Bug 35933 – [Qt] [Symbian] Can not backward select (highlight) text using virtual keyboard

• Component: WebKit Qt
• Status: RESOLVED FIXED

[Shen Yi]

By using the virtual keyboard on a symbian device, the user can not select texts from right to left (the cursor position is before the anchor position);

[Shen Yi]

Created attachment 50334 [details]
proposal fix for bug 35933

[Shen Yi]

This issue is Qt only, and the root cause is that webcore assumes the selection's start position is always before the end position.

In RenderTextControl.cpp;

void RenderTextControl::setSelectionEnd(int end)
{
    setSelectionRange(min(end, selectionStart()), end);
}

The setSelectionEnd(int) function was called from QWebPagePrivate::inputMethodEvent(QInputMethodEvent*) at qwebpage.cpp

  case QInputMethodEvent::Selection: {
     if (renderTextControl) {
         renderTextControl->setSelectionStart(a.start);
         renderTextControl->setSelectionEnd(a.start + a.length);
     }
     break;
  }

However, in above code, the a.length, which is from QcoeFepInputContext, is negative when doing backward selection:

void QCoeFepInputContext::SetCursorSelectionForFepL(const TCursorSelection&) {
    int pos = aCursorSelection.iAnchorPos;
    int length = aCursorSelection.iCursorPos - pos;
    QList<QInputMethodEvent::Attribute> attributes;
    attributes << QInputMethodEvent::Attribute(QInputMethodEvent::Selection, pos, length, QVariant());
}

It can explain why the backward selection doesn't work, that is,

when start position is larger than end position,

setSelectionRange(min(end, selectionStart()), end);
  equals
setSelectionRange(end, end);

The patch I attached would check/adjust the start & end position before calling the setSelectionStart & setSelectionEnd. I have tested it on both s60 emulator & target.

[Shen Yi]

Created attachment 50795 [details]
proposal patch

[Shen Yi]

Created attachment 50812 [details]
patch for bug35933

[Simon Hausmann]

Comment on attachment 50812 [details]
patch for bug35933

I think the patch is fine, but please make a unit test for this. See the inputMethods() unit tests in WebKit/qt/tests/qwebpage.

You could test this by sending a synthetic input method event with a selection set. After sending the event you could verify that the selection is set correctly.

[Shen Yi]

Created attachment 51157 [details]
new patch with the unit test

The new patch contains the unit test for qwebpage.

[WebKit Commit Bot]

Comment on attachment 51157 [details]
new patch with the unit test

Clearing flags on attachment: 51157

Committed r56334: <http://trac.webkit.org/changeset/56334>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Simon Hausmann]

Cherry-picked into qtwebkit-4.6 with commit edc778e0b452640d8e05c4a88903c18b6afe20ec