Scroll TextInput to ensure preedit text is visible.

Update the scroll position on text input events and ensure the end of
the pre-edit text is visible, unless that hides the cursor in which
case display as much as possible while still displaying the cursor
and a preceding pre-edit character.

Change-Id: Iec6f82b00333f7c9ea21fe536c8f11be0f8de710
Task-number: QTBUG-16999
Reviewed-by: Martin Jones

1 files changed, 11 insertions, 1 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativetextinput.cpp b/src/declarative/graphicsitems/qdeclarativetextinput.cpp
index 57e60ac..2258ce6 100644
--- a/src/declarative/graphicsitems/qdeclarativetextinput.cpp
+++ b/src/declarative/graphicsitems/qdeclarativetextinput.cpp
@@ -980,6 +980,7 @@ void QDeclarativeTextInput::inputMethodEvent(QInputMethodEvent *ev)
     } else {
         d->control->processInputMethodEvent(ev);
         updateSize();
+        d->updateHorizontalScroll();
     }
     if (!ev->isAccepted())
         QDeclarativePaintedItem::inputMethodEvent(ev);
@@ -1098,7 +1099,8 @@ int QDeclarativeTextInputPrivate::calculateTextWidth()
 void QDeclarativeTextInputPrivate::updateHorizontalScroll()
 {
     Q_Q(QDeclarativeTextInput);
-    int cix = qRound(control->cursorToX());
+    const int preeditLength = control->preeditAreaText().length();
+    int cix = qRound(control->cursorToX(control->cursor() + preeditLength));
     QRect br(q->boundingRect().toRect());
     int widthUsed = calculateTextWidth();
     Qt::Alignment va = QStyle::visualAlignment(control->layoutDirection(), QFlag(Qt::Alignment(hAlign)));
@@ -1128,6 +1130,14 @@ void QDeclarativeTextInputPrivate::updateHorizontalScroll()
             // right
             hscroll = widthUsed - br.width() + 1;
         }
+        if (preeditLength > 0) {
+            // check to ensure long pre-edit text doesn't push the cursor
+            // off to the left
+             cix = qRound(control->cursorToX(
+                     control->cursor() + qMax(0, control->preeditCursor() - 1)));
+             if (cix < hscroll)
+                 hscroll = cix;
+        }
     } else {
         switch (va & ~(Qt::AlignAbsolute|Qt::AlignVertical_Mask)) {
         case Qt::AlignRight: