diff --git a/examples/custom_layout_tree_owned.rs b/examples/custom_layout_tree_owned.rs new file mode 100644 index 000000000..bbe773112 --- /dev/null +++ b/examples/custom_layout_tree_owned.rs @@ -0,0 +1,189 @@ +mod common { + pub mod image; + pub mod text; +} +use common::image::{image_measure_function, ImageContext}; +use common::text::{text_measure_function, FontMetrics, TextContext, WritingMode, LOREM_IPSUM}; +use taffy::tree::Cache; +use taffy::util::print_tree; +use taffy::{compute_flexbox_layout, compute_grid_layout, compute_layout, compute_leaf_layout, prelude::*}; + +#[derive(Debug, Copy, Clone)] +#[allow(dead_code)] +enum NodeKind { + Flexbox, + Grid, + Text, + Image, +} + +struct Node { + kind: NodeKind, + style: Style, + text_data: Option, + image_data: Option, + cache: Cache, + unrounded_layout: Layout, + final_layout: Layout, + children: Vec, +} + +impl Default for Node { + fn default() -> Self { + Node { + kind: NodeKind::Flexbox, + style: Style::default(), + text_data: None, + image_data: None, + cache: Cache::new(), + unrounded_layout: Layout::with_order(0), + final_layout: Layout::with_order(0), + children: Vec::new(), + } + } +} + +#[allow(dead_code)] +impl Node { + pub fn new_row(style: Style) -> Node { + Node { + kind: NodeKind::Flexbox, + style: Style { display: Display::Flex, flex_direction: FlexDirection::Row, ..style }, + ..Node::default() + } + } + pub fn new_column(style: Style) -> Node { + Node { + kind: NodeKind::Flexbox, + style: Style { display: Display::Flex, flex_direction: FlexDirection::Column, ..style }, + ..Node::default() + } + } + pub fn new_grid(style: Style) -> Node { + Node { kind: NodeKind::Grid, style: Style { display: Display::Grid, ..style }, ..Node::default() } + } + pub fn new_text(style: Style, text_data: TextContext) -> Node { + Node { kind: NodeKind::Text, style, text_data: Some(text_data), ..Node::default() } + } + pub fn new_image(style: Style, image_data: ImageContext) -> Node { + Node { kind: NodeKind::Image, style, image_data: Some(image_data), ..Node::default() } + } + pub fn append_child(&mut self, node: Node) { + self.children.push(node); + } + + unsafe fn as_id(&self) -> NodeId { + NodeId::from(self as *const Node as usize) + } + + pub fn compute_layout(&mut self, available_space: Size, use_rounding: bool) { + compute_layout(&mut StatelessLayoutTree, unsafe { self.as_id() }, available_space, use_rounding); + } + + pub fn print_tree(&mut self) { + print_tree(&mut StatelessLayoutTree, unsafe { self.as_id() }); + } +} + +struct ChildIter<'a>(std::slice::Iter<'a, Node>); +impl<'a> Iterator for ChildIter<'a> { + type Item = NodeId; + fn next(&mut self) -> Option { + self.0.next().map(|c| NodeId::from(c as *const Node as usize)) + } +} + +#[inline(always)] +unsafe fn node_from_id<'a>(node_id: NodeId) -> &'a Node { + &*(usize::from(node_id) as *const Node) +} + +#[inline(always)] +unsafe fn node_from_id_mut<'a>(node_id: NodeId) -> &'a mut Node { + &mut *(usize::from(node_id) as *mut Node) +} + +struct StatelessLayoutTree; +impl LayoutTree for StatelessLayoutTree { + type ChildIter<'a> = ChildIter<'a>; + + fn children(&self, node_id: NodeId) -> Self::ChildIter<'_> { + unsafe { ChildIter(node_from_id(node_id).children.iter()) } + } + + fn child_count(&self, node_id: NodeId) -> usize { + unsafe { node_from_id(node_id).children.len() } + } + + fn child(&self, node_id: NodeId, index: usize) -> NodeId { + unsafe { node_from_id(node_id).children[index].as_id() } + } + + fn style(&self, node_id: NodeId) -> &Style { + unsafe { &node_from_id(node_id).style } + } + + fn unrounded_layout_mut(&mut self, node_id: NodeId) -> &mut Layout { + unsafe { &mut node_from_id_mut(node_id).unrounded_layout } + } + + fn final_layout(&self, node_id: NodeId) -> &Layout { + unsafe { &node_from_id(node_id).final_layout } + } + + fn final_layout_mut(&mut self, node_id: NodeId) -> &mut Layout { + unsafe { &mut node_from_id_mut(node_id).final_layout } + } + + fn cache_mut(&mut self, node_id: NodeId) -> &mut Cache { + unsafe { &mut node_from_id_mut(node_id).cache } + } + + fn compute_child_layout(&mut self, node_id: NodeId, inputs: taffy::tree::LayoutInput) -> taffy::tree::LayoutOutput { + let node = unsafe { node_from_id_mut(node_id) }; + let font_metrics = FontMetrics { char_width: 10.0, char_height: 10.0 }; + + match node.kind { + NodeKind::Flexbox => compute_flexbox_layout(&mut StatelessLayoutTree, node_id, inputs), + NodeKind::Grid => compute_grid_layout(&mut StatelessLayoutTree, node_id, inputs), + NodeKind::Text => compute_leaf_layout( + inputs, + &node.style, + Some(|known_dimensions, available_space| { + text_measure_function( + known_dimensions, + available_space, + node.text_data.as_ref().unwrap(), + &font_metrics, + ) + }), + ), + NodeKind::Image => compute_leaf_layout( + inputs, + &node.style, + Some(|known_dimensions, _available_space| { + image_measure_function(known_dimensions, node.image_data.as_ref().unwrap()) + }), + ), + } + } +} + +fn main() -> Result<(), taffy::TaffyError> { + let mut root = Node::new_column(Style::DEFAULT); + + let text_node = Node::new_text( + Style::default(), + TextContext { text_content: LOREM_IPSUM.into(), writing_mode: WritingMode::Horizontal }, + ); + root.append_child(text_node); + + let image_node = Node::new_image(Style::default(), ImageContext { width: 400.0, height: 300.0 }); + root.append_child(image_node); + + // Compute layout and print result + root.compute_layout(Size::MAX_CONTENT, true); + root.print_tree(); + + Ok(()) +}