scroll the controls panel's rows instead of clipping them

src/ui/ControlsPanel.cpp

@@ -5,6 +5,8 @@
 #include <QHBoxLayout>
 #include <QLabel>
 #include <QMouseEvent>
+#include <QScrollArea>
+#include <QScrollBar>
 #include <QTimer>
 #include <QVBoxLayout>
 
@@ -15,10 +17,15 @@
 namespace
 {
 
-const int kMarginPx      = 8;   // between the band's edge and the panel
+const int kMarginPx      = 8;   // between the view's edge and the panel
 const int kCardMarginPx  = 8;   // inside the panel, around its content
+const int kHeadingGapPx  = 4;   // between the heading and the rows
 const int kRefreshMs     = 50;  // see the class comment on why this polls
 
+// The panel's border, from the stylesheet below. Spelled out because the stylesheet box
+// is what sets it and asking the style for it before the first show is unreliable.
+const int kBorderPx = 1;
+
 // Separates the heading's name from its detail, e.g. "BUILD MODE * Assembler".
 const QChar kHeadingSeparator(0x00B7);  // U+00B7 MIDDLE DOT
 
@@ -117,7 +124,7 @@ ControlsPanel::ControlsPanel(const GameWorldView* view, QWidget* parent)
     QVBoxLayout* outerLayout = new QVBoxLayout(this);
     outerLayout->setContentsMargins(kCardMarginPx, kCardMarginPx,
                                     kCardMarginPx, kCardMarginPx);
-    outerLayout->setSpacing(4);
+    outerLayout->setSpacing(kHeadingGapPx);
 
     m_heading = new QLabel(this);
     m_heading->setObjectName(QStringLiteral("controlHeading"));
@@ -125,11 +132,24 @@ ControlsPanel::ControlsPanel(const GameWorldView* view, QWidget* parent)
     m_heading->setFont(makeSpacedFont(font(), /*bold*/ true, /*pointSizeDelta*/ 0));
     outerLayout->addWidget(m_heading);
 
+    // Rows taller than the space available scroll rather than being cut off
+    // (REQ-UI-CONTROLS-PANEL). The viewport is transparent so the panel's own rounded
+    // chrome shows through, and horizontal scrolling is off because the width always
+    // follows the content.
     m_rows       = new QWidget(this);
     m_rowsLayout = new QVBoxLayout(m_rows);
     m_rowsLayout->setContentsMargins(0, 0, 0, 0);
     m_rowsLayout->setSpacing(0);
-    outerLayout->addWidget(m_rows);
+    m_rows->setAutoFillBackground(false);
+
+    m_scrollArea = new QScrollArea(this);
+    m_scrollArea->setFrameShape(QFrame::NoFrame);
+    m_scrollArea->setWidgetResizable(true);
+    m_scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    m_scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
+    m_scrollArea->viewport()->setAutoFillBackground(false);
+    m_scrollArea->setWidget(m_rows);
+    outerLayout->addWidget(m_scrollArea);
 
     // Polling rather than subscribing; see the class comment.
     m_refreshTimer = new QTimer(this);
@@ -153,7 +173,7 @@ void ControlsPanel::mousePressEvent(QMouseEvent* event)
     if (m_heading->geometry().contains(event->pos()))
     {
         m_collapsed = !m_collapsed;
-        m_rows->setVisible(!m_collapsed);
+        m_scrollArea->setVisible(!m_collapsed);
         refit();
     }
     event->accept();
@@ -220,7 +240,7 @@ void ControlsPanel::rebuild(const ControlContext& context)
         addAndShow(m_rowsLayout, makeRow(action, context, m_rows));
     }
 
-    m_rows->setVisible(!m_collapsed);
+    m_scrollArea->setVisible(!m_collapsed);
     refit();
 }
 
@@ -270,22 +290,33 @@ void ControlsPanel::refit()
     m_rowsLayout->invalidate();
     m_rowsLayout->activate();
 
-    // Deliberately not activating the panel's own layout here. That lays the heading
-    // and the rows out inside the geometry the panel still has from the previous
-    // context, which is the wrong frame of reference for choosing the new one.
-    // totalSizeHint answers "how big does this need to be" without reference to how big
-    // it currently is; setGeometry below then re-runs the outer layout on its own.
-    layout()->invalidate();
-    const QSize needed = layout()->totalSizeHint();
-
     const QRect band = m_worldRect.adjusted(kMarginPx, kMarginPx, -kMarginPx, -kMarginPx);
     if (band.width() <= 0 || band.height() <= 0) { return; }
 
+    // Measured from the heading and the rows directly rather than from the panel's own
+    // layout: the rows now sit in a scroll area, whose size hint describes a viewport
+    // and says nothing about how tall its contents are. Deliberately not activating the
+    // panel's own layout either -- that lays its children out inside the geometry left
+    // over from the previous context, which is the wrong frame of reference for
+    // choosing the new one. setGeometry below re-runs it.
+    const int   chromePx    = 2 * (kCardMarginPx + kBorderPx);
+    const QSize headingHint = m_heading->sizeHint();
+    const QSize rowsHint    = m_rows->sizeHint();
+
+    int contentWidthPx  = headingHint.width();
+    int contentHeightPx = headingHint.height();
+    if (!m_collapsed)
+    {
+        contentWidthPx  = qMax(contentWidthPx, rowsHint.width());
+        contentHeightPx += kHeadingGapPx + rowsHint.height();
+    }
+    const int wantedHeightPx = contentHeightPx + chromePx;
+
     // The bottom-left corner of the view, growing upward as rows are added
     // (REQ-UI-CONTROLS-PANEL).
-    const int widthPx  = qMin(needed.width(), band.width());
-    int       heightPx = qMin(needed.height(), band.height());
-    int       topPx    = band.bottom() - heightPx + 1;
+    int widthPx  = qMin(contentWidthPx + chromePx, band.width());
+    int heightPx = qMin(wantedHeightPx, band.height());
+    int topPx    = band.bottom() - heightPx + 1;
 
     // The build button bar is centered and sized to its buttons, so it usually leaves
     // this corner free and the panel can share the bottom edge with it. Only when the
@@ -299,5 +330,13 @@ void ControlsPanel::refit()
         topPx    = m_buildBarRect.top() - kMarginPx - heightPx;
     }
 
+    // Whatever the rows lost to either cap, they scroll for. The scrollbar needs its
+    // own width, or it would appear over the labels.
+    if (heightPx < wantedHeightPx)
+    {
+        widthPx = qMin(widthPx + m_scrollArea->verticalScrollBar()->sizeHint().width(),
+                       band.width());
+    }
+
     setGeometry(band.left(), topPx, widthPx, heightPx);
 }

src/ui/ControlsPanel.h

@@ -10,6 +10,7 @@
 
 class GameWorldView;
 class QLabel;
+class QScrollArea;
 class QTimer;
 class QVBoxLayout;
 
@@ -64,6 +65,9 @@ private:
     const GameWorldView* m_view;
 
     QLabel*      m_heading;
+    // Scrolls the rows once they outgrow the space the panel has (REQ-UI-CONTROLS-PANEL).
+    // The heading is deliberately outside it, so it stays put and stays clickable.
+    QScrollArea* m_scrollArea;
     QWidget*     m_rows;
     QVBoxLayout* m_rowsLayout;
     QTimer*      m_refreshTimer;