mirror of
https://github.com/Astatin3/IntroToWebAuthoring.git
synced 2026-06-09 08:38:00 -06:00
Work on constraint layout
This commit is contained in:
Michael Mikovsky
@@ -0,0 +1,331 @@
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use std::collections::{HashMap, HashSet};
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use crate::{
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log,
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render::Renderer,
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views::{LayoutView, View},
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};
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pub enum Constraint {
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Left(f32, usize),
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Right(f32, usize),
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Top(f32, usize),
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Bottom(f32, usize),
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LeftParent(f32),
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RightParent(f32),
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TopParent(f32),
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BottomParent(f32),
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}
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pub trait ConstraintView: LayoutView {
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fn set_constraints(
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&mut self,
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top: Option<Constraint>,
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left: Option<Constraint>,
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right: Option<Constraint>,
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bottom: Option<Constraint>,
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);
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fn get_constraints(
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&self,
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) -> (
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&Option<Constraint>,
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&Option<Constraint>,
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&Option<Constraint>,
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&Option<Constraint>,
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);
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}
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pub struct ConstraintLayout {
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pub children: Vec<Box<dyn ConstraintView>>,
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child_positions: Option<Vec<Rect>>,
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}
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struct Rect {
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x: f32,
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y: f32,
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width: f32,
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height: f32,
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}
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impl ConstraintLayout {
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pub fn new(children: Vec<Box<dyn ConstraintView>>) -> Self {
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for child in &children {
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let (top, left, right, bottom) = child.get_constraints();
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assert!(
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top.is_some() || bottom.is_some(),
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"Vertically underconstrained"
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);
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assert!(
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left.is_some() || right.is_some(),
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"Horizontally underconstrained"
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);
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}
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let this = ConstraintLayout {
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children,
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child_positions: None,
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};
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this.test();
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this
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}
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pub fn test(&self) {
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let dependencies = self
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.children
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.iter()
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.map(|c| {
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let constraints = c.get_constraints();
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[constraints.0, constraints.1, constraints.2, constraints.3]
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})
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.collect::<Vec<_>>();
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let dac = topological_sort(&dependencies);
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for i in 0..dac.len() {
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log!("{:?}", dac[i])
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}
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}
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}
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impl View for ConstraintLayout {
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fn draw(&mut self, renderer: &mut Renderer, x: f32, y: f32, self_w: f32, self_h: f32) {
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let self_top = y;
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let self_left = x;
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let self_right = x + self_w;
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let self_bottom = y + self_h;
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let mut calculated_positions: HashMap<usize, Rect> = HashMap::new();
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let dependencies = self
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.children
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.iter()
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.map(|c| {
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let constraints = c.get_constraints();
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[constraints.0, constraints.1, constraints.2, constraints.3]
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})
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.collect::<Vec<_>>();
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let sorted = topological_sort(&dependencies);
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for idx in sorted {
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let child = &mut self.children[idx];
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let (c_top, c_left, c_right, c_bottom) = child.get_constraints();
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let (c_width, c_height) = child.bounds(self_w, self_h);
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let c_width = match c_width {
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crate::views::Bounds::MatchParent => self_w,
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crate::views::Bounds::Pixels(x) => x,
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};
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let c_height = match c_height {
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crate::views::Bounds::MatchParent => self_h,
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crate::views::Bounds::Pixels(x) => x,
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};
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let (y, height) = match (c_top, c_bottom) {
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(None, None) => unreachable!("Vertically unconstrained"),
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(Some(Constraint::TopParent(top_margin)), None) => {
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(self_top + top_margin, c_height)
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}
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(Some(Constraint::BottomParent(top_margin)), None) => {
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(self_top + top_margin + c_height, c_height)
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}
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(None, Some(Constraint::TopParent(top_margin))) => {
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(self_top - top_margin, c_height)
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}
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(None, Some(Constraint::BottomParent(bottom_margin))) => {
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(self_h - (bottom_margin + c_height), c_height)
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}
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(Some(Constraint::TopParent(_)), Some(Constraint::TopParent(_))) => unreachable!(),
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(Some(Constraint::BottomParent(_)), Some(Constraint::BottomParent(_))) => {
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unreachable!()
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}
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(Some(Constraint::BottomParent(_)), Some(Constraint::TopParent(_))) => {
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unreachable!()
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}
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(Some(Constraint::TopParent(_)), Some(Constraint::BottomParent(top_margin))) => {
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(self_top + top_margin + c_height, c_height)
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}
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_ => todo!(),
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};
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assert!(height >= 0.);
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let x_align = |constraint: &Option<Constraint>| match constraint {
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Some(Constraint::LeftParent(margin)) => Some(self_left + margin),
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Some(Constraint::RightParent(margin)) => Some(self_right - margin),
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Some(Constraint::Left(margin, id)) => {
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let other = calculated_positions.get(&id).unwrap();
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Some(other.x - margin - c_width)
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}
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Some(Constraint::Right(margin, id)) => {
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let other = calculated_positions.get(&id).unwrap();
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Some(other.x + other.width + margin)
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}
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None => None,
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_ => unreachable!(),
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};
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let x = match (x_align(c_left), x_align(c_right)) {
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(Some(left), Some(right)) => (right + left - c_width) / 2.,
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(Some(left), None) => left,
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(None, Some(right)) => right - c_width,
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(None, None) => unreachable!("Horizontally unconstrained"),
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};
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// let (x, width) = match (c_left, c_right) {
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// (None, None) => unreachable!("Vertically unconstrained"),
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// (Some(Constraint::LeftParent(left_margin)), None) => {
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// (self_top + left_margin, width)
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// }
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// (Some(Constraint::RightParent(right_margin)), None) => {
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// (self_top - right_margin + width, width)
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// }
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// (None, Some(Constraint::LeftParent(left_margin))) => {
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// (self_top - left_margin, width)
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// }
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// (None, Some(Constraint::RightParent(right_margin))) => {
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// (self_w - (right_margin + width), width)
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// // (self_top + top_margin + height, height)
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// }
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// (Some(Constraint::Left(left_margin, n)), None) => {
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// let other = calculated_positions.get(n).unwrap();
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// (other.x - (width + left_margin), width)
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// }
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// (Some(Constraint::Right(right_margin, idx)), None) => {
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// (self_top - right_margin + width, width)
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// }
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// (None, Some(Constraint::Left(left_margin, idx))) => (self_top - left_margin, width),
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// (None, Some(Constraint::Right(right_margin, idx))) => {
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// (self_w - (right_margin + width), width)
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// // (self_top + top_margin + height, height)
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// }
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// (Some(Constraint::LeftParent(_)), Some(Constraint::LeftParent(_))) => {
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// unreachable!()
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// }
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// (Some(Constraint::RightParent(_)), Some(Constraint::RightParent(_))) => {
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// unreachable!()
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// }
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// (Some(Constraint::RightParent(_)), Some(Constraint::LeftParent(_))) => {
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// unreachable!()
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// }
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// (Some(Constraint::TopParent(_)), Some(Constraint::BottomParent(top_margin))) => {
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// (self_top + top_margin + width, width)
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// }
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// _ => todo!(),
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// };
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assert!(c_width >= 0.);
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calculated_positions.insert(
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idx,
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Rect {
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x: x,
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y: y,
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width: c_width,
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height: height,
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},
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);
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child.draw(renderer, x, y, c_width, height);
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// match c_top {
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// None => {}
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// Some(Constraint::TopParent(top_margin)) => {
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// // let child_top = self_top + top_margin;
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// // let child_left = self_left;
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// // let child_right = self_right;
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// // let child_bottom = child_top + child.get_height();
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// // child.draw(renderer, child_left, child_top, child_right - child_left, child_bottom - child_top);
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// }
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// _ => unreachable!(),
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// }
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// match
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// let child_top = child_top.unwrap_or(self_top);
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// let child_left = child_left.unwrap_or(self_left);
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// let child_right = child_right.unwrap_or(self_right);
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// let child_bottom = child_bottom.unwrap_or(self_bottom);
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}
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}
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}
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#[derive(Clone, Copy, PartialEq)]
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enum VisitState {
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Unvisited,
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Visiting,
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Visited,
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}
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/// Performs a topological sort on objects with constraints.
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/// Returns indices in topologically sorted order (dependencies before dependents).
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/// Panics if a cycle is detected.
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pub fn topological_sort(objects: &Vec<[&Option<Constraint>; 4]>) -> Vec<usize> {
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let n = objects.len();
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let mut states = vec![VisitState::Unvisited; n];
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let mut result = Vec::with_capacity(n);
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for i in 0..n {
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if states[i] == VisitState::Unvisited {
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dfs(i, objects, &mut states, &mut result);
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}
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}
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result
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}
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fn dfs(
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node: usize,
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objects: &Vec<[&Option<Constraint>; 4]>,
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states: &mut Vec<VisitState>,
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result: &mut Vec<usize>,
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) {
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if states[node] == VisitState::Visiting {
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panic!("Cycle detected in constraint graph at node {}", node);
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}
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if states[node] == VisitState::Visited {
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return;
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}
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states[node] = VisitState::Visiting;
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// Visit all dependencies
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for constraint in &objects[node] {
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if let Some(c) = constraint {
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if let Some(dep) = get_dependency(c) {
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if dep >= objects.len() {
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panic!("Invalid dependency index {} in node {}", dep, node);
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}
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dfs(dep, objects, states, result);
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}
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}
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}
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states[node] = VisitState::Visited;
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result.push(node);
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}
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/// Extracts the dependency index from a constraint, if it has one.
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fn get_dependency(constraint: &Constraint) -> Option<usize> {
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match constraint {
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Constraint::Left(_, idx) => Some(*idx),
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Constraint::Right(_, idx) => Some(*idx),
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Constraint::Top(_, idx) => Some(*idx),
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Constraint::Bottom(_, idx) => Some(*idx),
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_ => None, // Parent constraints have no dependencies
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}
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}
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// impl LayoutView for ConstraintLayout {
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// fn set_bounds(&mut self, width: Option<Bounds>, height: Option<Bounds>) {
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// // Implement bounds setting logic here
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// }
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// }
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