mirui 0.45.0

A lightweight, no_std ECS-driven UI framework for embedded, desktop, and WebAssembly
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

use crate::render::font::Font;
use crate::types::{Fixed, Point, Rect, Transform};

/// Paired shaped glyphs and path-placement frames for one posed run.
#[derive(Clone, Copy, Debug)]
pub struct PosedGlyphs<'a> {
    glyphs: &'a [textflow::shaping::PositionedGlyph],
    frames: &'a [textflow::placement::GlyphFrame],
}

impl<'a> PosedGlyphs<'a> {
    pub const fn new(
        glyphs: &'a [textflow::shaping::PositionedGlyph],
        frames: &'a [textflow::placement::GlyphFrame],
    ) -> Option<Self> {
        if glyphs.len() != frames.len() {
            return None;
        }
        Some(Self { glyphs, frames })
    }

    pub const fn glyphs(self) -> &'a [textflow::shaping::PositionedGlyph] {
        self.glyphs
    }

    pub const fn frames(self) -> &'a [textflow::placement::GlyphFrame] {
        self.frames
    }

    pub fn iter(
        self,
    ) -> impl ExactSizeIterator<
        Item = (
            &'a textflow::shaping::PositionedGlyph,
            &'a textflow::placement::GlyphFrame,
        ),
    > {
        self.glyphs.iter().zip(self.frames)
    }

    pub(crate) fn ink_bounds(
        self,
        font: &Font,
        pos: Point,
        transform: Transform,
        output_scale: Fixed,
    ) -> Option<Rect> {
        let requested_size = font.size.max(1);
        let output_ppem = crate::render::font::output_ppem(
            requested_size,
            output_scale * transform.raster_scale(),
        );
        self.ink_bounds_for_output(font, pos, transform, output_ppem)
    }

    pub(crate) fn ink_bounds_for_output(
        self,
        font: &Font,
        pos: Point,
        transform: Transform,
        output_ppem: u16,
    ) -> Option<Rect> {
        let requested_size = font.size.max(1);
        let mut bounds: Option<Rect> = None;
        for (glyph, frame) in self.iter() {
            let Some(raster) =
                font.raster_for_output(glyph.glyph_id(), requested_size, output_ppem)
            else {
                continue;
            };
            let Some(quad) = raster.posed_quad(pos, *frame, requested_size, transform) else {
                continue;
            };
            let glyph_bounds = quad.transform.apply_rect_bbox(quad.rect);
            bounds = Some(match bounds {
                Some(bounds) => bounds.union(&glyph_bounds),
                None => glyph_bounds,
            });
        }
        bounds
    }
}

#[cfg(test)]
mod tests {
    use super::PosedGlyphs;
    use crate::render::font::Font;
    use crate::types::{Fixed, Point, Transform};
    use textflow::placement::GlyphFrame;
    use textflow::shaping::{FlowPoint, GlyphId, PositionedGlyph};

    #[test]
    fn construction_rejects_unpaired_geometry() {
        let glyphs = [PositionedGlyph::new(
            GlyphId::new(1),
            FlowPoint { x: 0, y: 0 },
        )];

        assert!(PosedGlyphs::new(&glyphs, &[]).is_none());
        assert!(PosedGlyphs::new(&glyphs, &[GlyphFrame::default()]).is_some());
    }

    #[test]
    fn ink_bounds_use_the_same_oriented_raster_quads_as_rendering() {
        let glyphs = [PositionedGlyph::new(
            GlyphId::new(u16::from(b'A')),
            FlowPoint { x: 0, y: 0 },
        )];
        let frames = [GlyphFrame {
            local_origin: FlowPoint {
                x: 12 << 8,
                y: 1 << 8,
            },
            unit_tangent: FlowPoint { x: 0, y: 1 << 8 },
        }];
        let posed = PosedGlyphs::new(&glyphs, &frames).unwrap();

        assert_eq!(
            posed.ink_bounds(
                &Font::bitmap_8x8(),
                Point::ZERO,
                Transform::IDENTITY,
                Fixed::ONE,
            ),
            Some(crate::types::Rect {
                x: Fixed::from_int(11),
                y: Fixed::from_int(1),
                w: Fixed::from_int(8),
                h: Fixed::from_int(8),
            })
        );
    }
}