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Fix clipped text when combining multiple writing systems

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When a QTextLine consists of multiple different scripts and the
fonts had negative bearing, the background for a script item could
overdraw the previous item's text, causing it to look clipped.

This was because the background and text was drawn in a single pass,
and moving the background drawing into its own pre-pass fixes the
issue.

[ChangeLog][QtGui] Fixed an issue where drawing text from different
writing systems in the same line and including a background could
cause parts of the text to be clipped.

Pick-to: 6.5
Fixes: QTBUG-121040
Change-Id: I3f79e6d33c09a2a92853bc8752dbe11a0bea2dd0
Reviewed-by: Lars Knoll <lars@knoll.priv.no>
(cherry picked from commit 8be3c9f4867ce7982387b075739b8f55c5c45753)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 55b2011bcd3cfd93baf9db1a03a6672220c26413)
This commit is contained in:
Eskil Abrahamsen Blomfeldt 2024-01-23 10:50:43 +01:00 committed by Qt Cherry-pick Bot
parent 7de26479e1
commit c64fb06afa
2 changed files with 216 additions and 173 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

72
src/gui/text/qtextlayout.cpp
View File

@ -2232,20 +2232,20 @@ int QTextLine::textLength() const
return eng->lines.at(index).length + eng->lines.at(index).trailingSpaces;
}
static void setPenAndDrawBackground(QPainter *p, const QPen &defaultPen, const QTextCharFormat &chf, const QRectF &r)
static void drawBackground(QPainter *p, const QTextCharFormat &chf, const QRectF &r)
{
QBrush c = chf.foreground();
if (c.style() == Qt::NoBrush) {
p->setPen(defaultPen);
}
QBrush bg = chf.background();
if (bg.style() != Qt::NoBrush && !chf.property(SuppressBackground).toBool())
p->fillRect(r.toAlignedRect(), bg);
if (c.style() != Qt::NoBrush) {
p->setPen(QPen(c, 0));
}
}
static void setPen(QPainter *p, const QPen &defaultPen, const QTextCharFormat &chf)
{
QBrush c = chf.foreground();
if (c.style() == Qt::NoBrush)
p->setPen(defaultPen);
else
p->setPen(QPen(c, 0));
}
#if !defined(QT_NO_RAWFONT)
@ -2640,7 +2640,6 @@ void QTextLine::draw_internal(QPainter *p, const QPointF &origPos,
Q_ASSERT(!eng->useRawFont);
#endif
const QScriptLine &line = eng->lines[index];
QPen pen = p->pen();
bool noText = (selection && selection->format.property(SuppressText).toBool());
@ -2652,8 +2651,7 @@ void QTextLine::draw_internal(QPainter *p, const QPointF &origPos,
const qreal lineHeight = line.height().toReal();
QRectF r(origPos.x() + line.x.toReal(), origPos.y() + line.y.toReal(),
lineHeight / 2, QFontMetrics(eng->font()).horizontalAdvance(u' '));
setPenAndDrawBackground(p, QPen(), selection->format, r);
p->setPen(pen);
drawBackground(p, selection->format, r);
}
return;
}
@ -2666,7 +2664,7 @@ void QTextLine::draw_internal(QPainter *p, const QPointF &origPos,
else
p->translate(origPos);
QTextLineItemIterator iterator(eng, index, pos, selection);
QFixed lineBase = line.base();
eng->clearDecorations();
eng->enableDelayDecorations();
@ -2676,6 +2674,39 @@ void QTextLine::draw_internal(QPainter *p, const QPointF &origPos,
const QTextFormatCollection *formatCollection = eng->formatCollection();
bool suppressColors = (eng->option.flags() & QTextOption::SuppressColors);
auto prepareFormat = [suppressColors, selection, this](QTextCharFormat &format,
QScriptItem *si) {
format.merge(eng->format(si));
if (suppressColors) {
format.clearForeground();
format.clearBackground();
format.clearProperty(QTextFormat::TextUnderlineColor);
}
if (selection)
format.merge(selection->format);
};
{
QTextLineItemIterator iterator(eng, index, pos, selection);
while (!iterator.atEnd()) {
QScriptItem &si = iterator.next();
if (eng->hasFormats() || selection || formatCollection) {
QTextCharFormat format;
if (formatCollection != nullptr)
format = formatCollection->defaultTextFormat();
prepareFormat(format, &si);
drawBackground(p, format, QRectF(iterator.x.toReal(), (y - lineBase).toReal(),
iterator.itemWidth.toReal(), line.height().toReal()));
}
}
}
QPen pen = p->pen();
{
QTextLineItemIterator iterator(eng, index, pos, selection);
while (!iterator.atEnd()) {
QScriptItem &si = iterator.next();
@ -2693,18 +2724,8 @@ void QTextLine::draw_internal(QPainter *p, const QPointF &origPos,
format = formatCollection->defaultTextFormat();
if (eng->hasFormats() || selection || formatCollection) {
format.merge(eng->format(&si));
if (suppressColors) {
format.clearForeground();
format.clearBackground();
format.clearProperty(QTextFormat::TextUnderlineColor);
}
if (selection)
format.merge(selection->format);
setPenAndDrawBackground(p, pen, format, QRectF(iterator.x.toReal(), (y - lineBase).toReal(),
iterator.itemWidth.toReal(), line.height().toReal()));
prepareFormat(format, &si);
setPen(p, pen, format);
const qreal baseLineOffset = format.baselineOffset() / 100.0;
QTextCharFormat::VerticalAlignment valign = format.verticalAlignment();
@ -2855,6 +2876,7 @@ void QTextLine::draw_internal(QPainter *p, const QPointF &origPos,
p->setFont(oldFont);
}
}
}
eng->drawDecorations(p);
if (xlateToFixedRange)

21
tests/baseline/text/tst_baseline_text.cpp
View File

@ -17,6 +17,7 @@ public:
private slots:
void tst_render_data();
void tst_render();
void tst_differentScriptsBackgrounds();
private:
QDir htmlDir;
@ -81,6 +82,26 @@ void tst_Text::tst_render()
QBASELINE_TEST(image);
}
void tst_Text::tst_differentScriptsBackgrounds()
{
QTextDocument textDocument;
textDocument.setPageSize(QSizeF(800, 600));
textDocument.setHtml(QString::fromUtf8("<i><font style=\"font-size:72px\"><font style=\"background:#FFFF00\">イ雨ｴ</font></font></i>"));
QImage image(800, 600, QImage::Format_ARGB32);
image.fill(Qt::white);
{
QPainter painter(&image);
QAbstractTextDocumentLayout::PaintContext context;
context.palette.setColor(QPalette::Text, Qt::black);
textDocument.documentLayout()->draw(&painter, context);
}
QBASELINE_CHECK(image, "tst_differentScriptsBackgrounds");
}
#define main _realmain
QTEST_MAIN(tst_Text)