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fix(canvas): Lines that start outside the visible grid are now drawn (#1501)
Previously lines with points that were outside the canvas bounds were not drawn at all. Now they are clipped to the bounds of the canvas so that the portion of the line within the canvas is draw. To facilitate this, a new `Painter::bounds()` method which returns the bounds of the canvas is added. Fixes: #1489
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Lines changed: 122 additions & 12 deletions

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‎Cargo.lock‎

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‎ratatui-widgets/Cargo.toml‎

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Original file line numberDiff line numberDiff line change
@@ -53,6 +53,7 @@ unicode-segmentation.workspace = true
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unicode-width.workspace = true
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serde = { workspace = true, optional = true }
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document-features = { workspace = true, optional = true }
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line-clipping = "0.2.1"
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[dev-dependencies]
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rstest.workspace = true

‎ratatui-widgets/src/canvas.rs‎

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Original file line numberDiff line numberDiff line change
@@ -424,6 +424,25 @@ impl<'a, 'b> Painter<'a, 'b> {
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pub fn paint(&mut self, x: usize, y: usize, color: Color) {
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self.context.grid.paint(x, y, color);
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}
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/// Canvas context bounds by axis.
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///
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/// # Example
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///
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/// ```
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/// use ratatui::{
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/// style::Color,
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/// symbols,
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/// widgets::canvas::{Context, Painter},
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/// };
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///
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/// let mut ctx = Context::new(1, 1, [0.0, 2.0], [0.0, 2.0], symbols::Marker::Braille);
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/// let mut painter = Painter::from(&mut ctx);
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/// assert_eq!(painter.bounds(), (&[0.0, 2.0], &[0.0, 2.0]));
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/// ```
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pub fn bounds(&self) -> (&[f64; 2], &[f64; 2]) {
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(&self.context.x_bounds, &self.context.y_bounds)
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}
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}
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impl<'a, 'b> From<&'a mut Context<'b>> for Painter<'a, 'b> {

‎ratatui-widgets/src/canvas/line.rs‎

Lines changed: 92 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,4 @@
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use line_clipping::{cohen_sutherland, LineSegment, Point, Window};
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use ratatui_core::style::Color;
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use crate::canvas::{Painter, Shape};
@@ -31,13 +32,21 @@ impl Line {
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}
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impl Shape for Line {
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#[allow(clippy::similar_names)]
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fn draw(&self, painter: &mut Painter) {
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let Some((x1, y1)) = painter.get_point(self.x1, self.y1) else {
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let (x_bounds, y_bounds) = painter.bounds();
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let Some((world_x1, world_y1, world_x2, world_y2)) =
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clip_line(x_bounds, y_bounds, self.x1, self.y1, self.x2, self.y2)
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else {
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return;
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};
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let Some((x2, y2)) = painter.get_point(self.x2, self.y2) else {
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let Some((x1, y1)) = painter.get_point(world_x1, world_y1) else {
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return;
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};
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let Some((x2, y2)) = painter.get_point(world_x2, world_y2) else {
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return;
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};
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let (dx, x_range) = if x2 >= x1 {
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(x2 - x1, x1..=x2)
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} else {
@@ -71,6 +80,27 @@ impl Shape for Line {
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}
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}
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fn clip_line(
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&[xmin, xmax]: &[f64; 2],
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&[ymin, ymax]: &[f64; 2],
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x1: f64,
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y1: f64,
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x2: f64,
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y2: f64,
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) -> Option<(f64, f64, f64, f64)> {
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if let Some(LineSegment {
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p1: Point { x: x1, y: y1 },
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p2: Point { x: x2, y: y2 },
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}) = cohen_sutherland::clip_line(
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LineSegment::new(Point::new(x1, y1), Point::new(x2, y2)),
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Window::new(xmin, xmax, ymin, ymax),
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) {
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Some((x1, y1, x2, y2))
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} else {
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None
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}
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}
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fn draw_line_low(painter: &mut Painter, x1: usize, y1: usize, x2: usize, y2: usize, color: Color) {
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let dx = (x2 - x1) as isize;
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let dy = (y2 as isize - y1 as isize).abs();
@@ -124,9 +154,59 @@ mod tests {
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use crate::canvas::Canvas;
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#[rstest]
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#[case::off_grid(&Line::new(-1.0, -1.0, 10.0, 10.0, Color::Red), [" "; 10])]
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#[case::off_grid(&Line::new(0.0, 0.0, 11.0, 11.0, Color::Red), [" "; 10])]
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#[case::horizontal(&Line::new(0.0, 0.0, 10.0, 0.0, Color::Red), [
157+
#[case::off_grid1(&Line::new(-1.0, 0.0, -1.0, 10.0, Color::Red), [" "; 10])]
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#[case::off_grid2(&Line::new(0.0, -1.0, 10.0, -1.0, Color::Red), [" "; 10])]
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#[case::off_grid3(&Line::new(-10.0, 5.0, -1.0, 5.0, Color::Red), [" "; 10])]
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#[case::off_grid4(&Line::new(5.0, 11.0, 5.0, 20.0, Color::Red), [" "; 10])]
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#[case::off_grid5(&Line::new(-10.0, 0.0, 5.0, 0.0, Color::Red), [
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" ",
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" ",
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" ",
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" ",
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" ",
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" ",
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" ",
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" ",
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" ",
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"••••• ",
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])]
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#[case::off_grid6(&Line::new(-1.0, -1.0, 10.0, 10.0, Color::Red), [
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" •",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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"• ",
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])]
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#[case::off_grid7(&Line::new(0.0, 0.0, 11.0, 11.0, Color::Red), [
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" •",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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"• ",
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])]
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#[case::off_grid8(&Line::new(-1.0, -1.0, 11.0, 11.0, Color::Red), [
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" •",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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" • ",
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"• ",
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])]
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#[case::horizontal1(&Line::new(0.0, 0.0, 10.0, 0.0, Color::Red), [
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" ",
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" ",
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" ",
@@ -138,7 +218,7 @@ mod tests {
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" ",
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"••••••••••",
140220
])]
141-
#[case::horizontal(&Line::new(10.0, 10.0, 0.0, 10.0, Color::Red), [
221+
#[case::horizontal2(&Line::new(10.0, 10.0, 0.0, 10.0, Color::Red), [
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"••••••••••",
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" ",
144224
" ",
@@ -150,10 +230,10 @@ mod tests {
150230
" ",
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" ",
152232
])]
153-
#[case::vertical(&Line::new(0.0, 0.0, 0.0, 10.0, Color::Red), ["• "; 10])]
154-
#[case::vertical(&Line::new(10.0, 10.0, 10.0, 0.0, Color::Red), [" •"; 10])]
233+
#[case::vertical1(&Line::new(0.0, 0.0, 0.0, 10.0, Color::Red), ["• "; 10])]
234+
#[case::vertical2(&Line::new(10.0, 10.0, 10.0, 0.0, Color::Red), [" •"; 10])]
155235
// dy < dx, x1 < x2
156-
#[case::diagonal(&Line::new(0.0, 0.0, 10.0, 5.0, Color::Red), [
236+
#[case::diagonal1(&Line::new(0.0, 0.0, 10.0, 5.0, Color::Red), [
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" ",
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" ",
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" ",
@@ -166,7 +246,7 @@ mod tests {
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"• ",
167247
])]
168248
// dy < dx, x1 > x2
169-
#[case::diagonal(&Line::new(10.0, 0.0, 0.0, 5.0, Color::Red), [
249+
#[case::diagonal2(&Line::new(10.0, 0.0, 0.0, 5.0, Color::Red), [
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" ",
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" ",
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" ",
@@ -179,7 +259,7 @@ mod tests {
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" •",
180260
])]
181261
// dy > dx, y1 < y2
182-
#[case::diagonal(&Line::new(0.0, 0.0, 5.0, 10.0, Color::Red), [
262+
#[case::diagonal3(&Line::new(0.0, 0.0, 5.0, 10.0, Color::Red), [
183263
" • ",
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" • ",
185265
" • ",
@@ -192,7 +272,7 @@ mod tests {
192272
"• ",
193273
])]
194274
// dy > dx, y1 > y2
195-
#[case::diagonal(&Line::new(0.0, 10.0, 5.0, 0.0, Color::Red), [
275+
#[case::diagonal4(&Line::new(0.0, 10.0, 5.0, 0.0, Color::Red), [
196276
"• ",
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"• ",
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" • ",

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