Display an indicator next to each playlist item showing its position in the queue

src/playlist/playlist.cpp

@@ -161,6 +161,9 @@ QVariant Playlist::data(const QModelIndex& index, int role) const {
     case Role_StopAfter:
       return stop_after_.isValid() && stop_after_.row() == index.row();
 
+    case Role_QueuePosition:
+      return queue_->PositionOf(index);
+
     case Qt::EditRole:
     case Qt::ToolTipRole:
     case Qt::DisplayRole: {

src/playlist/playlist.h

@@ -83,6 +83,7 @@ class Playlist : public QAbstractListModel {
     Role_IsCurrent = Qt::UserRole + 1,
     Role_IsPaused,
     Role_StopAfter,
+    Role_QueuePosition,
   };
 
   static const char* kRowsMimetype;

src/playlist/playlistdelegates.cpp

@@ -15,6 +15,7 @@
 */
 
 #include "playlistdelegates.h"
+#include "queue.h"
 #include "core/utilities.h"
 #include "library/librarybackend.h"
 #include "widgets/trackslider.h"
@@ -27,11 +28,72 @@
 #include <QHelpEvent>
 #include <QHeaderView>
 #include <QScrollBar>
+#include <QLinearGradient>
 
 const int PlaylistDelegateBase::kMinHeight = 19;
 
+QueuedItemDelegate::QueuedItemDelegate(QObject *parent)
+  : QStyledItemDelegate(parent)
+{
+}
+
+void QueuedItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const {
+  QStyledItemDelegate::paint(painter, option, index);
+
+  if (index.column() == Playlist::Column_Title ||
+      index.column() == Queue::Column_CombinedArtistTitle) {
+    const int queue_pos = index.data(Playlist::Role_QueuePosition).toInt();
+    if (queue_pos != -1) {
+      QFont smaller = option.font;
+      smaller.setPointSize(smaller.pointSize() - 2);
+      smaller.setBold(true);
+
+      const int kQueueBoxBorder = 1;
+      const int kQueueBoxCornerRadius = 3;
+      const int kQueueBoxLength = QFontMetrics(smaller).width('7') * 4;
+      const QRgb kQueueBoxGradientColor1 = qRgb(102, 150, 227);
+      const QRgb kQueueBoxGradientColor2 = qRgb(77, 121, 200);
+      const int kQueueOpacitySteps = 10;
+      const float kQueueOpacityLowerBound = 0.4;
+
+      QRect rect(option.rect);
+      rect.setLeft(rect.right() - kQueueBoxLength - kQueueBoxBorder);
+      rect.setWidth(kQueueBoxLength);
+      rect.setTop(rect.top() + kQueueBoxBorder);
+      rect.setBottom(rect.bottom() - kQueueBoxBorder - 1);
+
+      QRect text_rect(rect);
+      text_rect.setBottom(text_rect.bottom() + 1);
+
+      QLinearGradient gradient(rect.topLeft(), rect.bottomLeft());
+      gradient.setColorAt(0.0, kQueueBoxGradientColor1);
+      gradient.setColorAt(1.0, kQueueBoxGradientColor2);
+
+      // Turn on antialisaing
+      painter->setRenderHint(QPainter::Antialiasing);
+
+      float opacity = kQueueOpacitySteps - qMin(kQueueOpacitySteps, queue_pos);
+      opacity /= kQueueOpacitySteps;
+      opacity *= 1.0 - kQueueOpacityLowerBound;
+      opacity += kQueueOpacityLowerBound;
+      painter->setOpacity(opacity);
+
+      // Draw the box
+      painter->setPen(QPen(Qt::white, 1));
+      painter->setBrush(gradient);
+      painter->drawRoundedRect(rect, kQueueBoxCornerRadius, kQueueBoxCornerRadius);
+
+      // Draw the text
+      painter->setFont(smaller);
+      painter->drawText(rect, Qt::AlignCenter, QString::number(queue_pos+1));
+
+      painter->setOpacity(1.0);
+    }
+  }
+}
+
 PlaylistDelegateBase::PlaylistDelegateBase(QTreeView* view, const QString& suffix)
-  : QStyledItemDelegate(view),
+  : QueuedItemDelegate(view),
     view_(view),
     suffix_(suffix)
 {
@@ -67,18 +129,19 @@ QString PlaylistDelegateBase::displayText(const QVariant& value, const QLocale&)
 }
 
 QSize PlaylistDelegateBase::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const {
-  QSize size = QStyledItemDelegate::sizeHint(option, index);
+  QSize size = QueuedItemDelegate::sizeHint(option, index);
   if (size.height() < kMinHeight)
     size.setHeight(kMinHeight);
   return size;
 }
 
 void PlaylistDelegateBase::paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const {
-  QStyledItemDelegate::paint(painter, Adjusted(option, index), index);
+  QueuedItemDelegate::paint(painter, Adjusted(option, index), index);
 
   QPoint top_left(-view_->horizontalScrollBar()->value(),
                   -view_->verticalScrollBar()->value());
 
+  // Stop after indicator
   if (view_->header()->logicalIndexAt(top_left) == index.column()) {
     if (index.data(Playlist::Role_StopAfter).toBool()) {
       QColor color(Qt::white);

src/playlist/playlistdelegates.h

@@ -25,7 +25,13 @@
 #include <QStringListModel>
 #include <QCompleter>
 
-class PlaylistDelegateBase : public QStyledItemDelegate {
+class QueuedItemDelegate : public QStyledItemDelegate {
+public:
+  QueuedItemDelegate(QObject* parent);
+  void paint(QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index) const;
+};
+
+class PlaylistDelegateBase : public QueuedItemDelegate {
   Q_OBJECT
  public:
   PlaylistDelegateBase(QTreeView* view, const QString& suffix = QString());

src/playlist/queue.cpp

@@ -101,20 +101,28 @@ int Queue::columnCount(const QModelIndex &parent) const {
 }
 
 QVariant Queue::data(const QModelIndex& proxy_index, int role) const {
-  if (role != Qt::DisplayRole)
-    return QVariant();
+  switch (role) {
+    case Playlist::Role_QueuePosition:
+      return proxy_index.row();
 
-  QModelIndex source_index = source_indexes_[proxy_index.row()];
+    case Qt::DisplayRole: {
+      QModelIndex source_index = source_indexes_[proxy_index.row()];
 
-  if (proxy_index.column() == Column_CombinedArtistTitle) {
-    const QString artist = source_index.sibling(source_index.row(), Playlist::Column_Artist).data().toString();
-    const QString title = source_index.sibling(source_index.row(), Playlist::Column_Title).data().toString();
+      if (proxy_index.column() == Column_CombinedArtistTitle) {
+        const QString artist = source_index.sibling(source_index.row(), Playlist::Column_Artist).data().toString();
+        const QString title = source_index.sibling(source_index.row(), Playlist::Column_Title).data().toString();
 
-    if (artist.isEmpty())
-      return title;
-    return artist + " - " + title;
+        if (artist.isEmpty())
+          return title;
+        return artist + " - " + title;
+      }
+    }
+
+    default: {
+      QModelIndex source_index = source_indexes_[proxy_index.row()];
+      return source_index.data(role);
+    }
   }
-  return source_index.data(role);
 }
 
 void Queue::ToggleTracks(const QModelIndexList &source_indexes) {
@@ -135,3 +143,7 @@ void Queue::ToggleTracks(const QModelIndexList &source_indexes) {
     }
   }
 }
+
+int Queue::PositionOf(const QModelIndex& source_index) const {
+  return mapFromSource(source_index).row();
+}

src/playlist/queue.h

@@ -34,6 +34,7 @@ public:
   };
 
   bool is_empty() const;
+  int PositionOf(const QModelIndex& source_index) const;
 
   QModelIndex TakeNext();
   void ToggleTracks(const QModelIndexList& source_indexes);

src/playlist/queuemanager.cpp

@@ -15,6 +15,7 @@
 */
 
 #include "playlist.h"
+#include "playlistdelegates.h"
 #include "playlistmanager.h"
 #include "queue.h"
 #include "queuemanager.h"
@@ -27,6 +28,8 @@ QueueManager::QueueManager(QWidget *parent)
     current_playlist_(NULL)
 {
   ui_->setupUi(this);
+
+  ui_->list->setItemDelegate(new QueuedItemDelegate(this));
 }
 
 QueueManager::~QueueManager() {

src/playlist/queuemanager.ui

@@ -21,7 +21,17 @@
    <item>
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>
-      <widget class="QListView" name="list"/>
+      <widget class="QListView" name="list">
+       <property name="alternatingRowColors">
+        <bool>true</bool>
+       </property>
+       <property name="selectionBehavior">
+        <enum>QAbstractItemView::SelectRows</enum>
+       </property>
+       <property name="uniformItemSizes">
+        <bool>true</bool>
+       </property>
+      </widget>
      </item>
      <item>
       <layout class="QVBoxLayout" name="verticalLayout">