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use crate::{algorithms::AffineTransformable, BoundingBox};
use euclid::Transform2D;
pub trait ScaleNonUniform {
fn scale_non_uniform(&mut self, factor_x: f64, factor_y: f64);
fn scaled_non_uniform(&self, factor_x: f64, factor_y: f64) -> Self
where
Self: Sized + Clone,
{
let mut clone = self.clone();
clone.scale_non_uniform(factor_x, factor_y);
clone
}
}
impl<A: AffineTransformable> ScaleNonUniform for A {
fn scale_non_uniform(&mut self, factor_x: f64, factor_y: f64) {
self.transform(Transform2D::create_scale(factor_x, factor_y));
}
}
impl<Space> ScaleNonUniform for BoundingBox<Space> {
fn scale_non_uniform(&mut self, factor_x: f64, factor_y: f64) {
let bottom_left =
self.bottom_left().scaled_non_uniform(factor_x, factor_y);
let top_right = self.top_right().scaled_non_uniform(factor_x, factor_y);
*self = BoundingBox::new(bottom_left, top_right);
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{algorithms::Translate, primitives::Line};
type Point = euclid::default::Point2D<f64>;
type Vector = euclid::default::Vector2D<f64>;
#[test]
fn scale_point() {
let x = -1.0;
let y = 5.0;
let original = Point::new(x, y);
let factor_x = 2.0;
let factor_y = 2.5;
let should_be = Point::new(x * factor_x, y * factor_y);
let actual = original.scaled_non_uniform(factor_x, factor_y);
assert_eq!(actual, should_be);
}
#[test]
fn scale_point_around_base() {
let original = Point::new(-1.0, 5.0);
let factor_x = 2.0;
let factor_y = 2.5;
let base = Vector::new(2.0, 0.0);
let expected = Point::new(-4.0, 12.5);
let mut transformed = original.translated(-base);
transformed.scale_non_uniform(factor_x, factor_y);
transformed.translate(base);
assert_eq!(transformed, expected);
let combined_transform =
Transform2D::create_translation(-base.x, -base.y)
.post_scale(factor_x, factor_y)
.post_translate(base);
let transformed = original.transformed(combined_transform);
assert_eq!(transformed, expected);
}
#[test]
fn scale_line() {
let start = Point::new(2.0, 4.0);
let end = Point::new(3.0, -5.0);
let original = Line::new(start, end);
let factor_x = 1.5;
let factor_y = -2.0;
let actual = original.scaled_non_uniform(factor_x, factor_y);
let expected = Line::new(
Point::new(2.0 * factor_x, 4.0 * factor_y),
Point::new(3.0 * factor_x, -5.0 * factor_y),
);
assert_eq!(actual, expected);
}
#[test]
fn scale_line_around_base() {
let start = Point::new(2.0, 4.0);
let end = Point::new(3.0, -5.0);
let original = Line::new(start, end);
let factor_x = 1.5;
let factor_y = -2.0;
let expected = Line::new(Point::new(1.75, -9.5), Point::new(3.25, 8.5));
let mid_point = (start + original.displacement() * 0.5).to_vector();
let mut transformed = original.translated(-mid_point);
transformed.scale_non_uniform(factor_x, factor_y);
transformed.translate(mid_point);
assert_eq!(transformed, expected);
}
}