ratatui/examples/demo2/colors.rs
Josh McKinney 8061813f32
refactor: expand glob imports (#1152)
Consensus is that explicit imports make it easier to understand the
example code. This commit removes the prelude import from all examples
and replaces it with the necessary imports, and expands other glob
imports (widget::*, Constraint::*, KeyCode::*, etc.) everywhere else.
Prelude glob imports not in examples are not covered by this PR.

See https://github.com/ratatui-org/ratatui/issues/1150 for more details.
2024-05-29 04:42:29 -07:00

35 lines
1.6 KiB
Rust

use palette::{IntoColor, Okhsv, Srgb};
use ratatui::{buffer::Buffer, layout::Rect, style::Color, widgets::Widget};
/// A widget that renders a color swatch of RGB colors.
///
/// The widget is rendered as a rectangle with the hue changing along the x-axis from 0.0 to 360.0
/// and the value changing along the y-axis (from 1.0 to 0.0). Each pixel is rendered as a block
/// character with the top half slightly lighter than the bottom half.
pub struct RgbSwatch;
impl Widget for RgbSwatch {
#[allow(clippy::cast_precision_loss, clippy::similar_names)]
fn render(self, area: Rect, buf: &mut Buffer) {
for (yi, y) in (area.top()..area.bottom()).enumerate() {
let value = f32::from(area.height) - yi as f32;
let value_fg = value / f32::from(area.height);
let value_bg = (value - 0.5) / f32::from(area.height);
for (xi, x) in (area.left()..area.right()).enumerate() {
let hue = xi as f32 * 360.0 / f32::from(area.width);
let fg = color_from_oklab(hue, Okhsv::max_saturation(), value_fg);
let bg = color_from_oklab(hue, Okhsv::max_saturation(), value_bg);
buf.get_mut(x, y).set_char('▀').set_fg(fg).set_bg(bg);
}
}
}
}
/// Convert a hue and value into an RGB color via the Oklab color space.
///
/// See <https://bottosson.github.io/posts/oklab/> for more details.
pub fn color_from_oklab(hue: f32, saturation: f32, value: f32) -> Color {
let color: Srgb = Okhsv::new(hue, saturation, value).into_color();
let color = color.into_format();
Color::Rgb(color.red, color.green, color.blue)
}