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/// PieChart / DonutChart component
use crate::hooks::use_container_size;
use leptos::prelude::*;
use lodviz_core::algorithms::arc::{arc_centroid, arc_path, compute_arcs};
use lodviz_core::core::theme::{ChartConfig, ChartTheme};
/// A single pie data entry: label + value
#[derive(Debug, Clone)]
pub struct PieEntry {
/// Category label
pub label: String,
/// Numerical value (determines angular size)
pub value: f64,
}
/// PieChart component for rendering pie and donut charts
///
/// Features:
/// - Pie or donut mode (controlled by `donut` prop)
/// - Percentage labels on each slice
/// - Hover tooltip with value details
/// - A11y: ARIA labels per slice, keyboard navigable
/// - Responsive SVG rendering
#[component]
pub fn PieChart(
/// Data entries (label, value pairs)
data: Signal<Vec<PieEntry>>,
/// Width (optional)
#[prop(optional)]
width: Option<u32>,
/// Height (optional)
#[prop(optional)]
height: Option<u32>,
/// Chart title
#[prop(optional)]
title: Option<String>,
/// Donut mode (true = hollow center)
#[prop(default = false)]
donut: bool,
/// Inner radius ratio for donut (0.0 to 1.0, fraction of outer radius)
#[prop(default = 0.5)]
inner_ratio: f64,
/// Chart configuration
#[prop(default = Signal::derive(|| ChartConfig::default()), into)]
config: Signal<ChartConfig>,
) -> impl IntoView {
let ctx_theme = use_context::<Signal<ChartTheme>>();
let theme = Memo::new(move |_| {
config
.get()
.theme
.unwrap_or_else(|| ctx_theme.map(|s| s.get()).unwrap_or_default())
});
let donut_computed = Memo::new(move |_| config.get().pie_donut.unwrap_or(donut));
let inner_ratio_computed =
Memo::new(move |_| config.get().pie_inner_ratio.unwrap_or(inner_ratio));
let (container_width, container_height, container_ref) = use_container_size();
let chart_width = Memo::new(move |_| {
let measured = container_width.get();
if measured > 0.0 {
return measured as u32;
}
config.get().width.or(width).unwrap_or(400)
});
let chart_height = Memo::new(move |_| {
let measured = container_height.get();
if measured > 0.0 {
return measured as u32;
}
config.get().height.or(height).unwrap_or(400)
});
let final_title = Memo::new(move |_| config.get().title.or(title.clone()));
// Compute center and radius
let cx = Memo::new(move |_| chart_width.get() as f64 / 2.0);
let cy = Memo::new(move |_| chart_height.get() as f64 / 2.0);
let outer_radius = Memo::new(move |_| {
let w = chart_width.get() as f64;
let h = chart_height.get() as f64;
(w.min(h) / 2.0 - 40.0).max(20.0) // 40px margin for labels
});
// Hover state
let (hovered_index, set_hovered_index) = signal(None::<usize>);
let is_empty = Memo::new(move |_| {
let entries = data.get();
entries.is_empty() || entries.iter().all(|e| e.value <= 0.0)
});
let aria_label = Memo::new(move |_| {
final_title.get().unwrap_or_else(|| {
if donut_computed.get() {
"Donut chart".to_string()
} else {
"Pie chart".to_string()
}
})
});
let a11y_title_id =
StoredValue::new_local(format!("chart-title-{}", uuid::Uuid::new_v4().as_simple()));
let a11y_desc_id =
StoredValue::new_local(format!("chart-desc-{}", uuid::Uuid::new_v4().as_simple()));
let a11y_labelledby = StoredValue::new_local(format!(
"{} {}",
a11y_title_id.get_value(),
a11y_desc_id.get_value()
));
view! {
<div
class="pie-chart"
style=move || {
format!(
"width: 100%; height: 100%; display: flex; flex-direction: column; background-color: {};",
theme.get().background_color,
)
}
>
{move || {
final_title
.get()
.map(|t| {
let th = theme.get();
view! {
<h3 style=format!(
"text-align: center; margin: 0; padding-top: {}px; padding-bottom: {}px; font-size: {}px; font-family: {}; color: {}; font-weight: {};",
th.title_padding_top,
th.title_padding_bottom,
th.title_font_size,
th.font_family,
th.text_color,
th.title_font_weight,
)>{t}</h3>
}
})
}}
<div node_ref=container_ref style="flex: 1; position: relative; min-height: 0;">
{move || {
use crate::components::svg::empty_state::{EmptyStateMessage, EmptyStateProps};
if is_empty.get() {
view! { <EmptyStateMessage props=EmptyStateProps::no_data() theme=theme /> }
.into_any()
} else {
view! {
<svg
role="img"
aria-labelledby=a11y_labelledby.get_value()
tabindex="0"
viewBox=move || {
format!("0 0 {} {}", chart_width.get(), chart_height.get())
}
style="width: 100%; height: 100%; display: block; outline: none;"
>
<title id=a11y_title_id
.get_value()>{move || aria_label.get()}</title>
<desc id=a11y_desc_id
.get_value()>
"Pie chart showing the proportional distribution of categories."
</desc>
// Slices
{move || {
let entries = data.get();
let values: Vec<f64> = entries
.iter()
.map(|e| e.value)
.collect();
let arcs = compute_arcs(&values);
let th = theme.get();
let center_x = cx.get();
let center_y = cy.get();
let r = outer_radius.get();
let ir = if donut_computed.get() {
r * inner_ratio_computed.get()
} else {
0.0
};
let label_r = if donut_computed.get() {
(r + ir) / 2.0
} else {
r * 0.65
};
let hover = hovered_index.get();
let mut arc_idx = 0;
let mut views = Vec::new();
for (entry_idx, entry) in entries.iter().enumerate() {
if entry.value <= 0.0 {
continue;
}
let arc = &arcs[arc_idx];
let color = th
.palette[entry_idx % th.palette.len()]
.clone();
let is_hovered = hover == Some(entry_idx);
let scale_transform = if is_hovered {
let mid = arc.mid_angle();
let offset = 6.0;
let dx = offset * mid.cos();
let dy = offset * mid.sin();
format!("translate({dx:.2}, {dy:.2})")
} else {
String::new()
};
let path_d = arc_path(
center_x,
center_y,
r,
ir,
arc.start_angle,
arc.end_angle,
);
let label_text = format!("{:.0}%", arc.percentage);
let (lx, ly) = arc_centroid(
center_x,
center_y,
label_r,
arc.start_angle,
arc.end_angle,
);
let aria = format!(
"{}: {:.1} ({:.1}%)",
entry.label,
entry.value,
arc.percentage,
);
let idx = entry_idx;
views
.push(
// Build slices - we need to track the mapping from arcs back to entries
// since compute_arcs skips non-positive values
// Hover scale effect
view! {
<g
transform=scale_transform
style="cursor: pointer;"
on:mouseenter=move |_| set_hovered_index.set(Some(idx))
on:mouseleave=move |_| set_hovered_index.set(None)
>
<path
d=path_d
fill=color
stroke=th.background_color.clone()
stroke-width="2"
aria-label=aria
/>
// Percentage label (only show if slice is big enough)
{if arc.percentage >= 5.0 {
Some(
view! {
<text
x=format!("{lx:.2}")
y=format!("{ly:.2}")
text-anchor="middle"
dominant-baseline="central"
font-size=format!("{}", th.axis_font_size)
fill=th.text_color.clone()
font-weight="bold"
pointer-events="none"
>
{label_text}
</text>
},
)
} else {
None
}}
</g>
},
);
arc_idx += 1;
}
views.collect_view()
}}
// Tooltip on hover
{move || {
let entries = data.get();
let th = theme.get();
hovered_index
.get()
.and_then(|idx| {
let entry = entries.get(idx)?;
let values: Vec<f64> = entries
.iter()
.map(|e| e.value)
.collect();
let total: f64 = values.iter().filter(|v| **v > 0.0).sum();
let pct = if total > 0.0 {
(entry.value / total) * 100.0
} else {
0.0
};
Some(
view! {
<g>
<rect
x=format!("{:.2}", cx.get() - 60.0)
y=format!("{:.2}", cy.get() - 20.0)
width="120"
height="40"
fill=th.background_color.clone()
stroke=th.axis_color.clone()
rx="4"
opacity="0.9"
/>
<text
x=format!("{:.2}", cx.get())
y=format!("{:.2}", cy.get() - 4.0)
text-anchor="middle"
font-size=format!("{}", th.axis_font_size)
fill=th.text_color.clone()
font-weight="bold"
>
{entry.label.clone()}
</text>
<text
x=format!("{:.2}", cx.get())
y=format!("{:.2}", cy.get() + 12.0)
text-anchor="middle"
font-size=format!("{}", th.axis_font_size)
fill=th.text_color.clone()
>
{format!("{:.1} ({:.1}%)", entry.value, pct)}
</text>
</g>
},
)
})
}}
// Legend below the chart
{move || {
let entries = data.get();
let th = theme.get();
let start_y = chart_height.get() as f64 - 20.0;
let total_width = entries.len() as f64 * 100.0;
let start_x = (chart_width.get() as f64 - total_width) / 2.0;
entries
.iter()
.enumerate()
.map(|(i, entry)| {
let color = th.palette[i % th.palette.len()].clone();
let x = start_x + i as f64 * 100.0;
view! {
<g>
<rect
x=format!("{x:.2}")
y=format!("{:.2}", start_y)
width="10"
height="10"
fill=color
rx="2"
/>
<text
x=format!("{:.2}", x + 14.0)
y=format!("{:.2}", start_y + 9.0)
font-size=format!("{}", th.axis_font_size)
fill=th.text_color.clone()
>
{entry.label.clone()}
</text>
</g>
}
})
.collect_view()
}}
</svg>
}
.into_any()
}
}}
</div>
</div>
}
}