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

   1 #include "mainwindow.h"
   2
   3 #include <math.h>
   4 #include <stdio.h>
   5 #include <signal.h>
   6 #include <algorithm>
   7 #include <chrono>
   8 #include <string>
   9 #include <vector>
  10 #include <QBoxLayout>
  11 #include <QInputDialog>
  12 #include <QKeySequence>
  13 #include <QLabel>
  14 #include <QMetaType>
  15 #include <QPushButton>
  16 #include <QResizeEvent>
  17 #include <QShortcut>
  18 #include <QSize>
  19 #include <QString>
  20
  21 #include "aboutdialog.h"
  22 #include "disk_space_estimator.h"
  23 #include "flags.h"
  24 #include "glwidget.h"
  25 #include "input_mapping_dialog.h"
  26 #include "lrameter.h"
  27 #include "mixer.h"
  28 #include "post_to_main_thread.h"
  29 #include "ui_audio_miniview.h"
  30 #include "ui_display.h"
  31 #include "ui_mainwindow.h"
  32 #include "vumeter.h"
  33
  34 class QResizeEvent;
  35
  36 using namespace std;
  37 using namespace std::chrono;
  38 using namespace std::placeholders;
  39
  40 Q_DECLARE_METATYPE(std::string);
  41 Q_DECLARE_METATYPE(std::vector<std::string>);
  42
  43 MainWindow *global_mainwindow = nullptr;
  44
  45 namespace {
  46
  47 void schedule_cut_signal(int ignored)
  48 {
  49         global_mixer->schedule_cut();
  50 }
  51
  52 void quit_signal(int ignored)
  53 {
  54         global_mainwindow->close();
  55 }
  56
  57 constexpr unsigned DB_NO_FLAGS = 0x0;
  58 constexpr unsigned DB_WITH_SIGN = 0x1;
  59 constexpr unsigned DB_BARE = 0x2;
  60
  61 string format_db(double db, unsigned flags)
  62 {
  63         string text;
  64         if (flags & DB_WITH_SIGN) {
  65                 if (isfinite(db)) {
  66                         char buf[256];
  67                         snprintf(buf, sizeof(buf), "%+.1f", db);
  68                         text = buf;
  69                 } else if (db < 0.0) {
  70                         text = "-∞";
  71                 } else {
  72                         // Should never happen, really.
  73                         text = "+∞";
  74                 }
  75         } else {
  76                 if (isfinite(db)) {
  77                         char buf[256];
  78                         snprintf(buf, sizeof(buf), "%.1f", db);
  79                         text = buf;
  80                 } else if (db < 0.0) {
  81                         text = "-∞";
  82                 } else {
  83                         // Should never happen, really.
  84                         text = "∞";
  85                 }
  86         }
  87         if (!(flags & DB_BARE)) {
  88                 text += " dB";
  89         }
  90         return text;
  91 }
  92
  93 }  // namespace
  94
  95 MainWindow::MainWindow()
  96         : ui(new Ui::MainWindow)
  97 {
  98         global_mainwindow = this;
  99         ui->setupUi(this);
 100
 101         global_disk_space_estimator = new DiskSpaceEstimator(bind(&MainWindow::report_disk_space, this, _1, _2));
 102         disk_free_label = new QLabel(this);
 103         disk_free_label->setStyleSheet("QLabel {padding-right: 5px;}");
 104         ui->menuBar->setCornerWidget(disk_free_label);
 105
 106         ui->me_live->set_output(Mixer::OUTPUT_LIVE);
 107         ui->me_preview->set_output(Mixer::OUTPUT_PREVIEW);
 108
 109         // The menus.
 110         connect(ui->cut_action, &QAction::triggered, this, &MainWindow::cut_triggered);
 111         connect(ui->exit_action, &QAction::triggered, this, &MainWindow::exit_triggered);
 112         connect(ui->about_action, &QAction::triggered, this, &MainWindow::about_triggered);
 113         connect(ui->input_mapping_action, &QAction::triggered, this, &MainWindow::input_mapping_triggered);
 114
 115         if (global_flags.x264_video_to_http) {
 116                 connect(ui->x264_bitrate_action, &QAction::triggered, this, &MainWindow::x264_bitrate_triggered);
 117         } else {
 118                 ui->x264_bitrate_action->setEnabled(false);
 119         }
 120
 121         // Hook up the transition buttons. (Keyboard shortcuts are set in set_transition_names().)
 122         // TODO: Make them dynamic.
 123         connect(ui->transition_btn1, &QPushButton::clicked, bind(&MainWindow::transition_clicked, this, 0));
 124         connect(ui->transition_btn2, &QPushButton::clicked, bind(&MainWindow::transition_clicked, this, 1));
 125         connect(ui->transition_btn3, &QPushButton::clicked, bind(&MainWindow::transition_clicked, this, 2));
 126
 127         // Aiee...
 128         transition_btn1 = ui->transition_btn1;
 129         transition_btn2 = ui->transition_btn2;
 130         transition_btn3 = ui->transition_btn3;
 131         qRegisterMetaType<string>("std::string");
 132         qRegisterMetaType<vector<string>>("std::vector<std::string>");
 133         connect(ui->me_live, &GLWidget::transition_names_updated, this, &MainWindow::set_transition_names);
 134         qRegisterMetaType<Mixer::Output>("Mixer::Output");
 135
 136         last_audio_level_callback = steady_clock::now() - seconds(1);
 137 }
 138
 139 void MainWindow::resizeEvent(QResizeEvent* event)
 140 {
 141         QMainWindow::resizeEvent(event);
 142
 143         // Ask for a relayout, but only after the event loop is done doing relayout
 144         // on everything else.
 145         QMetaObject::invokeMethod(this, "relayout", Qt::QueuedConnection);
 146 }
 147
 148 void MainWindow::mixer_created(Mixer *mixer)
 149 {
 150         // Make the previews.
 151         unsigned num_previews = mixer->get_num_channels();
 152
 153         for (unsigned i = 0; i < num_previews; ++i) {
 154                 Mixer::Output output = Mixer::Output(Mixer::OUTPUT_INPUT0 + i);
 155
 156                 QWidget *preview = new QWidget(this);
 157                 Ui::Display *ui_display = new Ui::Display;
 158                 ui_display->setupUi(preview);
 159                 ui_display->label->setText(mixer->get_channel_name(output).c_str());
 160                 ui_display->display->set_output(output);
 161                 ui->preview_displays->insertWidget(previews.size(), preview, 1);
 162                 previews.push_back(ui_display);
 163
 164                 // Hook up the click.
 165                 connect(ui_display->display, &GLWidget::clicked, bind(&MainWindow::channel_clicked, this, i));
 166
 167                 // Let the theme update the text whenever the resolution or color changed.
 168                 connect(ui_display->display, &GLWidget::name_updated, this, &MainWindow::update_channel_name);
 169                 connect(ui_display->display, &GLWidget::color_updated, this, &MainWindow::update_channel_color);
 170
 171                 // Hook up the keyboard key.
 172                 QShortcut *shortcut = new QShortcut(QKeySequence(Qt::Key_1 + i), this);
 173                 connect(shortcut, &QShortcut::activated, bind(&MainWindow::channel_clicked, this, i));
 174
 175                 // Hook up the white balance button (irrelevant if invisible).
 176                 ui_display->wb_button->setVisible(mixer->get_supports_set_wb(output));
 177                 connect(ui_display->wb_button, &QPushButton::clicked, bind(&MainWindow::wb_button_clicked, this, i));
 178         }
 179
 180         setup_audio_miniview();
 181
 182         // TODO: Fetch all of the values these for completeness,
 183         // not just the enable knobs implied by flags.
 184         ui->locut_enabled->setChecked(global_mixer->get_audio_mixer()->get_locut_enabled());
 185         ui->gainstaging_knob->setValue(global_mixer->get_audio_mixer()->get_gain_staging_db());
 186         ui->gainstaging_auto_checkbox->setChecked(global_mixer->get_audio_mixer()->get_gain_staging_auto());
 187         ui->compressor_enabled->setChecked(global_mixer->get_audio_mixer()->get_compressor_enabled());
 188         ui->limiter_enabled->setChecked(global_mixer->get_audio_mixer()->get_limiter_enabled());
 189         ui->makeup_gain_auto_checkbox->setChecked(global_mixer->get_audio_mixer()->get_final_makeup_gain_auto());
 190
 191         ui->limiter_threshold_db_display->setText(
 192                 QString::fromStdString(format_db(mixer->get_audio_mixer()->get_limiter_threshold_dbfs(), DB_WITH_SIGN)));
 193         ui->compressor_threshold_db_display->setText(
 194                 QString::fromStdString(format_db(mixer->get_audio_mixer()->get_compressor_threshold_dbfs(), DB_WITH_SIGN)));
 195
 196         connect(ui->locut_cutoff_knob, &QDial::valueChanged, this, &MainWindow::cutoff_knob_changed);
 197         cutoff_knob_changed(ui->locut_cutoff_knob->value());
 198         connect(ui->locut_enabled, &QCheckBox::stateChanged, [this](int state){
 199                 global_mixer->get_audio_mixer()->set_locut_enabled(state == Qt::Checked);
 200         });
 201
 202         connect(ui->gainstaging_knob, &QAbstractSlider::valueChanged, this, &MainWindow::gain_staging_knob_changed);
 203         connect(ui->gainstaging_auto_checkbox, &QCheckBox::stateChanged, [this](int state){
 204                 global_mixer->get_audio_mixer()->set_gain_staging_auto(state == Qt::Checked);
 205         });
 206         connect(ui->makeup_gain_knob, &QAbstractSlider::valueChanged, this, &MainWindow::final_makeup_gain_knob_changed);
 207         connect(ui->makeup_gain_auto_checkbox, &QCheckBox::stateChanged, [this](int state){
 208                 global_mixer->get_audio_mixer()->set_final_makeup_gain_auto(state == Qt::Checked);
 209         });
 210
 211         connect(ui->limiter_threshold_knob, &QDial::valueChanged, this, &MainWindow::limiter_threshold_knob_changed);
 212         connect(ui->compressor_threshold_knob, &QDial::valueChanged, this, &MainWindow::compressor_threshold_knob_changed);
 213         connect(ui->limiter_enabled, &QCheckBox::stateChanged, [this](int state){
 214                 global_mixer->get_audio_mixer()->set_limiter_enabled(state == Qt::Checked);
 215         });
 216         connect(ui->compressor_enabled, &QCheckBox::stateChanged, [this](int state){
 217                 global_mixer->get_audio_mixer()->set_compressor_enabled(state == Qt::Checked);
 218         });
 219         connect(ui->reset_meters_button, &QPushButton::clicked, this, &MainWindow::reset_meters_button_clicked);
 220         mixer->get_audio_mixer()->set_audio_level_callback(bind(&MainWindow::audio_level_callback, this, _1, _2, _3, _4, _5, _6, _7, _8, _9));
 221
 222         struct sigaction act;
 223         memset(&act, 0, sizeof(act));
 224         act.sa_handler = schedule_cut_signal;
 225         act.sa_flags = SA_RESTART;
 226         sigaction(SIGHUP, &act, nullptr);
 227
 228         // Mostly for debugging. Don't override SIGINT, that's so evil if
 229         // shutdown isn't instant.
 230         memset(&act, 0, sizeof(act));
 231         act.sa_handler = quit_signal;
 232         act.sa_flags = SA_RESTART;
 233         sigaction(SIGUSR1, &act, nullptr);
 234 }
 235
 236 void MainWindow::setup_audio_miniview()
 237 {
 238         // Remove any existing channels.
 239         for (QLayoutItem *item; (item = ui->faders->takeAt(0)) != nullptr; ) {
 240                 delete item->widget();
 241                 delete item;
 242         }
 243         audio_miniviews.clear();
 244
 245         // Set up brand new ones from the input mapping.
 246         InputMapping mapping = global_mixer->get_audio_mixer()->get_input_mapping();
 247         audio_miniviews.resize(mapping.buses.size());
 248         for (unsigned bus_index = 0; bus_index < mapping.buses.size(); ++bus_index) {
 249                 QWidget *channel = new QWidget(this);
 250                 Ui::AudioMiniView *ui_audio_miniview = new Ui::AudioMiniView;
 251                 ui_audio_miniview->setupUi(channel);
 252                 ui_audio_miniview->bus_desc_label->setFullText(
 253                         QString::fromStdString(mapping.buses[bus_index].name));
 254                 audio_miniviews[bus_index] = ui_audio_miniview;
 255                 // TODO: Set the fader position.
 256                 ui->faders->addWidget(channel);
 257
 258                 connect(ui_audio_miniview->fader, &NonLinearFader::dbValueChanged,
 259                         bind(&MainWindow::mini_fader_changed, this, ui_audio_miniview, bus_index, _1));
 260         }
 261 }
 262
 263 void MainWindow::mixer_shutting_down()
 264 {
 265         ui->me_live->clean_context();
 266         ui->me_preview->clean_context();
 267         for (Ui::Display *display : previews) {
 268                 display->display->clean_context();
 269         }
 270 }
 271
 272 void MainWindow::cut_triggered()
 273 {
 274         global_mixer->schedule_cut();
 275 }
 276
 277 void MainWindow::x264_bitrate_triggered()
 278 {
 279         bool ok;
 280         int new_bitrate = QInputDialog::getInt(this, "Change x264 bitrate", "Choose new bitrate for x264 HTTP output (from 100–100,000 kbit/sec):", global_flags.x264_bitrate, /*min=*/100, /*max=*/100000, /*step=*/100, &ok);
 281         if (ok && new_bitrate >= 100 && new_bitrate <= 100000) {
 282                 global_flags.x264_bitrate = new_bitrate;
 283                 global_mixer->change_x264_bitrate(new_bitrate);
 284         }
 285 }
 286
 287 void MainWindow::exit_triggered()
 288 {
 289         close();
 290 }
 291
 292 void MainWindow::about_triggered()
 293 {
 294         AboutDialog().exec();
 295 }
 296
 297 void MainWindow::input_mapping_triggered()
 298 {
 299         if (InputMappingDialog().exec() == QDialog::Accepted) {
 300                 setup_audio_miniview();
 301         }
 302 }
 303
 304 void MainWindow::gain_staging_knob_changed(int value)
 305 {
 306         ui->gainstaging_auto_checkbox->setCheckState(Qt::Unchecked);
 307
 308         float gain_db = value * 0.1f;
 309         global_mixer->get_audio_mixer()->set_gain_staging_db(gain_db);
 310
 311         // The label will be updated by the audio level callback.
 312 }
 313
 314 void MainWindow::final_makeup_gain_knob_changed(int value)
 315 {
 316         ui->makeup_gain_auto_checkbox->setCheckState(Qt::Unchecked);
 317
 318         float gain_db = value * 0.1f;
 319         global_mixer->get_audio_mixer()->set_final_makeup_gain_db(gain_db);
 320
 321         // The label will be updated by the audio level callback.
 322 }
 323
 324 void MainWindow::cutoff_knob_changed(int value)
 325 {
 326         float octaves = value * 0.1f;
 327         float cutoff_hz = 20.0 * pow(2.0, octaves);
 328         global_mixer->get_audio_mixer()->set_locut_cutoff(cutoff_hz);
 329
 330         char buf[256];
 331         snprintf(buf, sizeof(buf), "%ld Hz", lrintf(cutoff_hz));
 332         ui->locut_cutoff_display->setText(buf);
 333 }
 334
 335 void MainWindow::report_disk_space(off_t free_bytes, double estimated_seconds_left)
 336 {
 337         char time_str[256];
 338         if (estimated_seconds_left < 60.0) {
 339                 strcpy(time_str, "<font color=\"red\">Less than a minute</font>");
 340         } else if (estimated_seconds_left < 1800.0) {  // Less than half an hour: Xm Ys (red).
 341                 int s = lrintf(estimated_seconds_left);
 342                 int m = s / 60;
 343                 s %= 60;
 344                 snprintf(time_str, sizeof(time_str), "<font color=\"red\">%dm %ds</font>", m, s);
 345         } else if (estimated_seconds_left < 3600.0) {  // Less than an hour: Xm.
 346                 int m = lrintf(estimated_seconds_left / 60.0);
 347                 snprintf(time_str, sizeof(time_str), "%dm", m);
 348         } else if (estimated_seconds_left < 36000.0) {  // Less than ten hours: Xh Ym.
 349                 int m = lrintf(estimated_seconds_left / 60.0);
 350                 int h = m / 60;
 351                 m %= 60;
 352                 snprintf(time_str, sizeof(time_str), "%dh %dm", h, m);
 353         } else {  // More than ten hours: Xh.
 354                 int h = lrintf(estimated_seconds_left / 3600.0);
 355                 snprintf(time_str, sizeof(time_str), "%dh", h);
 356         }
 357         char buf[256];
 358         snprintf(buf, sizeof(buf), "Disk free: %'.0f MB (approx. %s)", free_bytes / 1048576.0, time_str);
 359
 360         std::string label = buf;
 361
 362         post_to_main_thread([this, label]{
 363                 disk_free_label->setText(QString::fromStdString(label));
 364                 ui->menuBar->setCornerWidget(disk_free_label);  // Need to set this again for the sizing to get right.
 365         });
 366 }
 367
 368 void MainWindow::limiter_threshold_knob_changed(int value)
 369 {
 370         float threshold_dbfs = value * 0.1f;
 371         global_mixer->get_audio_mixer()->set_limiter_threshold_dbfs(threshold_dbfs);
 372         ui->limiter_threshold_db_display->setText(
 373                 QString::fromStdString(format_db(threshold_dbfs, DB_WITH_SIGN)));
 374 }
 375
 376 void MainWindow::compressor_threshold_knob_changed(int value)
 377 {
 378         float threshold_dbfs = value * 0.1f;
 379         global_mixer->get_audio_mixer()->set_compressor_threshold_dbfs(threshold_dbfs);
 380         ui->compressor_threshold_db_display->setText(
 381                 QString::fromStdString(format_db(threshold_dbfs, DB_WITH_SIGN)));
 382 }
 383
 384 void MainWindow::mini_fader_changed(Ui::AudioMiniView *ui, int channel, double volume_db)
 385 {
 386         char buf[256];
 387         if (isfinite(volume_db)) {
 388                 snprintf(buf, sizeof(buf), "%+.1f dB", volume_db);
 389                 ui->fader_label->setText(buf);
 390         } else {
 391                 ui->fader_label->setText("-∞ dB");
 392         }
 393
 394         global_mixer->get_audio_mixer()->set_fader_volume(channel, volume_db);
 395 }
 396
 397 void MainWindow::reset_meters_button_clicked()
 398 {
 399         global_mixer->get_audio_mixer()->reset_meters();
 400         ui->peak_display->setText(QString::fromStdString(format_db(-HUGE_VAL, DB_WITH_SIGN | DB_BARE)));
 401         ui->peak_display->setStyleSheet("");
 402 }
 403
 404 void MainWindow::audio_level_callback(float level_lufs, float peak_db, vector<float> bus_level_lufs,
 405                                       float global_level_lufs,
 406                                       float range_low_lufs, float range_high_lufs,
 407                                       float gain_staging_db, float final_makeup_gain_db,
 408                                       float correlation)
 409 {
 410         steady_clock::time_point now = steady_clock::now();
 411
 412         // The meters are somewhat inefficient to update. Only update them
 413         // every 100 ms or so (we get updates every 5–20 ms).
 414         double last_update_age = duration<double>(now - last_audio_level_callback).count();
 415         if (last_update_age < 0.100) {
 416                 return;
 417         }
 418         last_audio_level_callback = now;
 419
 420         post_to_main_thread([=]() {
 421                 ui->vu_meter->set_level(level_lufs);
 422                 for (unsigned bus_index = 0; bus_index < bus_level_lufs.size(); ++bus_index) {
 423                         if (bus_index < audio_miniviews.size()) {
 424                                 audio_miniviews[bus_index]->vu_meter_meter->set_level(
 425                                         bus_level_lufs[bus_index]);
 426                         }
 427                 }
 428                 ui->lra_meter->set_levels(global_level_lufs, range_low_lufs, range_high_lufs);
 429                 ui->correlation_meter->set_correlation(correlation);
 430
 431                 ui->peak_display->setText(QString::fromStdString(format_db(peak_db, DB_BARE)));
 432                 if (peak_db > -0.1f) {  // -0.1 dBFS is EBU peak limit.
 433                         ui->peak_display->setStyleSheet("QLabel { background-color: red; color: white; }");
 434                 } else {
 435                         ui->peak_display->setStyleSheet("");
 436                 }
 437
 438                 ui->gainstaging_knob->blockSignals(true);
 439                 ui->gainstaging_knob->setValue(lrintf(gain_staging_db * 10.0f));
 440                 ui->gainstaging_knob->blockSignals(false);
 441                 ui->gainstaging_db_display->setText(
 442                         QString::fromStdString(format_db(gain_staging_db, DB_WITH_SIGN)));
 443
 444                 ui->makeup_gain_knob->blockSignals(true);
 445                 ui->makeup_gain_knob->setValue(lrintf(final_makeup_gain_db * 10.0f));
 446                 ui->makeup_gain_knob->blockSignals(false);
 447                 ui->makeup_gain_db_display->setText(
 448                         QString::fromStdString(format_db(final_makeup_gain_db, DB_WITH_SIGN)));
 449         });
 450 }
 451
 452 void MainWindow::relayout()
 453 {
 454         int height = ui->vertical_layout->geometry().height();
 455
 456         double remaining_height = height;
 457
 458         // Allocate the height; the most important part is to keep the main displays
 459         // at 16:9 if at all possible.
 460         double me_width = ui->me_preview->width();
 461         double me_height = me_width * 9.0 / 16.0 + ui->label_preview->height() + ui->preview_vertical_layout->spacing();
 462
 463         // TODO: Scale the widths when we need to do this.
 464         if (me_height / double(height) > 0.8) {
 465                 me_height = height * 0.8;
 466         }
 467         remaining_height -= me_height + ui->vertical_layout->spacing();
 468
 469         // Space between the M/E displays and the audio strip.
 470         remaining_height -= ui->vertical_layout->spacing();
 471
 472         // The previews will be constrained by the remaining height, and the width.
 473         double preview_label_height = previews[0]->title_bar->geometry().height() +
 474                 previews[0]->main_vertical_layout->spacing();
 475         int preview_total_width = ui->preview_displays->geometry().width() - (previews.size() - 1) * ui->preview_displays->spacing();
 476         double preview_height = min(remaining_height - preview_label_height, (preview_total_width / double(previews.size())) * 9.0 / 16.0);
 477         remaining_height -= preview_height + preview_label_height + ui->vertical_layout->spacing();
 478
 479         ui->vertical_layout->setStretch(0, lrintf(me_height));
 480         ui->vertical_layout->setStretch(1, lrintf(remaining_height));  // Audio strip.
 481         ui->vertical_layout->setStretch(2, lrintf(preview_height + preview_label_height));
 482
 483         // Set the widths for the previews.
 484         double preview_width = preview_height * 16.0 / 9.0;
 485         for (unsigned i = 0; i < previews.size(); ++i) {
 486                 ui->preview_displays->setStretch(i, lrintf(preview_width));
 487         }
 488
 489         // The preview horizontal spacer.
 490         double remaining_preview_width = preview_total_width - previews.size() * preview_width;
 491         ui->preview_displays->setStretch(previews.size(), lrintf(remaining_preview_width));
 492 }
 493
 494 void MainWindow::set_transition_names(vector<string> transition_names)
 495 {
 496         if (transition_names.size() < 1 || transition_names[0].empty()) {
 497                 transition_btn1->setText(QString(""));
 498         } else {
 499                 transition_btn1->setText(QString::fromStdString(transition_names[0] + " (J)"));
 500                 ui->transition_btn1->setShortcut(QKeySequence("J"));
 501         }
 502         if (transition_names.size() < 2 || transition_names[1].empty()) {
 503                 transition_btn2->setText(QString(""));
 504         } else {
 505                 transition_btn2->setText(QString::fromStdString(transition_names[1] + " (K)"));
 506                 ui->transition_btn2->setShortcut(QKeySequence("K"));
 507         }
 508         if (transition_names.size() < 3 || transition_names[2].empty()) {
 509                 transition_btn3->setText(QString(""));
 510         } else {
 511                 transition_btn3->setText(QString::fromStdString(transition_names[2] + " (L)"));
 512                 ui->transition_btn3->setShortcut(QKeySequence("L"));
 513         }
 514 }
 515
 516 void MainWindow::update_channel_name(Mixer::Output output, const string &name)
 517 {
 518         if (output >= Mixer::OUTPUT_INPUT0) {
 519                 unsigned channel = output - Mixer::OUTPUT_INPUT0;
 520                 previews[channel]->label->setText(name.c_str());
 521         }
 522 }
 523
 524 void MainWindow::update_channel_color(Mixer::Output output, const string &color)
 525 {
 526         if (output >= Mixer::OUTPUT_INPUT0) {
 527                 unsigned channel = output - Mixer::OUTPUT_INPUT0;
 528                 previews[channel]->frame->setStyleSheet(QString::fromStdString("background-color:" + color));
 529         }
 530 }
 531
 532 void MainWindow::transition_clicked(int transition_number)
 533 {
 534         global_mixer->transition_clicked(transition_number);
 535 }
 536
 537 void MainWindow::channel_clicked(int channel_number)
 538 {
 539         if (current_wb_pick_display == channel_number) {
 540                 // The picking was already done from eventFilter(), since we don't get
 541                 // the mouse pointer here.
 542         } else {
 543                 global_mixer->channel_clicked(channel_number);
 544         }
 545 }
 546
 547 void MainWindow::wb_button_clicked(int channel_number)
 548 {
 549         current_wb_pick_display = channel_number;
 550         QApplication::setOverrideCursor(Qt::CrossCursor);
 551 }
 552
 553 bool MainWindow::eventFilter(QObject *watched, QEvent *event)
 554 {
 555         if (current_wb_pick_display != -1 &&
 556             event->type() == QEvent::MouseButtonRelease &&
 557             watched->isWidgetType()) {
 558                 QApplication::restoreOverrideCursor();
 559                 if (watched == previews[current_wb_pick_display]->display) {
 560                         const QMouseEvent *mouse_event = (QMouseEvent *)event;
 561                         set_white_balance(current_wb_pick_display, mouse_event->x(), mouse_event->y());
 562                 } else {
 563                         // The user clicked on something else, give up.
 564                         // (The click goes through, which might not be ideal, but, yes.)
 565                         current_wb_pick_display = -1;
 566                 }
 567         }
 568         return false;
 569 }
 570
 571 namespace {
 572
 573 double srgb_to_linear(double x)
 574 {
 575         if (x < 0.04045) {
 576                 return x / 12.92;
 577         } else {
 578                 return pow((x + 0.055) / 1.055, 2.4);
 579         }
 580 }
 581
 582 }  // namespace
 583
 584 void MainWindow::set_white_balance(int channel_number, int x, int y)
 585 {
 586         // Set the white balance to neutral for the grab. It's probably going to
 587         // flicker a bit, but hopefully this display is not live anyway.
 588         global_mixer->set_wb(Mixer::OUTPUT_INPUT0 + channel_number, 0.5, 0.5, 0.5);
 589         previews[channel_number]->display->updateGL();
 590         QRgb reference_color = previews[channel_number]->display->grabFrameBuffer().pixel(x, y);
 591
 592         double r = srgb_to_linear(qRed(reference_color) / 255.0);
 593         double g = srgb_to_linear(qGreen(reference_color) / 255.0);
 594         double b = srgb_to_linear(qBlue(reference_color) / 255.0);
 595         global_mixer->set_wb(Mixer::OUTPUT_INPUT0 + channel_number, r, g, b);
 596         previews[channel_number]->display->updateGL();
 597 }