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use std::collections::{hash_map::IntoIter as HashMapIter, HashMap};
use std::hash::Hash;
use std::marker::PhantomData;
use std::ops::AddAssign;
use crate::chart::ChartContext;
use crate::coord::{DiscreteRanged, Ranged, RangedCoord};
use crate::drawing::DrawingBackend;
use crate::element::Rectangle;
use crate::style::{Color, ShapeStyle, GREEN};
pub trait HistogramType {}
pub struct Vertical;
pub struct Horizontal;
impl HistogramType for Vertical {}
impl HistogramType for Horizontal {}
/// The series that aggregate data into a histogram
pub struct Histogram<'a, BR, A, Tag = Vertical>
where
BR: DiscreteRanged,
BR::ValueType: Eq + Hash,
A: AddAssign<A> + Default,
Tag: HistogramType,
{
style: Box<dyn Fn(&BR::ValueType, &A) -> ShapeStyle + 'a>,
margin: u32,
iter: HashMapIter<BR::ValueType, A>,
baseline: Box<dyn Fn(BR::ValueType) -> A + 'a>,
br_param: BR::RangeParameter,
_p: PhantomData<(BR, Tag)>,
}
impl<'a, BR, A, Tag> Histogram<'a, BR, A, Tag>
where
BR: DiscreteRanged,
BR::ValueType: Eq + Hash,
A: AddAssign<A> + Default + 'a,
Tag: HistogramType,
{
fn empty(br_param: BR::RangeParameter) -> Self {
Self {
style: Box::new(|_, _| GREEN.filled()),
margin: 5,
iter: HashMap::new().into_iter(),
baseline: Box::new(|_| A::default()),
br_param,
_p: PhantomData,
}
}
/// Set the style of the histogram
pub fn style<S: Into<ShapeStyle>>(mut self, style: S) -> Self {
let style = style.into();
self.style = Box::new(move |_, _| style.clone());
self
}
/// Set the style of histogram using a lambda function
pub fn style_func(
mut self,
style_func: impl Fn(&BR::ValueType, &A) -> ShapeStyle + 'a,
) -> Self {
self.style = Box::new(style_func);
self
}
/// Set the baseline of the histogram
pub fn baseline(mut self, baseline: A) -> Self
where
A: Clone,
{
self.baseline = Box::new(move |_| baseline.clone());
self
}
/// Set a function that defines variant baseline
pub fn baseline_func(mut self, func: impl Fn(BR::ValueType) -> A + 'a) -> Self {
self.baseline = Box::new(func);
self
}
/// Set the margin for each bar
pub fn margin(mut self, value: u32) -> Self {
self.margin = value;
self
}
/// Set the data iterator
pub fn data<I: IntoIterator<Item = (BR::ValueType, A)>>(mut self, iter: I) -> Self {
let mut buffer = HashMap::<BR::ValueType, A>::new();
for (x, y) in iter.into_iter() {
*buffer.entry(x).or_insert_with(Default::default) += y;
}
self.iter = buffer.into_iter();
self
}
}
pub trait UseDefaultParameter: Default {
fn new() -> Self {
Default::default()
}
}
impl UseDefaultParameter for () {}
impl<'a, BR, A> Histogram<'a, BR, A, Vertical>
where
BR: DiscreteRanged,
BR::ValueType: Eq + Hash,
A: AddAssign<A> + Default + 'a,
{
/// Create a new histogram series.
///
/// - `iter`: The data iterator
/// - `margin`: The margin between bars
/// - `style`: The style of bars
///
/// Returns the newly created histogram series
#[allow(clippy::redundant_closure)]
pub fn new<S: Into<ShapeStyle>, I: IntoIterator<Item = (BR::ValueType, A)>>(
iter: I,
margin: u32,
style: S,
) -> Self
where
BR::RangeParameter: UseDefaultParameter,
{
let mut buffer = HashMap::<BR::ValueType, A>::new();
for (x, y) in iter.into_iter() {
*buffer.entry(x).or_insert_with(Default::default) += y;
}
let style = style.into();
Self {
style: Box::new(move |_, _| style.clone()),
margin,
iter: buffer.into_iter(),
baseline: Box::new(|_| A::default()),
br_param: BR::RangeParameter::new(),
_p: PhantomData,
}
}
pub fn vertical<ACoord, DB: DrawingBackend + 'a>(
parent: &ChartContext<DB, RangedCoord<BR, ACoord>>,
) -> Self
where
ACoord: Ranged<ValueType = A>,
{
let dp = parent.as_coord_spec().x_spec().get_range_parameter();
Self::empty(dp)
}
}
impl<'a, BR, A> Histogram<'a, BR, A, Horizontal>
where
BR: DiscreteRanged,
BR::ValueType: Eq + Hash,
A: AddAssign<A> + Default + 'a,
{
pub fn horizontal<ACoord, DB: DrawingBackend>(
parent: &ChartContext<DB, RangedCoord<ACoord, BR>>,
) -> Self
where
ACoord: Ranged<ValueType = A>,
{
let dp = parent.as_coord_spec().y_spec().get_range_parameter();
Self::empty(dp)
}
}
impl<'a, BR, A> Iterator for Histogram<'a, BR, A, Vertical>
where
BR: DiscreteRanged,
BR::ValueType: Eq + Hash,
A: AddAssign<A> + Default,
{
type Item = Rectangle<(BR::ValueType, A)>;
fn next(&mut self) -> Option<Self::Item> {
if let Some((x, y)) = self.iter.next() {
let nx = BR::next_value(&x, &self.br_param);
let base = (self.baseline)(BR::previous_value(&nx, &self.br_param));
let style = (self.style)(&x, &y);
let mut rect = Rectangle::new([(x, y), (nx, base)], style);
rect.set_margin(0, 0, self.margin, self.margin);
return Some(rect);
}
None
}
}
impl<'a, BR, A> Iterator for Histogram<'a, BR, A, Horizontal>
where
BR: DiscreteRanged,
BR::ValueType: Eq + Hash,
A: AddAssign<A> + Default,
{
type Item = Rectangle<(A, BR::ValueType)>;
fn next(&mut self) -> Option<Self::Item> {
if let Some((y, x)) = self.iter.next() {
let ny = BR::next_value(&y, &self.br_param);
// With this trick we can avoid the clone trait bound
let base = (self.baseline)(BR::previous_value(&ny, &self.br_param));
let style = (self.style)(&y, &x);
let mut rect = Rectangle::new([(x, y), (base, ny)], style);
rect.set_margin(self.margin, self.margin, 0, 0);
return Some(rect);
}
None
}
}
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