ggplot-rs 0.2.0

A Rust implementation of ggplot2's Grammar of Graphics
Documentation 
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use crate::aes::Aesthetic;
use crate::coord::Coord;
use crate::data::DataFrame;
use crate::position::identity::PositionIdentity;
use crate::position::Position;
use crate::render::backend::{DrawBackend, PointShape, PointStyle};
use crate::render::RenderError;
use crate::scale::ScaleSet;
use crate::stat::identity::StatIdentity;
use crate::stat::Stat;
use crate::theme::Theme;

use super::{Geom, GeomParams};

/// Scatter plot points.
pub struct GeomPoint {
    pub size: f64,
    pub color: (u8, u8, u8),
    pub alpha: f64,
}

impl Default for GeomPoint {
    fn default() -> Self {
        GeomPoint {
            size: 3.0,
            color: (0, 0, 0),
            alpha: 1.0,
        }
    }
}

impl Geom for GeomPoint {
    fn draw(
        &self,
        data: &DataFrame,
        coord: &dyn Coord,
        scales: &ScaleSet,
        _theme: &Theme,
        backend: &mut dyn DrawBackend,
    ) -> Result<(), RenderError> {
        let x_col = data
            .column("x")
            .ok_or(RenderError::MissingAesthetic("x".into()))?;
        let y_col = data
            .column("y")
            .ok_or(RenderError::MissingAesthetic("y".into()))?;
        let color_col = data.column("color");
        let size_col = data.column("size");
        let alpha_col = data.column("alpha");
        let shape_col = data.column("shape");

        let plot_area = backend.plot_area();
        let x_scale = scales.get(&Aesthetic::X);
        let y_scale = scales.get(&Aesthetic::Y);

        for i in 0..data.nrows() {
            let nx = x_scale.map(|s| s.map(&x_col[i])).unwrap_or(0.0);
            let ny = y_scale.map(|s| s.map(&y_col[i])).unwrap_or(0.0);
            let (px, py) = coord.transform((nx, ny), &plot_area);

            let (r, g, b) = if let Some(cc) = color_col {
                scales
                    .map_color(&Aesthetic::Color, &cc[i])
                    .unwrap_or(self.color)
            } else {
                self.color
            };

            let alpha = alpha_col
                .and_then(|c| scales.map_alpha(&c[i]))
                .or_else(|| alpha_col.and_then(|c| c[i].as_f64()))
                .unwrap_or(self.alpha);

            let size = size_col
                .and_then(|c| scales.map_size(&c[i]))
                .or_else(|| size_col.and_then(|c| c[i].as_f64()))
                .unwrap_or(self.size);

            let shape = shape_col
                .and_then(|c| scales.map_shape(&c[i]))
                .unwrap_or(PointShape::Circle);

            backend.draw_shape(
                (px, py),
                size,
                &PointStyle {
                    color: (r, g, b),
                    alpha,
                    filled: true,
                    shape,
                },
            )?;
        }

        Ok(())
    }

    fn required_aes(&self) -> Vec<Aesthetic> {
        vec![Aesthetic::X, Aesthetic::Y]
    }

    fn default_stat(&self) -> Box<dyn Stat> {
        Box::new(StatIdentity)
    }

    fn default_position(&self) -> Box<dyn Position> {
        Box::new(PositionIdentity)
    }

    fn default_params(&self) -> GeomParams {
        GeomParams::default()
    }

    fn name(&self) -> &str {
        "point"
    }

    fn set_series_color(&mut self, color: (u8, u8, u8)) {
        self.color = color;
    }
}