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