Qt: make grid view customizable by stylesheet

ui/drivers/qt/gridview.cpp

@@ -6,21 +6,20 @@
 
 /* http://www.informit.com/articles/article.aspx?p=1613548 */
 
-ThumbnailDelegate::ThumbnailDelegate(QObject* parent) :
+ThumbnailDelegate::ThumbnailDelegate(const GridItem &gridItem, QObject* parent) :
-   QStyledItemDelegate(parent)
+   QStyledItemDelegate(parent), m_style(gridItem)
 {
 }
-
 void ThumbnailDelegate::paint(QPainter* painter, const QStyleOptionViewItem &option, const QModelIndex& index) const
 {
    QStyleOptionViewItem opt = option;
    const QWidget *widget = opt.widget;
    QStyle *style = widget->style();
-   int margin = 11;
+   int padding = m_style.padding;
-   int textMargin = 4;
+   int textTopMargin = 4; /* Qt seemingly reports -4 the actual line height. */
-   int textHeight = painter->fontMetrics().height() + margin + margin;
+   int textHeight = painter->fontMetrics().height() + padding + padding;
    QRect rect = opt.rect;
-   QRect adjusted = rect.adjusted(margin, margin, -margin, -textHeight + textMargin);
+   QRect adjusted = rect.adjusted(padding, padding, -padding, -textHeight + textTopMargin);
    QPixmap pixmap = index.data(PlaylistModel::THUMBNAIL).value<QPixmap>();
 
    painter->save();
@@ -34,14 +33,14 @@ void ThumbnailDelegate::paint(QPainter* painter, const QStyleOptionViewItem &opt
    if (!pixmap.isNull())
    {
       QPixmap pixmapScaled = pixmap.scaled(adjusted.size(), Qt::KeepAspectRatio, Qt::SmoothTransformation);
-      style->drawItemPixmap(painter, adjusted, Qt::AlignHCenter | Qt::AlignBottom, pixmapScaled);
+      style->drawItemPixmap(painter, adjusted, Qt::AlignHCenter | m_style.thumbnailVerticalAlignmentFlag, pixmapScaled);
    }
 
    /* draw the text */
    if (!opt.text.isEmpty())
    {
       QPalette::ColorGroup cg = opt.state & QStyle::State_Enabled ? QPalette::Normal : QPalette::Disabled;
-      QRect textRect = QRect(rect.x() + margin, rect.y() + adjusted.height() - textMargin + margin, rect.width() - 2 * margin, textHeight);
+      QRect textRect = QRect(rect.x() + padding, rect.y() + adjusted.height() - textTopMargin + padding, rect.width() - 2 * padding, textHeight);
       QString elidedText = painter->fontMetrics().elidedText(opt.text, opt.textElideMode, textRect.width(), Qt::TextShowMnemonic);
 
       if (cg == QPalette::Normal && !(opt.state & QStyle::State_Active))
@@ -95,7 +94,8 @@ void GridView::calculateRectsIfNecessary() const
 
    const int maxWidth = viewport()->width();
 
-   switch (m_viewMode) {
+   switch (m_viewMode)
+   {
       case Anchored:
       {
          int columns = (maxWidth - m_spacing) / (m_size + m_spacing);
@@ -114,7 +114,6 @@ void GridView::calculateRectsIfNecessary() const
                m_rectForRow[row] = QRectF(x, y, m_size, m_size);
                x = nextX;
             }
-         m_idealHeight = y + m_size + m_spacing;
          }
          break;
       }
@@ -137,7 +136,6 @@ void GridView::calculateRectsIfNecessary() const
                m_rectForRow[row] = QRectF(x, y, m_size, m_size);
                x = nextX;
             }
-         m_idealHeight = y + m_size + m_spacing;
          }
          break;
       }
@@ -156,7 +154,7 @@ void GridView::calculateRectsIfNecessary() const
          }
          break;
    }
-
+   m_idealHeight = y + m_size + m_spacing;
    m_hashIsDirty = false;
    viewport()->update();
 }
@@ -407,3 +405,77 @@ void GridView::updateGeometries()
 
    emit(visibleItemsChangedMaybe());
 }
+
+QString GridView::getLayout() const
+{
+   switch (m_viewMode)
+   {
+      case Simple:
+         return "simple";
+      case Anchored:
+         return "anchored";
+      case Centered:
+      default:
+         return "centered";
+   }
+}
+
+void GridView::setLayout(QString layout)
+{
+   if (layout == "anchored")
+      m_viewMode = Anchored;
+   else if (layout == "centered")
+      m_viewMode = Centered;
+   else if (layout == "fixed")
+      m_viewMode = Simple;
+}
+
+int GridView::getSpacing() const
+{
+   return m_spacing;
+}
+
+void GridView::setSpacing(const int spacing)
+{
+   m_spacing = spacing;
+}
+
+GridItem::GridItem(QWidget* parent) : QWidget(parent)
+, thumbnailVerticalAlignmentFlag(Qt::AlignBottom)
+, padding(11)
+{
+}
+
+int GridItem::getPadding() const
+{
+   return padding;
+}
+
+void GridItem::setPadding(const int value)
+{
+   padding = value;
+}
+
+QString GridItem::getThumbnailVerticalAlign() const
+{
+   switch (thumbnailVerticalAlignmentFlag)
+   {
+   case Qt::AlignTop:
+      return "top";
+   case Qt::AlignVCenter:
+      return "center";
+   case Qt::AlignBottom:
+   default:
+      return "bottom";
+   }
+}
+
+void GridItem::setThumbnailVerticalAlign(const QString valign)
+{
+   if (valign == "top")
+      thumbnailVerticalAlignmentFlag = Qt::AlignTop;
+   else if (valign == "center")
+      thumbnailVerticalAlignmentFlag = Qt::AlignVCenter;
+   else if (valign == "bottom")
+      thumbnailVerticalAlignmentFlag = Qt::AlignBottom;
+}

ui/drivers/qt/gridview.h

@@ -4,19 +4,32 @@
 #include <QAbstractItemView>
 #include <QStyledItemDelegate>
 
+#define DEFAULT_GRID_ITEM_MARGIN 11
+#define DEFAULT_GRID_ITEM_THUMBNAIL_ALIGNMENT "bottom"
+#define DEFAULT_GRID_SPACING 7
+#define DEFAULT_GRID_LAYOUT "centered"
+
+class GridItem;
+
 class ThumbnailDelegate : public QStyledItemDelegate
 {
    Q_OBJECT
 
 public:
-   ThumbnailDelegate(QObject* parent = 0);
+   ThumbnailDelegate(const GridItem &gridItem, QObject* parent = 0);
    void paint(QPainter* painter, const QStyleOptionViewItem &option, const QModelIndex& index) const;
+
+private:
+   const GridItem &m_style;
 };
 
 class GridView : public QAbstractItemView
 {
    Q_OBJECT
 
+   Q_PROPERTY(QString layout READ getLayout WRITE setLayout DESIGNABLE true SCRIPTABLE true)
+   Q_PROPERTY(int spacing READ getSpacing WRITE setSpacing DESIGNABLE true SCRIPTABLE true)
+
 public:
    enum ViewMode
    {
@@ -35,6 +48,10 @@ public:
    void scrollTo(const QModelIndex &index, QAbstractItemView::ScrollHint);
    void setGridSize(const int newSize);
    void setviewMode(ViewMode mode);
+   QString getLayout() const;
+   void setLayout(QString layout);
+   int getSpacing() const;
+   void setSpacing(const int spacing);
 
 signals:
    void visibleItemsChangedMaybe() const;
@@ -63,7 +80,7 @@ private:
    void refresh();
 
    int m_size = 255;
-   int m_spacing = 7;
+   int m_spacing = DEFAULT_GRID_SPACING;
    QVector<QModelIndex> m_visibleIndexes;
    ViewMode m_viewMode = Centered;
    mutable int m_idealHeight;

ui/drivers/qt/ui_qt_themes.h

@@ -431,5 +431,9 @@ static const QString qt_theme_dark_stylesheet = QStringLiteral(R"(
    GridView {
       background-color:rgb(25,25,25);
       selection-color: white;
+      qproperty-layout: "fixed";
+   }
+   GridItem {
+      qproperty-thumbnailvalign: "center";
    }
 )");

ui/drivers/qt/ui_qt_window.cpp

@@ -322,6 +322,7 @@ MainWindow::MainWindow(QWidget *parent) :
    ,m_playlistThumbnailDownloadWasCanceled(false)
    ,m_pendingDirScrollPath()
    ,m_thumbnailTimer(new QTimer(this))
+   ,m_gridItem(this)
 {
    settings_t *settings = config_get_ptr();
    QDir playlistDir(settings->paths.directory_playlist);
@@ -417,7 +418,7 @@ MainWindow::MainWindow(QWidget *parent) :
    m_tableView->setSortingEnabled(true);
    m_tableView->verticalHeader()->setVisible(false);
 
-   m_gridView->setItemDelegate(new ThumbnailDelegate(this));
+   m_gridView->setItemDelegate(new ThumbnailDelegate(m_gridItem, this));
    m_gridView->setModel(m_proxyModel);
 
    m_logWidget->setObjectName("logWidget");
@@ -566,6 +567,7 @@ MainWindow::MainWindow(QWidget *parent) :
    connect(m_thumbnailTimer, SIGNAL(timeout()), this, SLOT(updateVisibleItems()));
    connect(this, SIGNAL(updateThumbnails()), this, SLOT(updateVisibleItems()));
 
+   /* TODO: Handle scroll and resize differently. */
    connect(m_gridView, SIGNAL(visibleItemsChangedMaybe()), this, SLOT(startTimer()));
 
    connect(m_gridView, SIGNAL(clicked(const QModelIndex&)), this, SLOT(currentItemChanged(const QModelIndex&)));
@@ -1134,6 +1136,8 @@ void MainWindow::setTheme(Theme theme)
 {
    m_currentTheme = theme;
 
+   setDefaultCustomProperties();
+
    switch(theme)
    {
       case THEME_SYSTEM_DEFAULT:
@@ -1159,6 +1163,14 @@ void MainWindow::setTheme(Theme theme)
    }
 }
 
+void MainWindow::setDefaultCustomProperties()
+{
+   m_gridView->setLayout(QString(DEFAULT_GRID_LAYOUT));
+   m_gridView->setSpacing(DEFAULT_GRID_SPACING);
+   m_gridItem.setThumbnailVerticalAlign(QString(DEFAULT_GRID_ITEM_THUMBNAIL_ALIGNMENT));
+   m_gridItem.setPadding(DEFAULT_GRID_ITEM_MARGIN);
+}
+
 void MainWindow::changeThumbnailType(ThumbnailType type)
 {
    m_playlistModel->setThumbnailType(type);

ui/drivers/ui_qt.h

@@ -271,6 +271,26 @@ public slots:
    void appendMessage(const QString& text);
 };
 
+/* Used to store styling since delegates don't inherit QWidget. */
+class GridItem : public QWidget
+{
+   Q_OBJECT
+
+   Q_PROPERTY(QString thumbnailvalign READ getThumbnailVerticalAlign WRITE setThumbnailVerticalAlign)
+   Q_PROPERTY(int padding READ getPadding WRITE setPadding)
+
+public:
+   GridItem(QWidget* parent);
+
+   Qt::AlignmentFlag thumbnailVerticalAlignmentFlag;
+   int padding;
+
+   int getPadding() const;
+   void setPadding(const int value);
+   QString getThumbnailVerticalAlign() const;
+   void setThumbnailVerticalAlign(const QString valign);
+};
+
 class MainWindow : public QMainWindow
 {
    Q_OBJECT
@@ -347,6 +367,7 @@ public:
    QString getSpecialPlaylistPath(SpecialPlaylist playlist);
    QVector<QPair<QString, QString> > getPlaylists();
    QString getScrubbedString(QString str);
+   void setDefaultCustomProperties();
 
 signals:
    void thumbnailChanged(const QPixmap &pixmap);
@@ -574,6 +595,7 @@ private:
    QString m_pendingDirScrollPath;
 
    QTimer *m_thumbnailTimer;
+   GridItem m_gridItem;
 
 protected:
    void closeEvent(QCloseEvent *event);