feat(widget): Reimplement FlexRow as iced::Widget

src/widget/flex_row/layout.rs

@@ -0,0 +1,70 @@
+// Copyright 2023 System76 <info@system76.com>
+// SPDX-License-Identifier: MPL-2.0
+
+use crate::{Element, Renderer};
+use iced_core::layout::{Limits, Node};
+use iced_core::{Padding, Point, Size};
+
+pub fn resolve<Message>(
+    renderer: &Renderer,
+    limits: &Limits,
+    items: &[Element<'_, Message>],
+    padding: Padding,
+    column_spacing: f32,
+    row_spacing: f32,
+) -> Node {
+    let limits = limits.pad(padding);
+
+    let mut nodes = Vec::with_capacity(items.len());
+
+    let max_flex_width = limits.max().width;
+    let mut flex_width = 0.0f32;
+    let mut flex_height = 0.0f32;
+
+    let mut current_row_width = 0.0f32;
+    let mut current_row_height = 0.0f32;
+
+    let mut row_buffer = Vec::with_capacity(8);
+
+    for child in items {
+        // Calculate the dimensions of the item.
+        let child_node = child.as_widget().layout(renderer, &limits);
+        let size = child_node.size();
+
+        // Calculate the required additional width to fit the item into the current row.
+        let required_width = size.width
+            + if row_buffer.is_empty() {
+                0.0
+            } else {
+                row_spacing
+            };
+
+        // If it fits, add it to the current row, or create a new one.
+        if current_row_width + required_width <= max_flex_width {
+            current_row_width += required_width;
+            current_row_height = current_row_height.max(size.height);
+
+            row_buffer.push(child_node);
+        } else {
+            if flex_height != 0.0f32 {
+                flex_height += column_spacing;
+            }
+
+            let mut pos_x = 0.0f32;
+            let pos_y = flex_height;
+
+            for mut child_node in row_buffer.drain(..) {
+                child_node.move_to(Point::new(pos_x, pos_y));
+                pos_x += row_spacing + child_node.size().width;
+                nodes.push(child_node);
+            }
+
+            flex_height += current_row_height;
+            flex_width = flex_width.max(current_row_width);
+            current_row_width = 0.0f32;
+        }
+    }
+
+    let flex_size = limits.resolve(Size::new(flex_width, flex_height));
+    Node::with_children(flex_size.pad(padding), nodes)
+}