Merge remote-tracking branch 'origin/tqtc/lts-5.15.5' into tqtc/lts-5.15-opensourcev5.15.5-lts-lgpl

Change-Id: I31594ab27a7be14283f1e2b415540a6d28e2a5bc

5 files changed, 72 insertions, 16 deletions

diff --git a/.qmake.conf b/.qmake.conf
index 7dc754c7..0eeba9a5 100644
--- a/.qmake.conf
+++ b/.qmake.conf
@@ -2,4 +2,4 @@ load(qt_build_config)
 
 DEFINES += QT_NO_JAVA_STYLE_ITERATORS QT_NO_LINKED_LIST
 
-MODULE_VERSION = 5.15.4
+MODULE_VERSION = 5.15.5
diff --git a/src/charts/axis/chartaxiselement.cpp b/src/charts/axis/chartaxiselement.cpp
index 8db5ef36..33a31242 100644
--- a/src/charts/axis/chartaxiselement.cpp
+++ b/src/charts/axis/chartaxiselement.cpp
@@ -419,7 +419,11 @@ QStringList ChartAxisElement::createValueLabels(qreal min, qreal max, int ticks,
         return labels;
 
     if (format.isEmpty()) {
-        int n = qMax(int(-qFloor(std::log10((max - min) / (ticks - 1)))), 0) + 1;
+        // Calculate how many decimal digits are needed to show difference between ticks,
+        // for example tick marks 1.002 and 1.003 have a difference of 0.001 and need 3 decimals.
+        // For differences >= 1 (positive log10) use always 1 decimal.
+        double l10 = std::log10((max - min) / (ticks - 1));
+        int n = qMax(int(-qFloor(l10)), 0) + 1;
         if (tickType == QValueAxis::TicksFixed) {
             for (int i = 0; i < ticks; i++) {
                 qreal value = min + (i * (max - min) / (ticks - 1));
diff --git a/src/charts/axis/horizontalaxis.cpp b/src/charts/axis/horizontalaxis.cpp
index 3bbc5ebe..5b74b563 100644
--- a/src/charts/axis/horizontalaxis.cpp
+++ b/src/charts/axis/horizontalaxis.cpp
@@ -102,7 +102,6 @@ void HorizontalAxis::updateGeometry()
     else if (axis()->alignment() == Qt::AlignBottom)
         arrowItem->setLine(gridRect.left(), axisRect.top(), gridRect.right(), axisRect.top());
 
-    qreal width = 0;
     const QLatin1String ellipsis("...");
 
     //title
@@ -133,6 +132,8 @@ void HorizontalAxis::updateGeometry()
     QList<QGraphicsItem *> lines = gridItems();
     QList<QGraphicsItem *> shades = shadeItems();
 
+    qreal last_label_max_x = 0;
+
     for (int i = 0; i < layout.size(); ++i) {
         //items
         QGraphicsLineItem *gridItem = static_cast<QGraphicsLineItem*>(lines.at(i));
@@ -160,6 +161,7 @@ void HorizontalAxis::updateGeometry()
             labelItem->setHtml(text);
         } else  {
             qreal labelWidth = axisRect.width() / layout.count() - (2 * labelPadding());
+            // Replace digits with ellipsis "..." if number does not fit
             QString truncatedText = ChartPresenter::truncatedText(axis()->labelsFont(), text,
                                                                   axis()->labelsAngle(),
                                                                   labelWidth,
@@ -255,13 +257,14 @@ void HorizontalAxis::updateGeometry()
         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) ||
-            (labelItem->pos().x() + (widthDiff / 2.0) - 1.0) > axisRect.right()) {
+        if ((labelItem->pos().x() < last_label_max_x && labelItem->toPlainText() == ellipsis)
+            || forceHide
+            || (labelItem->pos().x() + (widthDiff / 2.0))       < (axisRect.left() - 1.0)
+            || (labelItem->pos().x() + (widthDiff / 2.0) - 1.0) > axisRect.right()) {
             labelItem->setVisible(false);
         } else {
             labelItem->setVisible(true);
-            width = boundingRect.width() + labelItem->pos().x();
+            last_label_max_x = boundingRect.width() + labelItem->pos().x();
         }
 
         //shades
diff --git a/src/charts/chartpresenter.cpp b/src/charts/chartpresenter.cpp
index 6be0b141..12d3958d 100644
--- a/src/charts/chartpresenter.cpp
+++ b/src/charts/chartpresenter.cpp
@@ -478,18 +478,59 @@ ChartTitle *ChartPresenter::titleElement()
     return m_title;
 }
 
+template <int TSize>
+struct TextBoundCache
+{
+    struct element
+    {
+        quint32 lastUsed;
+        QRectF bounds;
+    };
+    QHash<QString, element> elements;
+    quint32 usedCounter = 0;
+    QGraphicsTextItem dummyText;
+
+    QRectF bounds(const QFont &font, const QString &text)
+    {
+        const QString key = font.key() + text;
+        auto elem = elements.find(key);
+        if (elem != elements.end()) {
+            usedCounter++;
+            elem->lastUsed = usedCounter;
+            return elem->bounds;
+        }
+        dummyText.setFont(font);
+        dummyText.setHtml(text);
+        const QRectF bounds = dummyText.boundingRect();
+        if (elements.size() >= TSize) {
+            auto elem = std::min_element(elements.begin(), elements.end(),
+                                         [](const element &a, const element &b) {
+                return a.lastUsed < b.lastUsed;
+            });
+            if (elem != elements.end()) {
+                const QString key = elem.key();
+                elements.remove(key);
+            }
+        }
+        elements.insert(key, {usedCounter++, bounds});
+        return bounds;
+    }
+    QTextDocument *document()
+    {
+        return dummyText.document();
+    }
+};
+
 QRectF ChartPresenter::textBoundingRect(const QFont &font, const QString &text, qreal angle)
 {
-    static QGraphicsTextItem dummyTextItem;
+    static TextBoundCache<32> textBoundCache;
     static bool initMargin = true;
     if (initMargin) {
-        dummyTextItem.document()->setDocumentMargin(textMargin());
+        textBoundCache.document()->setDocumentMargin(textMargin());
         initMargin = false;
     }
 
-    dummyTextItem.setFont(font);
-    dummyTextItem.setHtml(text);
-    QRectF boundingRect = dummyTextItem.boundingRect();
+    QRectF boundingRect = textBoundCache.bounds(font, text);
 
     // Take rotation into account
     if (angle) {
diff --git a/src/charts/layout/cartesianchartlayout.cpp b/src/charts/layout/cartesianchartlayout.cpp
index 5e32c2e1..a446c7d5 100644
--- a/src/charts/layout/cartesianchartlayout.cpp
+++ b/src/charts/layout/cartesianchartlayout.cpp
@@ -193,14 +193,18 @@ QRectF CartesianChartLayout::calculateAxisGeometry(const QRectF &geometry,
             if (leftSqueezeRatio < 1.0)
                 width *= leftSqueezeRatio;
             leftOffset+=width;
-            axis->setGeometry(QRect(chartRect.left()-leftOffset, geometry.top(),width, geometry.bottom()),chartRect);
+            axis->setGeometry(QRect(chartRect.left() - leftOffset, chartRect.top(),
+                                    width, chartRect.bottom()),
+                              chartRect);
             break;
         }
         case Qt::AlignRight:{
             qreal width = size.width();
             if (rightSqueezeRatio < 1.0)
                 width *= rightSqueezeRatio;
-            axis->setGeometry(QRect(chartRect.right()+rightOffset,geometry.top(),width,geometry.bottom()),chartRect);
+            axis->setGeometry(QRect(chartRect.right() + rightOffset, chartRect.top(),
+                                    width, chartRect.bottom()),
+                              chartRect);
             rightOffset+=width;
             break;
         }
@@ -208,7 +212,9 @@ QRectF CartesianChartLayout::calculateAxisGeometry(const QRectF &geometry,
             qreal height = size.height();
             if (topSqueezeRatio < 1.0)
                 height *= topSqueezeRatio;
-            axis->setGeometry(QRect(geometry.left(), chartRect.top() - topOffset - height, geometry.width(), height), chartRect);
+            axis->setGeometry(QRect(chartRect.left(), chartRect.top() - topOffset - height,
+                                    chartRect.width(), height),
+                              chartRect);
             topOffset += height;
             break;
         }
@@ -216,7 +222,9 @@ QRectF CartesianChartLayout::calculateAxisGeometry(const QRectF &geometry,
             qreal height = size.height();
             if (bottomSqueezeRatio < 1.0)
                 height *= bottomSqueezeRatio;
-            axis->setGeometry(QRect(geometry.left(), chartRect.bottom() + bottomOffset, geometry.width(), height), chartRect);
+            axis->setGeometry(QRect(chartRect.left(), chartRect.bottom() + bottomOffset,
+                                    chartRect.width(), height),
+                              chartRect);
             bottomOffset += height;
             break;
         }