QmlProfiler: Restrict rendering of timeline to visible area

The timeline can cover a large vertical space. The introduction of
the Flickable element to navigate that space has reverted the effect
of commit 5eb057c7e. This change restores the performance
improvements and avoids overflows in the underlying buffers.

Change-Id: I86ddd66652ee0a26c81619682a883622072b0f87
Reviewed-by: Kai Koehne <kai.koehne@digia.com>

src/plugins/qmlprofiler/qml/MainView.qml

@@ -408,12 +408,15 @@ Rectangle {
                 profilerModelProxy: qmlProfilerModelProxy
 
                 x: flick.contentX
+                y: vertflick.contentY
                 width: flick.width
-                height: parent.height
+                height: vertflick.height
 
                 property real startX: 0
 
                 onEndTimeChanged: requestPaint()
+                onYChanged: requestPaint()
+                onHeightChanged: requestPaint()
 
                 onStartXChanged: {
                     var newStartTime = Math.round(startX * (endTime - startTime) / flick.width) +

src/plugins/qmlprofiler/timelinerenderer.cpp

@@ -118,15 +118,14 @@ void TimelineRenderer::drawItemsToPainter(QPainter *p, int modelIndex, int fromI
     int modelRowStart = 0;
     for (int mi = 0; mi < modelIndex; mi++)
         modelRowStart += m_profilerModelProxy->rowCount(mi);
-    QRect window = p->window();
 
     for (int i = fromIndex; i <= toIndex; i++) {
         int currentX, currentY, itemWidth, itemHeight;
         currentX = (m_profilerModelProxy->getStartTime(modelIndex, i) - m_startTime) * m_spacing;
 
         int rowNumber = m_profilerModelProxy->getEventRow(modelIndex, i);
-        currentY = (modelRowStart + rowNumber) * DefaultRowHeight;
+        currentY = (modelRowStart + rowNumber) * DefaultRowHeight - y();
-        if (currentY >= window.bottom())
+        if (currentY >= height())
             continue;
 
         itemWidth = m_profilerModelProxy->getDuration(modelIndex, i) * m_spacing;
@@ -135,7 +134,7 @@ void TimelineRenderer::drawItemsToPainter(QPainter *p, int modelIndex, int fromI
 
         itemHeight = DefaultRowHeight * m_profilerModelProxy->getHeight(modelIndex, i);
         currentY += DefaultRowHeight - itemHeight;
-        if (currentY + itemHeight < window.top())
+        if (currentY + itemHeight < 0)
             continue;
 
         // normal events
@@ -175,7 +174,9 @@ void TimelineRenderer::drawSelectionBoxes(QPainter *p, int modelIndex, int fromI
             continue;
 
         currentX = (m_profilerModelProxy->getStartTime(modelIndex, i) - m_startTime) * m_spacing;
-        currentY = (modelRowStart + m_profilerModelProxy->getEventRow(modelIndex, i)) * DefaultRowHeight;
+        currentY = (modelRowStart + m_profilerModelProxy->getEventRow(modelIndex, i)) * DefaultRowHeight - y();
+        if (currentY + DefaultRowHeight < 0 || height() < currentY)
+            continue;
 
         itemWidth = m_profilerModelProxy->getDuration(modelIndex, i) * m_spacing;
         if (itemWidth < 1)
@@ -206,7 +207,6 @@ void TimelineRenderer::drawBindingLoopMarkers(QPainter *p, int modelIndex, int f
     QPen markerPen = QPen(QColor("orange"),2);
     QBrush shadowBrush = QBrush(QColor("grey"));
     QBrush markerBrush = QBrush(QColor("orange"));
-    QRect window = p->window();
 
     p->save();
     for (int i = fromIndex; i <= toIndex; i++) {
@@ -216,15 +216,13 @@ void TimelineRenderer::drawBindingLoopMarkers(QPainter *p, int modelIndex, int f
             xfrom = (m_profilerModelProxy->getStartTime(modelIndex, i) +
                      m_profilerModelProxy->getDuration(modelIndex, i)/2 -
                      m_startTime) * m_spacing;
-            yfrom = getYPosition(modelIndex, i);
+            yfrom = getYPosition(modelIndex, i) + DefaultRowHeight / 2 - y();
-            yfrom += DefaultRowHeight / 2;
 
             // to
             xto = (m_profilerModelProxy->getStartTime(modelIndex, destindex) +
                    m_profilerModelProxy->getDuration(modelIndex, destindex)/2 -
                    m_startTime) * m_spacing;
-            yto = getYPosition(modelIndex, destindex);
+            yto = getYPosition(modelIndex, destindex) + DefaultRowHeight / 2 - y();
-            yto += DefaultRowHeight / 2;
 
             // radius
             int eventWidth = m_profilerModelProxy->getDuration(modelIndex, i) * m_spacing;
@@ -235,8 +233,8 @@ void TimelineRenderer::drawBindingLoopMarkers(QPainter *p, int modelIndex, int f
                 radius = 2;
 
             int shadowoffset = 2;
-            if ((yfrom + radius + shadowoffset < window.top() && yto + radius + shadowoffset < window.top()) ||
+            if ((yfrom + radius + shadowoffset < 0 && yto + radius + shadowoffset < 0) ||
-                    (yfrom - radius >= window.bottom() && yto - radius >= window.bottom()))
+                    (yfrom - radius >= height() && yto - radius >= height()))
                 return;
 
             // shadow
@@ -322,8 +320,8 @@ void TimelineRenderer::manageHovered(int mouseX, int mouseY)
         return;
 
     qint64 time = mouseX * (m_endTime - m_startTime) / width() + m_startTime;
-    int row = mouseY / DefaultRowHeight;
+    int row = (mouseY + y()) / DefaultRowHeight;
-    int modelIndex = modelFromPosition(mouseY);
+    int modelIndex = modelFromPosition(mouseY + y());
 
     // already covered? nothing to do
     if (m_currentSelection.eventIndex != -1 &&