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qt: Preserve complex script ligatures and shaping in kdenlivetitle
Refactor PlainTextItem to populate QPainterPath directly using HarfBuzz-shaped vector glyph runs via appendShapedText(). This preserves HarfBuzz complex OpenType script shaping (Sinhala Rakaransaya, Indic conjuncts, and Arabic cursive joining) while fully preserving: - Baseline vertical alignment matching QPainterPath::addText() - Text decorations (underline, overline, strikeout) - Multi-color linear/radial gradients (QBrush) - True stroke path outlines (painter->strokePath) - Horizontal advance alignment and custom tab width calculations - Aligned drop shadow path geometry - Italic glyph ink bounds without QImage clipping Adds a regression test suite covering positioning, baseline, decorations, tabs, alignment, gradients, outlines, shadows, and multi-script shaping across Sinhala, Indic, Arabic/Urdu, CJK, and Korean scripts.
1 parent 2ac487b commit 593a257

4 files changed

Lines changed: 744 additions & 10 deletions

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‎src/modules/qt/kdenlivetitle_wrapper.cpp‎

Lines changed: 73 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -33,19 +33,23 @@
3333
#include <QDebug>
3434
#include <QDir>
3535
#include <QFileInfo>
36+
#include <QGlyphRun>
37+
#include <QGraphicsBlurEffect>
3638
#include <QGraphicsScene>
3739
#include <QGraphicsSvgItem>
3840
#include <QGraphicsTextItem>
3941
#include <QImage>
4042
#include <QMutex>
4143
#include <QPainter>
44+
#include <QRawFont>
4245
#include <QString>
4346
#include <QStyleOptionGraphicsItem>
4447
#include <QSvgRenderer>
4548
#include <QTextBlockFormat>
4649
#include <QTextCharFormat>
4750
#include <QTextCursor>
4851
#include <QTextDocument>
52+
#include <QTextLayout>
4953
#include <QTextOption>
5054

5155
#include <framework/mlt_log.h>
@@ -145,6 +149,60 @@ void blur(QImage &image, int radius)
145149
}
146150
}
147151

152+
void appendShapedText(QPainterPath &path, const QPointF &pos, const QFont &font, const QString &text)
153+
{
154+
if (text.isEmpty()) {
155+
return;
156+
}
157+
QFont shapedFont(font);
158+
shapedFont.setHintingPreference(QFont::PreferFullHinting);
159+
160+
QTextLayout layout(text, shapedFont);
161+
QTextOption opt = layout.textOption();
162+
opt.setTextDirection(Qt::LayoutDirectionAuto);
163+
layout.setTextOption(opt);
164+
layout.beginLayout();
165+
while (true) {
166+
QTextLine textLine = layout.createLine();
167+
if (!textLine.isValid()) {
168+
break;
169+
}
170+
}
171+
layout.endLayout();
172+
173+
for (int i = 0; i < layout.lineCount(); ++i) {
174+
QTextLine textLine = layout.lineAt(i);
175+
const auto glyphRuns = textLine.glyphRuns();
176+
for (const QGlyphRun &run : glyphRuns) {
177+
const auto glyphIndexes = run.glyphIndexes();
178+
const auto positions = run.positions();
179+
const QRawFont rawFont = run.rawFont();
180+
for (int g = 0; g < glyphIndexes.size(); ++g) {
181+
QPainterPath glyphPath = rawFont.pathForGlyph(glyphIndexes[g]);
182+
QPointF glyphPos = pos + positions[g] - QPointF(0, textLine.ascent());
183+
glyphPath.translate(glyphPos);
184+
path.addPath(glyphPath);
185+
}
186+
}
187+
}
188+
189+
// Same decoration geometry as QPainterPath::addText().
190+
if (font.underline() || font.overline() || font.strikeOut()) {
191+
const QFontMetricsF metrics(font);
192+
const qreal lineWidth = metrics.lineWidth();
193+
const qreal textWidth = layout.maximumWidth();
194+
if (font.underline()) {
195+
path.addRect(QRectF(pos.x(), pos.y() + metrics.underlinePos(), textWidth, lineWidth));
196+
}
197+
if (font.overline()) {
198+
path.addRect(QRectF(pos.x(), pos.y() - metrics.overlinePos(), textWidth, lineWidth));
199+
}
200+
if (font.strikeOut()) {
201+
path.addRect(QRectF(pos.x(), pos.y() - metrics.strikeOutPos(), textWidth, lineWidth));
202+
}
203+
}
204+
}
205+
148206
class PlainTextItem : public QGraphicsItem
149207
{
150208
public:
@@ -167,6 +225,7 @@ class PlainTextItem : public QGraphicsItem
167225
m_pen.setWidthF(outline);
168226
m_pen.setJoinStyle(Qt::RoundJoin);
169227
m_font = font;
228+
m_font.setHintingPreference(QFont::PreferFullHinting);
170229
m_lineSpacing = lineSpacing + m_metrics.lineSpacing();
171230
m_align = align;
172231
m_width = width;
@@ -176,11 +235,12 @@ class PlainTextItem : public QGraphicsItem
176235

177236
void updateText(const QString text)
178237
{
179-
m_path.clear();
180-
// Calculate line width
181-
const QStringList lines = text.split('\n');
238+
const QStringList lines = text.split(QLatin1Char('\n'));
182239
double linePos = m_metrics.ascent();
183-
foreach (const QString &line, lines) {
240+
m_path.clear();
241+
m_path.setFillRule(Qt::WindingFill);
242+
243+
for (const QString &line : lines) {
184244
QPainterPath linePath;
185245
const QStringList tabLines = line.split(QLatin1Char('\t'));
186246
if (m_tabWidth > 0 && tabLines.count() > 1) {
@@ -189,18 +249,17 @@ class PlainTextItem : public QGraphicsItem
189249
for (const QString &tline : tabLines) {
190250
QPainterPath tabPath;
191251
if (!tline.isEmpty()) {
192-
tabPath.addText(pos, linePos, m_font, tline);
252+
appendShapedText(tabPath, QPointF(pos, linePos), m_font, tline);
193253
linePath.addPath(tabPath);
194254
currentPos = pos + tabPath.boundingRect().width();
195255
} else {
196-
// Several chained tabs
197256
currentPos = pos + m_tabWidth / 2;
198257
}
199258
int tabsCount = ceil(currentPos / m_tabWidth);
200259
pos = tabsCount * m_tabWidth;
201260
}
202261
} else {
203-
linePath.addText(0, linePos, m_font, line);
262+
appendShapedText(linePath, QPointF(0, linePos), m_font, line);
204263
}
205264
linePos += m_lineSpacing;
206265
if (m_align == Qt::AlignHCenter) {
@@ -212,7 +271,7 @@ class PlainTextItem : public QGraphicsItem
212271
}
213272
m_path.addPath(linePath);
214273
}
215-
m_path.setFillRule(Qt::WindingFill);
274+
216275
if (!m_path.isEmpty()) {
217276
int minWidth = m_path.boundingRect().width();
218277
int minHeight = m_lineSpacing * lines.size();
@@ -223,6 +282,7 @@ class PlainTextItem : public QGraphicsItem
223282
m_boundingRect.setHeight(minHeight);
224283
}
225284
}
285+
updateShadows();
226286
}
227287

228288
virtual QRectF boundingRect() const { return m_boundingRect; }
@@ -247,10 +307,8 @@ class PlainTextItem : public QGraphicsItem
247307
void updateShadows()
248308
{
249309
if (m_params.count() < 5 || m_params.at(0).toInt() == false) {
250-
// Invalid or no shadow wanted
251310
return;
252311
}
253-
// Build shadow image
254312
QColor shadowColor = QColor(m_params.at(1));
255313
int blurRadius = m_params.at(2).toInt();
256314
int offsetX = m_params.at(3).toInt();
@@ -396,6 +454,7 @@ void loadFromXml(producer_ktitle self,
396454
if (nodeAttributes.namedItem("type").nodeValue() == "QGraphicsTextItem") {
397455
QDomNamedNodeMap txtProperties = node.namedItem("content").attributes();
398456
QFont font(txtProperties.namedItem("font").nodeValue());
457+
font.setHintingPreference(QFont::PreferFullHinting);
399458
QDomNode propsNode = txtProperties.namedItem("font-bold");
400459
if (!propsNode.isNull()) {
401460
// Old: Bold/Not bold.
@@ -687,6 +746,10 @@ void loadFromXml(producer_ktitle self,
687746
gitem = txt;
688747
} else {
689748
QGraphicsTextItem *txt = scene->addText(text, font);
749+
txt->document()->setDefaultFont(font);
750+
QTextOption opt = txt->document()->defaultTextOption();
751+
opt.setTextDirection(Qt::LayoutDirectionAuto);
752+
txt->document()->setDefaultTextOption(opt);
690753
gitem = txt;
691754
if (txtProperties.namedItem("font-outline").nodeValue().toDouble() > 0.0) {
692755
QTextDocument *doc = txt->document();

‎src/tests/CMakeLists.txt‎

Lines changed: 49 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -63,6 +63,55 @@ if(MOD_QT6)
6363
"${CMAKE_SOURCE_DIR}/src/modules/qt/gps_parser.h"
6464
"${CMAKE_SOURCE_DIR}/src/modules/qt/gps_parser.cpp"
6565
)
66+
add_qt_test(
67+
TEST_NAME kdenlivetitle
68+
LINK_LIBRARIES Qt${QT_MAJOR_VERSION}::Gui Qt${QT_MAJOR_VERSION}::Widgets Qt${QT_MAJOR_VERSION}::Xml Qt${QT_MAJOR_VERSION}::SvgWidgets
69+
SOURCE_FILES
70+
"${CMAKE_SOURCE_DIR}/src/modules/qt/kdenlivetitle_wrapper.cpp"
71+
"${CMAKE_SOURCE_DIR}/src/modules/qt/kdenlivegraphics.cpp"
72+
"${CMAKE_SOURCE_DIR}/src/modules/qt/typewriter.cpp"
73+
"${CMAKE_SOURCE_DIR}/src/modules/qt/common.cpp"
74+
)
75+
76+
# A/B visual regression harness for the kdenlivetitle renderer.
77+
set(KDENLIVETITLE_BASELINE_REV "2ac487b5" CACHE STRING "git revision used as kdenlivetitle rendering baseline")
78+
find_package(Git QUIET)
79+
if(GIT_FOUND)
80+
set(_baseline_dir "${CMAKE_CURRENT_BINARY_DIR}/kdenlivetitle_baseline")
81+
file(MAKE_DIRECTORY "${_baseline_dir}")
82+
execute_process(
83+
COMMAND ${GIT_EXECUTABLE} show "${KDENLIVETITLE_BASELINE_REV}:src/modules/qt/kdenlivetitle_wrapper.cpp"
84+
WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
85+
OUTPUT_FILE "${_baseline_dir}/kdenlivetitle_wrapper_baseline.cpp"
86+
RESULT_VARIABLE _git_res
87+
)
88+
if(_git_res EQUAL 0)
89+
foreach(_variant baseline new)
90+
if(_variant STREQUAL "baseline")
91+
set(_wrapper "${_baseline_dir}/kdenlivetitle_wrapper_baseline.cpp")
92+
else()
93+
set(_wrapper "${CMAKE_SOURCE_DIR}/src/modules/qt/kdenlivetitle_wrapper.cpp")
94+
endif()
95+
add_executable(kdenlivetitle_regress_${_variant}
96+
kdenlivetitle_regress/kdenlivetitle_regress.cpp
97+
${_wrapper}
98+
"${CMAKE_SOURCE_DIR}/src/modules/qt/kdenlivegraphics.cpp"
99+
"${CMAKE_SOURCE_DIR}/src/modules/qt/typewriter.cpp"
100+
"${CMAKE_SOURCE_DIR}/src/modules/qt/common.cpp"
101+
)
102+
target_include_directories(kdenlivetitle_regress_${_variant} PRIVATE "${CMAKE_SOURCE_DIR}/src/modules/qt")
103+
if(_variant STREQUAL "new")
104+
target_compile_definitions(kdenlivetitle_regress_new PRIVATE KDT_NEW)
105+
endif()
106+
target_link_libraries(kdenlivetitle_regress_${_variant} PRIVATE
107+
Qt${QT_MAJOR_VERSION}::Core Qt${QT_MAJOR_VERSION}::Gui Qt${QT_MAJOR_VERSION}::Widgets
108+
Qt${QT_MAJOR_VERSION}::Xml Qt${QT_MAJOR_VERSION}::SvgWidgets mlt mlt++)
109+
if(MSVC)
110+
target_link_libraries(kdenlivetitle_regress_${_variant} PRIVATE PThreads4W::PThreads4W)
111+
endif()
112+
endforeach()
113+
endif()
114+
endif()
66115
endif()
67116

68117
if(Kwalify_FOUND)

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