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Diffstat (limited to 'vendor/plotters/src/series/histogram.rs')
| -rw-r--r-- | vendor/plotters/src/series/histogram.rs | 280 |
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diff --git a/vendor/plotters/src/series/histogram.rs b/vendor/plotters/src/series/histogram.rs new file mode 100644 index 000000000..2d7d8f48c --- /dev/null +++ b/vendor/plotters/src/series/histogram.rs @@ -0,0 +1,280 @@ +use std::collections::{hash_map::IntoIter as HashMapIter, HashMap}; +use std::marker::PhantomData; +use std::ops::AddAssign; + +use crate::chart::ChartContext; +use crate::coord::cartesian::Cartesian2d; +use crate::coord::ranged1d::{DiscreteRanged, Ranged}; +use crate::element::Rectangle; +use crate::style::{Color, ShapeStyle, GREEN}; +use plotters_backend::DrawingBackend; + +pub trait HistogramType {} +pub struct Vertical; +pub struct Horizontal; + +impl HistogramType for Vertical {} +impl HistogramType for Horizontal {} + +/** +Presents data in a histogram. Input data can be raw or aggregated. + +# Examples + +``` +use plotters::prelude::*; +let data = [1, 1, 2, 2, 1, 3, 3, 2, 2, 1, 1, 2, 2, 2, 3, 3, 1, 2, 3]; +let drawing_area = SVGBackend::new("histogram_vertical.svg", (300, 200)).into_drawing_area(); +drawing_area.fill(&WHITE).unwrap(); +let mut chart_builder = ChartBuilder::on(&drawing_area); +chart_builder.margin(5).set_left_and_bottom_label_area_size(20); +let mut chart_context = chart_builder.build_cartesian_2d((1..3).into_segmented(), 0..9).unwrap(); +chart_context.configure_mesh().draw().unwrap(); +chart_context.draw_series(Histogram::vertical(&chart_context).style(BLUE.filled()).margin(10) + .data(data.map(|x| (x, 1)))).unwrap(); +``` + +The result is a histogram counting the occurrences of 1, 2, and 3 in `data`: + + + +Here is a variation with [`Histogram::horizontal()`], replacing `(1..3).into_segmented(), 0..9` with +`0..9, (1..3).into_segmented()`: + + + +The spacing between histogram bars is adjusted with [`Histogram::margin()`]. +Here is a version of the figure where `.margin(10)` has been replaced by `.margin(20)`; +the resulting bars are narrow and more spaced: + + + +[`crate::coord::ranged1d::IntoSegmentedCoord::into_segmented()`] is useful for discrete data; it makes sure the histogram bars +are centered on each data value. Here is another variation with `(1..3).into_segmented()` +replaced by `1..4`: + + + +[`Histogram::style()`] sets the style of the bars. Here is a histogram without `.filled()`: + + + +The following version uses [`Histogram::style_func()`] for finer control. Let's replace `.style(BLUE.filled())` with +`.style_func(|x, _bar_height| if let SegmentValue::Exact(v) = x {[BLACK, RED, GREEN, BLUE][*v as usize].filled()} else {BLACK.filled()})`. +The resulting bars come in different colors: + + + +[`Histogram::baseline()`] adjusts the base of the bars. The following figure adds `.baseline(1)` +to the right of `.margin(10)`. The lower portion of the bars are removed: + + + +The following figure uses [`Histogram::baseline_func()`] for finer control. Let's add +`.baseline_func(|x| if let SegmentValue::Exact(v) = x {*v as i32} else {0})` +to the right of `.margin(10)`. The lower portion of the bars are removed; the removed portion is taller +to the right: + + +*/ +pub struct Histogram<'a, BR, A, Tag = Vertical> +where + BR: DiscreteRanged, + A: AddAssign<A> + Default, + Tag: HistogramType, +{ + style: Box<dyn Fn(&BR::ValueType, &A) -> ShapeStyle + 'a>, + margin: u32, + iter: HashMapIter<usize, A>, + baseline: Box<dyn Fn(&BR::ValueType) -> A + 'a>, + br: BR, + _p: PhantomData<Tag>, +} + +impl<'a, BR, A, Tag> Histogram<'a, BR, A, Tag> +where + BR: DiscreteRanged + Clone, + A: AddAssign<A> + Default + 'a, + Tag: HistogramType, +{ + fn empty(br: &BR) -> Self { + Self { + style: Box::new(|_, _| GREEN.filled()), + margin: 5, + iter: HashMap::new().into_iter(), + baseline: Box::new(|_| A::default()), + br: br.clone(), + _p: PhantomData, + } + } + /** + Sets the style of the histogram bars. + + See [`Histogram`] for more information and examples. + */ + pub fn style<S: Into<ShapeStyle>>(mut self, style: S) -> Self { + let style = style.into(); + self.style = Box::new(move |_, _| style); + self + } + + /** + Sets the style of histogram using a closure. + + The closure takes the position of the bar in guest coordinates as argument. + The argument may need some processing if the data range has been transformed by + [`crate::coord::ranged1d::IntoSegmentedCoord::into_segmented()`] as shown in the [`Histogram`] example. + */ + pub fn style_func( + mut self, + style_func: impl Fn(&BR::ValueType, &A) -> ShapeStyle + 'a, + ) -> Self { + self.style = Box::new(style_func); + self + } + + /** + Sets the baseline of the histogram. + + See [`Histogram`] for more information and examples. + */ + pub fn baseline(mut self, baseline: A) -> Self + where + A: Clone, + { + self.baseline = Box::new(move |_| baseline.clone()); + self + } + + /** + Sets the histogram bar baselines using a closure. + + The closure takes the bar position and height as argument. + The argument may need some processing if the data range has been transformed by + [`crate::coord::ranged1d::IntoSegmentedCoord::into_segmented()`] as shown in the [`Histogram`] example. + */ + pub fn baseline_func(mut self, func: impl Fn(&BR::ValueType) -> A + 'a) -> Self { + self.baseline = Box::new(func); + self + } + + /** + Sets the margin for each bar, in backend pixels. + + See [`Histogram`] for more information and examples. + */ + pub fn margin(mut self, value: u32) -> Self { + self.margin = value; + self + } + + /** + Specifies the input data for the histogram through an appropriate data iterator. + + See [`Histogram`] for more information and examples. + */ + pub fn data<TB: Into<BR::ValueType>, I: IntoIterator<Item = (TB, A)>>( + mut self, + iter: I, + ) -> Self { + let mut buffer = HashMap::<usize, A>::new(); + for (x, y) in iter.into_iter() { + if let Some(x) = self.br.index_of(&x.into()) { + *buffer.entry(x).or_insert_with(Default::default) += y; + } + } + self.iter = buffer.into_iter(); + self + } +} + +impl<'a, BR, A> Histogram<'a, BR, A, Vertical> +where + BR: DiscreteRanged + Clone, + A: AddAssign<A> + Default + 'a, +{ + /** + Creates a vertical histogram. + + See [`Histogram`] for more information and examples. + */ + pub fn vertical<ACoord, DB: DrawingBackend + 'a>( + parent: &ChartContext<DB, Cartesian2d<BR, ACoord>>, + ) -> Self + where + ACoord: Ranged<ValueType = A>, + { + let dp = parent.as_coord_spec().x_spec(); + + Self::empty(dp) + } +} + +impl<'a, BR, A> Histogram<'a, BR, A, Horizontal> +where + BR: DiscreteRanged + Clone, + A: AddAssign<A> + Default + 'a, +{ + /** + Creates a horizontal histogram. + + See [`Histogram`] for more information and examples. + */ + pub fn horizontal<ACoord, DB: DrawingBackend>( + parent: &ChartContext<DB, Cartesian2d<ACoord, BR>>, + ) -> Self + where + ACoord: Ranged<ValueType = A>, + { + let dp = parent.as_coord_spec().y_spec(); + Self::empty(dp) + } +} + +impl<'a, BR, A> Iterator for Histogram<'a, BR, A, Vertical> +where + BR: DiscreteRanged, + A: AddAssign<A> + Default, +{ + type Item = Rectangle<(BR::ValueType, A)>; + fn next(&mut self) -> Option<Self::Item> { + while let Some((x, y)) = self.iter.next() { + if let Some((x, Some(nx))) = self + .br + .from_index(x) + .map(|v| (v, self.br.from_index(x + 1))) + { + let base = (self.baseline)(&x); + 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, + A: AddAssign<A> + Default, +{ + type Item = Rectangle<(A, BR::ValueType)>; + fn next(&mut self) -> Option<Self::Item> { + while let Some((y, x)) = self.iter.next() { + if let Some((y, Some(ny))) = self + .br + .from_index(y) + .map(|v| (v, self.br.from_index(y + 1))) + { + let base = (self.baseline)(&y); + 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 + } +} |