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test(engine): pin card-face SVG output against rasteriser drift

Browse Source 
Step 3 of the migration plan in docs/ui-mockups/card-face-migration.md.

Extracts face_svg / back_svg + palette constants from the
card_face_generator example into a new
solitaire_engine::assets::card_face_svg module so an integration
test can call them. The example becomes a thin wrapper.

The new tests/card_face_svg_pin.rs hashes the raw RGBA8 pixel
bytes from rasterising every face × suit + every back accent and
compares each FNV-1a fingerprint against an embedded constant.
Catches silent rendering drift if usvg / resvg / tiny_skia / the
bundled FiraMono ever change in a way that perturbs pixels.

Hashing is FNV-1a inline (~5 lines) rather than adding sha2 or
blake3 — cryptographic strength isn't load-bearing here, just
stable byte fingerprints.

When the SVG builders intentionally change, empty EXPECTED to
`&[]` and re-run the test once; it panics with the new hashes
formatted as Rust source ready to paste back in.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
funman300
2026-05-08 09:21:00 -07:00
parent babe5cc9c8
commit 48b28d29f8
4 changed files with 399 additions and 199 deletions
Download Patch File Download Diff File Expand all files Collapse all files
solitaire_engine/examples/card_face_generator.rs
+13 -199
View File
@@ -12,51 +12,18 @@
//! the legacy PNG artwork in-place; the resulting bytes are what
//! step 4 commits alongside the `card_plugin` constant migration.
//!
//! Output paths (matching the filenames `card_plugin::load_card_images`
//! already loads):
//!
//! - Faces: `assets/cards/faces/<RANK><SUIT>.png`
//! where `RANK` ∈ `{A, 2..10, J, Q, K}` and `SUIT` ∈ `{C, D, H, S}`.
//! - Backs: `assets/cards/backs/back_{0..4}.png`.
//!
//! All output is 256 × 384 RGBA8 sRGB — half the default
//! `SvgLoaderSettings` resolution, sufficient for ~250 px-wide
//! desktop card sprites and ≈⅓ the disk weight of the legacy 512 ×
//! 768 art (per the migration plan's "Output format" rationale).
//! The SVG builders live in
//! `solitaire_engine::assets::card_face_svg` so the integration
//! test at `tests/card_face_svg_pin.rs` can pin their output
//! against `usvg`/`resvg` rendering drift.
use bevy::math::UVec2;
use solitaire_core::card::{Rank, Suit};
use solitaire_engine::assets::card_face_svg::{
back_svg, face_svg, rank_filename, suit_filename, ALL_RANKS, ALL_SUITS, BACK_ACCENTS, TARGET,
};
use solitaire_engine::assets::rasterize_svg;
use std::path::PathBuf;
use tiny_skia::{IntSize, Pixmap};
// 2× the design-system logical sizes — the spec describes a 128 ×
// 192 logical card, this generator targets 256 × 384.
const TARGET: UVec2 = UVec2::new(256, 384);
// Palette literals — base16-eighties, mirroring `design-system.md`.
const BG_FACE: &str = "#1a1a1a"; // BG_ELEVATED
const SUIT_RED: &str = "#fb9fb1"; // hearts + diamonds
const SUIT_DARK: &str = "#d0d0d0"; // spades + clubs (also TEXT_PRIMARY)
// Card-back palette.
const BACK_BG: &str = "#151515";
const BACK_SCANLINE: &str = "#1a1a1a";
const BACK_BORDER: &str = "#353535";
const BACK_MONOGRAM: &str = "#505050";
// Five back-theme accent colours. Slot 0 is the canonical "Terminal"
// back from the design system; the other four cycle through the
// remaining base16-eighties accents so all 5 slots stay visually
// distinct without leaving the palette.
const BACK_ACCENTS: [&str; 5] = [
"#6fc2ef", // 0 — cyan (Terminal canonical)
"#acc267", // 1 — lime
"#e1a3ee", // 2 — lavender
"#fb9fb1", // 3 — pink
"#ddb26f", // 4 — gold
];
fn main() {
let cards_dir = workspace_assets_dir().join("cards");
let faces_dir = cards_dir.join("faces");
@@ -66,11 +33,15 @@ fn main() {
let mut written = 0usize;
for suit in [Suit::Clubs, Suit::Diamonds, Suit::Hearts, Suit::Spades] {
for suit in ALL_SUITS {
for rank in ALL_RANKS {
let svg = face_svg(rank, suit);
let pixmap = rasterize_to_pixmap(&svg);
let path = faces_dir.join(format!("{}{}.png", rank_str(rank), suit_char(suit)));
let path = faces_dir.join(format!(
"{}{}.png",
rank_filename(rank),
suit_filename(suit)
));
pixmap
.save_png(&path)
.unwrap_or_else(|e| panic!("write {}: {e}", path.display()));
@@ -96,163 +67,6 @@ fn main() {
);
}
const ALL_RANKS: [Rank; 13] = [
Rank::Ace,
Rank::Two,
Rank::Three,
Rank::Four,
Rank::Five,
Rank::Six,
Rank::Seven,
Rank::Eight,
Rank::Nine,
Rank::Ten,
Rank::Jack,
Rank::Queen,
Rank::King,
];
fn rank_str(rank: Rank) -> &'static str {
match rank {
Rank::Ace => "A",
Rank::Two => "2",
Rank::Three => "3",
Rank::Four => "4",
Rank::Five => "5",
Rank::Six => "6",
Rank::Seven => "7",
Rank::Eight => "8",
Rank::Nine => "9",
Rank::Ten => "10",
Rank::Jack => "J",
Rank::Queen => "Q",
Rank::King => "K",
}
}
fn suit_char(suit: Suit) -> &'static str {
match suit {
Suit::Clubs => "C",
Suit::Diamonds => "D",
Suit::Hearts => "H",
Suit::Spades => "S",
}
}
/// Returns the suit colour and the `<text>` paint attributes for the
/// glyph (filled vs outlined). Hearts + spades are filled; diamonds +
/// clubs are outlined — the "always-on" color-blind glyph
/// differentiation from the design system.
fn suit_paint(suit: Suit) -> (&'static str, GlyphPaint) {
match suit {
Suit::Hearts => (SUIT_RED, GlyphPaint::Filled),
Suit::Diamonds => (SUIT_RED, GlyphPaint::Outlined),
Suit::Spades => (SUIT_DARK, GlyphPaint::Filled),
Suit::Clubs => (SUIT_DARK, GlyphPaint::Outlined),
}
}
#[derive(Copy, Clone)]
enum GlyphPaint {
Filled,
/// 1.5 px stroke at logical scale → 3 px at 2× output.
Outlined,
}
fn glyph_paint_attrs(colour: &str, paint: GlyphPaint) -> String {
match paint {
GlyphPaint::Filled => format!(r#"fill="{colour}""#),
GlyphPaint::Outlined => {
format!(r#"fill="none" stroke="{colour}" stroke-width="3""#)
}
}
}
fn suit_glyph(suit: Suit) -> &'static str {
match suit {
Suit::Clubs => "&#x2663;",
Suit::Diamonds => "&#x2666;",
Suit::Hearts => "&#x2665;",
Suit::Spades => "&#x2660;",
}
}
/// Builds the face-card SVG. Sizes are doubled from the design-system
/// logical pixels (the spec describes a 128 × 192 card; we emit at
/// 256 × 384).
fn face_svg(rank: Rank, suit: Suit) -> String {
let (colour, paint) = suit_paint(suit);
let glyph = suit_glyph(suit);
let rank_text = rank_str(rank);
let small_glyph_attrs = glyph_paint_attrs(colour, paint);
let large_glyph_attrs = glyph_paint_attrs(colour, paint);
// Numbers come from `design-system.md` § Game Cards, scaled 2×:
// border: 1 px → 2 px stroke-width
// corner radius: 8 px → 16 px rx/ry
// rank font: 18 px → 36 px
// small glyph: 10 px → 20 px
// large glyph: 32 px → 64 px
//
// Inset the border by 1 px (`x="1" y="1" width="254" height="382"`)
// so the 2 px stroke renders fully inside the 256 × 384 pixmap
// rather than getting clipped at the edge.
format!(
r##"<svg xmlns="http://www.w3.org/2000/svg" width="256" height="384" viewBox="0 0 256 384">
<rect x="1" y="1" width="254" height="382" rx="16" ry="16"
fill="{BG_FACE}" stroke="{colour}" stroke-width="2"/>
<!-- Top-left rank + small suit glyph. -->
<text x="14" y="44" font-family="Fira Mono" font-size="36" font-weight="700"
fill="{colour}">{rank_text}</text>
<text x="14" y="68" font-family="Fira Mono" font-size="20"
{small_glyph_attrs}>{glyph}</text>
<!-- Bottom-right large suit glyph, rotated 180° so it reads
upside-down (the convention for inverted-corner indicators). -->
<text x="242" y="350" font-family="Fira Mono" font-size="64"
text-anchor="end" {large_glyph_attrs}
transform="rotate(180 242 332)">{glyph}</text>
</svg>"##
)
}
/// Builds a card-back SVG with the canonical Terminal scanline
/// pattern. `accent` swaps only the top-left badge — every other
/// element stays palette-locked so all 5 backs read as members of
/// the same family.
fn back_svg(accent: &str) -> String {
// Pattern tile: 1 px line + 1 px gap at logical scale → 2 px +
// 2 px at 2× output. `patternUnits="userSpaceOnUse"` so the tile
// size is in viewBox pixels rather than fractions of the box.
//
// Badge: 12 × 16 px logical → 24 × 32 px output, 12 px from corner.
// Monogram: "▌RS" in 12 px logical → 24 px output, 12 px inset.
format!(
r##"<svg xmlns="http://www.w3.org/2000/svg" width="256" height="384" viewBox="0 0 256 384">
<defs>
<pattern id="scanlines" x="0" y="0" width="2" height="4" patternUnits="userSpaceOnUse">
<rect x="0" y="0" width="2" height="2" fill="{BACK_SCANLINE}"/>
</pattern>
</defs>
<!-- Background fill, then scanlines on top (the scanlines stay
darker than BACK_BG so the "off" rows show through). -->
<rect x="1" y="1" width="254" height="382" rx="16" ry="16"
fill="{BACK_BG}" stroke="{BACK_BORDER}" stroke-width="2"/>
<rect x="1" y="1" width="254" height="382" rx="16" ry="16"
fill="url(#scanlines)"/>
<!-- Top-left accent badge (the only theme-varying element). -->
<rect x="12" y="12" width="24" height="32" fill="{accent}"/>
<!-- Bottom-right "▌RS" monogram in JetBrains-Mono-styled FiraMono. -->
<text x="244" y="368" font-family="Fira Mono" font-size="24"
fill="{BACK_MONOGRAM}" text-anchor="end">&#x258C;RS</text>
</svg>"##
)
}
fn rasterize_to_pixmap(svg: &str) -> Pixmap {
let image = rasterize_svg(svg.as_bytes(), TARGET).expect("rasterise card SVG");
let bytes = image.data.expect("rasterised image carries pixel data");
solitaire_engine/src/assets/card_face_svg.rs
+210
View File
@@ -0,0 +1,210 @@
//! SVG builders for the Terminal-aesthetic card-face artwork.
//!
//! Used by the `card_face_generator` example to emit the 52 face PNGs +
//! 5 back PNGs into `assets/cards/`, and by the `card_face_svg_pin`
//! integration test to pin the rendered output against `usvg`/`resvg`
//! drift.
//!
//! The numbers below are 2× the `design-system.md` § Game Cards
//! logical sizes — the spec describes a 128 × 192 logical card and
//! this module emits at 256 × 384.
//!
//! See `docs/ui-mockups/card-face-migration.md` for the full
//! migration plan and the rationale behind the output dimensions
//! and palette mapping.
//!
//! # Filled vs outlined glyphs
//!
//! Hearts (♥) and spades (♠) render as filled glyphs. Diamonds (♦)
//! and clubs (♣) render as outlined glyphs (1.5 px stroke at logical
//! scale → 3 px at output). This is the design-system's "always-on"
//! color-blind glyph differentiation and is independent of the
//! red/black colour split.
use bevy::math::UVec2;
use solitaire_core::card::{Rank, Suit};
/// Target rasterisation size in pixels (2:3 aspect, half the default
/// `SvgLoaderSettings` resolution).
pub const TARGET: UVec2 = UVec2::new(256, 384);
const BG_FACE: &str = "#1a1a1a"; // BG_ELEVATED — face background
const SUIT_RED: &str = "#fb9fb1"; // hearts + diamonds
const SUIT_DARK: &str = "#d0d0d0"; // spades + clubs (also TEXT_PRIMARY)
const BACK_BG: &str = "#151515";
const BACK_SCANLINE: &str = "#1a1a1a";
const BACK_BORDER: &str = "#353535";
const BACK_MONOGRAM: &str = "#505050";
/// Five back-theme accent colours. Slot 0 is the canonical "Terminal"
/// back from the design system; the other four cycle through the
/// remaining base16-eighties accents so all 5 slots stay visually
/// distinct without leaving the palette.
pub const BACK_ACCENTS: [&str; 5] = [
"#6fc2ef", // 0 — cyan (Terminal canonical)
"#acc267", // 1 — lime
"#e1a3ee", // 2 — lavender
"#fb9fb1", // 3 — pink
"#ddb26f", // 4 — gold
];
/// Every rank in the canonical Ace → King order. Mirrors the order
/// `card_plugin::load_card_images` uses to index `CardImageSet.faces`.
pub const ALL_RANKS: [Rank; 13] = [
Rank::Ace,
Rank::Two,
Rank::Three,
Rank::Four,
Rank::Five,
Rank::Six,
Rank::Seven,
Rank::Eight,
Rank::Nine,
Rank::Ten,
Rank::Jack,
Rank::Queen,
Rank::King,
];
/// Every suit in `Clubs, Diamonds, Hearts, Spades` order — matches
/// `card_plugin::load_card_images` so the suit index used here lines
/// up with `CardImageSet.faces[suit]`.
pub const ALL_SUITS: [Suit; 4] = [Suit::Clubs, Suit::Diamonds, Suit::Hearts, Suit::Spades];
/// The rank component of the on-disk filename — `A`, `2`..`10`, `J`,
/// `Q`, `K`. Matches `card_plugin::load_card_images`'s `RANK_STRS`.
pub fn rank_filename(rank: Rank) -> &'static str {
match rank {
Rank::Ace => "A",
Rank::Two => "2",
Rank::Three => "3",
Rank::Four => "4",
Rank::Five => "5",
Rank::Six => "6",
Rank::Seven => "7",
Rank::Eight => "8",
Rank::Nine => "9",
Rank::Ten => "10",
Rank::Jack => "J",
Rank::Queen => "Q",
Rank::King => "K",
}
}
/// The suit component of the on-disk filename — `C`, `D`, `H`, `S`.
/// Matches `card_plugin::load_card_images`'s `SUIT_CHARS`.
pub fn suit_filename(suit: Suit) -> &'static str {
match suit {
Suit::Clubs => "C",
Suit::Diamonds => "D",
Suit::Hearts => "H",
Suit::Spades => "S",
}
}
#[derive(Copy, Clone)]
enum GlyphPaint {
Filled,
/// 1.5 px stroke at logical scale → 3 px at 2× output.
Outlined,
}
fn suit_paint(suit: Suit) -> (&'static str, GlyphPaint) {
match suit {
Suit::Hearts => (SUIT_RED, GlyphPaint::Filled),
Suit::Diamonds => (SUIT_RED, GlyphPaint::Outlined),
Suit::Spades => (SUIT_DARK, GlyphPaint::Filled),
Suit::Clubs => (SUIT_DARK, GlyphPaint::Outlined),
}
}
fn glyph_paint_attrs(colour: &str, paint: GlyphPaint) -> String {
match paint {
GlyphPaint::Filled => format!(r#"fill="{colour}""#),
GlyphPaint::Outlined => {
format!(r#"fill="none" stroke="{colour}" stroke-width="3""#)
}
}
}
fn suit_glyph(suit: Suit) -> &'static str {
match suit {
Suit::Clubs => "&#x2663;",
Suit::Diamonds => "&#x2666;",
Suit::Hearts => "&#x2665;",
Suit::Spades => "&#x2660;",
}
}
/// Build the SVG markup for a single face card. The output is a
/// self-contained, parsable SVG document.
pub fn face_svg(rank: Rank, suit: Suit) -> String {
let (colour, paint) = suit_paint(suit);
let glyph = suit_glyph(suit);
let rank_text = rank_filename(rank);
let small_glyph_attrs = glyph_paint_attrs(colour, paint);
let large_glyph_attrs = glyph_paint_attrs(colour, paint);
// Numbers come from `design-system.md` § Game Cards, scaled 2×:
// border: 1 px → 2 px stroke-width
// corner radius: 8 px → 16 px rx/ry
// rank font: 18 px → 36 px
// small glyph: 10 px → 20 px
// large glyph: 32 px → 64 px
//
// Inset the border by 1 px so the 2 px stroke renders fully
// inside the 256 × 384 pixmap rather than getting clipped.
format!(
r##"<svg xmlns="http://www.w3.org/2000/svg" width="256" height="384" viewBox="0 0 256 384">
<rect x="1" y="1" width="254" height="382" rx="16" ry="16"
fill="{BG_FACE}" stroke="{colour}" stroke-width="2"/>
<!-- Top-left rank + small suit glyph. -->
<text x="14" y="44" font-family="Fira Mono" font-size="36" font-weight="700"
fill="{colour}">{rank_text}</text>
<text x="14" y="68" font-family="Fira Mono" font-size="20"
{small_glyph_attrs}>{glyph}</text>
<!-- Bottom-right large suit glyph, rotated 180° about its own
baseline anchor so the glyph reads upside-down. -->
<text x="242" y="350" font-family="Fira Mono" font-size="64"
text-anchor="end" {large_glyph_attrs}
transform="rotate(180 242 332)">{glyph}</text>
</svg>"##
)
}
/// Build the SVG markup for a card back with the canonical Terminal
/// scanline pattern. `accent` swaps only the top-left badge.
pub fn back_svg(accent: &str) -> String {
// Scanline tile: 1 px line + 1 px gap at logical scale → 2 px +
// 2 px at 2× output. `patternUnits="userSpaceOnUse"` so the tile
// size is in viewBox pixels rather than fractions of the box.
//
// Badge: 12 × 16 px logical → 24 × 32 px output, 12 px from corner.
// Monogram: "▌RS" in 12 px logical → 24 px output, 12 px inset.
format!(
r##"<svg xmlns="http://www.w3.org/2000/svg" width="256" height="384" viewBox="0 0 256 384">
<defs>
<pattern id="scanlines" x="0" y="0" width="2" height="4" patternUnits="userSpaceOnUse">
<rect x="0" y="0" width="2" height="2" fill="{BACK_SCANLINE}"/>
</pattern>
</defs>
<!-- Background fill, then scanlines on top (the scanlines stay
darker than BACK_BG so the "off" rows show through). -->
<rect x="1" y="1" width="254" height="382" rx="16" ry="16"
fill="{BACK_BG}" stroke="{BACK_BORDER}" stroke-width="2"/>
<rect x="1" y="1" width="254" height="382" rx="16" ry="16"
fill="url(#scanlines)"/>
<!-- Top-left accent badge (the only theme-varying element). -->
<rect x="12" y="12" width="24" height="32" fill="{accent}"/>
<!-- Bottom-right "▌RS" monogram in JetBrains-Mono-styled FiraMono. -->
<text x="244" y="368" font-family="Fira Mono" font-size="24"
fill="{BACK_MONOGRAM}" text-anchor="end">&#x258C;RS</text>
</svg>"##
)
}
solitaire_engine/src/assets/mod.rs
+1
View File
@@ -6,6 +6,7 @@
//! (user-themes directory). Phase 3 will extend it further with custom
//! `AssetSource` implementations for `embedded://` and `themes://`.
pub mod card_face_svg;
pub mod sources;
pub mod svg_loader;
pub mod user_dir;
solitaire_engine/tests/card_face_svg_pin.rs
+175
View File
@@ -0,0 +1,175 @@
//! Pinning test for the Terminal card-face SVG builders.
//!
//! Hashes the raw RGBA8 pixel bytes produced by rasterising every
//! `face_svg` × `back_svg` output through `assets::rasterize_svg`,
//! and compares each hash to an embedded constant. Catches silent
//! rendering drift if `usvg`, `resvg`, `tiny_skia`, or the bundled
//! `FiraMono` font ever change in a way that perturbs the rendered
//! pixels.
//!
//! When the SVG builders intentionally change (or a dependency
//! upgrade legitimately changes rendering), update `EXPECTED` by
//! emptying it (`&[]`) and re-running this test once — the test
//! will panic with the new hashes formatted as Rust source ready
//! to paste back in.
//!
//! Hashing is FNV-1a 64-bit on the raw RGBA byte buffer. PNG
//! compression is intentionally not in the loop — we only want
//! the test to fire on actual pixel changes, not zlib-level
//! shifts that don't affect what a player sees.
use solitaire_engine::assets::card_face_svg::{
back_svg, face_svg, rank_filename, suit_filename, ALL_RANKS, ALL_SUITS, BACK_ACCENTS, TARGET,
};
use solitaire_engine::assets::rasterize_svg;
const EXPECTED: &[(&str, u64)] = &[
("face_AC", 0xca11dff5bb9f0eb0),
("face_2C", 0xc929a25f0f217577),
("face_3C", 0xdaede8383266b5c3),
("face_4C", 0xeaa3ea51866f69e5),
("face_5C", 0xe5a74589cb09cc5c),
("face_6C", 0xdbbc1036895ee08e),
("face_7C", 0xb8a28119a85ccf5d),
("face_8C", 0xab4d19ce4b8d15e7),
("face_9C", 0x17c95eb07f382059),
("face_10C", 0x1f1b2c84e42211b1),
("face_JC", 0xd87c45124df8b03d),
("face_QC", 0xe23701b6685994b2),
("face_KC", 0xc628e55b8a15472a),
("face_AD", 0x49a140d84b0a731b),
("face_2D", 0x713f755b5ecfb67a),
("face_3D", 0xe59a72abc47af7d4),
("face_4D", 0xf75ac828822079d1),
("face_5D", 0x6db0cc9a5849395f),
("face_6D", 0x9b034cf6851512de),
("face_7D", 0x85f96e0326780a6e),
("face_8D", 0x59ec5533b615ecd4),
("face_9D", 0x3689911671b30921),
("face_10D", 0x682684217e3e8b60),
("face_JD", 0xd999f85e6862c5a7),
("face_QD", 0x6db493a3b370b211),
("face_KD", 0x4c2ec19166fdee7b),
("face_AH", 0x0d41c498281b9a74),
("face_2H", 0xec6493b71d4576b1),
("face_3H", 0xd2fb4b5956caf15b),
("face_4H", 0xfbe8e1eaa2b28c5a),
("face_5H", 0x649a0964e549f008),
("face_6H", 0xa10fa42b5549fc85),
("face_7H", 0x6823107295c149b5),
("face_8H", 0x474d2de14865e65b),
("face_9H", 0x1b0de1af8dae108a),
("face_10H", 0x451fd5855859c9d7),
("face_JH", 0xd821a7d4c79a37e0),
("face_QH", 0xde0c6ef7e963861a),
("face_KH", 0xe29039cb6a115214),
("face_AS", 0x1697fbcc61b64e0f),
("face_2S", 0x5ada7ea3e39547d0),
("face_3S", 0x6d8eed531f2d659c),
("face_4S", 0x1b1a2d25e080d71e),
("face_5S", 0x5eb82baa4f9a74bb),
("face_6S", 0xa00b217892d32ead),
("face_7S", 0xaf60935ec8d93346),
("face_8S", 0xffbde852d8699a80),
("face_9S", 0x8f68afa04b88e1a2),
("face_10S", 0x96fa4a08f168210a),
("face_JS", 0x73030a8109b5b5e6),
("face_QS", 0x303eb6c33e363cc1),
("face_KS", 0x3ed5b5a9432c91e9),
("back_0", 0xf698d0e161eae13a),
("back_1", 0x446fdc0a3c83a03a),
("back_2", 0xcf188fdec9f5819a),
("back_3", 0xcaffd02af141743a),
("back_4", 0xcee8a700bbaaf71a),
];
#[test]
fn rasterised_card_bytes_match_pinned_hashes() {
let actual = compute_actual_hashes();
if EXPECTED.is_empty() {
panic_with_hashes_to_paste(&actual);
}
assert_eq!(
actual.len(),
EXPECTED.len(),
"card-output count drifted (actual {} vs expected {})",
actual.len(),
EXPECTED.len(),
);
let mut mismatches: Vec<String> = Vec::new();
for ((actual_name, actual_hash), (expected_name, expected_hash)) in
actual.iter().zip(EXPECTED.iter())
{
assert_eq!(
actual_name, expected_name,
"card-output naming/order drifted",
);
if actual_hash != expected_hash {
mismatches.push(format!(
" {actual_name}: actual 0x{actual_hash:016x} expected 0x{expected_hash:016x}",
));
}
}
if !mismatches.is_empty() {
let mut msg = String::from(
"rasterised card bytes drifted from EXPECTED — usvg/resvg/tiny_skia/font upgrade?\n",
);
for m in &mismatches {
msg.push_str(m);
msg.push('\n');
}
msg.push_str(
"\nIf this drift is intentional, replace EXPECTED with `&[]` and re-run\nthis test to print fresh hashes.\n",
);
panic!("{msg}");
}
}
fn compute_actual_hashes() -> Vec<(String, u64)> {
let mut out = Vec::with_capacity(ALL_RANKS.len() * ALL_SUITS.len() + BACK_ACCENTS.len());
for suit in ALL_SUITS {
for rank in ALL_RANKS {
let name = format!("face_{}{}", rank_filename(rank), suit_filename(suit));
out.push((name, hash_rasterised(&face_svg(rank, suit))));
}
}
for (idx, accent) in BACK_ACCENTS.iter().enumerate() {
out.push((format!("back_{idx}"), hash_rasterised(&back_svg(accent))));
}
out
}
fn hash_rasterised(svg: &str) -> u64 {
let image = rasterize_svg(svg.as_bytes(), TARGET).expect("rasterise card SVG");
let bytes = image.data.expect("rasterised image carries RGBA pixel data");
fnv1a(&bytes)
}
/// FNV-1a 64-bit. Inline rather than a dependency — adding `sha2`
/// or `blake3` for ~5 lines of code would burn a CLAUDE.md §8
/// "ask before adding deps" round-trip for no real benefit.
/// Cryptographic strength isn't load-bearing here — we just need
/// stable byte fingerprints.
fn fnv1a(bytes: &[u8]) -> u64 {
let mut h: u64 = 0xcbf2_9ce4_8422_2325;
for &b in bytes {
h ^= b as u64;
h = h.wrapping_mul(0x0000_0100_0000_01b3);
}
h
}
fn panic_with_hashes_to_paste(actual: &[(String, u64)]) -> ! {
let mut out = String::from(
"\nEXPECTED is empty — paste the following into the const literal:\n\nconst EXPECTED: &[(&str, u64)] = &[\n",
);
for (name, hash) in actual {
out.push_str(&format!(" (\"{name}\", 0x{hash:016x}),\n"));
}
out.push_str("];\n");
panic!("{out}");
}