52 lines
1.2 KiB
Rust
52 lines
1.2 KiB
Rust
use std::f32::MAX as f32_max;
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/// `graph` generates a string representation of the values as a sparkline.
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///
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/// # Arguments
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///
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/// * `values` - The values to graph.
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///
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/// # Example
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///
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/// ```rust
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/// let sparkline = spark::graph(&[1.0, 5.0, 22.0, 13.0, 53.0]);
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/// assert_eq!(sparkline, "▁▁▃▂█");
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/// ```
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pub struct Graph {
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pub min: Option<f32>,
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pub max: Option<f32>,
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}
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impl Graph {
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pub fn render(&self, values: &[f32]) -> String {
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let ticks = "▁▂▃▄▅▆▇█";
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/* XXX: This doesn't feel like idiomatic Rust */
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let mut min: f32 = self.min.unwrap_or(f32_max);
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let mut max: f32 = self.max.unwrap_or(0.);
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for &i in values.iter() {
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if i > max {
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max = i;
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}
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if i < min {
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min = i;
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}
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}
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let ratio = if max == min {
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1.0
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} else {
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(ticks.chars().count() - 1) as f32 / (max - min)
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};
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values
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.iter()
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.cloned()
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.map(|n| (n - min) * ratio)
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.map(|n| n.floor() as usize)
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.filter_map(|n| ticks.chars().nth(n))
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.collect()
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}
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}
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