1 files changed, 60 insertions, 32 deletions

diff --git a/src/gui/painting/qpainter.cpp b/src/gui/painting/qpainter.cpp
index 48629d1..fc1863f 100644
--- a/src/gui/painting/qpainter.cpp
+++ b/src/gui/painting/qpainter.cpp
@@ -5886,7 +5886,12 @@ void QPainter::drawText(const QRectF &r, const QString &text, const QTextOption
     Draws the text item \a ti at position \a p.
 */
 
-/*! \internal
+/*!
+    \fn void QPainter::drawTextItem(const QPointF &p, const QTextItem &ti)
+
+    \internal
+    \since 4.1
+
     Draws the text item \a ti at position \a p.
 
     This method ignores the painters background mode and
@@ -5899,34 +5904,57 @@ void QPainter::drawText(const QRectF &r, const QString &text, const QTextOption
     ignored aswell. You'll need to pass in the correct flags to get
     underlining and strikeout.
 */
-static QPainterPath generateWavyPath(qreal minWidth, qreal maxRadius, QPaintDevice *device)
+
+static QPixmap generateWavyPixmap(qreal maxRadius, const QPen &pen)
 {
-    extern int qt_defaultDpi();
+    const qreal radiusBase = qMax(qreal(1), maxRadius);
+
+    QString key = QLatin1String("WaveUnderline-");
+    key += pen.color().name();
+    key += QLatin1Char('-');
+    key += QString::number(radiusBase);
+
+    QPixmap pixmap;
+    if (QPixmapCache::find(key, pixmap))
+        return pixmap;
+
+    const qreal halfPeriod = qMax(qreal(2), radiusBase * 1.61803399); // the golden ratio
+    const int width = qCeil(100 / (2 * halfPeriod)) * (2 * halfPeriod);
+    const int radius = qFloor(radiusBase);
+
     QPainterPath path;
 
-    bool up = true;
-    const qreal radius = qMax(qreal(.5), qMin(qreal(1.25 * device->logicalDpiY() / qt_defaultDpi()), maxRadius));
-    qreal xs, ys;
-    int i = 0;
-    path.moveTo(0, radius);
-    do {
-        xs = i*(2*radius);
-        ys = 0;
+    qreal xs = 0;
+    qreal ys = radius;
 
-        qreal remaining = minWidth - xs;
-        qreal angle = 180;
+    while (xs < width) {
+        xs += halfPeriod;
+        ys = -ys;
+        path.quadTo(xs - halfPeriod / 2, ys, xs, 0);
+    }
 
-        // cut-off at the last arc segment
-        if (remaining < 2 * radius)
-            angle = 180 * remaining / (2 * radius);
+    pixmap = QPixmap(width, radius * 2);
+    pixmap.fill(Qt::transparent);
+    {
+        QPen wavePen = pen;
+        wavePen.setCapStyle(Qt::SquareCap);
+
+        // This is to protect against making the line too fat, as happens on Mac OS X
+        // due to it having a rather thick width for the regular underline.
+        const qreal maxPenWidth = .8 * radius;
+        if (wavePen.widthF() > maxPenWidth)
+            wavePen.setWidth(maxPenWidth);
 
-        path.arcTo(xs, ys, 2*radius, 2*radius, 180, up ? angle : -angle);
+        QPainter imgPainter(&pixmap);
+        imgPainter.setPen(wavePen);
+        imgPainter.setRenderHint(QPainter::Antialiasing);
+        imgPainter.translate(0, radius);
+        imgPainter.drawPath(path);
+    }
 
-        up = !up;
-        ++i;
-    } while (xs + 2*radius < minWidth);
+    QPixmapCache::insert(key, pixmap);
 
-    return path;
+    return pixmap;
 }
 
 static void drawTextItemDecoration(QPainter *painter, const QPointF &pos, const QTextItemInt &ti)
@@ -5947,9 +5975,11 @@ static void drawTextItemDecoration(QPainter *painter, const QPointF &pos, const
     pen.setCapStyle(Qt::FlatCap);
 
     QLineF line(pos.x(), pos.y(), pos.x() + ti.width.toReal(), pos.y());
+
+    const qreal underlineOffset = fe->underlinePosition().toReal();
     // deliberately ceil the offset to avoid the underline coming too close to
     // the text above it.
-    const qreal underlinePos = pos.y() + qCeil(fe->underlinePosition().toReal());
+    const qreal underlinePos = pos.y() + qCeil(underlineOffset);
 
     if (underlineStyle == QTextCharFormat::SpellCheckUnderline) {
         underlineStyle = QTextCharFormat::UnderlineStyle(QApplication::style()->styleHint(QStyle::SH_SpellCheckUnderlineStyle));
@@ -5957,16 +5987,18 @@ static void drawTextItemDecoration(QPainter *painter, const QPointF &pos, const
 
     if (underlineStyle == QTextCharFormat::WaveUnderline) {
         painter->save();
-        painter->setRenderHint(QPainter::Antialiasing);
-        painter->translate(pos.x(), underlinePos);
+        painter->translate(0, pos.y() + 1);
 
         QColor uc = ti.charFormat.underlineColor();
         if (uc.isValid())
-            painter->setPen(uc);
+            pen.setColor(uc);
 
-        painter->drawPath(generateWavyPath(ti.width.toReal(),
-                                           fe->underlinePosition().toReal(),
-                                           painter->device()));
+        // Adapt wave to underlineOffset or pen width, whatever is larger, to make it work on all platforms
+        const QPixmap wave = generateWavyPixmap(qMax(underlineOffset, pen.widthF()), pen);
+        const int descent = (int) ti.descent.toReal();
+
+        painter->setBrushOrigin(painter->brushOrigin().x(), 0);
+        painter->fillRect(pos.x(), 0, qCeil(ti.width.toReal()), qMin(wave.height(), descent), wave);
         painter->restore();
     } else if (underlineStyle != QTextCharFormat::NoUnderline) {
         QLineF underLine(line.x1(), underlinePos, line.x2(), underlinePos);
@@ -6001,10 +6033,6 @@ static void drawTextItemDecoration(QPainter *painter, const QPointF &pos, const
     painter->setBrush(oldBrush);
 }
 
-/*!
-    \internal
-    \since 4.1
-*/
 void QPainter::drawTextItem(const QPointF &p, const QTextItem &_ti)
 {
 #ifdef QT_DEBUG_DRAW