Fix text issue with Hiragana characters when stylesheet is applied.

When typing into a QTextEdit or QLineEdit with a Japanese IME on
Windows, some characters have both a black foreground and background
and hence cannot be seen. This patch fixes the issue by setting the
appropriate colors for the text in these scenarios.

The change also fixes a similar situation with QSyntaxHighlighter and
Hiragana, where the background and foreground colors were the same.
Now it will use underlining to highlight the text (like WordPad does,
for example).

Task-number: QTBUG-29442
Change-Id: I364d327a8f6573a73b227b79cc5f570cd02611c9
Reviewed-by: Andy Shaw <andy.shaw@digia.com>
Reviewed-by: Titta Heikkala <titta.heikkala@digia.com>
Reviewed-by: David Faure (KDE) <faure@kde.org>
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gui/text/qtextcontrol.cpp b/src/gui/text/qtextcontrol.cpp
index 2fee68abb9..35705040d7 100644
--- a/src/gui/text/qtextcontrol.cpp
+++ b/src/gui/text/qtextcontrol.cpp
@@ -1981,6 +1981,12 @@ void QTextControlPrivate::inputMethodEvent(QInputMethodEvent *e)
         } else if (a.type == QInputMethodEvent::TextFormat) {
             QTextCharFormat f = qvariant_cast<QTextFormat>(a.value).toCharFormat();
             if (f.isValid()) {
+                if (f.background().color().alphaF() == 1 && f.background().style() == Qt::SolidPattern) {
+                    f.setForeground(f.background().color());
+                    f.setBackground(Qt::transparent);
+                    f.setUnderlineStyle(QTextCharFormat::SingleUnderline);
+                    f.setFontUnderline(true);
+                }
                 QTextLayout::FormatRange o;
                 o.start = a.start + cursor.position() - block.position();
                 o.length = a.length;