1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173

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::{DescreteRanged, Ranged, RangedCoord};
use crate::drawing::DrawingBackend;
use crate::element::Rectangle;
use crate::style::{Color, Green, ShapeStyle};

pub trait HistogramType {}
pub struct Vertical;
pub struct Horizental;

impl HistogramType for Vertical {}
impl HistogramType for Horizental {}

/// The series that aggregate data into a histogram
pub struct Histogram<BR, A, Tag = Vertical>
where
    BR: DescreteRanged,
    BR::ValueType: Eq + Hash + Default,
    A: AddAssign<A> + Default,
    Tag: HistogramType,
{
    style: ShapeStyle,
    margin: u32,
    iter: HashMapIter<BR::ValueType, A>,
    baseline: Box<dyn Fn() -> A>,
    _p: PhantomData<(BR, Tag)>,
}

impl<BR, A, Tag> Histogram<BR, A, Tag>
where
    BR: DescreteRanged,
    BR::ValueType: Eq + Hash + Default,
    A: AddAssign<A> + Default,
    Tag: HistogramType,
{
    fn empty() -> Self {
        Self {
            style: Green.filled(),
            margin: 5,
            iter: HashMap::new().into_iter(),
            baseline: Box::new(|| A::default()),
            _p: PhantomData,
        }
    }
    /// Set the style of the histogram
    pub fn style<S: Into<ShapeStyle>>(mut self, style: S) -> Self {
        self.style = style.into();
        self
    }

    /// Set the baseline of the histogram
    pub fn baseline(mut self, baseline: A) -> Self
    where
        A: Clone + 'static,
    {
        self.baseline = Box::new(move || baseline.clone());
        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
    }
}

impl<BR, A> Histogram<BR, A, Vertical>
where
    BR: DescreteRanged,
    BR::ValueType: Eq + Hash + Default,
    A: AddAssign<A> + Default,
{
    /// 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
    pub fn new<S: Into<ShapeStyle>, I: IntoIterator<Item = (BR::ValueType, A)>>(
        iter: I,
        margin: u32,
        style: S,
    ) -> 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 {
            style: style.into(),
            margin,
            iter: buffer.into_iter(),
            baseline: Box::new(|| A::default()),
            _p: PhantomData,
        }
    }

    pub fn vertical<ACoord, DB: DrawingBackend>(
        _: &ChartContext<DB, RangedCoord<BR, ACoord>>,
    ) -> Self
    where
        ACoord: Ranged<ValueType = A>,
    {
        Self::empty()
    }
}

impl<BR, A> Histogram<BR, A, Horizental>
where
    BR: DescreteRanged,
    BR::ValueType: Eq + Hash + Default,
    A: AddAssign<A> + Default,
{
    pub fn horizental<ACoord, DB: DrawingBackend>(
        _: &ChartContext<DB, RangedCoord<ACoord, BR>>,
    ) -> Self
    where
        ACoord: Ranged<ValueType = A>,
    {
        Self::empty()
    }
}

impl<BR, A> Iterator for Histogram<BR, A, Vertical>
where
    BR: DescreteRanged,
    BR::ValueType: Eq + Hash + Default,
    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);
            let mut rect = Rectangle::new([(x, y), (nx, (self.baseline)())], self.style.clone());
            rect.set_margin(0, 0, self.margin, self.margin);
            return Some(rect);
        }
        None
    }
}

impl<BR, A> Iterator for Histogram<BR, A, Horizental>
where
    BR: DescreteRanged,
    BR::ValueType: Eq + Hash + Default,
    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);
            let mut rect = Rectangle::new([(x, y), ((self.baseline)(), ny)], self.style.clone());
            rect.set_margin(self.margin, self.margin, 0, 0);
            return Some(rect);
        }
        None
    }
}