rust_widgets 2.8.7

// SPDX-FileCopyrightText: Copyright (c) 2026 Mike Li/Mikewolfli/Wei Li(mikewolfli@163.com)
// SPDX-License-Identifier: MIT

//! Icon census probe (BLUE25 ICON-6) — the machine-readable view of the icon set.
//!
//! # What this measures, and why a gate needs it
//!
//! The icon data is only useful if a *draw* uses it. `tests/icon_data_integrity_test.rs` proves the
//! table is complete and distinct; it cannot prove the table **reaches a picture**. So this probe
//! renders every `IconName` through the real pipeline and prints, per token, what came out:
//!
//! | Field | Meaning |
//! |---|---|
//! | `token` | the canonical name |
//! | `contours` | closed subpaths the flattened icon produced |
//! | `ink` | painted pixels in the 24 px software rendering (the picture is not blank) |
//! | `runs` | opaque segments the middle scanline crosses (a ring crosses it twice or more) |
//! | `sha256` | digest of the rendering, so two tokens cannot draw one picture unnoticed |
//!
//! `tests/icon_census_test.rs` asserts the same facts, and `tools/icon_census.txt` is the committed
//! output — so a change in what an icon draws shows up as a diff in a reviewable file.
//!
//! # Why `ink` is a pixel count and not a contour count
//!
//! `ink` used to be `ink = contours` — a copy of the field beside it, which cannot fail and
//! measures nothing. Worse, it encoded the wrong model: it counted every contour as its own ink, so
//! a counter (the inner ring of `info`) read as ink rather than as an erased hole. BLUE27 §19.3.1
//! names that as one of the two records that could not see the defect, and the fix is to measure
//! the picture instead of restating the data: `ink` is now the number of pixels the software
//! backend actually painted.
//!
//! `runs` is the second half of the same evidence, and it is the one a reader can check by eye.
//! Drawing a ring as a solid disk is invisible in a pixel *total* — the total only grows — but it
//! collapses the middle scanline from `runs=3` (`info`) to `runs=1`, so the committed census shows
//! it. `runs=0` means the middle scanline misses the shape entirely (`user`, `fullscreen`), which
//! is a property of the scanline and not a missing icon; `ink` covers that case.
//!
//! # Why the census is a digest and not a shape description
//!
//! The defect this replaces — `Close` and `Cross` drawn by one method — is not visible in any
//! summary statistic: both names had ink, both had contours, and both were "a valid icon". The only
//! property that distinguishes them is that their **pictures differ**, so the census records a
//! digest of the picture and lets the gate require all of them to be distinct.
//!
//! # Why the probe prints and does not assert
//!
//! Same reason as `widget_reachability`: an example is the smallest target that can be built on
//! demand, and the assertion belongs in a test the suite runs. This file is the producer for the
//! committed census; the test is the judge.

// The consumer of this file is `tests/icon_census_test.rs`, which states the same gate for the same
// reason: the probe renders the `Icon` widget, so it needs the unstripped widget set, not merely
// "a profile that is not `mini`".
#![cfg(all(feature = "icons", widgets_unstripped))]

use rust_widgets::core::{Color, Rect, Size};
use rust_widgets::render::{PaintBackend, RenderContext, SoftwarePaintBackend};
use rust_widgets::widget::draw::Draw;
use rust_widgets::widget::svg::render_to_svg;
use rust_widgets::widget::{Icon, IconName};

/// The frame the census rasterises into, in pixels.
const SIDE: u32 = 24;

fn main() {
    for token in IconName::ALL {
        let mut icon = Icon::new(Rect::new(0, 0, SIDE, SIDE));
        icon.set_icon_enum(token);
        let svg = render_to_svg(&mut icon);
        // Each `M` starts one closed contour in the emitted compound path.
        let contours = svg.matches("M ").count();
        let (ink, runs) = measure_ink(&mut icon);
        println!(
            "{}\tcontours={}\tink={}\truns={}\tsha256={}",
            token.as_str(),
            contours,
            ink,
            runs,
            sha256_hex(svg.as_bytes())
        );
    }
}

/// Draws `icon` into a fresh software frame and measures the ink it laid down.
///
/// Returns `(painted pixels, opaque segments on the middle scanline)`. The second number is what
/// separates a ring from a disk; `tests/icon_census_test.rs` computes the same two numbers (it
/// cannot import from an example) and asserts the committed census still agrees with them.
fn measure_ink(icon: &mut Icon) -> (usize, usize) {
    let mut backend = SoftwarePaintBackend::new(Size::new(SIDE, SIDE), 1.0);
    backend.begin_frame(Color::TRANSPARENT);
    {
        let mut context = RenderContext::new(&mut backend);
        icon.draw(&mut context);
    }
    backend.end_frame();
    let pixels = backend.frame_rgba();
    let painted = |x: u32, y: u32| pixels[((y * SIDE + x) * 4 + 3) as usize] > 0;

    let ink = (0..SIDE * SIDE).filter(|&i| pixels[(i * 4 + 3) as usize] > 0).count();
    let mut runs = 0;
    let mut inside = false;
    for x in 0..SIDE {
        let painted = painted(x, SIDE / 2);
        if painted && !inside {
            runs += 1;
        }
        inside = painted;
    }
    (ink, runs)
}

/// A SHA-256 of `data`, hex-encoded.
///
/// Hand-rolled rather than pulled in as a dependency: this is a probe, not the library, and the
/// crate deliberately has no digest crate. The algorithm is short enough that a second
/// implementation is not a maintenance risk, and it is only ever run for a report.
fn sha256_hex(data: &[u8]) -> String {
    // The round constants and initial state, per FIPS 180-4.
    const K: [u32; 64] = [
        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4,
        0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe,
        0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f,
        0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
        0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc,
        0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
        0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116,
        0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
        0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7,
        0xc67178f2,
    ];
    let mut h: [u32; 8] = [
        0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab,
        0x5be0cd19,
    ];
    let mut message = data.to_vec();
    let bit_len = (data.len() as u64) * 8;
    message.push(0x80);
    while message.len() % 64 != 56 {
        message.push(0);
    }
    message.extend_from_slice(&bit_len.to_be_bytes());

    for chunk in message.chunks(64) {
        let mut w = [0u32; 64];
        for (index, word) in chunk.chunks(4).enumerate() {
            w[index] = u32::from_be_bytes([word[0], word[1], word[2], word[3]]);
        }
        for index in 16..64 {
            let s0 = w[index - 15].rotate_right(7)
                ^ w[index - 15].rotate_right(18)
                ^ (w[index - 15] >> 3);
            let s1 = w[index - 2].rotate_right(17)
                ^ w[index - 2].rotate_right(19)
                ^ (w[index - 2] >> 10);
            w[index] = w[index - 16].wrapping_add(s0).wrapping_add(w[index - 7]).wrapping_add(s1);
        }
        let [mut a, mut b, mut c, mut d, mut e, mut f, mut g, mut hh] = h;
        for index in 0..64 {
            let s1 = e.rotate_right(6) ^ e.rotate_right(11) ^ e.rotate_right(25);
            let ch = (e & f) ^ (!e & g);
            let temp1 =
                hh.wrapping_add(s1).wrapping_add(ch).wrapping_add(K[index]).wrapping_add(w[index]);
            let s0 = a.rotate_right(2) ^ a.rotate_right(13) ^ a.rotate_right(22);
            let maj = (a & b) ^ (a & c) ^ (b & c);
            let temp2 = s0.wrapping_add(maj);
            hh = g;
            g = f;
            f = e;
            e = d.wrapping_add(temp1);
            d = c;
            c = b;
            b = a;
            a = temp1.wrapping_add(temp2);
        }
        h[0] = h[0].wrapping_add(a);
        h[1] = h[1].wrapping_add(b);
        h[2] = h[2].wrapping_add(c);
        h[3] = h[3].wrapping_add(d);
        h[4] = h[4].wrapping_add(e);
        h[5] = h[5].wrapping_add(f);
        h[6] = h[6].wrapping_add(g);
        h[7] = h[7].wrapping_add(hh);
    }

    let mut out = String::with_capacity(64);
    for word in h {
        out.push_str(&format!("{word:08x}"));
    }
    out
}