repose_core/
geometry.rs

1#[derive(Clone, Copy, Debug, Default, PartialEq)]
2pub struct Vec2 {
3    pub x: f32,
4    pub y: f32,
5}
6
7impl Vec2 {
8    pub const ZERO: Vec2 = Vec2 { x: 0.0, y: 0.0 };
9}
10
11impl std::ops::Add for Vec2 {
12    type Output = Vec2;
13    fn add(self, other: Vec2) -> Vec2 {
14        Vec2 {
15            x: self.x + other.x,
16            y: self.y + other.y,
17        }
18    }
19}
20
21impl std::ops::Sub for Vec2 {
22    type Output = Vec2;
23    fn sub(self, other: Vec2) -> Vec2 {
24        Vec2 {
25            x: self.x - other.x,
26            y: self.y - other.y,
27        }
28    }
29}
30
31impl std::ops::Neg for Vec2 {
32    type Output = Vec2;
33    fn neg(self) -> Vec2 {
34        Vec2 {
35            x: -self.x,
36            y: -self.y,
37        }
38    }
39}
40
41#[derive(Clone, Copy, Debug, Default, PartialEq)]
42pub struct Size {
43    pub width: f32,
44    pub height: f32,
45}
46
47#[derive(Clone, Copy, Debug, Default, PartialEq)]
48pub struct Rect {
49    pub x: f32,
50    pub y: f32,
51    pub w: f32,
52    pub h: f32,
53}
54
55impl Rect {
56    pub fn contains(&self, p: Vec2) -> bool {
57        p.x >= self.x && p.x <= self.x + self.w && p.y >= self.y && p.y <= self.y + self.h
58    }
59}
60
61#[derive(Clone, Copy, Debug, Default, PartialEq)]
62pub struct Transform {
63    pub translate_x: f32,
64    pub translate_y: f32,
65    pub scale_x: f32,
66    pub scale_y: f32,
67    pub rotate: f32, // radians
68    pub origin_x: f32,
69    pub origin_y: f32,
70}
71
72impl Transform {
73    pub fn identity() -> Self {
74        Self {
75            translate_x: 0.0,
76            translate_y: 0.0,
77            scale_x: 1.0,
78            scale_y: 1.0,
79            rotate: 0.0,
80            origin_x: 0.5,
81            origin_y: 0.5,
82        }
83    }
84
85    pub fn translate(x: f32, y: f32) -> Self {
86        Self {
87            translate_x: x,
88            translate_y: y,
89            scale_x: 1.0,
90            scale_y: 1.0,
91            rotate: 0.0,
92            origin_x: 0.5,
93            origin_y: 0.5,
94        }
95    }
96
97    pub fn apply_to_point(&self, p: Vec2) -> Vec2 {
98        // Apply in order: scale, rotate, translate
99        let mut x = p.x * self.scale_x;
100        let mut y = p.y * self.scale_y;
101
102        if self.rotate != 0.0 {
103            let cos = self.rotate.cos();
104            let sin = self.rotate.sin();
105            let nx = x * cos - y * sin;
106            let ny = x * sin + y * cos;
107            x = nx;
108            y = ny;
109        }
110
111        Vec2 {
112            x: x + self.translate_x,
113            y: y + self.translate_y,
114        }
115    }
116
117    pub fn apply_to_rect(&self, r: Rect) -> Rect {
118        let corners = [
119            Vec2 { x: r.x, y: r.y },
120            Vec2 {
121                x: r.x + r.w,
122                y: r.y,
123            },
124            Vec2 {
125                x: r.x,
126                y: r.y + r.h,
127            },
128            Vec2 {
129                x: r.x + r.w,
130                y: r.y + r.h,
131            },
132        ];
133        let mut min_x = f32::MAX;
134        let mut min_y = f32::MAX;
135        let mut max_x = f32::MIN;
136        let mut max_y = f32::MIN;
137        for c in corners {
138            let p = self.apply_to_point(c);
139            min_x = min_x.min(p.x);
140            min_y = min_y.min(p.y);
141            max_x = max_x.max(p.x);
142            max_y = max_y.max(p.y);
143        }
144        Rect {
145            x: min_x,
146            y: min_y,
147            w: max_x - min_x,
148            h: max_y - min_y,
149        }
150    }
151
152    /// Compose two transforms: `self` then `other` (post-multiply).
153    ///
154    /// Returns a transform such that `combined.apply_to_point(p) ==
155    /// other.apply_to_point(self.apply_to_point(p))`.
156    ///
157    /// **Limitation:** the T*R*S representation is not closed under matrix
158    /// multiplication when both transforms have rotation *and* non-uniform
159    /// scale. In that case the result is an approximation (off-diagonal
160    /// rotation/scale coupling is dropped). For UI use (uniform scale or no
161    /// rotation) this is exact.
162    pub fn combine(&self, other: &Transform) -> Transform {
163        let c = self.rotate.cos();
164        let s = self.rotate.sin();
165
166        Transform {
167            translate_x: other.translate_x * self.scale_x * c
168                - other.translate_y * self.scale_y * s
169                + self.translate_x,
170            translate_y: other.translate_x * self.scale_x * s
171                + other.translate_y * self.scale_y * c
172                + self.translate_y,
173            scale_x: self.scale_x * other.scale_x,
174            scale_y: self.scale_y * other.scale_y,
175            rotate: self.rotate + other.rotate,
176            origin_x: self.origin_x,
177            origin_y: self.origin_y,
178        }
179    }
180}
repose_core/geometry.rs

repose_core/
geometry.rs
