refactor(engine): move the page filters to page_filter.rs

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/lib.rs

@@ -38,6 +38,7 @@ pub mod links;
 pub mod ocr;
 mod open;
 pub mod optimizer;
+mod page_filter;
 mod pictures;
 pub mod print_raster;
 pub mod printcheck;
@@ -162,6 +163,7 @@ pub use fill_sign::{displayed_offset, text_box_at, typed_signature_graphic, type
 pub use history::Label;
 use layers::{apply_layer_state, set_default_layer_state, use_layer_choices};
 pub use open::{OpenContext, PreparedDocument};
+pub use page_filter::{PageOrientation, PageParity, filter_pages};
 pub use pictures::MarkFile;
 use pictures::{embed_image, fit_picture, mark_source};
 use protection::unrestricted;
@@ -269,43 +271,3 @@ pub struct OptimizeReport {
 
 #[cfg(test)]
 mod tests;
-
-/// Page filters of Acrobat's Rotate Pages and page selection: even/odd page numbers and
-/// orientation (as displayed).
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
-pub enum PageParity {
-    #[default]
-    Both,
-    Even,
-    Odd,
-}
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
-pub enum PageOrientation {
-    #[default]
-    Both,
-    Landscape,
-    Portrait,
-}
-
-/// The pages of `pages` (0-based) that pass the filters.
-pub fn filter_pages(info: &pdfcraft_render::DocInfo, pages: &[usize], parity: PageParity, orientation: PageOrientation) -> Vec<usize> {
-    pages
-        .iter()
-        .copied()
-        .filter(|p| match parity {
-            PageParity::Both => true,
-            // Page numbers are 1-based: index 1 is page 2, an even page.
-            PageParity::Even => p % 2 == 1,
-            PageParity::Odd => p % 2 == 0,
-        })
-        .filter(|p| {
-            let Some(pg) = info.pages.get(*p) else { return false };
-            match orientation {
-                PageOrientation::Both => true,
-                PageOrientation::Landscape => pg.width > pg.height,
-                PageOrientation::Portrait => pg.width <= pg.height,
-            }
-        })
-        .collect()
-}

crates/engine/src/page_filter.rs

@@ -0,0 +1,41 @@
+//! Page filters: even or odd page numbers, and orientation as displayed.
+
+/// Page filters of Acrobat's Rotate Pages and page selection: even/odd page numbers and
+/// orientation (as displayed).
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
+pub enum PageParity {
+    #[default]
+    Both,
+    Even,
+    Odd,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
+pub enum PageOrientation {
+    #[default]
+    Both,
+    Landscape,
+    Portrait,
+}
+
+/// The pages of `pages` (0-based) that pass the filters.
+pub fn filter_pages(info: &pdfcraft_render::DocInfo, pages: &[usize], parity: PageParity, orientation: PageOrientation) -> Vec<usize> {
+    pages
+        .iter()
+        .copied()
+        .filter(|p| match parity {
+            PageParity::Both => true,
+            // Page numbers are 1-based: index 1 is page 2, an even page.
+            PageParity::Even => p % 2 == 1,
+            PageParity::Odd => p % 2 == 0,
+        })
+        .filter(|p| {
+            let Some(pg) = info.pages.get(*p) else { return false };
+            match orientation {
+                PageOrientation::Both => true,
+                PageOrientation::Landscape => pg.width > pg.height,
+                PageOrientation::Portrait => pg.width <= pg.height,
+            }
+        })
+        .collect()
+}