libcosmic/src/widget/flex_row/layout.rs
2024-02-06 11:28:27 -05:00

91 lines
2.8 KiB
Rust

// 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::widget::Tree;
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,
tree: &mut [Tree],
) -> Node {
let limits = limits.shrink(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::<Node>::with_capacity(8);
for (child, tree) in items.iter().zip(tree.iter_mut()) {
// Calculate the dimensions of the item.
let child_node = child.as_widget().layout(tree, renderer, &limits);
let size = child_node.size();
// Calculate the required additional width to fit the item into the current row.
let mut 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 {
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 = 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);
required_width -= row_spacing;
current_row_width = 0.0;
}
current_row_width += required_width;
current_row_height = current_row_height.max(size.height);
row_buffer.push(child_node);
}
if !row_buffer.is_empty() {
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 = 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);
}
let flex_size = limits.resolve(flex_width, flex_height, Size::new(flex_width, flex_height));
Node::with_children(flex_size.expand(padding), nodes)
}