Review: report module beside rasterfx, ids checked without a tree walk, docs trimmed (#1147)

The report module moves to cmd/rasterfx/report.rs (the crate's foo.rs +
foo/ layout instead of #[path]). An object is the document's when its id
is below the document's next id, so building the report no longer walks
the whole document (and its symbols and patterns) on every PDF, SVG,
print and clipboard export. The parity docs say what changed in the
status line and one evidence bullet instead of a separate paragraph.

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

crates/engine/src/cmd/rasterfx.rs

@@ -26,7 +26,6 @@ use vectorcraft_render::{AntiAlias, RenderOptions};
 
 use super::*;
 
-#[path = "rasterfx_report.rs"]
 mod report;
 use report::FlattenReport;
 

crates/engine/src/cmd/rasterfx/report.rs

@@ -1,4 +1,5 @@
-use std::collections::HashSet;
+//! The PDF export warnings for raster effects whose images the 64 million pixel cap rendered below
+//! the document's raster effects resolution, one per object of the document.
 
 use vectorcraft_doc::{Document, Node, NodeId, NodeKind};
 
@@ -8,7 +9,8 @@ pub(super) struct FlattenReport {
     pub which: Which,
     requested_ppi: f64,
     reductions: Vec<Reduction>,
-    originals: HashSet<NodeId>,
+    /// Ids from here on are the flattening's own (split appearance items, groups under shadows).
+    first_new_id: u64,
 }
 
 struct Reduction {
@@ -19,13 +21,10 @@ struct Reduction {
 
 impl FlattenReport {
     pub fn new(which: Which, doc: &Document) -> Self {
-        let mut originals = HashSet::new();
-        for node in doc.layers.iter().chain(doc.symbols.iter().map(|s| &s.art)).chain(doc.patterns.iter().flat_map(|p| &p.art)) {
-            collect_ids(node, &mut originals);
-        }
-        Self { which, requested_ppi: super::effects_scale(doc) * 72.0, reductions: vec![], originals }
+        Self { which, requested_ppi: super::effects_scale(doc) * 72.0, reductions: vec![], first_new_id: doc.peek_next_id() }
     }
 
+    /// Note `image` (made for the raster effects of `original`) when the cap lowered its resolution.
     pub fn record(&mut self, original: &Node, image: &Node) {
         if let NodeKind::Image(image) = &image.kind {
             let [pixel_size, ..] = image.xf.as_coeffs();
@@ -40,12 +39,15 @@ impl FlattenReport {
         self.reductions.len()
     }
 
+    /// Give the reductions recorded since `checkpoint` on pieces the flattening made to `original`,
+    /// a document object (the innermost one, as the walk returns from it).
     pub fn attribute_since(&mut self, checkpoint: usize, original: &Node) {
-        if !self.originals.contains(&original.id) {
+        let first_new_id = self.first_new_id;
+        if original.id.0 >= first_new_id {
             return;
         }
         for reduction in self.reductions.iter_mut().skip(checkpoint) {
-            if !self.originals.contains(&reduction.id) {
+            if reduction.id.0 >= first_new_id {
                 reduction.id = original.id;
                 reduction.name.clone_from(&original.name);
             }
@@ -74,16 +76,6 @@ impl FlattenReport {
     }
 }
 
-fn collect_ids(node: &Node, ids: &mut HashSet<NodeId>) {
-    ids.insert(node.id);
-    for child in node.children().into_iter().flatten() {
-        collect_ids(child, ids);
-    }
-    if let Some(mask) = &node.mask {
-        collect_ids(&mask.art, ids);
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;