use cursive::theme::{Color, ColorStyle}; use cursive::view::Boxable; use cursive::views::Canvas; use cursive::{Cursive, Printer}; // This example will draw a colored square with a gradient. // // We'll use a Canvas, which lets us only define a draw method. // // We will combine 2 gradients: one for the background, // and one for the foreground. // // Note: color reproduction is not as good on all backends. // termion can do full 16M true colors, but ncurses is currently limited to // 256 colors. fn main() { // Start as usual let mut siv = Cursive::default(); siv.add_global_callback('q', |s| s.quit()); // Canvas lets us easily override any method. // Canvas can have states, but we don't need any here, so we use `()`. siv.add_layer(Canvas::new(()).with_draw(draw).fixed_size((20, 10))); siv.run(); } /// Method used to draw the cube. /// /// This takes as input the Canvas state and a printer. fn draw(_: &(), p: &Printer) { // We use the view size to calibrate the color let x_max = p.size.x as u8; let y_max = p.size.y as u8; // Print each cell individually for x in 0..x_max { for y in 0..y_max { // We'll use a different style for each cell let style = ColorStyle::new( front_color(x, y, x_max, y_max), back_color(x, y, x_max, y_max), ); p.with_color(style, |printer| { printer.print((x, y), "+"); }); } } } // Gradient for the front color fn front_color(x: u8, y: u8, x_max: u8, y_max: u8) -> Color { // We return a full 24-bits RGB color, but some backends // will project it to a 256-colors palette. Color::Rgb( x * (255 / x_max), y * (255 / y_max), (x + 2 * y) * (255 / (x_max + 2 * y_max)), ) } // Gradient for the background color fn back_color(x: u8, y: u8, x_max: u8, y_max: u8) -> Color { // Let's try to have a gradient in a different direction than the front color. Color::Rgb( 128 + (2 * y_max + x - 2 * y) * (128 / (x_max + 2 * y_max)), 255 - y * (255 / y_max), 255 - x * (255 / x_max), ) }