git.sesse.net Git - nageru/blob - midi_mapping_dialog.cpp

   1 #include "midi_mapping_dialog.h"
   2
   3 #include "midi_mapper.h"
   4 #include "midi_mapping.pb.h"
   5 #include "post_to_main_thread.h"
   6 #include "ui_midi_mapping.h"
   7
   8 #include <QComboBox>
   9 #include <QFileDialog>
  10 #include <QMessageBox>
  11 #include <QSpinBox>
  12
  13 #include <algorithm>
  14 #include <string>
  15
  16 using namespace google::protobuf;
  17 using namespace std;
  18
  19 vector<MIDIMappingDialog::Control> per_bus_controllers = {
  20         { "Treble",                   MIDIMappingBusProto::kTrebleFieldNumber, MIDIMappingProto::kTrebleBankFieldNumber },
  21         { "Mid",                      MIDIMappingBusProto::kMidFieldNumber,    MIDIMappingProto::kMidBankFieldNumber },
  22         { "Bass",                     MIDIMappingBusProto::kBassFieldNumber,   MIDIMappingProto::kBassBankFieldNumber },
  23         { "Gain",                     MIDIMappingBusProto::kGainFieldNumber,   MIDIMappingProto::kGainBankFieldNumber },
  24         { "Compressor threshold",     MIDIMappingBusProto::kCompressorThresholdFieldNumber,
  25                                       MIDIMappingProto::kCompressorThresholdBankFieldNumber},
  26         { "Fader",                    MIDIMappingBusProto::kFaderFieldNumber,  MIDIMappingProto::kFaderBankFieldNumber }
  27 };
  28 vector<MIDIMappingDialog::Control> per_bus_buttons = {
  29         { "Toggle locut",             MIDIMappingBusProto::kToggleLocutFieldNumber,
  30                                       MIDIMappingProto::kToggleLocutBankFieldNumber },
  31         { "Togle auto gain staging",  MIDIMappingBusProto::kToggleAutoGainStagingFieldNumber,
  32                                       MIDIMappingProto::kToggleAutoGainStagingBankFieldNumber },
  33         { "Togle compressor",         MIDIMappingBusProto::kToggleCompressorFieldNumber,
  34                                       MIDIMappingProto::kToggleCompressorBankFieldNumber },
  35         { "Clear peak",               MIDIMappingBusProto::kClearPeakFieldNumber,
  36                                       MIDIMappingProto::kClearPeakBankFieldNumber }
  37 };
  38 vector<MIDIMappingDialog::Control> per_bus_lights = {
  39         { "Locut is on",              MIDIMappingBusProto::kLocutIsOnFieldNumber, 0 },
  40         { "Auto gain staging is on",  MIDIMappingBusProto::kAutoGainStagingIsOnFieldNumber, 0 },
  41         { "Compressor is on",         MIDIMappingBusProto::kCompressorIsOnFieldNumber, 0 },
  42         { "Bus has peaked",           MIDIMappingBusProto::kHasPeakedFieldNumber, 0 }
  43 };
  44 vector<MIDIMappingDialog::Control> global_controllers = {
  45         { "Locut cutoff",             MIDIMappingBusProto::kLocutFieldNumber,  MIDIMappingProto::kLocutBankFieldNumber },
  46         { "Limiter threshold",        MIDIMappingBusProto::kLimiterThresholdFieldNumber,
  47                                       MIDIMappingProto::kLimiterThresholdBankFieldNumber },
  48         { "Makeup gain",              MIDIMappingBusProto::kMakeupGainFieldNumber,
  49                                       MIDIMappingProto::kMakeupGainBankFieldNumber }
  50 };
  51 vector<MIDIMappingDialog::Control> global_buttons = {
  52         { "Previous bank",            MIDIMappingBusProto::kPrevBankFieldNumber, 0 },
  53         { "Next bank",                MIDIMappingBusProto::kNextBankFieldNumber, 0 },
  54         { "Select bank 1",            MIDIMappingBusProto::kSelectBank1FieldNumber, 0 },
  55         { "Select bank 2",            MIDIMappingBusProto::kSelectBank2FieldNumber, 0 },
  56         { "Select bank 3",            MIDIMappingBusProto::kSelectBank3FieldNumber, 0 },
  57         { "Select bank 4",            MIDIMappingBusProto::kSelectBank4FieldNumber, 0 },
  58         { "Select bank 5",            MIDIMappingBusProto::kSelectBank5FieldNumber, 0 },
  59         { "Toggle limiter",           MIDIMappingBusProto::kToggleLimiterFieldNumber, MIDIMappingProto::kToggleLimiterBankFieldNumber },
  60         { "Toggle auto makeup gain",  MIDIMappingBusProto::kToggleAutoMakeupGainFieldNumber, MIDIMappingProto::kToggleAutoMakeupGainBankFieldNumber }
  61 };
  62 vector<MIDIMappingDialog::Control> global_lights = {
  63         { "Bank 1 is selected",       MIDIMappingBusProto::kBank1IsSelectedFieldNumber, 0 },
  64         { "Bank 2 is selected",       MIDIMappingBusProto::kBank2IsSelectedFieldNumber, 0 },
  65         { "Bank 3 is selected",       MIDIMappingBusProto::kBank3IsSelectedFieldNumber, 0 },
  66         { "Bank 4 is selected",       MIDIMappingBusProto::kBank4IsSelectedFieldNumber, 0 },
  67         { "Bank 5 is selected",       MIDIMappingBusProto::kBank5IsSelectedFieldNumber, 0 },
  68         { "Limiter is on",            MIDIMappingBusProto::kLimiterIsOnFieldNumber, 0 },
  69         { "Auto makeup gain is on",   MIDIMappingBusProto::kAutoMakeupGainIsOnFieldNumber, 0 },
  70 };
  71
  72 namespace {
  73
  74 int get_bank(const MIDIMappingProto &mapping_proto, int bank_field_number, int default_value)
  75 {
  76         const FieldDescriptor *bank_descriptor = mapping_proto.GetDescriptor()->FindFieldByNumber(bank_field_number);
  77         const Reflection *reflection = mapping_proto.GetReflection();
  78         if (!reflection->HasField(mapping_proto, bank_descriptor)) {
  79                 return default_value;
  80         }
  81         return reflection->GetInt32(mapping_proto, bank_descriptor);
  82 }
  83
  84 int get_controller_mapping(const MIDIMappingProto &mapping_proto, size_t bus_idx, int field_number, int default_value)
  85 {
  86         if (bus_idx >= size_t(mapping_proto.bus_mapping_size())) {
  87                 return default_value;
  88         }
  89
  90         const MIDIMappingBusProto &bus_mapping = mapping_proto.bus_mapping(bus_idx);
  91         const FieldDescriptor *descriptor = bus_mapping.GetDescriptor()->FindFieldByNumber(field_number);
  92         const Reflection *bus_reflection = bus_mapping.GetReflection();
  93         if (!bus_reflection->HasField(bus_mapping, descriptor)) {
  94                 return default_value;
  95         }
  96         const MIDIControllerProto &controller_proto =
  97                 static_cast<const MIDIControllerProto &>(bus_reflection->GetMessage(bus_mapping, descriptor));
  98         return controller_proto.controller_number();
  99 }
 100
 101 int get_button_mapping(const MIDIMappingProto &mapping_proto, size_t bus_idx, int field_number, int default_value)
 102 {
 103         if (bus_idx >= size_t(mapping_proto.bus_mapping_size())) {
 104                 return default_value;
 105         }
 106
 107         const MIDIMappingBusProto &bus_mapping = mapping_proto.bus_mapping(bus_idx);
 108         const FieldDescriptor *descriptor = bus_mapping.GetDescriptor()->FindFieldByNumber(field_number);
 109         const Reflection *bus_reflection = bus_mapping.GetReflection();
 110         if (!bus_reflection->HasField(bus_mapping, descriptor)) {
 111                 return default_value;
 112         }
 113         const MIDIButtonProto &bus_proto =
 114                 static_cast<const MIDIButtonProto &>(bus_reflection->GetMessage(bus_mapping, descriptor));
 115         return bus_proto.note_number();
 116 }
 117
 118 int get_light_mapping(const MIDIMappingProto &mapping_proto, size_t bus_idx, int field_number, int default_value)
 119 {
 120         if (bus_idx >= size_t(mapping_proto.bus_mapping_size())) {
 121                 return default_value;
 122         }
 123
 124         const MIDIMappingBusProto &bus_mapping = mapping_proto.bus_mapping(bus_idx);
 125         const FieldDescriptor *descriptor = bus_mapping.GetDescriptor()->FindFieldByNumber(field_number);
 126         const Reflection *bus_reflection = bus_mapping.GetReflection();
 127         if (!bus_reflection->HasField(bus_mapping, descriptor)) {
 128                 return default_value;
 129         }
 130         const MIDILightProto &bus_proto =
 131                 static_cast<const MIDILightProto &>(bus_reflection->GetMessage(bus_mapping, descriptor));
 132         return bus_proto.note_number();
 133 }
 134
 135 }  // namespace
 136
 137 MIDIMappingDialog::MIDIMappingDialog(MIDIMapper *mapper)
 138         : ui(new Ui::MIDIMappingDialog),
 139           mapper(mapper)
 140 {
 141         ui->setupUi(this);
 142
 143         const MIDIMappingProto mapping_proto = mapper->get_current_mapping();  // Take a copy.
 144         old_receiver = mapper->set_receiver(this);
 145
 146         QStringList labels;
 147         labels << "";
 148         labels << "Controller bank";
 149         for (unsigned bus_idx = 0; bus_idx < num_buses; ++bus_idx) {
 150                 char buf[256];
 151                 snprintf(buf, sizeof(buf), "Bus %d", bus_idx + 1);
 152                 labels << buf;
 153         }
 154         labels << "";
 155         ui->treeWidget->setColumnCount(num_buses + 3);
 156         ui->treeWidget->setHeaderLabels(labels);
 157
 158         add_controls("Per-bus controllers", ControlType::CONTROLLER, SpinnerGroup::PER_BUS_CONTROLLERS, mapping_proto, per_bus_controllers);
 159         add_controls("Per-bus buttons", ControlType::BUTTON, SpinnerGroup::PER_BUS_BUTTONS, mapping_proto, per_bus_buttons);
 160         add_controls("Per-bus lights", ControlType::LIGHT, SpinnerGroup::PER_BUS_LIGHTS, mapping_proto, per_bus_lights);
 161         add_controls("Global controllers", ControlType::CONTROLLER, SpinnerGroup::GLOBAL_CONTROLLERS, mapping_proto, global_controllers);
 162         add_controls("Global buttons", ControlType::BUTTON, SpinnerGroup::GLOBAL_BUTTONS, mapping_proto, global_buttons);
 163         add_controls("Global lights", ControlType::LIGHT, SpinnerGroup::GLOBAL_LIGHTS, mapping_proto, global_lights);
 164         fill_controls_from_mapping(mapping_proto);
 165
 166         // Auto-resize every column but the last.
 167         for (unsigned column_idx = 0; column_idx < num_buses + 3; ++column_idx) {
 168                 ui->treeWidget->resizeColumnToContents(column_idx);
 169         }
 170
 171         connect(ui->guess_bus_button, &QPushButton::clicked,
 172                 bind(&MIDIMappingDialog::guess_clicked, this, false));
 173         connect(ui->guess_group_button, &QPushButton::clicked,
 174                 bind(&MIDIMappingDialog::guess_clicked, this, true));
 175         connect(ui->ok_cancel_buttons, &QDialogButtonBox::accepted, this, &MIDIMappingDialog::ok_clicked);
 176         connect(ui->ok_cancel_buttons, &QDialogButtonBox::rejected, this, &MIDIMappingDialog::cancel_clicked);
 177         connect(ui->save_button, &QPushButton::clicked, this, &MIDIMappingDialog::save_clicked);
 178         connect(ui->load_button, &QPushButton::clicked, this, &MIDIMappingDialog::load_clicked);
 179
 180         update_guess_button_state();
 181 }
 182
 183 MIDIMappingDialog::~MIDIMappingDialog()
 184 {
 185         mapper->set_receiver(old_receiver);
 186         mapper->refresh_highlights();
 187 }
 188
 189 bool MIDIMappingDialog::eventFilter(QObject *obj, QEvent *event)
 190 {
 191         if (event->type() == QEvent::FocusIn ||
 192             event->type() == QEvent::FocusOut) {
 193                 // We ignore the guess buttons themselves; it should be allowed
 194                 // to navigate from a spinner to focus on a button (to click it).
 195                 if (obj != ui->guess_bus_button && obj != ui->guess_group_button) {
 196                         update_guess_button_state();
 197                 }
 198         }
 199         return false;
 200 }
 201
 202 void MIDIMappingDialog::guess_clicked(bool limit_to_group)
 203 {
 204         FocusInfo focus = find_focus();
 205         if (focus.bus_idx == -1) {
 206                 // The guess button probably took the focus away from us.
 207                 focus = last_focus;
 208         }
 209         assert(focus.bus_idx != -1);  // The button should have been disabled.
 210         pair<int, int> bus_and_offset = guess_offset(focus.bus_idx, limit_to_group ? focus.spinner_group : SpinnerGroup::ALL_GROUPS);
 211         const int source_bus_idx = bus_and_offset.first;
 212         const int offset = bus_and_offset.second;
 213         assert(source_bus_idx != -1);  // The button should have been disabled.
 214
 215         for (const auto &field_number_and_spinner : spinners[focus.bus_idx]) {
 216                 int field_number = field_number_and_spinner.first;
 217                 QSpinBox *spinner = field_number_and_spinner.second.spinner;
 218                 SpinnerGroup this_spinner_group = field_number_and_spinner.second.group;
 219
 220                 if (limit_to_group && this_spinner_group != focus.spinner_group) {
 221                         continue;
 222                 }
 223
 224                 assert(spinners[source_bus_idx].count(field_number));
 225                 QSpinBox *source_spinner = spinners[source_bus_idx][field_number].spinner;
 226                 assert(spinners[source_bus_idx][field_number].group == this_spinner_group);
 227
 228                 if (source_spinner->value() != 0) {
 229                         spinner->setValue(source_spinner->value() + offset);
 230                 }
 231         }
 232
 233         // See if we can find a “next” bus to move the focus to.
 234         const int next_bus_idx = focus.bus_idx + (focus.bus_idx - source_bus_idx);  // Note: Could become e.g. -1.
 235         for (const InstantiatedSpinner &is : controller_spinners) {
 236                 if (int(is.bus_idx) == next_bus_idx && is.field_number == focus.field_number) {
 237                         is.spinner->setFocus();
 238                 }
 239         }
 240         for (const InstantiatedSpinner &is : button_spinners) {
 241                 if (int(is.bus_idx) == next_bus_idx && is.field_number == focus.field_number) {
 242                         is.spinner->setFocus();
 243                 }
 244         }
 245         for (const InstantiatedSpinner &is : light_spinners) {
 246                 if (int(is.bus_idx) == next_bus_idx && is.field_number == focus.field_number) {
 247                         is.spinner->setFocus();
 248                 }
 249         }
 250 }
 251
 252 void MIDIMappingDialog::ok_clicked()
 253 {
 254         unique_ptr<MIDIMappingProto> new_mapping = construct_mapping_proto_from_ui();
 255         mapper->set_midi_mapping(*new_mapping);
 256         mapper->set_receiver(old_receiver);
 257         accept();
 258 }
 259
 260 void MIDIMappingDialog::cancel_clicked()
 261 {
 262         mapper->set_receiver(old_receiver);
 263         reject();
 264 }
 265
 266 void MIDIMappingDialog::save_clicked()
 267 {
 268         unique_ptr<MIDIMappingProto> new_mapping = construct_mapping_proto_from_ui();
 269         QString filename = QFileDialog::getSaveFileName(this,
 270                 "Save MIDI mapping", QString(), tr("Mapping files (*.midimapping)"));
 271         if (!filename.endsWith(".midimapping")) {
 272                 filename += ".midimapping";
 273         }
 274         if (!save_midi_mapping_to_file(*new_mapping, filename.toStdString())) {
 275                 QMessageBox box;
 276                 box.setText("Could not save mapping to '" + filename + "'. Check that you have the right permissions and try again.");
 277                 box.exec();
 278         }
 279 }
 280
 281 void MIDIMappingDialog::load_clicked()
 282 {
 283         QString filename = QFileDialog::getOpenFileName(this,
 284                 "Load MIDI mapping", QString(), tr("Mapping files (*.midimapping)"));
 285         MIDIMappingProto new_mapping;
 286         if (!load_midi_mapping_from_file(filename.toStdString(), &new_mapping)) {
 287                 QMessageBox box;
 288                 box.setText("Could not load mapping from '" + filename + "'. Check that the file exists, has the right permissions and is valid.");
 289                 box.exec();
 290                 return;
 291         }
 292
 293         fill_controls_from_mapping(new_mapping);
 294 }
 295
 296 namespace {
 297
 298 template<class T>
 299 T *get_mutable_bus_message(MIDIMappingProto *mapping_proto, unsigned bus_idx, int field_number)
 300 {
 301         while (size_t(mapping_proto->bus_mapping_size()) <= bus_idx) {
 302                 mapping_proto->add_bus_mapping();
 303         }
 304
 305         MIDIMappingBusProto *bus_mapping = mapping_proto->mutable_bus_mapping(bus_idx);
 306         const FieldDescriptor *descriptor = bus_mapping->GetDescriptor()->FindFieldByNumber(field_number);
 307         const Reflection *bus_reflection = bus_mapping->GetReflection();
 308         return static_cast<T *>(bus_reflection->MutableMessage(bus_mapping, descriptor));
 309 }
 310
 311 }  // namespace
 312
 313 unique_ptr<MIDIMappingProto> MIDIMappingDialog::construct_mapping_proto_from_ui()
 314 {
 315         unique_ptr<MIDIMappingProto> mapping_proto(new MIDIMappingProto);
 316         for (const InstantiatedSpinner &is : controller_spinners) {
 317                 const int val = is.spinner->value();
 318                 if (val == 0) {
 319                         continue;
 320                 }
 321
 322                 MIDIControllerProto *controller_proto =
 323                         get_mutable_bus_message<MIDIControllerProto>(mapping_proto.get(), is.bus_idx, is.field_number);
 324                 controller_proto->set_controller_number(val);
 325         }
 326         for (const InstantiatedSpinner &is : button_spinners) {
 327                 const int val = is.spinner->value();
 328                 if (val == 0) {
 329                         continue;
 330                 }
 331
 332                 MIDIButtonProto *button_proto =
 333                         get_mutable_bus_message<MIDIButtonProto>(mapping_proto.get(), is.bus_idx, is.field_number);
 334                 button_proto->set_note_number(val);
 335         }
 336         for (const InstantiatedSpinner &is : light_spinners) {
 337                 const int val = is.spinner->value();
 338                 if (val == 0) {
 339                         continue;
 340                 }
 341
 342                 MIDILightProto *light_proto =
 343                         get_mutable_bus_message<MIDILightProto>(mapping_proto.get(), is.bus_idx, is.field_number);
 344                 light_proto->set_note_number(val);
 345         }
 346         int highest_bank_used = 0;  // 1-indexed.
 347         for (const InstantiatedComboBox &ic : bank_combo_boxes) {
 348                 const int val = ic.combo_box->currentIndex();
 349                 highest_bank_used = std::max(highest_bank_used, val);
 350                 if (val == 0) {
 351                         continue;
 352                 }
 353
 354                 const FieldDescriptor *descriptor = mapping_proto->GetDescriptor()->FindFieldByNumber(ic.field_number);
 355                 const Reflection *bus_reflection = mapping_proto->GetReflection();
 356                 bus_reflection->SetInt32(mapping_proto.get(), descriptor, val - 1);
 357         }
 358         mapping_proto->set_num_controller_banks(highest_bank_used);
 359         return mapping_proto;
 360 }
 361
 362 void MIDIMappingDialog::add_bank_selector(QTreeWidgetItem *item, const MIDIMappingProto &mapping_proto, int bank_field_number)
 363 {
 364         if (bank_field_number == 0) {
 365                 return;
 366         }
 367         QComboBox *bank_selector = new QComboBox(this);
 368         bank_selector->addItems(QStringList() << "" << "Bank 1" << "Bank 2" << "Bank 3" << "Bank 4" << "Bank 5");
 369         bank_selector->setAutoFillBackground(true);
 370
 371         bank_combo_boxes.push_back(InstantiatedComboBox{ bank_selector, bank_field_number });
 372
 373         ui->treeWidget->setItemWidget(item, 1, bank_selector);
 374 }
 375
 376 void MIDIMappingDialog::add_controls(const string &heading,
 377                                      MIDIMappingDialog::ControlType control_type,
 378                                      MIDIMappingDialog::SpinnerGroup spinner_group,
 379                                      const MIDIMappingProto &mapping_proto,
 380                                      const vector<MIDIMappingDialog::Control> &controls)
 381 {
 382         QTreeWidgetItem *heading_item = new QTreeWidgetItem(ui->treeWidget);
 383         heading_item->setText(0, QString::fromStdString(heading));
 384         heading_item->setFirstColumnSpanned(true);
 385         heading_item->setExpanded(true);
 386         for (const Control &control : controls) {
 387                 QTreeWidgetItem *item = new QTreeWidgetItem(heading_item);
 388                 heading_item->addChild(item);
 389                 add_bank_selector(item, mapping_proto, control.bank_field_number);
 390                 item->setText(0, QString::fromStdString(control.label + "   "));
 391
 392                 for (unsigned bus_idx = 0; bus_idx < num_buses; ++bus_idx) {
 393                         QSpinBox *spinner = new QSpinBox(this);
 394                         spinner->setRange(0, 127);
 395                         spinner->setAutoFillBackground(true);
 396                         spinner->setSpecialValueText("\u200d");  // Zero-width joiner (ie., empty).
 397                         spinner->installEventFilter(this);  // So we know when the focus changes.
 398                         ui->treeWidget->setItemWidget(item, bus_idx + 2, spinner);
 399
 400                         if (control_type == ControlType::CONTROLLER) {
 401                                 controller_spinners.push_back(InstantiatedSpinner{ spinner, bus_idx, spinner_group, control.field_number });
 402                         } else if (control_type == ControlType::BUTTON) {
 403                                 button_spinners.push_back(InstantiatedSpinner{ spinner, bus_idx, spinner_group, control.field_number });
 404                         } else {
 405                                 assert(control_type == ControlType::LIGHT);
 406                                 light_spinners.push_back(InstantiatedSpinner{ spinner, bus_idx, spinner_group, control.field_number });
 407                         }
 408                         spinners[bus_idx][control.field_number] = SpinnerAndGroup{ spinner, spinner_group };
 409                         connect(spinner, static_cast<void(QSpinBox::*)(int)>(&QSpinBox::valueChanged),
 410                                 bind(&MIDIMappingDialog::update_guess_button_state, this));
 411                 }
 412         }
 413         ui->treeWidget->addTopLevelItem(heading_item);
 414 }
 415
 416 void MIDIMappingDialog::fill_controls_from_mapping(const MIDIMappingProto &mapping_proto)
 417 {
 418         for (const InstantiatedSpinner &is : controller_spinners) {
 419                 is.spinner->setValue(get_controller_mapping(mapping_proto, is.bus_idx, is.field_number, 0));
 420         }
 421         for (const InstantiatedSpinner &is : button_spinners) {
 422                 is.spinner->setValue(get_button_mapping(mapping_proto, is.bus_idx, is.field_number, 0));
 423         }
 424         for (const InstantiatedSpinner &is : light_spinners) {
 425                 is.spinner->setValue(get_light_mapping(mapping_proto, is.bus_idx, is.field_number, 0));
 426         }
 427         for (const InstantiatedComboBox &ic : bank_combo_boxes) {
 428                 ic.combo_box->setCurrentIndex(get_bank(mapping_proto, ic.field_number, -1) + 1);
 429         }
 430 }
 431
 432 void MIDIMappingDialog::controller_changed(unsigned controller)
 433 {
 434         for (const InstantiatedSpinner &is : controller_spinners) {
 435                 if (is.spinner->hasFocus()) {
 436                         is.spinner->setValue(controller);
 437                         is.spinner->selectAll();
 438                 }
 439         }
 440 }
 441
 442 void MIDIMappingDialog::note_on(unsigned note)
 443 {
 444         for (const InstantiatedSpinner &is : button_spinners) {
 445                 if (is.spinner->hasFocus()) {
 446                         is.spinner->setValue(note);
 447                         is.spinner->selectAll();
 448                 }
 449         }
 450         for (const InstantiatedSpinner &is : light_spinners) {
 451                 if (is.spinner->hasFocus()) {
 452                         is.spinner->setValue(note);
 453                         is.spinner->selectAll();
 454                 }
 455         }
 456 }
 457
 458 pair<int, int> MIDIMappingDialog::guess_offset(unsigned bus_idx, MIDIMappingDialog::SpinnerGroup spinner_group)
 459 {
 460         constexpr pair<int, int> not_found(-1, 0);
 461
 462         if (bus_is_empty(bus_idx, spinner_group)) {
 463                 return not_found;
 464         }
 465
 466         // See if we can find a non-empty bus to source from (prefer from the left).
 467         unsigned source_bus_idx;
 468         if (bus_idx > 0 && !bus_is_empty(bus_idx - 1, spinner_group)) {
 469                 source_bus_idx = bus_idx - 1;
 470         } else if (bus_idx < num_buses - 1 && !bus_is_empty(bus_idx + 1, spinner_group)) {
 471                 source_bus_idx = bus_idx + 1;
 472         } else {
 473                 return not_found;
 474         }
 475
 476         // See if we can find a consistent offset.
 477         bool found_offset = false;
 478         int offset = 0;
 479         int minimum_allowed_offset = numeric_limits<int>::min();
 480         int maximum_allowed_offset = numeric_limits<int>::max();
 481         for (const auto &field_number_and_spinner : spinners[bus_idx]) {
 482                 int field_number = field_number_and_spinner.first;
 483                 QSpinBox *spinner = field_number_and_spinner.second.spinner;
 484                 SpinnerGroup this_spinner_group = field_number_and_spinner.second.group;
 485                 assert(spinners[source_bus_idx].count(field_number));
 486                 QSpinBox *source_spinner = spinners[source_bus_idx][field_number].spinner;
 487                 assert(spinners[source_bus_idx][field_number].group == this_spinner_group);
 488
 489                 if (spinner_group != SpinnerGroup::ALL_GROUPS &&
 490                     spinner_group != this_spinner_group) {
 491                         continue;
 492                 }
 493                 if (spinner->value() == 0) {
 494                         if (source_spinner->value() != 0) {
 495                                 // If the source value is e.g. 3, offset can't be less than -2 or larger than 124.
 496                                 // Otherwise, we'd extrapolate values outside [1..127].
 497                                 minimum_allowed_offset = max(minimum_allowed_offset, 1 - source_spinner->value());
 498                                 maximum_allowed_offset = min(maximum_allowed_offset, 127 - source_spinner->value());
 499                         }
 500                         continue;
 501                 }
 502                 if (source_spinner->value() == 0) {
 503                         // The bus has a controller set that the source bus doesn't set.
 504                         return not_found;
 505                 }
 506
 507                 int candidate_offset = spinner->value() - source_spinner->value();
 508                 if (!found_offset) {
 509                         offset = candidate_offset;
 510                         found_offset = true;
 511                 } else if (candidate_offset != offset) {
 512                         return not_found;
 513                 }
 514         }
 515
 516         if (!found_offset) {
 517                 // Given that the bus wasn't empty, this shouldn't happen.
 518                 assert(false);
 519                 return not_found;
 520         }
 521
 522         if (offset < minimum_allowed_offset || offset > maximum_allowed_offset) {
 523                 return not_found;
 524         }
 525         return make_pair(source_bus_idx, offset);
 526 }
 527
 528 bool MIDIMappingDialog::bus_is_empty(unsigned bus_idx, SpinnerGroup spinner_group)
 529 {
 530         for (const auto &field_number_and_spinner : spinners[bus_idx]) {
 531                 QSpinBox *spinner = field_number_and_spinner.second.spinner;
 532                 SpinnerGroup this_spinner_group = field_number_and_spinner.second.group;
 533                 if (spinner_group != SpinnerGroup::ALL_GROUPS &&
 534                     spinner_group != this_spinner_group) {
 535                         continue;
 536                 }
 537                 if (spinner->value() != 0) {
 538                         return false;
 539                 }
 540         }
 541         return true;
 542 }
 543
 544 void MIDIMappingDialog::update_guess_button_state()
 545 {
 546         FocusInfo focus = find_focus();
 547         if (focus.bus_idx < 0) {
 548                 return;
 549         }
 550         {
 551                 pair<int, int> bus_and_offset = guess_offset(focus.bus_idx, SpinnerGroup::ALL_GROUPS);
 552                 ui->guess_bus_button->setEnabled(bus_and_offset.first != -1);
 553         }
 554         {
 555                 pair<int, int> bus_and_offset = guess_offset(focus.bus_idx, focus.spinner_group);
 556                 ui->guess_group_button->setEnabled(bus_and_offset.first != -1);
 557         }
 558         last_focus = focus;
 559 }
 560
 561 MIDIMappingDialog::FocusInfo MIDIMappingDialog::find_focus() const
 562 {
 563         for (const InstantiatedSpinner &is : controller_spinners) {
 564                 if (is.spinner->hasFocus()) {
 565                         return FocusInfo{ int(is.bus_idx), is.spinner_group, is.field_number };
 566                 }
 567         }
 568         for (const InstantiatedSpinner &is : button_spinners) {
 569                 if (is.spinner->hasFocus()) {
 570                         return FocusInfo{ int(is.bus_idx), is.spinner_group, is.field_number };
 571                 }
 572         }
 573         for (const InstantiatedSpinner &is : light_spinners) {
 574                 if (is.spinner->hasFocus()) {
 575                         return FocusInfo{ int(is.bus_idx), is.spinner_group, is.field_number };
 576                 }
 577         }
 578         return FocusInfo{ -1, SpinnerGroup::ALL_GROUPS, -1 };
 579 }