ruviz 0.5.0

High-performance 2D plotting library for Rust
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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182

/// Shared text-anchor geometry helpers used by raster and vector renderers.
///
/// Static layout in ruviz uses:
/// - horizontal text anchors at top origin,
/// - rotated axis-label anchors at geometric center.
///
/// These helpers convert those layout anchors into draw coordinates.

#[derive(Debug, Clone, Copy, PartialEq)]
pub struct TextPlacementMetrics {
    pub width: f32,
    pub height: f32,
    pub baseline_from_top: f32,
}

impl TextPlacementMetrics {
    pub fn new(width: f32, height: f32, baseline_from_top: f32) -> Self {
        let width = width.max(0.0);
        let height = height.max(0.0);
        let baseline_from_top = baseline_from_top.clamp(0.0, height.max(0.0));
        Self {
            width,
            height,
            baseline_from_top,
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum TextAnchorKind {
    TopLeft,
    TopCenter,
    TopRight,
    CenterLeft,
    Center,
    CenterRight,
    BottomLeft,
    BottomCenter,
    BottomRight,
}

pub(crate) fn aligned_text_anchor(
    align: crate::core::TextAlign,
    valign: crate::core::TextVAlign,
) -> TextAnchorKind {
    use crate::core::{TextAlign, TextVAlign};

    match (align, valign) {
        (TextAlign::Left, TextVAlign::Top) => TextAnchorKind::TopLeft,
        (TextAlign::Center, TextVAlign::Top) => TextAnchorKind::TopCenter,
        (TextAlign::Right, TextVAlign::Top) => TextAnchorKind::TopRight,
        (TextAlign::Left, TextVAlign::Middle) => TextAnchorKind::CenterLeft,
        (TextAlign::Center, TextVAlign::Middle) => TextAnchorKind::Center,
        (TextAlign::Right, TextVAlign::Middle) => TextAnchorKind::CenterRight,
        (TextAlign::Left, TextVAlign::Bottom) => TextAnchorKind::BottomLeft,
        (TextAlign::Center, TextVAlign::Bottom) => TextAnchorKind::BottomCenter,
        (TextAlign::Right, TextVAlign::Bottom) => TextAnchorKind::BottomRight,
    }
}

#[derive(Debug, Clone, Copy, PartialEq)]
pub(crate) struct AnnotationTextLayout {
    pub text_x: f32,
    pub text_y: f32,
    pub box_x: f32,
    pub box_y: f32,
    pub box_width: f32,
    pub box_height: f32,
    /// Screen-coordinate rotation in degrees. Negative is visual counter-clockwise.
    pub rotation: f32,
}

pub(crate) fn annotation_text_layout(
    metrics: TextPlacementMetrics,
    align: crate::core::TextAlign,
    valign: crate::core::TextVAlign,
    padding: f32,
    counter_clockwise_rotation: f32,
) -> AnnotationTextLayout {
    let padding = padding.max(0.0);
    let (text_x, text_y) = anchor_to_top_left(
        0.0,
        0.0,
        metrics.width,
        metrics.height,
        aligned_text_anchor(align, valign),
    );
    AnnotationTextLayout {
        text_x,
        text_y,
        box_x: text_x - padding,
        box_y: text_y - padding,
        box_width: metrics.width + 2.0 * padding,
        box_height: metrics.height + 2.0 * padding,
        rotation: if counter_clockwise_rotation.is_finite() {
            -counter_clockwise_rotation
        } else {
            0.0
        },
    }
}

/// Convert an anchor coordinate and rendered bounds into top-left draw coordinates.
pub fn anchor_to_top_left(
    anchor_x: f32,
    anchor_y: f32,
    rendered_width: f32,
    rendered_height: f32,
    anchor: TextAnchorKind,
) -> (f32, f32) {
    let x = match anchor {
        TextAnchorKind::TopLeft | TextAnchorKind::CenterLeft | TextAnchorKind::BottomLeft => {
            anchor_x
        }
        TextAnchorKind::TopCenter | TextAnchorKind::Center | TextAnchorKind::BottomCenter => {
            anchor_x - rendered_width / 2.0
        }
        TextAnchorKind::TopRight | TextAnchorKind::CenterRight | TextAnchorKind::BottomRight => {
            anchor_x - rendered_width
        }
    };
    let y = match anchor {
        TextAnchorKind::TopLeft | TextAnchorKind::TopCenter | TextAnchorKind::TopRight => anchor_y,
        TextAnchorKind::CenterLeft | TextAnchorKind::Center | TextAnchorKind::CenterRight => {
            anchor_y - rendered_height / 2.0
        }
        TextAnchorKind::BottomLeft | TextAnchorKind::BottomCenter | TextAnchorKind::BottomRight => {
            anchor_y - rendered_height
        }
    };
    (x, y)
}

/// Convert a top-origin anchor y to baseline y.
pub fn top_anchor_to_baseline(anchor_top_y: f32, metrics: TextPlacementMetrics) -> f32 {
    anchor_top_y + metrics.baseline_from_top
}

/// Convert a center-origin anchor y to baseline y.
pub fn center_anchor_to_baseline(anchor_center_y: f32, metrics: TextPlacementMetrics) -> f32 {
    anchor_center_y - metrics.height / 2.0 + metrics.baseline_from_top
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn all_anchor_kinds_map_to_expected_top_left() {
        let cases = [
            (TextAnchorKind::TopLeft, (20.0, 30.0)),
            (TextAnchorKind::TopCenter, (15.0, 30.0)),
            (TextAnchorKind::TopRight, (10.0, 30.0)),
            (TextAnchorKind::CenterLeft, (20.0, 28.0)),
            (TextAnchorKind::Center, (15.0, 28.0)),
            (TextAnchorKind::CenterRight, (10.0, 28.0)),
            (TextAnchorKind::BottomLeft, (20.0, 26.0)),
            (TextAnchorKind::BottomCenter, (15.0, 26.0)),
            (TextAnchorKind::BottomRight, (10.0, 26.0)),
        ];

        for (anchor, expected) in cases {
            assert_eq!(anchor_to_top_left(20.0, 30.0, 10.0, 4.0, anchor), expected);
        }
    }

    #[test]
    fn annotation_layout_expands_padding_without_moving_text_anchor() {
        let layout = annotation_text_layout(
            TextPlacementMetrics::new(10.0, 4.0, 3.0),
            crate::core::TextAlign::Center,
            crate::core::TextVAlign::Middle,
            2.0,
            30.0,
        );

        assert_eq!((layout.text_x, layout.text_y), (-5.0, -2.0));
        assert_eq!((layout.box_x, layout.box_y), (-7.0, -4.0));
        assert_eq!((layout.box_width, layout.box_height), (14.0, 8.0));
        assert_eq!(layout.rotation, -30.0);
    }
}