fix(ui): bookmark, comment and command filters match Turkish İ/ı in any case (#937)

The bookmark filter, the Comments panel filter and the command palette
lowercased with str::to_lowercase, which follows no locale: "İSTANBUL"
became "i̇stanbul" (a combining dot added) and "ı" has no case pair, so
"istanbul" never found the bookmark "İSTANBUL ŞUBESİ" and "imzalayın" never
found a comment "Lütfen İMZALAYIN".

They now fold with pdfcraft_render::text::fold_case, the folding Find and
Search & Redact use (made public here): I, i, İ and ı count as one letter
and every other character folds to its own lowercase.

crates/render/src/text.rs

@@ -37,7 +37,7 @@ pub struct TextGlyph {
 /// combining dot (two characters) and leaves `ı` alone, so neither `İSTANBUL` nor `IRMAK` could
 /// be found by typing `istanbul` or `ırmak`. Search can't know the document's language, so the
 /// four are treated as one letter; this only adds matches where an `ı` or `İ` is involved.
-fn fold_case(s: &str) -> String {
+pub fn fold_case(s: &str) -> String {
     let mut out = String::with_capacity(s.len());
     for c in s.chars() {
         match c {

crates/ui-egui/src/comments_panel.rs

@@ -90,8 +90,13 @@ pub fn count(info: &DocInfo) -> usize {
 }
 
 fn matches(a: &Annotation, q: &str) -> bool {
-    let q = q.to_lowercase();
-    [a.author.as_deref(), a.contents.as_deref(), Some(kind_label(a))].into_iter().flatten().any(|s| s.to_lowercase().contains(&q))
+    any_contains([a.author.as_deref(), a.contents.as_deref(), Some(kind_label(a))].into_iter().flatten(), q)
+}
+
+/// Whether one of `fields` contains `q` in any case, Turkish dotted and dotless i included.
+fn any_contains<'a>(fields: impl IntoIterator<Item = &'a str>, q: &str) -> bool {
+    let q = pdfcraft_render::text::fold_case(q);
+    fields.into_iter().any(|s| pdfcraft_render::text::fold_case(s).contains(&q))
 }
 
 /// Draw the panel body. Returns an edit to apply (posting, replying, deleting…).
@@ -588,3 +593,17 @@ pub(crate) fn header_controls(ui: &mut egui::Ui, info: &DocInfo, view: &mut DocV
     });
     command
 }
+
+#[cfg(test)]
+mod filter {
+    use super::any_contains;
+
+    #[test]
+    fn comments_match_in_any_case_with_turkish_i() {
+        assert!(any_contains(["Ayşe Yılmaz", "Lütfen İMZALAYIN"], "imzalayın"));
+        assert!(any_contains(["Ayşe Yılmaz"], "YILMAZ"));
+        assert!(any_contains(["IRMAK"], "ırmak"));
+        assert!(any_contains(["Note"], "NOTE"));
+        assert!(!any_contains(["Ayşe Yılmaz"], "mehmet"));
+    }
+}

crates/ui-egui/src/palette.rs

@@ -17,11 +17,12 @@ struct Hit {
     ready: bool,
 }
 
+/// Where `needle` (folded with [`pdfcraft_render::text::fold_case`]) matches `hay`, for ranking.
 fn score(hay: &str, needle: &str) -> Option<usize> {
     if needle.is_empty() {
         return Some(0);
     }
-    let h = hay.to_lowercase();
+    let h = pdfcraft_render::text::fold_case(hay);
     if let Some(p) = h.find(needle) {
         return Some(p);
     }
@@ -48,7 +49,7 @@ pub fn show(app: &mut PdfCraftApp, ctx: &egui::Context) {
         app.palette_open = false;
         return;
     }
-    let q = app.palette_query.trim().to_lowercase();
+    let q = pdfcraft_render::text::fold_case(app.palette_query.trim());
     let mut hits: Vec<(usize, Hit)> = Vec::new();
     let active = app.active_ids().map(|(_, id)| id);
     for spec in pdfcraft_engine::commands::COMMANDS {
@@ -192,3 +193,18 @@ pub fn show(app: &mut PdfCraftApp, ctx: &egui::Context) {
         }
     }
 }
+
+#[cfg(test)]
+mod search {
+    use super::score;
+    use pdfcraft_render::text::fold_case;
+
+    #[test]
+    fn commands_match_in_any_case_with_turkish_i() {
+        assert_eq!(score("İçe aktar", &fold_case("içe")), Some(0));
+        assert_eq!(score("Yazdır", &fold_case("YAZDIR")), Some(0));
+        assert_eq!(score("Insert Pages", &fold_case("ınsert")), Some(0));
+        assert_eq!(score("Print", &fold_case("print")), Some(0));
+        assert_eq!(score("Print", &fold_case("zz")), None);
+    }
+}

crates/ui-egui/src/panels.rs

@@ -514,7 +514,7 @@ pub fn right_panel(app: &mut PdfCraftApp, ui: &mut egui::Ui) {
                     ui.data_mut(|d| d.insert_temp(search_id, bookmark_query.clone()));
                     ui.add_space(6.0);
                 }
-                let bookmark_query = bookmark_query.trim().to_lowercase();
+                let bookmark_query = pdfcraft_render::text::fold_case(bookmark_query.trim());
                 let mut bookmark_matches =
                     if panel == RightPanel::Bookmarks { outline_matches(&info.outline, &bookmark_query) } else { std::collections::HashSet::new() };
                 // A new bookmark must stay nameable even when its initial title doesn't match.
@@ -730,6 +730,7 @@ pub enum BmAction {
 }
 
 /// Matching titles plus their ancestors, keeping document paths rather than filtered indexes.
+/// `query` is folded with [`pdfcraft_render::text::fold_case`], as titles are here.
 fn outline_matches(items: &[OutlineItem], query: &str) -> std::collections::HashSet<Vec<usize>> {
     let mut matches = std::collections::HashSet::new();
     if query.is_empty() {
@@ -737,7 +738,7 @@ fn outline_matches(items: &[OutlineItem], query: &str) -> std::collections::Hash
     }
     let mut pending: Vec<_> = items.iter().enumerate().map(|(i, item)| (vec![i], item)).collect();
     while let Some((path, item)) = pending.pop() {
-        if item.title.to_lowercase().contains(query) {
+        if pdfcraft_render::text::fold_case(&item.title).contains(query) {
             let mut ancestor = path.clone();
             while !ancestor.is_empty() {
                 matches.insert(ancestor.clone());
@@ -1313,3 +1314,25 @@ mod label_column {
         assert!(shown.ends_with('\u{2026}') && label.starts_with(shown.trim_end_matches('\u{2026}')), "{shown:?}");
     }
 }
+
+#[cfg(test)]
+mod bookmark_filter {
+    use super::outline_matches;
+    use pdfcraft_render::OutlineItem;
+
+    fn item(title: &str, children: Vec<OutlineItem>) -> OutlineItem {
+        OutlineItem { title: title.into(), page: Some(0), view: pdfcraft_render::DestView::Top, children, open: true }
+    }
+
+    /// Turkish dotted and dotless i match in any case, as in Find (#892).
+    #[test]
+    fn titles_match_in_any_case_with_turkish_i() {
+        let outline = [item("İSTANBUL ŞUBESİ", vec![item("Kış dönemi", vec![])]), item("Ankara", vec![])];
+        let fold = pdfcraft_render::text::fold_case;
+        assert_eq!(outline_matches(&outline, &fold("istanbul")).len(), 1);
+        assert_eq!(outline_matches(&outline, &fold("şubesi")).len(), 1);
+        // A child match keeps its parent: [0] and [0, 0].
+        assert_eq!(outline_matches(&outline, &fold("KIŞ")).len(), 2);
+        assert!(outline_matches(&outline, &fold("izmir")).is_empty());
+    }
+}