.ai import: a PDF part cropped to the art no longer hides the layers

A PDF-compatible .ai whose PDF part's pages are cropped to its art (each
page the box of all the art, the editing data's bounding box) rather
than to its artboards came in as that PDF part: the editing data's
artboard wasn't the page's size, so its layers were refused. With
several artboards every page held all the art, so the document had a
copy of everything per page.

When the artboard isn't the page's size but the editing data's bounding
box is, the layers are compared with the page on that box and keep
their artboards. The comparison of their art with the page still
decides whether they are used.

crates/engine/src/cmd/fileio/tests_aiimport.rs

@@ -535,6 +535,27 @@ fn an_ai_file_whose_pdf_part_is_only_text_still_opens_from_editing_data_that_rea
     check_sample(&s);
 }
 
+#[test]
+fn an_ai_file_whose_pdf_part_is_cropped_to_its_art_opens_from_its_layers() {
+    // A 400 × 200 pt artboard with two red bars across (100, 50)–(300, 150). The PDF part's page
+    // is that art's box, 200 × 100 pt (the editing data's bounding box), not the artboard.
+    let red = "0 1 1 0 1 0 0 Xa\n";
+    let art = ai::layer("Art", &format!("{red}{}f\n{red}{}f\n", ai::rect(100.0, 50.0, 180.0, 150.0), ai::rect(220.0, 50.0, 300.0, 150.0)));
+    let data = ai::editing_data_in([100.0, 50.0, 300.0, 150.0], [0.0, 0.0, 400.0, 200.0], &art);
+    let page = "1 0 0 rg 0 0 80 100 re f 120 0 80 100 re f";
+    let mut s = Session::new();
+    let r = open(&mut s, "cropped.ai", &ai::ai(&compressed(data.as_bytes()), page), json!({})).unwrap();
+    assert!(!r["warnings"].to_string().contains("weren't read"), "{r}");
+    let doc = &s.doc().unwrap().doc;
+    assert_eq!(names(&doc.layers), ["Art"]);
+    assert_eq!(doc.artboards.len(), 1);
+    assert_eq!(doc.artboards[0].rect, vectorcraft_geom::Rect::new(0.0, 0.0, 400.0, 200.0), "the file's artboard, not its page");
+    let bars = doc.layers[0].children().unwrap();
+    assert_eq!(bars.len(), 2);
+    let b = bars[0].geometric_bounds().unwrap();
+    assert!((b.x0 - 100.0).abs() < 0.01 && (b.y0 - 50.0).abs() < 0.01, "where the artboard has it: {b:?}");
+}
+
 #[test]
 fn editing_data_false_opens_only_what_the_page_prints() {
     let mut s = Session::new();