lernie 0.1.23

lernie: the operator seat — the window and wire client for a yog server
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

//! The mark: the artifacts it pins, the three spellings that have to agree, and
//! the picture the raster actually paints.

use super::{APP_ID, CASING, ENGINE, PHOSPHOR, SEAT, rgba, shapes, svg};

/// One tracked asset, read out of the source tree rather than out of a target
/// directory: these files are the repository's, and the test is about what is
/// checked in.
fn asset(name: &str) -> String {
    let at = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
        .join("assets")
        .join(name);
    std::fs::read_to_string(&at).unwrap_or_else(|why| panic!("{}: {why}", at.display()))
}

/// **The checked-in vector source is a derivation, not a hand-edit.**
///
/// Byte for byte, which the mark's integer geometry is what makes safe: a
/// generator that emitted formatted floats could disagree with its own output
/// on another target, and this test would then fail for a reason that had
/// nothing to do with the picture.
#[test]
fn the_tracked_vector_source_is_exactly_what_the_generator_emits() {
    assert_eq!(
        asset(&format!("{APP_ID}.svg")),
        svg(),
        "assets/{APP_ID}.svg is stale — re-emit it with `make icon`, never by hand"
    );
}

/// **Three spellings, and nothing at runtime can check them.** A Wayland
/// compositor matches the window's app id against the desktop entry and reads
/// that entry's `Icon=` by name through the theme, so a disagreement between
/// any two of them is a mark that resolves nowhere — which looks exactly like
/// not having one.
#[test]
fn the_app_id_the_desktop_entry_and_the_icon_name_are_one_word() {
    let entry = asset(&format!("{APP_ID}.desktop"));
    for line in [
        format!("Icon={APP_ID}"),
        format!("StartupWMClass={APP_ID}"),
        format!("Exec={APP_ID}"),
    ] {
        assert!(
            entry.lines().any(|held| held == line),
            "the desktop entry has no {line:?}:\n{entry}"
        );
    }
}

/// **The tracked entry's `Exec` is the bare name, exactly once.**
///
/// `make icon-seats` rewrites `Exec=` into the copy it INSTALLS, because a
/// desktop environment resolves that line out of the session's own environment
/// and a bare name is silently unlaunchable wherever the binary's directory
/// reached `PATH` through a shell profile. The tracked file stays generic — it
/// is one repository's source for every box, and a real absolute path in it
/// would be a disclosure as well as a lie everywhere else.
///
/// Two halves, and the second is the one no reader would think to keep. The
/// bare spelling above is what the test before this one already pins. The
/// COUNT is what the substitution rides on: it replaces every line matching
/// `^Exec=`, so a second one would be rewritten to the same path and the entry
/// would carry the key twice — and a `.desktop` with a duplicate key in one
/// group is malformed, which launchers answer by ignoring the file rather than
/// by complaining about it.
#[test]
fn the_tracked_entry_carries_exactly_one_exec_and_it_is_generic() {
    let entry = asset(&format!("{APP_ID}.desktop"));
    let execs: Vec<&str> = entry
        .lines()
        .filter(|line| line.starts_with("Exec="))
        .collect();
    assert_eq!(
        execs,
        vec![format!("Exec={APP_ID}")],
        "the installed copy is where an absolute Exec belongs, and there is one \
         of them — `make icon-seats` rewrites every ^Exec= line:\n{entry}"
    );
}

/// The vector source is one element per shape, in the shape list's own order —
/// so the file reads as the list does and a reordering shows up in both.
#[test]
fn every_primitive_is_one_element_and_the_order_is_the_list_s() {
    let source = svg();
    let elements: Vec<&str> = source
        .lines()
        .filter(|line| line.starts_with("  <"))
        .collect();
    assert_eq!(elements.len(), shapes().len());
    assert!(elements[0].starts_with("  <line "), "{source}");
    assert!(elements[1].contains("fill=\"none\""), "{source}");
    assert!(elements[2].contains("fill=\"#5fd1b4\""), "{source}");
    assert!(source.ends_with("</svg>\n"), "{source}");
}

/// The pixel at unit coordinates (`x`, `y`) of an `n`×`n` raster.
fn spot(px: &[u8], n: u16, x: i64, y: i64) -> [u8; 4] {
    let at = |v: i64| usize::try_from(v * i64::from(n) / 1000).unwrap_or(0);
    let i = (at(y) * usize::from(n) + at(x)) * 4;
    let taken = px.get(i..i + 4).unwrap_or(&[0; 4]);
    [taken[0], taken[1], taken[2], taken[3]]
}

/// **The raster is the shape list and nothing else**, asserted where the four
/// facts of the picture are: the canvas is transparent, the seat is solid, the
/// engine is a RING and therefore hollow in the middle, and the wire between
/// them is the dimmer ink.
#[test]
fn the_raster_paints_a_hollow_engine_a_solid_seat_and_a_wire_between() {
    let n = 64_u16;
    let px = rgba(n);
    assert_eq!(px.len(), usize::from(n) * usize::from(n) * 4);

    assert_eq!(spot(&px, n, 20, 20), [0; 4], "the canvas is transparent");
    assert_eq!(
        spot(&px, n, SEAT.0, SEAT.1),
        [PHOSPHOR.red, PHOSPHOR.green, PHOSPHOR.blue, 255],
        "the seat is solid"
    );
    assert_eq!(
        spot(&px, n, ENGINE.0 + 73, ENGINE.1 + 68)[3],
        0,
        "the engine is a ring, so inside it is the canvas"
    );
    assert_eq!(
        spot(&px, n, ENGINE.0, ENGINE.1),
        [CASING.red, CASING.green, CASING.blue, 255],
        "and the wire runs to its centre rather than stopping at its edge"
    );
    assert_eq!(
        spot(&px, n, ENGINE.0, ENGINE.1 - 200),
        [PHOSPHOR.red, PHOSPHOR.green, PHOSPHOR.blue, 255],
        "and its stroke is on it"
    );
    assert_eq!(
        spot(
            &px,
            n,
            i64::midpoint(SEAT.0, ENGINE.0),
            i64::midpoint(SEAT.1, ENGINE.1)
        ),
        [CASING.red, CASING.green, CASING.blue, 255],
        "the wire is the dimmer ink"
    );
}

/// **A size with nothing in it is nothing**, which is the loop not taken rather
/// than a case: an icon of no pixels is not an error to refuse, it is a picture
/// with no room to be one.
#[test]
fn a_raster_of_no_size_is_empty() {
    assert!(rgba(0).is_empty());
}

/// Every edge the mark has, at the one size a taskbar actually uses. Two facts
/// ride on it: the antialiased band exists at all (a picture with only opaque
/// and transparent pixels is one the subsample grid never split), and no pixel
/// is ever partly one ink and partly the other's *neighbour* — every painted
/// pixel is a mean of the two inks and so lies between them.
#[test]
fn the_edges_are_antialiased_and_every_pixel_is_a_mean_of_the_two_inks() {
    let n = 16_u16;
    let px = rgba(n);
    let mut soft = 0;
    for pixel in px.chunks_exact(4) {
        let (red, alpha) = (pixel.first(), pixel.get(3));
        if alpha.copied().is_some_and(|a| a > 0 && a < 255) {
            soft += 1;
        }
        if alpha.copied().is_some_and(|a| a > 0) {
            let red = red.copied().unwrap_or(0);
            assert!(
                (CASING.red..=PHOSPHOR.red).contains(&red),
                "a pixel is neither ink nor a mean of them: {pixel:?}"
            );
        }
    }
    assert!(soft > 0, "nothing on the mark's edges was ever split");
}