Fix label clipping issues using QOpenGLWidget as ChartView viewport

Task-number: QTRD-3701
Change-Id: I8efc20300d2aa6065918e02190da746463a5d504
Reviewed-by: Titta Heikkala <titta.heikkala@theqtcompany.com>

4 files changed, 41 insertions, 28 deletions

diff --git a/src/charts/axis/horizontalaxis.cpp b/src/charts/axis/horizontalaxis.cpp
index fa4b0382..12d2cf8c 100644
--- a/src/charts/axis/horizontalaxis.cpp
+++ b/src/charts/axis/horizontalaxis.cpp
@@ -141,9 +141,10 @@ void HorizontalAxis::updateGeometry()
         qreal widthDiff = rect.width() - boundingRect.width();
 
         //ticks and label position
+        QPointF labelPos;
         if (axis()->alignment() == Qt::AlignTop) {
             if (axis()->isReverse()) {
-                labelItem->setPos(gridRect.right() - layout[layout.size() - i - 1]
+                labelPos = QPointF(gridRect.right() - layout[layout.size() - i - 1]
                         + gridRect.left() - center.x(),
                         axisRect.bottom() - rect.height()
                         + (heightDiff / 2.0) - labelPadding());
@@ -152,21 +153,21 @@ void HorizontalAxis::updateGeometry()
                                   gridRect.right() + gridRect.left() - layout[i],
                                   axisRect.bottom() - labelPadding());
             } else {
-                labelItem->setPos(layout[i] - center.x(), axisRect.bottom() - rect.height()
+                labelPos = QPointF(layout[i] - center.x(), axisRect.bottom() - rect.height()
                                   + (heightDiff / 2.0) - labelPadding());
                 tickItem->setLine(layout[i], axisRect.bottom(),
                                   layout[i], axisRect.bottom() - labelPadding());
             }
         } else if (axis()->alignment() == Qt::AlignBottom) {
             if (axis()->isReverse()) {
-                labelItem->setPos(gridRect.right() - layout[layout.size() - i - 1]
+                labelPos = QPointF(gridRect.right() - layout[layout.size() - i - 1]
                         + gridRect.left() - center.x(),
                         axisRect.top() - (heightDiff / 2.0) + labelPadding());
                 tickItem->setLine(gridRect.right() + gridRect.left() - layout[i], axisRect.top(),
                                   gridRect.right() + gridRect.left() - layout[i],
                                   axisRect.top() + labelPadding());
             } else {
-                labelItem->setPos(layout[i] - center.x(), axisRect.top() - (heightDiff / 2.0)
+                labelPos = QPointF(layout[i] - center.x(), axisRect.top() - (heightDiff / 2.0)
                                   + labelPadding());
                 tickItem->setLine(layout[i], axisRect.top(),
                                   layout[i], axisRect.top() + labelPadding());
@@ -193,7 +194,7 @@ void HorizontalAxis::updateGeometry()
                     && (leftBound == gridRect.left() || rightBound == gridRect.right())) {
                     forceHide = true;
                 } else {
-                    labelItem->setPos(leftBound + (delta / 2.0) - center.x(), labelItem->pos().y());
+                    labelPos.setX(leftBound + (delta / 2.0) - center.x());
                 }
             } else {
                 QCategoryAxis *categoryAxis = static_cast<QCategoryAxis *>(axis());
@@ -202,19 +203,21 @@ void HorizontalAxis::updateGeometry()
                         && (leftBound == gridRect.left() || rightBound == gridRect.right())) {
                         forceHide = true;
                     } else {
-                        labelItem->setPos(leftBound + (delta / 2.0) - center.x(),
-                                          labelItem->pos().y());
+                        labelPos.setX(leftBound + (delta / 2.0) - center.x());
                     }
                 } else if (categoryAxis->labelsPosition()
                            == QCategoryAxis::AxisLabelsPositionOnValue) {
                     if (axis()->isReverse())
-                        labelItem->setPos(leftBound - center.x(), labelItem->pos().y());
+                        labelPos.setX(leftBound - center.x());
                     else
-                        labelItem->setPos(rightBound - center.x(), labelItem->pos().y());
+                        labelPos.setX(rightBound - center.x());
                 }
             }
         }
 
+        // Round to full pixel via QPoint to avoid one pixel clipping on the edge in some cases
+        labelItem->setPos(labelPos.toPoint());
+
         //label overlap detection - compensate one pixel for rounding errors
         if ((labelItem->pos().x() < width && labelItem->toPlainText() == ellipsis) || forceHide ||
             (labelItem->pos().x() + (widthDiff / 2.0)) < (axisRect.left() - 1.0) ||
diff --git a/src/charts/axis/verticalaxis.cpp b/src/charts/axis/verticalaxis.cpp
index dfa1a3b0..0d858704 100644
--- a/src/charts/axis/verticalaxis.cpp
+++ b/src/charts/axis/verticalaxis.cpp
@@ -143,9 +143,10 @@ void VerticalAxis::updateGeometry()
         qreal heightDiff = rect.height() - boundingRect.height();
 
         //ticks and label position
+        QPointF labelPos;
         if (axis()->alignment() == Qt::AlignLeft) {
             if (axis()->isReverse()) {
-                labelItem->setPos(axisRect.right() - rect.width() + (widthDiff / 2.0)
+                labelPos = QPointF(axisRect.right() - rect.width() + (widthDiff / 2.0)
                                   - labelPadding(),
                                   gridRect.top() + gridRect.bottom()
                                   - layout[layout.size() - i - 1] - center.y());
@@ -154,7 +155,7 @@ void VerticalAxis::updateGeometry()
                                   axisRect.right(),
                                   gridRect.top() + gridRect.bottom() - layout[i]);
             } else {
-                labelItem->setPos(axisRect.right() - rect.width() + (widthDiff / 2.0)
+                labelPos = QPointF(axisRect.right() - rect.width() + (widthDiff / 2.0)
                                   - labelPadding(),
                                   layout[i] - center.y());
                 tickItem->setLine(axisRect.right() - labelPadding(), layout[i],
@@ -166,11 +167,11 @@ void VerticalAxis::updateGeometry()
                                   gridRect.top() + gridRect.bottom() - layout[i],
                                   axisRect.left() + labelPadding(),
                                   gridRect.top() + gridRect.bottom() - layout[i]);
-                labelItem->setPos(axisRect.left() + labelPadding() - (widthDiff / 2.0),
+                labelPos = QPointF(axisRect.left() + labelPadding() - (widthDiff / 2.0),
                                   gridRect.top() + gridRect.bottom()
                                   - layout[layout.size() - i - 1] - center.y());
             } else {
-                labelItem->setPos(axisRect.left() + labelPadding() - (widthDiff / 2.0),
+                labelPos = QPointF(axisRect.left() + labelPadding() - (widthDiff / 2.0),
                                   layout[i] - center.y());
                 tickItem->setLine(axisRect.left(), layout[i],
                                   axisRect.left() + labelPadding(), layout[i]);
@@ -199,8 +200,7 @@ void VerticalAxis::updateGeometry()
                     && (lowerBound == gridRect.bottom() || upperBound == gridRect.top())) {
                     forceHide = true;
                 } else {
-                    labelItem->setPos(labelItem->pos().x(),
-                                      lowerBound - (delta / 2.0) - center.y());
+                    labelPos.setY(lowerBound - (delta / 2.0) - center.y());
                 }
             } else {
                 QCategoryAxis *categoryAxis = static_cast<QCategoryAxis *>(axis());
@@ -209,22 +209,24 @@ void VerticalAxis::updateGeometry()
                         && (lowerBound == gridRect.bottom() || upperBound == gridRect.top())) {
                         forceHide = true;
                     } else {
-                        labelItem->setPos(labelItem->pos().x(),
-                                          lowerBound - (delta / 2.0) - center.y());
+                        labelPos.setY(lowerBound - (delta / 2.0) - center.y());
                     }
                 } else if (categoryAxis->labelsPosition()
                            == QCategoryAxis::AxisLabelsPositionOnValue) {
                     labelOnValue = true;
                     if (axis()->isReverse()) {
-                        labelItem->setPos(labelItem->pos().x(), gridRect.top() + gridRect.bottom()
+                        labelPos.setY(gridRect.top() + gridRect.bottom()
                                           - layout[i + 1] - center.y());
                     } else {
-                        labelItem->setPos(labelItem->pos().x(), upperBound - center.y());
+                        labelPos.setY(upperBound - center.y());
                     }
                 }
             }
         }
 
+        // Round to full pixel via QPoint to avoid one pixel clipping on the edge in some cases
+        labelItem->setPos(labelPos.toPoint());
+
         //label overlap detection - compensate one pixel for rounding errors
         if (axis()->isReverse()) {
             if (forceHide)
diff --git a/src/charts/layout/abstractchartlayout.cpp b/src/charts/layout/abstractchartlayout.cpp
index 32158988..223600b7 100644
--- a/src/charts/layout/abstractchartlayout.cpp
+++ b/src/charts/layout/abstractchartlayout.cpp
@@ -156,7 +156,9 @@ QRectF AbstractChartLayout::calculateLegendMinimum(const QRectF &geometry, QLege
 QRectF AbstractChartLayout::calculateTitleGeometry(const QRectF &geometry, ChartTitle *title) const
 {
     title->setGeometry(geometry);
-    QPointF center = geometry.center() - title->boundingRect().center();
+    // Round to full pixel via QPoint to avoid one pixel clipping on the edge in some cases
+    QPointF center((geometry.center() - title->boundingRect().center()).toPoint());
+
     title->setPos(center.x(), title->pos().y());
     return geometry.adjusted(0, title->boundingRect().height()+1, 0, 0);
 }
diff --git a/src/charts/legend/legendlayout.cpp b/src/charts/legend/legendlayout.cpp
index c7d88e18..1d7ea112 100644
--- a/src/charts/legend/legendlayout.cpp
+++ b/src/charts/legend/legendlayout.cpp
@@ -233,10 +233,13 @@ void LegendLayout::setAttachedGeometry(const QRectF &rect)
             // Delete structs from the container
             qDeleteAll(legendWidthList);
 
-            if (m_width < geometry.width())
-                m_legend->d_ptr->items()->setPos(geometry.width() / 2 - m_width / 2, geometry.top());
-            else
-                m_legend->d_ptr->items()->setPos(geometry.topLeft());
+            // Round to full pixel via QPoint to avoid one pixel clipping on the edge in some cases
+            if (m_width < geometry.width()) {
+                m_legend->d_ptr->items()->setPos(QPoint(geometry.width() / 2 - m_width / 2,
+                                                        geometry.top()));
+            } else {
+                m_legend->d_ptr->items()->setPos(geometry.topLeft().toPoint());
+            }
             m_height = size.height();
         }
         break;
@@ -262,10 +265,13 @@ void LegendLayout::setAttachedGeometry(const QRectF &rect)
                 }
             }
 
-            if (m_height < geometry.height())
-                m_legend->d_ptr->items()->setPos(geometry.left(), geometry.height() / 2 - m_height / 2);
-            else
-                m_legend->d_ptr->items()->setPos(geometry.topLeft());
+            // Round to full pixel via QPoint to avoid one pixel clipping on the edge in some cases
+            if (m_height < geometry.height()) {
+                m_legend->d_ptr->items()->setPos(QPoint(geometry.left(),
+                                                        geometry.height() / 2 - m_height / 2));
+            } else {
+                m_legend->d_ptr->items()->setPos(geometry.topLeft().toPoint());
+            }
             m_width = size.width();
             break;
             }