tikra 1.2.0

TikZ figures to SVG and PNG with no TeX install; math labels by mathra.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165

//! The shapes of `pgfmoduleshapes.code.tex` (coordinate, rectangle, circle) and the ellipse and
//! diamond of `shapes.geometric`.

use std::f64::consts::{FRAC_1_SQRT_2, SQRT_2};

use crate::scene::{Point, Segment};

use super::{Border, Geometry, Input};

/// `\pgfpathellipse`: a closed ellipse of radii `rx`, `ry` around `c`, from its east point,
/// counterclockwise, in four curves.
pub fn ellipse_path(c: Point, rx: f64, ry: f64) -> Vec<Segment> {
    let k = 0.55228475;
    let p = |x: f64, y: f64| c.plus(Point::new(x, y));
    vec![
        Segment::MoveTo(p(rx, 0.0)),
        Segment::CurveTo(p(rx, k * ry), p(k * rx, ry), p(0.0, ry)),
        Segment::CurveTo(p(-k * rx, ry), p(-rx, k * ry), p(-rx, 0.0)),
        Segment::CurveTo(p(-rx, -k * ry), p(-k * rx, -ry), p(0.0, -ry)),
        Segment::CurveTo(p(k * rx, -ry), p(rx, -k * ry), p(rx, 0.0)),
        Segment::Close,
    ]
}

/// A shape with nothing drawn and every anchor at its center.
pub fn coordinate(input: &mut Input) -> Geometry {
    let c = input.center_point();
    let mut g = Geometry::new(c, Border::Point);
    for a in ["center", "north", "north west", "north east", "west", "east", "mid", "mid west", "mid east", "base", "base west", "base east", "south", "south west", "south east"] {
        g.anchor_at(a, c);
    }
    // no text
    g.parts.clear();
    g
}

/// The anchors of a box from `sw` to `ne`, as the rectangle has them (and the shapes that
/// inherit them).
pub fn box_anchors(g: &mut Geometry, sw: Point, ne: Point, ex: f64) {
    let c = sw.lerp(ne, 0.5);
    let m = 0.5 * ex;
    for (name, p) in [
        ("center", c),
        ("mid", Point::new(c.x, m)),
        ("base", Point::new(c.x, 0.0)),
        ("north", Point::new(c.x, ne.y)),
        ("south", Point::new(c.x, sw.y)),
        ("west", Point::new(sw.x, c.y)),
        ("mid west", Point::new(sw.x, m)),
        ("base west", Point::new(sw.x, 0.0)),
        ("north west", Point::new(sw.x, ne.y)),
        ("south west", sw),
        ("east", Point::new(ne.x, c.y)),
        ("mid east", Point::new(ne.x, m)),
        ("base east", Point::new(ne.x, 0.0)),
        ("north east", ne),
        ("south east", Point::new(ne.x, sw.y)),
    ] {
        g.anchor_at(name, p);
    }
}

/// The text box with inner sep, enlarged to the minimum size: its south west and north east
/// corners, with outer sep (`\southwest`, `\northeast` of the rectangle).
pub fn rectangle_corners(input: &Input) -> (Point, Point) {
    let t = input.text();
    let w = (t.wd + 2.0 * input.inner_xsep).max(input.minimum_width);
    let h = (t.ht + t.dp + 2.0 * input.inner_ysep).max(input.minimum_height);
    let cy = (t.ht - t.dp) / 2.0;
    let ne = Point::new(t.wd / 2.0 + w / 2.0 + input.outer_xsep, cy + h / 2.0 + input.outer_ysep);
    let sw = Point::new(t.wd / 2.0 - w / 2.0 - input.outer_xsep, cy - h / 2.0 - input.outer_ysep);
    (sw, ne)
}

pub fn rectangle(input: &mut Input) -> Geometry {
    let (sw, ne) = rectangle_corners(input);
    let c = sw.lerp(ne, 0.5);
    let mut g = Geometry::new(c, Border::Rectangle(ne.minus(sw).scale(0.5)));
    box_anchors(&mut g, sw, ne, input.ex);
    let o = Point::new(input.outer_xsep, input.outer_ysep);
    let (a, b) = (sw.plus(o), ne.minus(o));
    // \pgfpathrectanglecorners, as the "re" operator draws it
    g.background(vec![Segment::MoveTo(a), Segment::LineTo(Point::new(b.x, a.y)), Segment::LineTo(b), Segment::LineTo(Point::new(a.x, b.y)), Segment::Close]);
    g.roundable = true;
    g
}

/// The anchors of a round shape of radii `r` around `c`: the corners at 45° of the radii.
fn round_anchors(g: &mut Geometry, c: Point, r: Point, ex: f64) {
    let m = 0.5 * ex;
    let k = FRAC_1_SQRT_2;
    for (name, p) in [
        ("center", c),
        ("mid", Point::new(c.x, m)),
        ("base", Point::new(c.x, 0.0)),
        ("north", Point::new(c.x, c.y + r.y)),
        ("south", Point::new(c.x, c.y - r.y)),
        ("west", Point::new(c.x - r.x, c.y)),
        ("east", Point::new(c.x + r.x, c.y)),
        ("mid west", Point::new(c.x - r.x, m)),
        ("mid east", Point::new(c.x + r.x, m)),
        ("base west", Point::new(c.x - r.x, 0.0)),
        ("base east", Point::new(c.x + r.x, 0.0)),
        ("north west", Point::new(c.x - k * r.x, c.y + k * r.y)),
        ("south west", Point::new(c.x - k * r.x, c.y - k * r.y)),
        ("north east", Point::new(c.x + k * r.x, c.y + k * r.y)),
        ("south east", Point::new(c.x + k * r.x, c.y - k * r.y)),
    ] {
        g.anchor_at(name, p);
    }
}

pub fn circle(input: &mut Input) -> Geometry {
    let c = input.center_point();
    let (xa, ya) = input.half_with_inner();
    let r = xa.hypot(ya).max(input.minimum_width / 2.0).max(input.minimum_height / 2.0) + input.outer_sep();
    let mut g = Geometry::new(c, Border::Ellipse(Point::new(r, r)));
    round_anchors(&mut g, c, Point::new(r, r), input.ex);
    let rr = r - input.outer_sep();
    g.background(ellipse_path(c, rr, rr));
    g
}

pub fn ellipse(input: &mut Input) -> Geometry {
    let c = input.center_point();
    let (xa, ya) = input.half_with_inner();
    let rx = (SQRT_2 * xa).max(input.minimum_width / 2.0) + input.outer_xsep;
    let ry = (SQRT_2 * ya).max(input.minimum_height / 2.0) + input.outer_ysep;
    let mut g = Geometry::new(c, Border::Ellipse(Point::new(rx, ry)));
    round_anchors(&mut g, c, Point::new(rx, ry), input.ex);
    g.background(ellipse_path(c, rx - input.outer_xsep, ry - input.outer_ysep));
    g
}

pub fn diamond(input: &mut Input) -> Geometry {
    let c = input.center_point();
    let (xa, ya) = input.half_with_inner();
    let aspect = if input.aspect.abs() > 1e-9 { input.aspect } else { 1.0 };
    let x = (xa + aspect * ya).max(input.minimum_width / 2.0) + input.outer_xsep;
    let y = (xa / aspect + ya).max(input.minimum_height / 2.0) + input.outer_ysep;
    let p = |dx: f64, dy: f64| c.plus(Point::new(dx, dy));
    let outline = vec![p(x, 0.0), p(0.0, y), p(-x, 0.0), p(0.0, -y)];
    let mut g = Geometry::new(c, Border::Outline(outline));
    for (name, q) in [
        ("center", c),
        ("mid", Point::new(c.x, 0.5 * input.ex)),
        ("base", Point::new(c.x, 0.0)),
        ("north", p(0.0, y)),
        ("south", p(0.0, -y)),
        ("west", p(-x, 0.0)),
        ("east", p(x, 0.0)),
        ("north west", p(-x / 2.0, y / 2.0)),
        ("south west", p(-x / 2.0, -y / 2.0)),
        ("north east", p(x / 2.0, y / 2.0)),
        ("south east", p(x / 2.0, -y / 2.0)),
    ] {
        g.anchor_at(name, q);
    }
    // the drawn diamond is in by the outer sep times √2 (not by the miter length)
    let xc = x - SQRT_2 * input.outer_xsep;
    let yc = y - SQRT_2 * input.outer_ysep;
    g.background(vec![Segment::MoveTo(p(xc, 0.0)), Segment::LineTo(p(0.0, yc)), Segment::LineTo(p(-xc, 0.0)), Segment::LineTo(p(0.0, -yc)), Segment::Close]);
    g.roundable = true;
    g
}