Added minor ticks to value axis

Added possibility to set minor tick for value axis. By default the
count of minor ticks is zero. The arrow of minor ticks follows the
color and pen of the arrows of the major ticks as it's part of axis.

Change-Id: I8a422caaeedcd18ee6144e8636e3903d16f0632c
Task-number: QTRD-3294
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@theqtcompany.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/src/charts/axis/verticalaxis.cpp b/src/charts/axis/verticalaxis.cpp
index f42b8e04..dfa1a3b0 100644
--- a/src/charts/axis/verticalaxis.cpp
+++ b/src/charts/axis/verticalaxis.cpp
@@ -96,6 +96,8 @@ void VerticalAxis::updateGeometry()
 
     QList<QGraphicsItem *> lines = gridItems();
     QList<QGraphicsItem *> shades = shadeItems();
+    QList<QGraphicsItem *> minorLines = minorGridItems();
+    QList<QGraphicsItem *> minorArrows = minorArrowItems();
 
     for (int i = 0; i < layout.size(); ++i) {
         //items
@@ -296,6 +298,54 @@ void VerticalAxis::updateGeometry()
             tickItem->setVisible(true);
         }
 
+        // add minor ticks
+        QValueAxis *valueAxis = qobject_cast<QValueAxis *>(axis());
+        if ((i + 1) != layout.size() && valueAxis) {
+            int minorTickCount = valueAxis->minorTickCount();
+            if (minorTickCount != 0) {
+                qreal minorTickDistance = (layout[i] - layout[i + 1]) / qreal(minorTickCount + 1);
+                for (int j = 0; j < minorTickCount; j++) {
+                    QGraphicsLineItem *minorGridItem =
+                        static_cast<QGraphicsLineItem *>(minorLines.at(i * minorTickCount + j));
+                    QGraphicsLineItem *minorArrowItem =
+                        static_cast<QGraphicsLineItem *>(minorArrows.at(i * minorTickCount + j));
+                    if (i == 0) {
+                        minorGridItem->setLine(gridRect.left(),
+                                               gridRect.bottom() - minorTickDistance * qreal(j + 1),
+                                               gridRect.right(),
+                                               gridRect.bottom() - minorTickDistance * qreal(j + 1));
+                    } else {
+                        minorGridItem->setLine(gridRect.left(),
+                                               gridItem->line().p1().y()
+                                               - minorTickDistance * qreal(j + 1),
+                                               gridRect.right(),
+                                               gridItem->line().p1().y()
+                                               - minorTickDistance * qreal(j + 1));
+                    }
+                    if (axis()->alignment() == Qt::AlignLeft) {
+                        minorArrowItem->setLine(gridRect.left() - labelPadding() / 2,
+                                                minorGridItem->line().p1().y(),
+                                                gridRect.left(),
+                                                minorGridItem->line().p1().y());
+                    } else if (axis()->alignment() == Qt::AlignRight){
+                        minorArrowItem->setLine(gridRect.right(),
+                                                minorGridItem->line().p1().y(),
+                                                gridRect.right() + labelPadding() / 2,
+                                                minorGridItem->line().p1().y());
+                    }
+
+                    // check if the minor grid line and the axis tick should be shown
+                    qreal minorYPos = minorGridItem->line().p1().y();
+                    if (minorYPos < gridRect.top() || minorYPos > gridRect.bottom()) {
+                        minorGridItem->setVisible(false);
+                        minorArrowItem->setVisible(false);
+                    } else {
+                        minorGridItem->setVisible(true);
+                        minorArrowItem->setVisible(true);
+                    }
+                }
+            }
+        }
     }
     //begin/end grid line in case labels between
     if (intervalAxis()) {