Lib UI Rust LineChart

chart.rs

extern crate ui;

use ui::{Area, AreaDrawParams, AreaHandler};
use ui::draw::{Brush, FillMode, Path, SolidBrush, StrokeParams, LineCap, LineJoin};
use ui::draw::text::{Layout, Font, FontDescriptor, Weight, Italic, Stretch};

pub struct LineChart {
    pub title: String, 
    pub x_axis_label: String,
    pub y_axis_label: String,
    pub values: Vec<i32>,
}

impl AreaHandler for LineChart {
    fn draw(&mut self, area: &Area, area_draw_params: &AreaDrawParams) {
        // AXIS LINES DRAWING
        let axis_path = Path::new(FillMode::Winding);

        let max_width = area_draw_params.area_width * 0.89;
        let min_width = area_draw_params.area_width - max_width;
        let max_height = area_draw_params.area_height * 0.92;
        let min_height = area_draw_params.area_height - max_height;
        let width_range = max_width - min_width;
        let height_range = max_height - min_height;

        axis_path.new_figure(min_width, min_height);
        axis_path.line_to(min_width, max_height);
        axis_path.line_to(max_width, max_height);
        axis_path.end();

        let axis_brush = Brush::Solid(SolidBrush {
            r: 0.0,
            g: 0.0,
            b: 0.0,
            a: 255.0,
        });

        let stroke_params = StrokeParams {
            cap: LineCap::Round,
            join: LineJoin:: Round,
            thickness: 3.0,
            miter_limit: 1.0,
            dashes: Vec::new(),
            dash_phase: 1.0,
        };

        area_draw_params.context.stroke(&axis_path, &axis_brush, &stroke_params);

        // TITLE DRAWING
        let title_fd = FontDescriptor::new("serif", 12.0, Weight::Normal, Italic::Normal, Stretch::Normal);
        let title_width = 200.0;
        let title_text_layout = Layout::new(self.title.as_str(), &title_fd.load_closest_font(), title_width);
        let title_location = min_width + (width_range * 0.5) - (title_width * 0.5);
        area_draw_params.context.draw_text(title_location, min_height * 0.5, &title_text_layout);

        // X AXIS DRAWING
        let x_axis_fd = FontDescriptor::new("serif", 10.0, Weight::Normal, Italic::Normal, Stretch::Normal);
        let x_axis_width = 200.0;
        let x_axis_text_layout = Layout::new(self.x_axis_label.as_str(), &x_axis_fd.load_closest_font(), title_width);
        let x_axis_location = min_width + (width_range * 0.5) - (title_width * 0.5);
        area_draw_params.context.draw_text(x_axis_location, max_height + (min_height * 0.5), &x_axis_text_layout);

        // Y AXIS DRAWING
        let y_axis_fd = FontDescriptor::new("serif", 10.0, Weight::Normal, Italic::Normal, Stretch::Normal);
        let y_axis_width = min_width * 0.7;
        let y_axis_text_layout = Layout::new(self.y_axis_label.as_str(), &y_axis_fd.load_closest_font(), title_width);
        let y_axis_location = min_width * 0.2;
        area_draw_params.context.draw_text(y_axis_location, min_height + (height_range * 0.5), &y_axis_text_layout);

        // DATA DRAWING
        let data_path = Path::new(FillMode::Winding);

        let value_count = self.values.len();
        let x_division = width_range / (value_count as f64 - 1.0);
        let y_min = self.values.iter().min().unwrap() - 1;
        let y_max = self.values.iter().max().unwrap() + 1;
        let y_range = y_max - y_min;

        data_path.new_figure(min_width, max_height - ((self.values[0] as f64 / (y_min as f64 + y_range as f64)) * height_range));
        for (raw_xval, raw_yval) in self.values.iter().enumerate() {
            let xval = min_width + (x_division * raw_xval as f64);
            let yval = max_height - ((*raw_yval as f64 / (y_min as f64 + y_range as f64)) * height_range);
            data_path.line_to(xval, yval);
        };
        data_path.end();

        let data_brush = Brush::Solid(SolidBrush {
            r: 255.0,
            g: 0.0,
            b: 0.0,
            a: 255.0,
        });

        area_draw_params.context.stroke(&data_path, &data_brush, &stroke_params);
    }
}