Place symbol texts: undo puts a group's texts back where they lay

Placing a group switches its alignment, which lays its texts out anew.
Undoing to AlignJustify, the default of the "Label and comment" group,
lays out nothing, so the texts stayed at their placed offsets. The
positions of the group's texts are now part of the undo step. The probe
reproduces the case from a group with freely placed texts.

Reported by ispyisail in the review of #1563.

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

sources/symboltextplacement.cpp

@@ -46,6 +46,9 @@ struct Line
 	QGraphicsItem *item;	///< for where it stands
 	QPointF old_pos;
 	QVariant old_alignment;
+		/// For a group, where its texts lay: a new alignment lays them out
+		/// anew, and undoing it to AlignJustify lays out nothing
+	QList<QPair<DynamicElementTextItem *, QPointF>> old_texts;
 };
 
 	/// Move @a item so that the top left of its box in the folio is at @a to
@@ -65,10 +68,15 @@ bool placeOne(Element *element, Qt::Alignment where, QUndoCommand *parent)
 	QList<Line> lines;
 	for (DynamicElementTextItem *text : element->dynamicTextItems())
 		if (!text->parentGroup() && text->isVisible())
-			lines.append({text, text, text->pos(), text->property("alignment")});
+			lines.append({text, text, text->pos(), text->property("alignment"), {}});
 	for (ElementTextItemGroup *group : element->textGroups())
 		if (group->isVisible())
-			lines.append({group, group, group->pos(), group->property("alignment")});
+		{
+			Line line {group, group, group->pos(), group->property("alignment"), {}};
+			for (DynamicElementTextItem *text : group->texts())
+				line.old_texts.append({text, text->pos()});
+			lines.append(line);
+		}
 	if (lines.isEmpty())
 		return false;
 
@@ -112,6 +120,11 @@ bool placeOne(Element *element, Qt::Alignment where, QUndoCommand *parent)
 			new QPropertyUndoCommand(line.object, "alignment", line.old_alignment, alignment, parent);
 		if (line.item->pos() != line.old_pos)
 			new QPropertyUndoCommand(line.object, "pos", line.old_pos, line.item->pos(), parent);
+			//The group's texts too: undoing its alignment to AlignJustify
+			//would leave them where the new alignment put them
+		for (const auto &text : line.old_texts)
+			if (text.first->pos() != text.second)
+				new QPropertyUndoCommand(text.first, "pos", text.second, text.first->pos(), parent);
 	}
 	return true;
 }

tests/qttest/symbol_text_placement_probe.cpp

@@ -136,6 +136,25 @@ int main(int argc, char **argv)
 			  "a group is placed as one line of the block");
 		check(group->alignment() == Qt::AlignRight, "and is aligned right too");
 
+		// A group whose texts lie freely (AlignJustify, the default of the
+		// "Label and comment" group): placing it lays its texts out anew,
+		// and one undo puts them back where they lay, not only the group.
+		scene->undoStack().undo();
+		group->setAlignment(Qt::AlignJustify);
+		texts[1]->setPos(0, 0);
+		texts[2]->setPos(5, 12);
+		const QPointF group_pos = group->pos();
+		scene->undoStack().push(SymbolTextPlacement::place({element}, Qt::AlignRight | Qt::AlignVCenter));
+		check(texts[2]->pos() != QPointF(5, 12), "placing lays the group's texts out anew");
+		scene->undoStack().undo();
+		check(group->alignment() == Qt::AlignJustify && group->pos() == group_pos,
+			  "undo puts the group's alignment and place back");
+		check(texts[1]->pos() == QPointF(0, 0) && texts[2]->pos() == QPointF(5, 12),
+			  "undo puts the group's texts back where they lay");
+		scene->undoStack().redo();
+		check(group->alignment() == Qt::AlignLeft && texts[2]->pos() != QPointF(5, 12),
+			  "redo places them again");
+
 		// A symbol with no texts: nothing to undo.
 		Element *other = nullptr;
 		for (Element *e : scene->elements()) if (e != element) other = e;