a rust tui to view amtrak train status
Relative speed coloring: brightness normalized across active trains
Speed brightness was absolute (0-90 mph scale), making most trains
look similarly dim since they cluster in the 30-80 mph range. Now
velocity is normalized relative to the fastest active train:
factor = velocity / max_velocity_across_all_active_trains
So the fastest train on the map is always brightest, stopped trains
are always dimmest, and everything in between spreads across the
full brightness range. Makes speed differences visually obvious.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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src/ui.rs
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src/ui.rs
···
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is_selected: bool,
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}
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/// Map velocity to color brightness. Fast trains are vivid, slow/stopped are muted.
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fn speed_adjusted_color(base: Color, velocity: f64) -> Color {
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// Scale brightness: stopped=40%, 30mph=60%, 60mph=80%, 90+=100%
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let factor = if velocity < 1.0 {
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0.4
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} else {
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(0.4 + (velocity / 90.0).min(1.0) * 0.6).min(1.0)
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};
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/// Map a 0.0–1.0 brightness factor to a colored RGB value.
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/// 0.0 = dimmest (stopped/slowest), 1.0 = brightest (fastest in current set).
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fn speed_adjusted_color(base: Color, factor: f64) -> Color {
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// Map factor 0.0–1.0 to brightness 0.35–1.0
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let b = 0.35 + factor.clamp(0.0, 1.0) * 0.65;
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match base {
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Color::Green => Color::Rgb(
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(40.0 * factor) as u8,
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(220.0 * factor) as u8,
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(40.0 * factor) as u8,
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),
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Color::Red => Color::Rgb(
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(220.0 * factor) as u8,
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(50.0 * factor) as u8,
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(50.0 * factor) as u8,
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),
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Color::Yellow => Color::Rgb(
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(200.0 * factor) as u8,
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(200.0 * factor) as u8,
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(50.0 * factor) as u8,
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),
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Color::Green => Color::Rgb((40.0 * b) as u8, (220.0 * b) as u8, (40.0 * b) as u8),
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Color::Red => Color::Rgb((220.0 * b) as u8, (50.0 * b) as u8, (50.0 * b) as u8),
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Color::Yellow => Color::Rgb((200.0 * b) as u8, (200.0 * b) as u8, (50.0 * b) as u8),
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_ => base,
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}
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}
···
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let selected_number = app.selected_train().map(|t| t.number.clone());
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// Collect train dots into owned data for the 'static paint closure
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let dots: Vec<TrainDot> = app
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// Compute velocity range across active trains for relative brightness
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let active_trains: Vec<&crate::model::Train> = app
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.trains
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.iter()
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.filter(|t| t.state == TrainState::Active)
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.collect();
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let max_velocity = active_trains
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.iter()
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.map(|t| t.velocity)
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.fold(1.0_f64, f64::max); // floor at 1.0 to avoid div by zero
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let dots: Vec<TrainDot> = active_trains
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.iter()
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.map(|t| {
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let is_selected = selected_number.as_deref() == Some(&t.number);
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let base_color = delay_color(&t.delay_status());
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// Normalize velocity: stopped=0.0, fastest train=1.0
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let speed_factor = if t.velocity < 1.0 {
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0.0
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} else {
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t.velocity / max_velocity
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};
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TrainDot {
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lon: t.lon,
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lat: t.lat,
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number: t.number.clone(),
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color: speed_adjusted_color(base_color, t.velocity),
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color: speed_adjusted_color(base_color, speed_factor),
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is_selected,
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}
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})