Fix plural handling for translations (#1424)

* .arg() doesn't handle plurals, replace %1 with %n and pass number to tr(), but only if there is an accompanying word for that we want singular/plural translations and only for whole numbers.

* Qt's translation methods only accept integers and we don't know what grammatical number form would be correct for floating-point numbers in different languages anyway.

* Add optional 2nd argument to SliderBase::SetFormat() to activate deferred plural handling:
  SetFormat(QT_TRANSLATE_N_NOOP("olive::SliderBase", "%n unit(s)"), true)

* Generate en_US.ts with lupdate's -pluralonly option. Only source strings that require plural handling need to be translated (as long as the source language is American English).

app/dialog/preferences/tabs/preferencesdisktab.cpp

@@ -69,7 +69,7 @@ PreferencesDiskTab::PreferencesDiskTab()
   cache_behavior_layout->addWidget(new QLabel(tr("Cache Ahead:")), row, 0);
 
   cache_ahead_slider_ = new FloatSlider();
-  cache_ahead_slider_->SetFormat(tr("%1 second(s)"));
+  cache_ahead_slider_->SetFormat(tr("%1 seconds"));
   cache_ahead_slider_->SetMinimum(0);
   cache_ahead_slider_->SetValue(Config::Current()["DiskCacheAhead"].value<rational>().toDouble());
   cache_behavior_layout->addWidget(cache_ahead_slider_, row, 1);
@@ -78,7 +78,7 @@ PreferencesDiskTab::PreferencesDiskTab()
 
   cache_behind_slider_ = new FloatSlider();
   cache_behind_slider_->SetMinimum(0);
-  cache_behind_slider_->SetFormat(tr("%1 second(s)"));
+  cache_behind_slider_->SetFormat(tr("%1 seconds"));
   cache_behind_slider_->SetValue(Config::Current()["DiskCacheBehind"].value<rational>().toDouble());
   cache_behavior_layout->addWidget(cache_behind_slider_, row, 3);
 

app/dialog/preferences/tabs/preferencesgeneraltab.cpp

@@ -103,7 +103,7 @@ PreferencesGeneralTab::PreferencesGeneralTab()
 
     default_still_length_ = new FloatSlider();
     default_still_length_->SetMinimum(0.1);
-    default_still_length_->SetFormat(tr("%1 second(s)"));
+    default_still_length_->SetFormat(tr("%1 seconds"));
     default_still_length_->SetValue(Config::Current()["DefaultStillLength"].value<rational>().toDouble());
     timeline_layout->addWidget(default_still_length_);
 
@@ -136,7 +136,7 @@ PreferencesGeneralTab::PreferencesGeneralTab()
     autorecovery_interval_ = new IntegerSlider();
     autorecovery_interval_->SetMinimum(1);
     autorecovery_interval_->SetMaximum(60);
-    autorecovery_interval_->SetFormat(tr("%1 minute(s)"));
+    autorecovery_interval_->SetFormat(QT_TRANSLATE_N_NOOP("olive::SliderBase", "%n minute(s)"), true);
     autorecovery_interval_->SetValue(Config::Current()[QStringLiteral("AutorecoveryInterval")].toLongLong());
     autorecovery_layout->addWidget(autorecovery_interval_, row, 1);
 

app/node/project/footage/footage.cpp

@@ -295,10 +295,9 @@ QString Footage::DescribeVideoStream(const VideoParams &params)
 
 QString Footage::DescribeAudioStream(const AudioParams &params)
 {
-  return tr("%1: Audio - %2 Channel(s), %3Hz")
-      .arg(QString::number(params.stream_index()),
-           QString::number(params.channel_count()),
-           QString::number(params.sample_rate()));
+  return tr("%1: Audio - %n Channel(s), %2Hz", nullptr, params.channel_count())
+    .arg(QString::number(params.stream_index()),
+         QString::number(params.sample_rate()));
 }
 
 void Footage::Hash(const QString& output, QCryptographicHash &hash, const rational &time) const

app/task/project/import/import.cpp

@@ -41,7 +41,7 @@ ProjectImportTask::ProjectImportTask(ProjectViewModel *model, Folder *folder, co
 
   file_count_ = Core::CountFilesInFileList(filenames_);
 
-  SetTitle(tr("Importing %1 file(s)").arg(file_count_));
+  SetTitle(tr("Importing %n file(s)", nullptr, file_count_));
 }
 
 const int &ProjectImportTask::GetFileCount() const

app/widget/nodeparamview/nodeparamviewarraywidget.cpp

@@ -53,7 +53,7 @@ void NodeParamViewArrayWidget::UpdateCounter(const QString& input, int old_size,
 {
   Q_UNUSED(old_size)
   if (input == input_) {
-    count_lbl_->setText(tr("%1 element(s)").arg(new_size));
+    count_lbl_->setText(tr("%n element(s)", nullptr, new_size));
   }
 }
 

app/widget/nodeparamview/nodeparamviewitem.cpp

@@ -376,7 +376,7 @@ void NodeParamViewItemBody::Retranslate()
 
     if (ic.IsArray() && ic.element() >= 0) {
       // Make the label the array index
-      i.value().main_label->setText(tr("%n:", nullptr, ic.element()));
+      i.value().main_label->setText(tr("%1:").arg(ic.element()));
     } else {
       // Set to the input's name
       i.value().main_label->setText(tr("%1:").arg(ic.name()));

app/widget/slider/sliderbase.cpp

@@ -39,6 +39,7 @@ SliderBase::SliderBase(Mode mode, QWidget *parent) :
   dragged_diff_(0),
   require_valid_input_(true),
   tristate_(false),
+  format_plural_(false),
   drag_ladder_(nullptr),
   ladder_element_count_(0),
   dragged_(false)
@@ -101,9 +102,10 @@ bool SliderBase::IsDragging() const
   return drag_ladder_;
 }
 
-void SliderBase::SetFormat(const QString &s)
+void SliderBase::SetFormat(const QString &s, const bool plural)
 {
   custom_format_ = s;
+  format_plural_ = plural;
   ForceLabelUpdate();
 }
 
@@ -113,6 +115,11 @@ void SliderBase::ClearFormat()
   ForceLabelUpdate();
 }
 
+bool SliderBase::IsFormatPlural() const
+{
+  return format_plural_;
+}
+
 void SliderBase::ForceLabelUpdate()
 {
   UpdateLabel(Value());
@@ -209,6 +216,8 @@ void SliderBase::UpdateLabel(const QVariant &v)
 {
   if (tristate_) {
     label_->setText("---");
+  } else if (format_plural_) {
+    label_->setText(tr(GetFormat().toUtf8().constData(), nullptr, v.toInt()));
   } else {
     label_->setText(GetFormat().arg(ValueToString(v)));
   }

app/widget/slider/sliderbase.h

@@ -60,9 +60,11 @@ public:
 
   bool IsDragging() const;
 
-  void SetFormat(const QString& s);
+  void SetFormat(const QString& s, const bool plural=false);
   void ClearFormat();
 
+  bool IsFormatPlural() const;
+
   void SetLadderElementCount(int b)
   {
     ladder_element_count_ = b;
@@ -127,6 +129,8 @@ private:
 
   QString custom_format_;
 
+  bool format_plural_;
+
   SliderLadder* drag_ladder_;
 
   int ladder_element_count_;

app/window/mainwindow/mainstatusbar.cpp

@@ -71,7 +71,7 @@ void MainStatusBar::UpdateStatus()
     if (manager_->GetTaskCount() == 1) {
       showMessage(t->GetTitle());
     } else {
-      showMessage(tr("Running %1 background task(s)").arg(manager_->GetTaskCount()));
+      showMessage(tr("Running %n background task(s)", nullptr, manager_->GetTaskCount()));
     }
 
     bar_->setVisible(true);