mirui 0.46.0

A lightweight, no_std ECS-driven UI framework for embedded, mobile, 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 super::SdlGpuRenderer;
use crate::render::path::Path;
use crate::render::raster::{FillRule, LineCap, LineJoin, StrokeSpec};
use crate::types::{Color, Fixed, Rect, Transform};

impl<S: AsRef<[u8]> + AsMut<[u8]>> SdlGpuRenderer<'_, S> {
    pub(super) fn fill_path_inner(
        &mut self,
        path: &Path,
        clip: &Rect,
        color: &Color,
        opa: u8,
        fill_rule: FillRule,
    ) {
        let phys_tf = self.viewport.as_transform();
        let phys_clip = self.viewport.rect_to_physical(*clip);
        self.tessellator
            .fill(path, Some(&phys_tf), color, opa, fill_rule);
        self.submit_geometry(&phys_clip, opa != 255 || color.a != 255);
    }

    pub(super) fn fill_path_transformed_inner(
        &mut self,
        path: &Path,
        clip: &Rect,
        cmd_tf: &Transform,
        color: &Color,
        opa: u8,
        fill_rule: FillRule,
    ) {
        let phys_tf = self.viewport.as_transform().compose(cmd_tf);
        let phys_clip = self.viewport.rect_to_physical(*clip);
        self.tessellator
            .fill(path, Some(&phys_tf), color, opa, fill_rule);
        self.submit_geometry(&phys_clip, opa != 255 || color.a != 255);
    }

    pub(super) fn stroke_path_inner(
        &mut self,
        path: &Path,
        clip: &Rect,
        width: Fixed,
        color: &Color,
        opa: u8,
    ) {
        self.stroke_path_styled_inner(
            path,
            clip,
            &Transform::IDENTITY,
            StrokeSpec {
                width,
                cap: LineCap::Butt,
                join: LineJoin::Miter,
                miter_limit: Fixed::from_int(4),
                dash: &[],
                dash_scale: Fixed::ONE,
            },
            color,
            opa,
        );
    }

    pub(super) fn stroke_path_styled_inner(
        &mut self,
        path: &Path,
        clip: &Rect,
        cmd_tf: &Transform,
        spec: StrokeSpec<'_>,
        color: &Color,
        opa: u8,
    ) {
        if spec.width <= Fixed::ZERO || opa == 0 {
            return;
        }
        let scale = self.viewport.scale();
        let phys_tf = self.viewport.as_transform().compose(cmd_tf);
        if spec.dash.is_empty() {
            let mut physical = StrokeSpec {
                width: spec.width * scale,
                dash_scale: scale,
                ..spec
            };
            let mut physical_opacity = opa;
            if physical.width <= Fixed::ONE {
                let requested = physical.width;
                physical.width += Fixed::HALF;
                physical_opacity = coverage_opacity(opa, requested, physical.width);
            }
            self.tessellator
                .stroke(path, Some(&phys_tf), physical, color, physical_opacity);
            let phys_clip = self.viewport.rect_to_physical(*clip);
            self.submit_geometry(&phys_clip, physical_opacity != 255 || color.a != 255);
            return;
        }
        let outline = self.stroke_scratch.outline(
            path,
            Some(&phys_tf),
            StrokeSpec {
                width: spec.width * scale,
                dash_scale: scale,
                ..spec
            },
        );
        self.tessellator
            .fill(outline, None, color, opa, FillRule::NonZero);
        let phys_clip = self.viewport.rect_to_physical(*clip);
        self.submit_geometry(&phys_clip, opa != 255 || color.a != 255);
    }
}

fn coverage_opacity(opacity: u8, requested_width: Fixed, raster_width: Fixed) -> u8 {
    if raster_width <= Fixed::ZERO {
        return 0;
    }
    (Fixed::from_int(i32::from(opacity)) * requested_width / raster_width)
        .round()
        .clamp(Fixed::ZERO, Fixed::from_int(255))
        .to_int() as u8
}

#[cfg(test)]
mod tests {
    use super::coverage_opacity;
    use crate::types::Fixed;

    #[test]
    fn one_pixel_stroke_preserves_integrated_coverage_when_expanded() {
        assert_eq!(
            coverage_opacity(150, Fixed::ONE, Fixed::from_ratio(3, 2)),
            100
        );
    }
}