (major_non_flex + major_flex)).max(0.0)
+            // means we don't have any extra
+            0.0
         };
 
         let mut spacing = Spacing::new(self.main_alignment, extra, self.children.len());
@@ -1085,7 +1074,7 @@ impl Widget for Flex {
                                 .pack(self.direction.major(child_size), minor_dim)
                                 .into();
                             if ctx.widget_state.layout_rect().size() != fill_size {
-                                let child_bc = BoxConstraints::tight(fill_size);
+                                let child_bc = BoxConstraints::new(fill_size);
                                 //TODO: this is the second call of layout on the same child, which
                                 // is bad, because it can lead to exponential increase in layout calls
                                 // when used multiple times in the widget hierarchy.

masonry/src/widget/grid.rs

@@ -255,7 +255,7 @@ impl Widget for Grid {
                 child.width as f64 * width_unit - self.grid_spacing,
                 child.height as f64 * height_unit - self.grid_spacing,
             );
-            let child_bc = BoxConstraints::new(cell_size, cell_size);
+            let child_bc = BoxConstraints::new(cell_size);
             let _ = ctx.run_layout(&mut child.widget, &child_bc);
             ctx.place_child(
                 &mut child.widget,

masonry/src/widget/image.rs

@@ -89,7 +89,7 @@ impl Widget for Image {
         // the image.
         let image_size = Size::new(self.image_data.width as f64, self.image_data.height as f64);
         if image_size.is_empty() {
-            let size = bc.min();
+            let size = Size::ZERO;
             trace!("Computed size: {}", size);
             return size;
         }

masonry/src/widget/label.rs

@@ -215,8 +215,6 @@ impl Widget for Label {
             None
         } else if bc.max().width.is_finite() {
             Some(bc.max().width as f32 - 2. * LABEL_X_PADDING as f32)
-        } else if bc.min().width.is_sign_negative() {
-            Some(0.0)
         } else {
             None
         };

masonry/src/widget/portal.rs

@@ -371,10 +371,9 @@ impl<W: Widget> Widget for Portal<W> {
 
     fn layout(&mut self, ctx: &mut LayoutCtx, bc: &BoxConstraints) -> Size {
         // TODO - How Portal handles BoxConstraints is due for a rework
-        let min_child_size = if self.must_fill { bc.min() } else { Size::ZERO };
         let max_child_size = bc.max();
 
-        let child_bc = BoxConstraints::new(min_child_size, max_child_size);
+        let child_bc = BoxConstraints::new(max_child_size);
 
         let content_size = ctx.run_layout(&mut self.child, &child_bc);
         let portal_size = bc.constrain(content_size);

masonry/src/widget/prose.rs

@@ -239,8 +239,6 @@ impl Widget for Prose {
         } else if bc.max().width.is_finite() {
             // TODO: Does Prose have different needs here?
             Some(bc.max().width as f32 - 2. * LABEL_X_PADDING as f32)
-        } else if bc.min().width.is_sign_negative() {
-            Some(0.0)
         } else {
             None
         };