can select many loopouts and change all of their lengths at once (or …

…convert all to crossovers by setting length 0)

lib/src/actions/actions.dart

@@ -1517,6 +1517,26 @@ abstract class LoopoutLengthChange
   static Serializer<LoopoutLengthChange> get serializer => _$loopoutLengthChangeSerializer;
 }
 
+abstract class LoopoutsLengthChange
+    with BuiltJsonSerializable, UndoableAction
+    implements Built<LoopoutsLengthChange, LoopoutsLengthChangeBuilder> {
+  BuiltList<Loopout> get loopouts;
+
+  int get length;
+
+  /************************ begin BuiltValue boilerplate ************************/
+  factory LoopoutsLengthChange(Iterable<Loopout> loopouts, int length) => LoopoutsLengthChange.from((b) => b
+    ..loopouts.replace(loopouts)
+    ..length = length);
+
+  factory LoopoutsLengthChange.from([void Function(LoopoutsLengthChangeBuilder) updates]) =
+      _$LoopoutsLengthChange;
+
+  LoopoutsLengthChange._();
+
+  static Serializer<LoopoutsLengthChange> get serializer => _$loopoutsLengthChangeSerializer;
+}
+
 abstract class ConvertCrossoverToLoopout
     with BuiltJsonSerializable, UndoableAction
     implements StrandPartAction, Built<ConvertCrossoverToLoopout, ConvertCrossoverToLoopoutBuilder> {

lib/src/reducers/change_loopout_length.dart

@@ -17,6 +17,7 @@ Strand convert_crossover_to_loopout_reducer(Strand strand, actions.ConvertCrosso
   var substrands_builder = strand.substrands.toBuilder();
   substrands_builder.insert(action.crossover.next_domain_idx, loopout_new);
   strand = strand.rebuild((s) => s..substrands = substrands_builder);
+  strand = strand.initialize();
   return strand;
 }
 
@@ -64,6 +65,59 @@ BuiltList<Strand> convert_crossovers_to_loopouts_reducer(BuiltList<Strand> stran
   return strands_builder.build();
 }
 
+BuiltList<Strand> loopouts_length_change_reducer(BuiltList<Strand> strands,
+    AppState state, actions.LoopoutsLengthChange action) {
+  Map<String, List<Loopout>> loopouts_on_strand_id = {};
+  for (var loopout in action.loopouts) {
+    String strand_id = loopout.strand_id;
+    if (!loopouts_on_strand_id.containsKey(strand_id)) {
+      loopouts_on_strand_id[strand_id] = [];
+    }
+    loopouts_on_strand_id[strand_id].add(loopout);
+  }
+
+  var strands_builder = strands.toBuilder();
+  for (String strand_id in loopouts_on_strand_id.keys) {
+    Strand strand = state.design.strands_by_id[strand_id];
+    int strand_idx = strands.indexOf(strand);
+    var substrands = strand.substrands.toList();
+
+    List<Loopout> loopouts = loopouts_on_strand_id[strand_id];
+    // must sort by crossover order for this logic to work with num_crossovers_processed_on_strand variable
+    loopouts.sort((c1, c2) => c1.prev_domain_idx - c2.prev_domain_idx);
+    for (var loopout in loopouts) {
+      int loopout_idx = substrands.indexOf(loopout);
+      if (action.length > 0) {
+        // shorten length of existing loopout
+        Loopout loopout_new = loopout.rebuild((l) => l..loopout_length = action.length);
+        substrands[loopout_idx] = loopout_new;
+      } else if (action.length == 0) {
+        // convert to crossover by removing loopout
+        substrands.removeAt(loopout_idx);
+      }
+    }
+    var new_strand = strand.rebuild((s) => s..substrands.replace(substrands));
+    new_strand = new_strand.initialize();
+    strands_builder[strand_idx] = new_strand;
+  }
+
+  return strands_builder.build();
+
+  // var substrands_builder = strand.substrands.toBuilder();
+  // int loopout_idx = strand.substrands.indexOf(action.loopout);
+  // var substrands_builder = strand.substrands.toBuilder();
+  // if (action.length > 0) {
+  //   // shorten length of existing loopout
+  //   Loopout loopout_new = action.loopout.rebuild((l) => l..loopout_length = action.length);
+  //   substrands_builder[loopout_idx] = loopout_new;
+  // } else if (action.length == 0) {
+  //   // convert to crossover by removing loopout
+  //   substrands_builder.removeAt(loopout_idx);
+  // }
+  // strand = strand.rebuild((s) => s..substrands = substrands_builder);
+  // return strand;
+}
+
 Strand loopout_length_change_reducer(Strand strand, actions.LoopoutLengthChange action) {
   int loopout_idx = strand.substrands.indexOf(action.loopout);
   var substrands_builder = strand.substrands.toBuilder();
@@ -76,5 +130,6 @@ Strand loopout_length_change_reducer(Strand strand, actions.LoopoutLengthChange
     substrands_builder.removeAt(loopout_idx);
   }
   strand = strand.rebuild((s) => s..substrands = substrands_builder);
+  strand = strand.initialize();
   return strand;
 }

lib/src/reducers/strands_reducer.dart

@@ -49,6 +49,8 @@ GlobalReducer<BuiltList<Strand>, AppState> strands_global_reducer = combineGloba
       join_strands_by_crossover_reducer),
   TypedGlobalReducer<BuiltList<Strand>, AppState, actions.ConvertCrossoversToLoopouts>(
       convert_crossovers_to_loopouts_reducer),
+  TypedGlobalReducer<BuiltList<Strand>, AppState, actions.LoopoutsLengthChange>(
+      loopouts_length_change_reducer),
 ]);
 
 BuiltList<Strand> replace_strands_reducer(BuiltList<Strand> strands, actions.ReplaceStrands action) {

lib/src/serializers.dart

@@ -133,6 +133,7 @@ part 'serializers.g.dart';
   Select,
   Loopout,
   LoopoutLengthChange,
+  LoopoutsLengthChange,
   ConvertCrossoverToLoopout,
   ConvertCrossoversToLoopouts,
   EditModeChoice,

lib/src/view/design_main_strand_loopout.dart

@@ -177,7 +177,14 @@ class DesignMainLoopoutComponent extends UiStatefulComponent2<DesignMainLoopoutP
     if (new_length == null || new_length == props.loopout.loopout_length) {
       return;
     }
-    app.dispatch(actions.LoopoutLengthChange(props.loopout, new_length));
+    var selected_loopouts = app.state.ui_state.selectables_store.selected_loopouts;
+    actions.UndoableAction action;
+    if (selected_loopouts.length > 0) {
+      action = actions.LoopoutsLengthChange(selected_loopouts, new_length);
+    } else {
+      action = actions.LoopoutLengthChange(props.loopout, new_length);
+    }
+    app.dispatch(action);
   }
 
   String loopout_path_description_between_groups() {