AskaEth
9519a89472
③ 的 primary `#0C6780` 偏青（teal），不是「天蓝」。新增 ④ 天蓝：种子 `#3C8DBC` （CAM16 hue 239.5°，夹 ③ 与 ①② 之间）+ 中性彩度 12 → primary `#236488`。 - `tests/skyseed_candidates.rs`：候选表 3 → 4 档，④ 的 9 角色 × light/dark 全部进 pin； `the_three_tiers_are_actually_distinguishable` 改为 `the_candidates_are_actually_distinguishable`， 增加「③ 与 ④ 中性彩度相同、主色/容器必须靠色相区分」的断言 - `tests/contrast_aa.rs`：候选 WCAG 门禁 3 → 4 档（26 × 4 × 2 = 208 项） - 默认值**不动**：仍为 ③ `#87CEEB`（临时默认，待用户看完四档再拍）； `product_default_is_the_recommended_candidate` 保持原样，专门在默认与推荐不一致时报警 - 文档：`color/mod.rs` 与 `palettes.rs` 的候选清单补上 ④ 与「改一行即可切 ④」的说明
256 lines
9.9 KiB
Rust
256 lines
9.9 KiB
Rust
//! WCAG AA 对比度门禁（M61 任务：「on-* 与其承载色至少满足 4.5:1，不达标的角色要显式标注例外」）。
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//!
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//! 三个性质让这条门禁可以做到「**换任何种子色都成立**」，而不是只对出厂紫成立：
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//! 1. 颜色建在 CIELAB `L*`（tone）轴上，`TonalPalette::tone` 精确命中 tone（误差 ≤1）；
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//! 2. WCAG 相对亮度只取决于同一条 Y 轴（`L*` ↔ Y 是双射）；
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//! 3. 角色 → tone 的映射与色相/彩度无关。
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//!
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//! 所以对比度主要由「两个角色的 tone 差」决定，与 user 选的强调色无关——下面对多组种子
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//! 逐一验证，就是在钉这个性质。
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use unlucky_design::color::{Color, Role, Scheme, SchemeFlavor};
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/// 正文文字：要求 ≥ 4.5:1（WCAG AA normal text）。
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const AA_TEXT: f32 = 4.5;
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/// 非文字元素（描边、图标块）：要求 ≥ 3:1（WCAG AA non-text）。
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const AA_NON_TEXT: f32 = 3.0;
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/// 文字/图标对（前景, 承载色）。两个模式都要过。
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const TEXT_PAIRS: [(Role, Role); 26] = [
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(Role::OnPrimary, Role::Primary),
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(Role::OnPrimaryContainer, Role::PrimaryContainer),
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(Role::OnSecondary, Role::Secondary),
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(Role::OnSecondaryContainer, Role::SecondaryContainer),
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(Role::OnTertiary, Role::Tertiary),
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(Role::OnTertiaryContainer, Role::TertiaryContainer),
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(Role::OnError, Role::Error),
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(Role::OnErrorContainer, Role::ErrorContainer),
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(Role::OnSurface, Role::Surface),
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(Role::OnSurfaceVariant, Role::SurfaceVariant),
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(Role::OnBackground, Role::Background),
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(Role::InverseOnSurface, Role::InverseSurface),
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(Role::InversePrimary, Role::InverseSurface),
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(Role::OnPrimaryFixed, Role::PrimaryFixed),
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(Role::OnPrimaryFixedVariant, Role::PrimaryFixedDim),
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(Role::OnSecondaryFixed, Role::SecondaryFixed),
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(Role::OnSecondaryFixedVariant, Role::SecondaryFixedDim),
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(Role::OnTertiaryFixed, Role::TertiaryFixed),
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(Role::OnTertiaryFixedVariant, Role::TertiaryFixedDim),
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// 卡片/浮层容器上的文字（M3 现行口径：层级靠 surface-container-* 表达）
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(Role::OnSurface, Role::SurfaceContainerLowest),
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(Role::OnSurface, Role::SurfaceContainerLow),
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(Role::OnSurface, Role::SurfaceContainer),
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(Role::OnSurface, Role::SurfaceContainerHigh),
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(Role::OnSurface, Role::SurfaceContainerHighest),
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(Role::OnSurfaceVariant, Role::SurfaceContainerHighest),
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(Role::OnSurfaceVariant, Role::SurfaceContainerLow),
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];
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/// 显式登记的例外：`(前景, 承载色, 目标阈值, 原因)`。
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///
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/// 这些不是缺陷，是 M3 定义决定的（非文字元素 3:1、装饰件无要求）。
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const EXCEPTIONS: [(Role, Role, f32, &str); 3] = [
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(
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Role::Outline,
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Role::Surface,
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AA_NON_TEXT,
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"输入框/卡片描边是 M3 定义的非文字元素，规范目标 3:1（light 实测 4.26:1、dark 5.89:1 已高于目标）",
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),
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(
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Role::OutlineVariant,
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Role::Surface,
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AA_NON_TEXT * 0.5,
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"分隔线是纯装饰，M3 不要求对比度下限；light 1.62:1 / dark 1.99:1 是「几乎看不见但要能数出层级」的取值",
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),
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(
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Role::SurfaceVariant,
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Role::Surface,
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1.0,
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"surface-variant 是容器色而不是前景色，不参与对比度门禁（M3 已不推荐用它做容器，保留仅为兼容旧值）",
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),
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];
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fn seeds() -> Vec<Color> {
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vec![
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// 出厂基线（M3 baseline 紫）
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Color::from_hex("#6750A4").expect("基线种子"),
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// 冷蓝（原 Fluent 强调色，用户大概率会选这一族）
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Color::from_hex("#0078D4").expect("蓝"),
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// 青绿
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Color::from_hex("#006A5C").expect("青"),
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// 暖橙（高彩度，gamut 压力大）
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Color::from_hex("#E8710A").expect("橙"),
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// 亮黄（最容易被白字吃掉的极端）
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Color::from_hex("#FFD400").expect("黄"),
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// 近灰（低彩度种子，检验 neutral 不塌）
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Color::from_hex("#6E6E6E").expect("灰"),
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]
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}
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#[test]
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fn text_pairs_meet_wcag_aa_for_every_seed_and_flavor() {
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let mut failures = Vec::new();
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for seed in seeds() {
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for flavor in [SchemeFlavor::Light, SchemeFlavor::Dark] {
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let scheme = Scheme::from_seed(flavor, seed);
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for (fg, bg) in TEXT_PAIRS {
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let ratio = scheme.contrast(fg, bg);
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if ratio < AA_TEXT {
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failures.push(format!(
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"seed {} / {} / {} on {} = {ratio:.2}",
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seed.to_hex(),
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flavor.name(),
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fg.name(),
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bg.name()
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));
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}
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}
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}
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}
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assert!(
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failures.is_empty(),
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"以下角色对未达 WCAG AA（4.5:1）：\n{}",
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failures.join("\n")
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);
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}
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#[test]
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fn exception_list_is_honest_about_its_thresholds() {
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// 例外必须**真的**是「非文字级」，不能悄悄把低于 3:1 的文字对塞进来。
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for seed in seeds() {
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for flavor in [SchemeFlavor::Light, SchemeFlavor::Dark] {
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let scheme = Scheme::from_seed(flavor, seed);
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for (fg, bg, threshold, reason) in EXCEPTIONS {
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assert!(
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!fg.is_foreground(),
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"例外 {} 不该是文字前景色（{reason}）",
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fg.name()
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);
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let ratio = scheme.contrast(fg, bg);
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assert!(
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ratio >= threshold,
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"例外 {} on {} 实测 {ratio:.2}，低于登记阈值 {threshold}（seed {} / {}）",
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fg.name(),
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bg.name(),
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seed.to_hex(),
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flavor.name()
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);
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}
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}
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}
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}
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#[test]
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fn baseline_light_and_dark_both_pass() {
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for flavor in [SchemeFlavor::Light, SchemeFlavor::Dark] {
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let scheme = Scheme::baseline(flavor);
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for (fg, bg) in TEXT_PAIRS {
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let ratio = scheme.contrast(fg, bg);
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assert!(
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ratio >= AA_TEXT,
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"baseline {} 的 {} on {} 只有 {ratio:.2}",
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flavor.name(),
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fg.name(),
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bg.name()
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);
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}
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}
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}
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#[test]
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fn sky_seed_candidates_meet_wcag_aa() {
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// M70：四档默认色候选（种子 + 中性彩度）必须过同一条 26 组门禁。
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// 中性彩度改变只影响色相/彩度，不影响 tone 轴，所以理论上恒过——这里就是要**证明**它恒过，
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// 而不是相信它。任何一档不达标，该档直接判为不可用（不许为了好看放宽阈值）。
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let candidates = [
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("① 保守蓝", "#2196F3", 6.0_f64),
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("② 冷调蓝", "#2196F3", 12.0),
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("③ 浅冷蓝", "#87CEEB", 12.0),
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("④ 天蓝", "#3C8DBC", 12.0),
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];
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let mut failures = Vec::new();
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let mut worst = (f32::MAX, String::new());
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let mut checked = 0;
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for (title, seed_hex, neutral_chroma) in candidates {
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let seed = Color::from_hex(seed_hex).expect("候选种子");
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let palettes =
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unlucky_design::color::Palettes::from_seed_with_neutral_chroma(seed, neutral_chroma);
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for flavor in [SchemeFlavor::Light, SchemeFlavor::Dark] {
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let scheme = Scheme::from_palettes(&palettes, flavor);
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for (fg, bg) in TEXT_PAIRS {
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let ratio = scheme.contrast(fg, bg);
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checked += 1;
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if ratio < worst.0 {
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worst = (
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ratio,
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format!(
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"{title}/{} 的 {} on {}",
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flavor.name(),
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fg.name(),
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bg.name()
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),
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);
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}
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if ratio < AA_TEXT {
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failures.push(format!(
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"{title}（{seed_hex} / 中性 {neutral_chroma}）/ {} / {} on {} = {ratio:.2}",
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flavor.name(),
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fg.name(),
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bg.name()
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));
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}
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}
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}
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}
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println!(
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"候选 WCAG：{checked} 项，最紧的一对 {} = {:.2}:1（阈值 {AA_TEXT}）",
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worst.1, worst.0
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);
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assert!(
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failures.is_empty(),
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"以下候选未达 WCAG AA（4.5:1），该档不可用：\n{}",
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failures.join("\n")
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);
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}
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#[test]
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fn accent_override_cannot_break_contrast() {
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// 换了强调色之后，primary 族仍必须过 AA——这是「tone 轴固定」带来的结构性保证。
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let base = Scheme::baseline(SchemeFlavor::Light);
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for seed in seeds() {
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let custom = Scheme::from_accent(SchemeFlavor::Light, seed);
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for (fg, bg) in [
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(Role::OnPrimary, Role::Primary),
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(Role::OnPrimaryContainer, Role::PrimaryContainer),
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(Role::OnSecondary, Role::Secondary),
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(Role::OnTertiary, Role::Tertiary),
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] {
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let ratio = custom.contrast(fg, bg);
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assert!(
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ratio >= AA_TEXT,
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"强调色 {} 下 {} on {} 只有 {ratio:.2}",
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seed.to_hex(),
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fg.name(),
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bg.name()
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);
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}
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// 表面色不受强调色影响（这条同时是 `from_accent` 的语义断言）。
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assert_eq!(custom.get(Role::Surface), base.get(Role::Surface));
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}
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}
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#[test]
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fn outline_is_registered_as_non_text_exception() {
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// 把「为什么 outline 不是 AA 例外失败项」钉死：它在 light 下 4.29:1（低于 4.5 但高于 3:1）。
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let light = Scheme::baseline(SchemeFlavor::Light);
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let ratio = light.contrast(Role::Outline, Role::Surface);
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assert!(
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ratio < AA_TEXT,
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"light 的 outline 若已达 4.5 应把例外删掉：{ratio:.2}"
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);
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assert!(
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ratio >= AA_NON_TEXT,
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"light 的 outline 低于非文字 3:1：{ratio:.2}"
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);
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}
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