From d5b919e17f685246e99e008997de897b0534fee4 Mon Sep 17 00:00:00 2001
From: mtlcl410 <chuanlin@niar.org.tw>
Date: Sun, 8 Nov 2026 12:09:47 +0800
Subject: [PATCH] fix(render): the allowance threshold in the failed-decode
 test is found by a binary search over the first page (hayro-interpret patch
 91)

Tests only: the search for the smallest JBIG2 allowance that draws the first picture renders the
first page alone and halves the range, about ten draws instead of up to two thousand.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCHD1R3rywQBPCHXZA
---
 .../src/raster/tests/failed_image_decodes.rs  | 28 +++++++++++--------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/crates/render/src/raster/tests/failed_image_decodes.rs b/crates/render/src/raster/tests/failed_image_decodes.rs
index 60b5e9f59e..48f76c29d6 100644
--- a/crates/render/src/raster/tests/failed_image_decodes.rs
+++ b/crates/render/src/raster/tests/failed_image_decodes.rs
@@ -210,20 +210,26 @@ fn a_picture_left_out_for_the_pages_allowance_draws_on_the_next_page() {
         [255, 255, 255, 255] => false,
         other => panic!("neither an image nor the page: {other:?}"),
     };
-    // Both pages through one cache, as a render worker keeps it.
-    let pages = |work: u64| {
+    // Both pages, or the first alone, through one cache, as a render worker keeps it.
+    let pages = |work: u64, count: usize| {
         let config = RenderConfig { jbig2_work: Some(work), ..RenderConfig::default() };
         let cache = RenderCache::new();
-        [0, 1].map(|page| {
-            let warnings = Arc::new(Mutex::new(Vec::new()));
-            let settings = warning_settings(&config.settings(), warnings.clone());
-            let req = RenderRequest { page, kind: RequestKind::Pixels, tile: None, scale: 1.0, tag: 0, ..Default::default() };
-            let (_, _, rgba, _) = render_page(&pdf, &cache, &settings, &config, req).expect("renders");
-            (rgba[..].to_vec(), take_warnings(&warnings))
-        })
+        (0..count)
+            .map(|page| {
+                let warnings = Arc::new(Mutex::new(Vec::new()));
+                let settings = warning_settings(&config.settings(), warnings.clone());
+                let req = RenderRequest { page, kind: RequestKind::Pixels, tile: None, scale: 1.0, tag: 0, ..Default::default() };
+                let (_, _, rgba, _) = render_page(&pdf, &cache, &settings, &config, req).expect("renders");
+                (rgba[..].to_vec(), take_warnings(&warnings))
+            })
+            .collect::<Vec<Drawn>>()
     };
-    let one = (1..1_000).find(|work| black(&pages(*work)[0], 10)).expect("a small image is cheap");
-    let [first, second] = pages(one);
+    // The smallest allowance that draws A on the first page. A larger allowance draws at least as
+    // much, so a binary search over the first page alone finds it in about ten draws.
+    let draws_a = |work: u64| pages(work, 1).first().is_some_and(|first| black(first, 10));
+    let candidates: Vec<u64> = (1..1_000).collect();
+    let one = candidates.get(candidates.partition_point(|work| !draws_a(*work))).copied().expect("a small image is cheap");
+    let Ok([first, second]) = <[Drawn; 2]>::try_from(pages(one, 2)) else { panic!("two pages") };
     assert_eq!((black(&first, 10), black(&first, 30)), (true, false), "the first page had enough for A alone");
     assert!(first.1.contains(&RenderWarning::ContentTruncated), "{:?}", first.1);
     assert!(black(&second, 30), "B, left out of the first page, draws on the second");