Draw 2 Rectangles below mount points to represent a disk capacity bar

Draws overtop text that's goes below the baseline like a 'j'. It's
fairly difficult to add extra space below the text as the places view
is a "details" view, so the text is vertically centered in the
widget's "row" as you'd desire it to in the main file view.

We can make the widget 8px taller, adding 4px above and below so
there's adequate room for the capacitybar, but that wastes 4px for
each mount point.

Ideally we'd use the "compact" view, which displays the text/size in a
column beside the icon. However the compact view was not designed to
take up the entire width of the viewport. It's also designed to
overflow with a horizontal scrollbar.

src/kitemviews/kstandarditemlistwidget.h

@@ -171,6 +171,14 @@ protected:
     void hideEvent(QHideEvent* event) override;
     bool event(QEvent *event) override;
 
+protected:
+    struct TextInfo
+    {
+        QPointF pos;
+        QStaticText staticText;
+    };
+    QHash<QByteArray, TextInfo*> m_textInfo;
+
 public slots:
     void finishRoleEditing();
 
@@ -239,13 +247,6 @@ private:
     QRectF m_iconRect;          // Cache for KItemListWidget::iconRect()
     QPixmap m_hoverPixmap;      // Cache for modified m_pixmap when hovering the item
 
-    struct TextInfo
-    {
-        QPointF pos;
-        QStaticText staticText;
-    };
-    QHash<QByteArray, TextInfo*> m_textInfo;
-
     QRectF m_textRect;
 
     QList<QByteArray> m_sortedVisibleRoles;

src/panels/places/placesitemlistwidget.cpp

@@ -6,6 +6,16 @@
 
 #include "placesitemlistwidget.h"
 
+#include <QGraphicsView>
+#include <QStyleOption>
+
+#include <KDiskFreeSpaceInfo>
+#include <KMountPoint>
+
+#define CAPACITYBAR_HEIGHT 2
+#define CAPACITYBAR_MARGIN 2
+
+
 PlacesItemListWidget::PlacesItemListWidget(KItemListWidgetInformant* informant, QGraphicsItem* parent) :
     KStandardItemListWidget(informant, parent)
 {
@@ -26,3 +36,78 @@ QPalette::ColorRole PlacesItemListWidget::normalTextColorRole() const
     return QPalette::WindowText;
 }
 
+void PlacesItemListWidget::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
+{
+    KStandardItemListWidget::paint(painter, option, widget);
+
+    bool drawCapacityBar = false;
+    const QUrl url = data().value("url").toUrl();
+    if (url.isLocalFile()) {
+        const QString mountPointPath = url.toLocalFile();
+        KMountPoint::Ptr mp = KMountPoint::currentMountPoints().findByPath(mountPointPath);
+        bool isMountPoint = (mp && mp->mountPoint() == mountPointPath);
+
+        if (isMountPoint) {
+            const KDiskFreeSpaceInfo info = KDiskFreeSpaceInfo::freeSpaceInfo(mountPointPath);
+            drawCapacityBar = info.size() != 0;
+            if (drawCapacityBar) {
+                const TextInfo* textInfo = m_textInfo.value("text");
+                if (textInfo) { // See KStandarItemListWidget::paint() for info on why we check textInfo.
+                    painter->save();
+
+                    QRect capacityRect(
+                        textInfo->pos.x(),
+                        option->rect.top() + option->rect.height() - CAPACITYBAR_HEIGHT - CAPACITYBAR_MARGIN,
+                        qMin((qreal)option->rect.width(), selectionRect().width()) - (textInfo->pos.x() - option->rect.left()),
+                        CAPACITYBAR_HEIGHT
+                    );
+
+                    const qreal ratio = (qreal)info.used() / (qreal)info.size();
+                    // qDebug() << "ratio:" << ratio << "(" << info.used() << "/" << info.size() << ")";
+
+                    const QPalette pal = palette();
+                    const QPalette::ColorGroup group = isActiveWindow() ? QPalette::Active : QPalette::Inactive;
+                    // QColor bgColor = QColor::fromRgb(230, 230, 230);
+                    // QColor outlineColor = QColor::fromRgb(208, 208, 208);
+                    // QColor bgColor = QColor::fromRgb(0, 230, 0);
+                    // QColor outlineColor = QColor::fromRgb(208, 0, 0, 127);
+                    // QColor normalUsedColor = QColor::fromRgb(38, 160, 218);
+                    // QColor dangerUsedColor = QColor::fromRgb(218, 38, 38);
+                    // QColor bgColor = pal.base().color().darker(130);
+                    // QColor outlineColor = pal.base().color().darker(150);
+
+                    QPalette::ColorRole role;
+                    // role = isSelected() ? QPalette::Highlight : QPalette::Window;
+                    // QColor bgColor = styleOption().palette.color(group, role).darker(150);
+                    // QColor outlineColor = styleOption().palette.color(group, role).darker(170);
+                    QColor bgColor = isSelected()
+                        ? styleOption().palette.color(group, QPalette::Highlight).darker(180)
+                        : styleOption().palette.color(group, QPalette::Window).darker(120);
+
+                    role = isSelected() ? QPalette::HighlightedText : QPalette::Highlight;
+                    QColor normalUsedColor = styleOption().palette.color(group, role);
+
+                    QColor dangerUsedColor = QColor::fromRgb(218, 38, 38);
+
+                    // Background
+                    painter->fillRect(capacityRect, bgColor);
+
+                    // Outline
+                    // const QRect outlineRect(capacityRect.x(), capacityRect.y(), capacityRect.width() - 1, capacityRect.height() - 1);
+                    // painter->setPen(outlineColor);
+                    // painter->drawRect(outlineRect);
+
+                    // Fill
+                    const QRect fillRect(capacityRect.x(), capacityRect.y(), capacityRect.width() * ratio, capacityRect.height());
+                    if (ratio < 0.95) { // Fill
+                        painter->fillRect(fillRect, normalUsedColor);
+                    } else {
+                        painter->fillRect(fillRect, dangerUsedColor);
+                    }
+
+                    painter->restore();
+                }
+            }
+        }
+    }
+}

src/panels/places/placesitemlistwidget.h

@@ -21,6 +21,8 @@ public:
     PlacesItemListWidget(KItemListWidgetInformant* informant, QGraphicsItem* parent);
     ~PlacesItemListWidget() override;
 
+    void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = nullptr) override;
+
 protected:
     bool isHidden() const override;
     QPalette::ColorRole normalTextColorRole() const override;