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use crate::*;
pub use cairo;
use cairo::Context;
use std::borrow::{Borrow, Cow};
pub fn write_img<V>(
dcel: &Dcel<V>,
ctx: &Context,
pos: impl Fn(&V) -> [f64; 2],
label: impl Fn(&V) -> Cow<str>,
font_size: f64,
) -> Result<(), cairo::Error> {
ctx.set_font_size(font_size);
for shell in dcel.iter_bodies().flat_map(Lens::iter_shells) {
for hedges in shell
.iter_edges()
.map(|x| x.half_edges())
.flat_map(|[a, b]| [[a, b], [b, a]])
{
let mut points = hedges.map(|h| pos(h.origin().data()));
let mut dir = [points[1][0] - points[0][0], points[1][1] - points[0][1]];
let scale = ctx.line_width() / (dir[0] * dir[0] + dir[1] * dir[1]).sqrt();
dir = [dir[0] * scale, dir[1] * scale];
let prp = [-dir[1], dir[0]];
points[0] = [points[0][0] + prp[0] * 2.0, points[0][1] + prp[1] * 2.0];
points[1] = [points[1][0] + prp[0] * 2.0, points[1][1] + prp[1] * 2.0];
ctx.move_to(points[0][0], points[0][1]);
ctx.line_to(points[1][0], points[1][1]);
ctx.stroke()?;
let arrow_pos = 1.2;
let arrow = [
(points[0][0] * (2.0 - arrow_pos) + points[1][0] * arrow_pos) / 2.0,
(points[0][1] * (2.0 - arrow_pos) + points[1][1] * arrow_pos) / 2.0,
];
let arrow_scale = 3.0;
ctx.move_to(arrow[0], arrow[1]);
ctx.rel_line_to(
(-dir[0] + prp[0]) * arrow_scale,
(-dir[1] + prp[1]) * arrow_scale,
);
ctx.rel_line_to(-prp[0] * 2.0 * arrow_scale, -prp[1] * 2.0 * arrow_scale);
ctx.line_to(arrow[0], arrow[1]);
ctx.close_path();
ctx.fill()?;
// edge ids
let num_pos = [arrow[0] + prp[0] * 4.0, arrow[1] + prp[1] * 4.0];
let num_text = hedges[0].id().to_string();
ctx.set_font_size(font_size / 2.0);
let ext = ctx.text_extents(&num_text)?;
ctx.move_to(
num_pos[0] - ext.x_advance() / 2.0,
num_pos[1] - ext.y_bearing() - ext.height() / 2.0,
);
ctx.show_text(&num_text)?;
ctx.set_font_size(font_size);
}
for vertex in shell.iter_vertices() {
let v = vertex.data();
let [x, y] = pos(v);
let text = label(v);
let ext = ctx.text_extents(text.borrow())?;
let mat = ctx.matrix();
ctx.translate(x, y);
ctx.scale(
(ext.x_advance() + ctx.line_width()) / 2.0f64.sqrt(),
(ext.height() + ctx.line_width()) / 2.0f64.sqrt(),
);
ctx.translate(-x, -y);
ctx.new_path();
ctx.arc(x, y, 1.0, 0.0, 2.0 * std::f64::consts::PI);
ctx.set_matrix(mat);
let path = ctx.copy_path()?;
ctx.set_source_rgb(1.0, 1.0, 1.0);
ctx.fill()?;
ctx.append_path(&path);
ctx.set_source_rgb(0.0, 0.0, 0.0);
ctx.stroke()?;
ctx.move_to(
x - ext.x_advance() / 2.0,
y - ext.y_bearing() - ext.height() / 2.0,
);
ctx.show_text(text.borrow())?;
}
}
Ok(())
}
|
