Struct GroupBy

pub struct GroupBy<T>(/* private fields */)
where
    T: DiscreteRanged;

Grouping the value in the coordinate specification.

This combinator doesn’t change the coordinate mapping behavior. But it changes how the key point is generated, this coordinate specification will enforce that only the first value in each group can be emitted as the bold key points.

This is useful, for example, when we have an X axis is a integer and denotes days. And we are expecting the tick mark denotes weeks, in this way we can make the range spec grouping by 7 elements. With the help of the GroupBy decorator, this can be archived quite easily:

use plotters::prelude::*;
let mut buf = vec![0;1024*768*3];
let area = BitMapBackend::with_buffer(buf.as_mut(), (1024, 768)).into_drawing_area();
let chart = ChartBuilder::on(&area)
    .build_cartesian_2d((0..100).group_by(7), 0..100)
    .unwrap();

To apply this combinator, call ToGroupByRange::group_by method on any discrete coordinate spec.

Trait Implementations

impl<T> Clone for GroupBy<T>

where T: Clone + DiscreteRanged,

fn clone(&self) -> GroupBy<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> DiscreteRanged for GroupBy<T>

where T: DiscreteRanged,

fn size(&self) -> usize

Get the number of element in the range Note: we assume that all the ranged discrete coordinate has finite value

fn index_of(&self, value: &<GroupBy<T> as Ranged>::ValueType) -> Option<usize>

Map a value to the index

fn from_index(&self, index: usize) -> Option<<GroupBy<T> as Ranged>::ValueType>

Reverse map the index to the value

fn values(&self) -> DiscreteValueIter<'_, Self>

where Self: Sized,

Return a iterator that iterates over the all possible values

fn previous(&self, value: &Self::ValueType) -> Option<Self::ValueType>

Returns the previous value in this range

fn next(&self, value: &Self::ValueType) -> Option<Self::ValueType>

Returns the next value in this range

impl<T> Ranged for GroupBy<T>

where T: DiscreteRanged,

type FormatOption = NoDefaultFormatting

This marker decides if Plotters default ValueFormatter implementation should be used. This associated type can be one of the following two types:

type ValueType = <T as Ranged>::ValueType

The type of this value in this range specification

fn map(&self, value: &<T as Ranged>::ValueType, limit: (i32, i32)) -> i32

This function maps the value to i32, which is the drawing coordinate

fn range(&self) -> Range<<T as Ranged>::ValueType>

Get the range of this value

fn key_points<HintType>(&self, hint: HintType) -> Vec<<T as Ranged>::ValueType>

where HintType: KeyPointHint,

This function gives the key points that we can draw a grid based on this

fn axis_pixel_range(&self, limit: (i32, i32)) -> Range<i32>

This function provides the on-axis part of its range

impl<T, R> ValueFormatter<T> for GroupBy<R>

where R: DiscreteRanged<ValueType = T> + ValueFormatter<T>,

fn format(value: &T) -> String

Format the value

fn format_ext(&self, value: &V) -> String

Determine how we can format a value in a coordinate system by default