Merge pull request #5893 from dotCooCoo/fix/empty-thread-frame-style

Text: empty later frames preserve an edited paragraph style

crates/engine/src/cmd/threads/tests.rs

@@ -20,6 +20,25 @@ fn text(s: &Session, id: u64) -> String {
     }
 }
 
+#[test]
+fn empty_later_frames_keep_the_first_frames_edited_paragraph_style() {
+    let mut s = Session::new();
+    s.execute("file.new", &json!({"width": 600, "height": 300})).unwrap();
+    let a =
+        s.execute("text.create", &json!({"x": 10, "y": 10, "text": "First", "area": {"width": 150, "height": 60}})).unwrap()["id"].as_u64().unwrap();
+    let b = s.execute("shape.rectangle", &json!({"x": 200, "y": 10, "width": 150, "height": 60})).unwrap()["id"].as_u64().unwrap();
+    let c = s.execute("shape.rectangle", &json!({"x": 400, "y": 10, "width": 150, "height": 60})).unwrap()["id"].as_u64().unwrap();
+    s.execute("select.set", &json!({"ids": [a, b, c]})).unwrap();
+    s.execute("text.thread.create", &json!({})).unwrap();
+    assert_eq!([text(&s, a), text(&s, b), text(&s, c)], ["First", "", ""]);
+    s.execute("text.setFormat", &json!({"ids": [a], "hyphenate": true})).unwrap();
+    let hyphenates = |id| match &s.doc().unwrap().doc.node(NodeId(id)).unwrap().kind {
+        NodeKind::Text(t) => t.para_at(0).hyphenate,
+        _ => panic!("not text"),
+    };
+    assert_eq!([hyphenates(a), hyphenates(b), hyphenates(c)], [true, true, true]);
+}
+
 #[test]
 fn thread_flows_reflows_on_edit_and_survives_delete() {
     let (mut s, a, b) = setup();

crates/text/src/thread.rs

@@ -34,7 +34,11 @@ pub fn story_paras(frames: &[&TextObject], later_wins: &[bool]) -> Vec<ParaStyle
         }
         out.extend(styles);
         let text = f.plain_text();
-        prev_empty_tail = text.is_empty() || text.ends_with('\n') || out.is_empty();
+        // An empty frame has no paragraph boundary of its own. Keep the preceding frame's
+        // boundary state so another empty frame cannot replace a paragraph's edited style.
+        if !text.is_empty() {
+            prev_empty_tail = text.ends_with('\n') || out.is_empty();
+        }
     }
     out
 }

crates/text/src/thread/tests.rs

@@ -144,6 +144,25 @@ fn paragraph_styles_flow_with_their_paragraphs() {
     assert_eq!(story_paras(&[&fa, &fb], &[false, false])[0].justify, Left);
 }
 
+#[test]
+fn empty_frames_do_not_replace_an_earlier_paragraph_style() {
+    let mut first = frame(0.0);
+    first.runs = vec![TextRun { text: "First".into(), style: CharStyle::default(), inline: None }];
+    first.set_all_paras(ParaStyle { justify: Justify::Right, ..Default::default() });
+    let middle = frame(200.0);
+    let last = frame(400.0);
+    assert_eq!(story_paras(&[&first, &middle, &last], &[true, false, false])[0].justify, Justify::Right);
+
+    // An empty frame between two parts of the same paragraph changes no style either.
+    let mut last_with_text = last.clone();
+    last_with_text.runs = vec![TextRun { text: "Tail".into(), style: CharStyle::default(), inline: None }];
+    assert_eq!(story_paras(&[&first, &middle, &last_with_text], &[true, false, false])[0].justify, Justify::Right);
+
+    let mut restyled_middle = middle.clone();
+    restyled_middle.set_all_paras(ParaStyle { justify: Justify::Center, ..Default::default() });
+    assert_eq!(story_paras(&[&first, &restyled_middle, &last], &[false, true, false])[0].justify, Justify::Center);
+}
+
 /// Numbered list paragraphs count on from one frame to the next: the second frame's first
 /// whole paragraph takes the next number. A paragraph split between the frames has its number
 /// in the first frame only, and the paragraph after it takes the next number.