Refactor: break out Layout to own struct/file

emigui/src/containers/collapsing_header.rs

@@ -46,7 +46,7 @@ impl CollapsingHeader {
 impl CollapsingHeader {
     pub fn show(self, ui: &mut Ui, add_contents: impl FnOnce(&mut Ui)) -> GuiResponse {
         assert!(
-            ui.direction() == Direction::Vertical,
+            ui.layout().dir() == Direction::Vertical,
             "Horizontal collapsing is unimplemented"
         );
         let Self {

emigui/src/containers/menu.rs

@@ -79,8 +79,7 @@ pub fn menu(ui: &mut Ui, title: impl Into<String>, add_contents: impl FnOnce(&mu
                     style.interact.hovered.corner_radius = 0.0;
                     style.interact.inactive.corner_radius = 0.0;
                     ui.set_style(style);
-                    ui.set_align(Align::Justified);
-
+                    ui.set_layout(Layout::justified(Direction::Vertical));
                     add_contents(ui)
                 })
             })

emigui/src/examples/app.rs

@@ -445,22 +445,27 @@ use crate::layout::*;
 #[serde(default)]
 struct LayoutExample {
     dir: Direction,
-    align: Align,
+    align: Option<Align>, // None == jusitifed
 }
 
 impl Default for LayoutExample {
     fn default() -> Self {
         Self {
             dir: Direction::Vertical,
-            align: Align::Min,
+            align: Some(Align::Center),
         }
     }
 }
 
 impl LayoutExample {
     pub fn ui(&mut self, ui: &mut Ui) {
-        ui.set_direction(self.dir);
-        ui.set_align(self.align);
+        Resize::default()
+            .default_size(vec2(200.0, 200.0))
+            .show(ui, |ui| self.contents_ui(ui));
+    }
+
+    pub fn contents_ui(&mut self, ui: &mut Ui) {
+        ui.set_layout(Layout::from_dir_align(self.dir, self.align));
 
         ui.add(label!("Available space: {:?}", ui.available().size()));
         if ui.add(Button::new("Reset")).clicked {
@@ -481,19 +486,27 @@ impl LayoutExample {
         }
 
         ui.add(Separator::new());
+
         ui.add(label!("Align:"));
 
-        for &align in &[Align::Min, Align::Center, Align::Max, Align::Justified] {
+        for &align in &[Align::Min, Align::Center, Align::Max] {
             if ui
                 .add(RadioButton::new(
-                    self.align == align,
+                    self.align == Some(align),
                     format!("{:?}", align),
                 ))
                 .clicked
             {
-                self.align = align;
+                self.align = Some(align);
             }
         }
+        if ui
+            .add(RadioButton::new(self.align == None, "Justified"))
+            .tooltip_text("Try to fill full width/heigth (e.g. buttons)")
+            .clicked
+        {
+            self.align = None;
+        }
     }
 }
 

emigui/src/layout.rs

@@ -1,6 +1,6 @@
 use serde_derive::{Deserialize, Serialize};
 
-use crate::math::*;
+use crate::{math::*, style::Style};
 
 // ----------------------------------------------------------------------------
 
@@ -29,10 +29,6 @@ pub enum Align {
     /// Right/Bottom
     /// Note: requires a bounded/known available_width.
     Max,
-
-    /// Full width/height.
-    /// Use this when you want
-    Justified,
 }
 
 impl Default for Align {
@@ -41,17 +37,135 @@ impl Default for Align {
     }
 }
 
+/// Used e.g. to anchor a piece of text to a part of the rectangle.
 /// Give a position within the rect, specified by the aligns
 pub fn align_rect(rect: Rect, align: (Align, Align)) -> Rect {
     let x = match align.0 {
-        Align::Min | Align::Justified => rect.left(),
+        Align::Min => rect.left(),
         Align::Center => rect.left() - 0.5 * rect.width(),
         Align::Max => rect.left() - rect.width(),
     };
     let y = match align.1 {
-        Align::Min | Align::Justified => rect.top(),
+        Align::Min => rect.top(),
         Align::Center => rect.top() - 0.5 * rect.height(),
         Align::Max => rect.top() - rect.height(),
     };
     Rect::from_min_size(pos2(x, y), rect.size())
 }
+
+// ----------------------------------------------------------------------------
+
+#[derive(Clone, Copy, Debug, PartialEq, Deserialize, Serialize)]
+pub struct Layout {
+    /// Lay out things horizontally or vertically?
+    dir: Direction,
+
+    /// For vertical layouts: put things to left, center or right?
+    /// For horizontal layouts: put things to top, center or bottom?
+    /// None means justified, which means full width (vertical layout) or height (horizontal layouts).
+    align: Option<Align>,
+}
+
+impl Default for Layout {
+    fn default() -> Self {
+        Self {
+            dir: Direction::Vertical,
+            align: Some(Align::Min),
+        }
+    }
+}
+
+impl Layout {
+    /// None align means justified, e.g. fill full width/height.
+    pub fn from_dir_align(dir: Direction, align: Option<Align>) -> Self {
+        Self { dir, align }
+    }
+
+    pub fn vertical(align: Align) -> Self {
+        Self {
+            dir: Direction::Vertical,
+            align: Some(align),
+        }
+    }
+
+    pub fn horizontal(align: Align) -> Self {
+        Self {
+            dir: Direction::Horizontal,
+            align: Some(align),
+        }
+    }
+
+    /// Full-width layout.
+    /// Nice for menues etc where each button is full width.
+    pub fn justified(dir: Direction) -> Self {
+        Self { dir, align: None }
+    }
+
+    pub fn dir(&self) -> Direction {
+        self.dir
+    }
+
+    /// Reserve this much space and move the cursor.
+    /// Returns where to put the widget.
+    ///
+    /// # How sizes are negotiated
+    /// Each widget should have a *minimum desired size* and a *desired size*.
+    /// When asking for space, ask AT LEAST for you minimum, and don't ask for more than you need.
+    /// If you want to fill the space, ask about `available().size()` and use that.
+    ///
+    /// You may get MORE space than you asked for, for instance
+    /// for `Justified` aligned layouts, like in menus.
+    ///
+    /// You may get LESS space than you asked for if the current layout won't fit what you asked for.
+    pub fn allocate_space(
+        &self,
+        cursor: &mut Pos2,
+        style: &Style,
+        available_size: Vec2,
+        mut child_size: Vec2,
+    ) -> Rect {
+        let available_size = available_size.max(child_size);
+
+        let mut child_pos = *cursor;
+        if self.dir == Direction::Horizontal {
+            if let Some(align) = self.align {
+                if align != Align::Min {
+                    debug_assert!(available_size.y.is_finite());
+                    debug_assert!(child_size.y.is_finite());
+                }
+
+                child_pos.y += match align {
+                    Align::Min => 0.0,
+                    Align::Center => 0.5 * (available_size.y - child_size.y),
+                    Align::Max => available_size.y - child_size.y,
+                };
+            } else {
+                // justified: fill full height
+                child_size.y = child_size.y.max(available_size.y);
+            }
+
+            cursor.x += child_size.x;
+            cursor.x += style.item_spacing.x; // Where to put next thing, if there is a next thing
+        } else {
+            if let Some(align) = self.align {
+                if align != Align::Min {
+                    debug_assert!(available_size.y.is_finite());
+                    debug_assert!(child_size.y.is_finite());
+                }
+
+                child_pos.x += match align {
+                    Align::Min => 0.0,
+                    Align::Center => 0.5 * (available_size.x - child_size.x),
+                    Align::Max => available_size.x - child_size.x,
+                };
+            } else {
+                // justified: fill full width
+                child_size.x = child_size.x.max(available_size.x);
+            };
+            cursor.y += child_size.y;
+            cursor.y += style.item_spacing.y; // Where to put next thing, if there is a next thing
+        }
+
+        Rect::from_min_size(child_pos, child_size)
+    }
+}

emigui/src/lib.rs

@@ -49,7 +49,7 @@ pub use {
     id::Id,
     input::*,
     layers::*,
-    layout::Align,
+    layout::*,
     math::*,
     memory::Memory,
     mesher::{Mesh, PaintBatches, Vertex},

emigui/src/ui.rs

@@ -41,18 +41,14 @@ pub struct Ui {
     /// Overide default style in this ui
     style: Style,
 
-    // Layout stuff follows. TODO: move to own type and abstract.
-    /// Doesn't change.
-    dir: Direction,
-
-    align: Align,
+    layout: Layout,
 
     /// Where the next widget will be put.
     /// Progresses along self.dir.
     /// Initially set to rect.min
     /// If something has already been added, this will point ot style.item_spacing beyond the latest child.
     /// The cursor can thus be style.item_spacing pixels outside of the child_bounds.
-    cursor: Pos2,
+    cursor: Pos2, // TODO: move into Layout?
 }
 
 impl Ui {
@@ -69,9 +65,8 @@ impl Ui {
             desired_rect: rect,
             child_bounds: Rect::from_min_size(rect.min, Vec2::zero()), // TODO: Rect::nothing() ?
             style,
+            layout: Default::default(),
             cursor: rect.min,
-            dir: Direction::Vertical,
-            align: Align::Min,
         }
     }
 
@@ -82,15 +77,14 @@ impl Ui {
         let clip_rect = self.clip_rect(); // Keep it unless the child explciitly desires differently
         Ui {
             ctx: self.ctx.clone(),
-            layer: self.layer,
-            style: self.style,
             id: self.id,
+            layer: self.layer,
             clip_rect,
             desired_rect: child_rect,
-            cursor: child_rect.min,
             child_bounds: Rect::from_min_size(child_rect.min, Vec2::zero()), // TODO: Rect::nothing() ?
-            dir: self.dir,
-            align: self.align,
+            style: self.style,
+            layout: self.layout,
+            cursor: child_rect.min,
         }
     }
 
@@ -248,19 +242,13 @@ impl Ui {
         Rect::from_min_max(self.cursor, self.finite_bottom_right())
     }
 
-    // TODO: remove
-    pub fn direction(&self) -> Direction {
-        self.dir
+    pub fn layout(&self) -> &Layout {
+        &self.layout
     }
 
     // TODO: remove
-    pub fn set_direction(&mut self, dir: Direction) {
-        self.dir = dir;
-    }
-
-    // TODO: remove
-    pub fn set_align(&mut self, align: Align) {
-        self.align = align;
+    pub fn set_layout(&mut self, layout: Layout) {
+        self.layout = layout;
     }
 
     // ------------------------------------------------------------------------
@@ -332,6 +320,7 @@ impl Ui {
 
     /// Reserve this much space and move the cursor.
     /// Returns where to put the widget.
+    ///
     /// # How sizes are negotiated
     /// Each widget should have a *minimum desired size* and a *desired size*.
     /// When asking for space, ask AT LEAST for you minimum, and don't ask for more than you need.
@@ -384,40 +373,13 @@ impl Ui {
 
     /// Reserve this much space and move the cursor.
     /// Returns where to put the widget.
-    fn reserve_space_impl(&mut self, mut child_size: Vec2) -> Rect {
+    fn reserve_space_impl(&mut self, child_size: Vec2) -> Rect {
         let available_size = self.available_finite().size();
-        let available_size = available_size.max(child_size);
-
-        let mut child_pos = self.cursor;
-        if self.dir == Direction::Horizontal {
-            child_pos.y += match self.align {
-                Align::Min | Align::Justified => 0.0,
-                Align::Center => 0.5 * (available_size.y - child_size.y),
-                Align::Max => available_size.y - child_size.y,
-            };
-            if self.align == Align::Justified && available_size.y.is_finite() {
-                // Fill full height
-                child_size.y = child_size.y.max(available_size.y);
-            }
-            self.child_bounds.extend_with(self.cursor + child_size);
-            self.cursor.x += child_size.x;
-            self.cursor.x += self.style.item_spacing.x; // Where to put next thing, if there is a next thing
-        } else {
-            child_pos.x += match self.align {
-                Align::Min | Align::Justified => 0.0,
-                Align::Center => 0.5 * (available_size.x - child_size.x),
-                Align::Max => available_size.x - child_size.x,
-            };
-            if self.align == Align::Justified && available_size.x.is_finite() {
-                // Fill full width
-                child_size.x = child_size.x.max(available_size.x);
-            }
-            self.child_bounds.extend_with(self.cursor + child_size);
-            self.cursor.y += child_size.y;
-            self.cursor.y += self.style.item_spacing.y; // Where to put next thing, if there is a next thing
-        }
-
-        Rect::from_min_size(child_pos, child_size)
+        let child_rect =
+            self.layout
+                .allocate_space(&mut self.cursor, &self.style, available_size, child_size);
+        self.child_bounds = self.child_bounds.union(child_rect);
+        child_rect
     }
 
     // ------------------------------------------------
@@ -564,14 +526,13 @@ impl Ui {
         add_contents: impl FnOnce(&mut Ui),
     ) -> InteractInfo {
         assert!(
-            self.dir == Direction::Vertical,
+            self.layout().dir() == Direction::Vertical,
             "You can only indent vertical layouts"
         );
         let indent = vec2(self.style.indent, 0.0);
         let child_rect = Rect::from_min_max(self.cursor + indent, self.bottom_right());
         let mut child_ui = Ui {
             id: self.id.with(id_source),
-            align: Align::Min,
             ..self.child_ui(child_rect)
         };
         add_contents(&mut child_ui);
@@ -603,15 +564,11 @@ impl Ui {
     }
 
     /// A column ui with a given width.
-    pub fn column(&mut self, column_position: Align, mut width: f32) -> Ui {
+    pub fn column(&mut self, column_position: Align, width: f32) -> Ui {
         let x = match column_position {
             Align::Min => 0.0,
             Align::Center => self.available().width() / 2.0 - width / 2.0,
             Align::Max => self.available().width() - width,
-            Align::Justified => {
-                width = self.available().width();
-                0.0
-            }
         };
         self.child_ui(Rect::from_min_size(
             self.cursor + vec2(x, 0.0),
@@ -621,24 +578,22 @@ impl Ui {
 
     /// Start a ui with horizontal layout
     pub fn horizontal(&mut self, add_contents: impl FnOnce(&mut Ui)) -> InteractInfo {
-        self.inner_layout(Direction::Horizontal, Align::Min, add_contents)
+        self.inner_layout(Layout::horizontal(Align::Min), add_contents)
     }
 
     /// Start a ui with vertical layout
     pub fn vertical(&mut self, add_contents: impl FnOnce(&mut Ui)) -> InteractInfo {
-        self.inner_layout(Direction::Vertical, Align::Min, add_contents)
+        self.inner_layout(Layout::vertical(Align::Min), add_contents)
     }
 
     pub fn inner_layout(
         &mut self,
-        dir: Direction,
-        align: Align,
+        layout: Layout,
         add_contents: impl FnOnce(&mut Self),
     ) -> InteractInfo {
         let child_rect = Rect::from_min_max(self.cursor, self.bottom_right());
         let mut child_ui = Self {
-            dir,
-            align,
+            layout,
             ..self.child_ui(child_rect)
         };
         add_contents(&mut child_ui);
@@ -646,7 +601,7 @@ impl Ui {
         self.reserve_space(size, None)
     }
 
-    /// Temporarily split split a vertical layout into several columns.
+    /// Temporarily split split an Ui into several columns.
     ///
     /// ``` ignore
     /// ui.columns(2, |columns| {
@@ -671,7 +626,6 @@ impl Ui {
 
                 Self {
                     id: self.make_child_id(&("column", col_idx)),
-                    dir: Direction::Vertical,
                     ..self.child_ui(child_rect)
                 }
             })

emigui/src/widgets.rs

@@ -421,7 +421,7 @@ impl Widget for Separator {
         let available_space = ui.available_finite().size();
 
         let extra = self.extra;
-        let (points, interact) = match ui.direction() {
+        let (points, interact) = match ui.layout().dir() {
             Direction::Horizontal => {
                 let interact = ui.reserve_space(vec2(self.min_spacing, available_space.y), None);
                 (

emigui/src/widgets/slider.rs

@@ -128,8 +128,7 @@ impl<'a> Widget for Slider<'a> {
 
                     // Place the text in line with the slider on the left:
                     columns[1].set_desired_height(slider_response.rect.height());
-                    columns[1].horizontal(|ui| {
-                        ui.set_align(Align::Center);
+                    columns[1].inner_layout(Layout::horizontal(Align::Center), |ui| {
                         ui.add(Label::new(full_text).multiline(false));
                     });
 

example_glium/src/main.rs

@@ -111,7 +111,7 @@ fn main() {
         let mut ui = ctx.fullscreen_ui();
         example_app.ui(&mut ui);
         let mut ui = ui.centered_column(ui.available().width().min(480.0));
-        ui.set_align(Align::Min);
+        ui.set_layout(Layout::vertical(Align::Min));
         ui.add(label!("Emigui running inside of Glium").text_style(emigui::TextStyle::Heading));
         if ui.add(Button::new("Quit")).clicked {
             running = false;

example_wasm/src/lib.rs

@@ -43,7 +43,7 @@ impl State {
         let mut ui = self.ctx.fullscreen_ui();
         self.example_app.ui(&mut ui);
         let mut ui = ui.centered_column(ui.available().width().min(480.0));
-        ui.set_align(Align::Min);
+        ui.set_layout(Layout::vertical(Align::Min));
         ui.add(label!("Emigui!").text_style(TextStyle::Heading));
         ui.add_label("Emigui is an immediate mode GUI written in Rust, compiled to WebAssembly, rendered with WebGL.");
         ui.add_label(
@@ -57,7 +57,6 @@ impl State {
         });
         ui.add(Separator::new());
 
-        ui.set_align(Align::Min);
         ui.add_label("WebGl painter info:");
         ui.indent("webgl region id", |ui| {
             ui.add_label(self.webgl_painter.debug_info());