showbits/showbits-common/src/tree.rs

110 lines
3 KiB
Rust

use image::RgbaImage;
use palette::Srgba;
use taffy::{AvailableSpace, NodeId, Point, Size, TaffyResult, TaffyTree};
use crate::{color, BoxedWidget, Rect, Vec2, View};
fn point_to_vec2(point: Point<f32>) -> Vec2 {
Vec2::new(point.x as i32, point.y as i32)
}
fn size_to_vec2(size: Size<f32>) -> Vec2 {
Vec2::new(size.width as i32, size.height as i32)
}
pub struct Tree<C> {
tree: TaffyTree<BoxedWidget<C>>,
background: Srgba,
}
impl<C> Tree<C> {
pub fn new(background: Srgba) -> Self {
Self {
tree: TaffyTree::new(),
background,
}
}
pub(crate) fn taffy_tree(&mut self) -> &mut TaffyTree<BoxedWidget<C>> {
&mut self.tree
}
fn layout(
&mut self,
ctx: &mut C,
root: NodeId,
available: Size<AvailableSpace>,
) -> TaffyResult<()> {
self.tree.enable_rounding(); // Just to make sure
self.tree.compute_layout_with_measure(
root,
available,
|known, available, _node, context| {
if let Some(widget) = context {
widget.size(ctx, known, available)
} else {
Size::ZERO
}
},
)
}
fn render_to_view(
&mut self,
ctx: &mut C,
node: NodeId,
view: &mut View<'_>,
) -> anyhow::Result<()> {
let layout = *self.tree.layout(node)?;
let area = Rect::from_nw(point_to_vec2(layout.location), size_to_vec2(layout.size));
let mut view = view.dup().zoom(area);
// First pass
if let Some(widget) = self.tree.get_node_context_mut(node) {
widget.draw_below(ctx, &mut view, &layout)?;
}
// Render children
let mut children = vec![];
for child in self.tree.children(node)? {
let order = self.tree.layout(child)?.order;
children.push((order, child));
}
children.sort_unstable_by_key(|(order, _)| *order);
for (_, child) in children {
self.render_to_view(ctx, child, &mut view)?;
}
// Second pass
if let Some(widget) = self.tree.get_node_context_mut(node) {
widget.draw_above(ctx, &mut view, &layout)?;
}
Ok(())
}
pub fn render(
&mut self,
ctx: &mut C,
root: NodeId,
available: Size<AvailableSpace>,
) -> anyhow::Result<RgbaImage> {
self.layout(ctx, root, available)?;
let layout = self.tree.layout(root)?;
assert_eq!(layout.location.x, 0.0);
assert_eq!(layout.location.y, 0.0);
// TODO Check how taffy treats the border?
let (width, height) = size_to_vec2(layout.size).to_u32();
let mut image =
RgbaImage::from_pixel(width, height, color::to_image_color(self.background));
self.render_to_view(ctx, root, &mut View::new(&mut image))?;
Ok(image)
}
pub fn print_debug(&mut self, root: NodeId) {
self.tree.print_tree(root)
}
}