fix(edit): restore inherited text state when arranging Forms

Track the text-state operators with saved drawing state, restoring inherited spacing, scaling, leading, rendering mode, rise and known font before relocated Form artwork. Emit restoration inside BT/ET, and leave a font selected by a replayed ExtGState authoritative over an older direct Tf. The exact inherited 12 Tc fixture failed its saved-PDF raster comparison before this fix; zero-spacing and destination-state controls now preserve rendering. Scoped Linux native, wasm, clippy and formatting checks pass.

Co-Authored-By: Codex GPT-6.1 <noreply@openai.com>

crates/edit/src/images.rs

@@ -763,14 +763,14 @@ impl ExtendedGStateTracker {
 }
 
 /// The drawing-state operators besides colour that a moved unit restores, in the order it writes them.
-const DRAWING_PARAMS: [&str; 7] = ["w", "J", "j", "M", "d", "ri", "i"];
+const DRAWING_PARAMS: [&str; 14] = ["w", "J", "j", "M", "d", "ri", "i", "Tc", "Tw", "Tz", "TL", "Tr", "Ts", "Tf"];
 
 #[derive(Clone, Default, Debug, PartialEq)]
 struct DrawingState {
     non_stroking_color: Option<SharedColorOps>,
     stroking_color: Option<SharedColorOps>,
     /// The last operator of each of [`DRAWING_PARAMS`].
-    params: [Option<std::rc::Rc<Op>>; 7],
+    params: [Option<std::rc::Rc<Op>>; DRAWING_PARAMS.len()],
 }
 
 // Save/restore shares operand storage, including when only the current colour changes under q.
@@ -822,7 +822,7 @@ impl DrawingStateTracker {
     }
 }
 
-/// Initial line-style parameters and rendering intent (ISO 32000-2 Table 51).
+/// Initial line style, rendering intent and text-state parameters.
 fn initial_param(name: &str) -> Option<Op> {
     use pdfcraft_content::num;
     let operands = match name {
@@ -831,6 +831,8 @@ fn initial_param(name: &str) -> Option<Op> {
         "M" => vec![num(10.0)],
         "d" => vec![Object::Array(vec![]), num(0.0)],
         "ri" => vec![Object::name("RelativeColorimetric")],
+        "Tc" | "Tw" | "TL" | "Tr" | "Ts" => vec![num(0.0)],
+        "Tz" => vec![num(100.0)],
         _ => return None,
     };
     Some(Op::new(name, operands))
@@ -851,13 +853,21 @@ fn compute_inherited_drawing_ops(source: &DrawingState, dest: &DrawingState, ext
             (false, None, Some(_)) => ops.push(Op::new(black, vec![pdfcraft_content::num(0.0)])),
         }
     }
+    let mut text_ops = Vec::new();
     for ((name, source), dest) in DRAWING_PARAMS.iter().zip(&source.params).zip(&dest.params) {
+        let output = if matches!(*name, "Tc" | "Tw" | "Tz" | "TL" | "Tr" | "Ts" | "Tf") { &mut text_ops } else { &mut ops };
         match (sets(&[name]), source, dest) {
             (true, _, _) | (false, None, None) => {}
-            (false, Some(op), _) => ops.push((**op).clone()),
-            (false, None, Some(_)) => ops.extend(initial_param(name)),
+            (false, Some(op), _) => output.push((**op).clone()),
+            (false, None, Some(_)) => output.extend(initial_param(name)),
         }
     }
+    if !text_ops.is_empty() {
+        // Forms inherit text state, even though each BT resets its text matrices.
+        ops.push(Op::new("BT", vec![]));
+        ops.extend(text_ops);
+        ops.push(Op::new("ET", vec![]));
+    }
     ops
 }
 
@@ -1307,6 +1317,13 @@ fn arrange_image(
         state.apply(op)?;
         tracker.step(op, &ext_gstates, doc, state.placement.matrix)?;
         drawing_tracker.step(op)?;
+        if op.is("gs")
+            && op.name(0).and_then(|name| tracker.definitions.get(name)).and_then(|gs| gs.as_dict()).is_some_and(|gs| gs.get(b"Font").is_some())
+            && let Some(font) = DRAWING_PARAMS.iter().position(|name| *name == "Tf").and_then(|index| drawing_tracker.current.params.get_mut(index))
+        {
+            // The replayed gs selects its font; do not overwrite it with an older direct Tf.
+            *font = None;
+        }
         if op.is("gs")
             && let Some(intent) = &tracker.current_state.rendering_intent
         {

crates/edit/src/tests.rs

@@ -10176,6 +10176,26 @@ fn review_state_raster(doc: &Document) -> Vec<u8> {
     renderer.render(pdfcraft_render::RenderRequest { page: 0, scale: 1.0, ..Default::default() }).rgba.to_vec()
 }
 
+#[test]
+fn review_arrange_form_keeps_inherited_text_spacing() {
+    for (spacing, later_spacing) in [(0, false), (12, false), (0, true)] {
+        let initial = if later_spacing { String::new() } else { format!("BT {spacing} Tc ET") };
+        let later = if later_spacing { "BT 12 Tc ET" } else { "" };
+        let content = format!("q {initial} q 1 0 0 1 20 20 cm /Fm0 Do Q Q {later} q 0 0 1 rg 200 200 5 5 re f Q");
+        let mut doc = form_page_with(&content);
+        let form = pdfcraft_cos::ObjRef::new(6, 0);
+        let dict = doc.get(form).as_dict().unwrap().clone();
+        doc.set(form, Object::Stream(pdfcraft_cos::Stream::from_raw(dict, b"BT /F1 20 Tf 0 15 Td (ABC) Tj ET".to_vec())));
+        let doc_before = reopen(&doc);
+        let before = review_state_raster(&doc_before);
+        assert!(before.as_chunks::<4>().0.iter().any(|p| p[0] == 0 && p[1] == 0 && p[2] == 0), "the Form actually paints text");
+        arrange(&mut doc, 0, 0, images::ArrangeOrder::BringToFront).unwrap();
+        let saved = reopen(&doc);
+        assert_eq!(images::page_images(&saved, 0).unwrap()[0].rect, images::page_images(&doc_before, 0).unwrap()[0].rect);
+        assert_eq!(review_state_raster(&saved), before, "inherited {spacing} Tc must survive arranging the Form and reopening");
+    }
+}
+
 fn review_shared_mask_page(states: &str, luminosity_b: bool, mask_paint: &str) -> Document {
     let content = format!("q {states} q 100 0 0 100 20 20 cm /Im0 Do Q Q q 0 0 1 rg 200 200 5 5 re f Q");
     let stream = format!("<< /Length {} >>\nstream\n{content}\nendstream", content.len());