Check selection handles position

This patch fixes the strange behavior when selecting text.

This patch (on a Left To Right text) makes sure that:
 - the left handle will select text only on the left & above of the right handle
 - the right handle will select text only on the right & below of the left handle

For RTL is way more complicated:
- the left handle is acuatually the right handle but on the left side and it acts as a right handle
- the right  handle is acuatually the left handle but on the right side and it acts as a left handle

Change-Id: Ifca591398103199d5aef479f0a080161c9f44c0e
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

src/plugins/platforms/android/qandroidinputcontext.cpp

@@ -605,27 +605,63 @@ void QAndroidInputContext::handleLocationChanged(int handleId, int x, int y)
     double pixelDensity = window
         ? QHighDpiScaling::factor(window)
         : QHighDpiScaling::factor(QtAndroid::androidPlatformIntegration()->screen());
-    QPoint point(x / pixelDensity, y / pixelDensity);
+    QPointF point(x / pixelDensity, y / pixelDensity);
-    y -= leftRect.width() / 2;
+    point.setY(point.y() - leftRect.width() / 2);
     if (handleId == 1) {
         setSelectionOnFocusObject(point, point);
         return;
     }
 
-    QInputMethodQueryEvent query(Qt::ImCursorPosition | Qt::ImAnchorPosition);
+    QInputMethodQueryEvent query(Qt::ImCursorPosition | Qt::ImAnchorPosition | Qt::ImCurrentSelection);
     QCoreApplication::sendEvent(m_focusObject, &query);
     int cpos = query.value(Qt::ImCursorPosition).toInt();
     int anchor = query.value(Qt::ImAnchorPosition).toInt();
-
+    bool rtl = query.value(Qt::ImCurrentSelection).toString().isRightToLeft();
     auto rightRect = im->anchorRectangle();
     if (cpos > anchor)
         std::swap(leftRect, rightRect);
 
+    auto checkLeftHandle = [&rightRect](QPointF &handlePos) {
+        if (handlePos.y() > rightRect.center().y())
+            handlePos.setY(rightRect.center().y()); // adjust Y handle pos
+        if (handlePos.y() >= rightRect.y() && handlePos.y() <= rightRect.bottom() && handlePos.x() >= rightRect.x())
+            return false; // same line and wrong X pos ?
+        return true;
+    };
+
+    auto checkRtlRightHandle = [&rightRect](QPointF &handlePos) {
+        if (handlePos.y() > rightRect.center().y())
+            handlePos.setY(rightRect.center().y()); // adjust Y handle pos
+        if (handlePos.y() >= rightRect.y() && handlePos.y() <= rightRect.bottom() && rightRect.x() >= handlePos.x())
+            return false; // same line and wrong X pos ?
+        return true;
+    };
+
+    auto checkRightHandle = [&leftRect](QPointF &handlePos) {
+        if (handlePos.y() < leftRect.center().y())
+            handlePos.setY(leftRect.center().y()); // adjust Y handle pos
+        if (handlePos.y() >= leftRect.y() && handlePos.y() <= leftRect.bottom() && leftRect.x() >= handlePos.x())
+            return false; // same line and wrong X pos ?
+        return true;
+    };
+
+    auto checkRtlLeftHandle = [&leftRect](QPointF &handlePos) {
+        if (handlePos.y() < leftRect.center().y())
+            handlePos.setY(leftRect.center().y()); // adjust Y handle pos
+        if (handlePos.y() >= leftRect.y() && handlePos.y() <= leftRect.bottom() && handlePos.x() >= leftRect.x())
+            return false; // same line and wrong X pos ?
+        return true;
+    };
+
     if (handleId == 2) {
-        QPoint rightPoint(rightRect.center().toPoint());
+        QPointF rightPoint(rightRect.center());
+        if ((!rtl && !checkLeftHandle(point)) || (rtl && !checkRtlRightHandle(point)))
+            return;
         setSelectionOnFocusObject(point, rightPoint);
     } else if (handleId == 3) {
-        QPoint leftPoint(leftRect.center().toPoint());
+        QPointF leftPoint(leftRect.center());
+        if ((!rtl && !checkRightHandle(point)) || (rtl && !checkRtlLeftHandle(point)))
+            return;
         setSelectionOnFocusObject(leftPoint, point);
     }
 }