Reduced the memory footprint of qttrace files.

A couple of improvements have been made:

 * Use single precision floats for the traces.
 * Reduce the number of variant wrapped transforms by introducing a new
   translate command.
 * Reduce the number of bytes streamed per image / pixmap draw command.
 * Add versioning info to qttrace files to be more future proof.

Reviewed-by: Gunnar Sletta

3 files changed, 114 insertions, 10 deletions

diff --git a/src/gui/painting/qpaintbuffer.cpp b/src/gui/painting/qpaintbuffer.cpp
index 664d864..39b76c8 100644
--- a/src/gui/painting/qpaintbuffer.cpp
+++ b/src/gui/painting/qpaintbuffer.cpp
@@ -308,6 +308,8 @@ public:
         Q_Q(QPaintBufferEngine);
         q->buffer->addCommand(QPaintBufferPrivate::Cmd_SystemStateChanged, QVariant(systemClip));
     }
+
+    QTransform last;
 };
 
 
@@ -494,6 +496,32 @@ void QPaintBufferEngine::renderHintsChanged()
 
 void QPaintBufferEngine::transformChanged()
 {
+    Q_D(QPaintBufferEngine);
+    const QTransform &transform = state()->matrix;
+
+    QTransform delta;
+
+    bool invertible = false;
+    if (transform.type() <= QTransform::TxScale && transform.type() == d->last.type())
+        delta = transform * d->last.inverted(&invertible);
+
+    d->last = transform;
+
+    if (invertible && delta.type() == QTransform::TxNone)
+        return;
+
+    if (invertible && delta.type() == QTransform::TxTranslate) {
+#ifdef QPAINTBUFFER_DEBUG_DRAW
+        qDebug() << "QPaintBufferEngine: transformChanged (translate only) " << state()->matrix;
+#endif
+        QPaintBufferCommand *cmd =
+            buffer->addCommand(QPaintBufferPrivate::Cmd_Translate);
+
+        qreal data[] = { delta.dx(), delta.dy() };
+        cmd->extra = buffer->addData((qreal *) data, 2);
+        return;
+    }
+
     // ### accumulate, like in QBrush case...
     if (!buffer->commands.isEmpty()
         && buffer->commands.last().id == QPaintBufferPrivate::Cmd_SetTransform) {
@@ -1013,6 +1041,7 @@ void QPaintBufferEngine::drawTextItem(const QPointF &pos, const QTextItem &ti)
 
 void QPaintBufferEngine::setState(QPainterState *s)
 {
+    Q_D(QPaintBufferEngine);
     if (m_begin_detected) {
 #ifdef QPAINTBUFFER_DEBUG_DRAW
             qDebug() << "QPaintBufferEngine: setState: begin, ignoring.";
@@ -1031,6 +1060,8 @@ void QPaintBufferEngine::setState(QPainterState *s)
         buffer->addCommand(QPaintBufferPrivate::Cmd_Restore);
     }
 
+    d->last = s->matrix;
+
     QPaintEngineEx::setState(s);
 }
 
@@ -1152,6 +1183,15 @@ void QPainterReplayer::process(const QPaintBufferCommand &cmd)
         painter->setTransform(xform * m_world_matrix);
         break; }
 
+    case QPaintBufferPrivate::Cmd_Translate: {
+        QPointF delta(d->floats.at(cmd.extra), d->floats.at(cmd.extra+1));
+#ifdef QPAINTBUFFER_DEBUG_DRAW
+        qDebug() << " -> Cmd_Translate, offset: " << cmd.offset << delta;
+#endif
+        painter->translate(delta.x(), delta.y());
+        return;
+    }
+
     case QPaintBufferPrivate::Cmd_SetCompositionMode: {
         QPainter::CompositionMode mode = (QPainter::CompositionMode) cmd.extra;
 #ifdef QPAINTBUFFER_DEBUG_DRAW
@@ -1797,8 +1837,28 @@ struct QPaintBufferCacheEntry
     QVariant::Type type;
     quint64 cacheKey;
 };
+
+struct QPaintBufferCacheEntryV2
+{
+    enum Type {
+        ImageKey,
+        PixmapKey
+    };
+
+    struct Flags {
+        uint type : 8;
+        uint key : 24;
+    };
+
+    union {
+        Flags flags;
+        uint bits;
+    };
+};
+
 QT_END_NAMESPACE
 Q_DECLARE_METATYPE(QPaintBufferCacheEntry)
+Q_DECLARE_METATYPE(QPaintBufferCacheEntryV2)
 QT_BEGIN_NAMESPACE
 
 QDataStream &operator<<(QDataStream &stream, const QPaintBufferCacheEntry &entry)
@@ -1811,10 +1871,22 @@ QDataStream &operator>>(QDataStream &stream, QPaintBufferCacheEntry &entry)
     return stream >> entry.type >> entry.cacheKey;
 }
 
+QDataStream &operator<<(QDataStream &stream, const QPaintBufferCacheEntryV2 &entry)
+{
+    return stream << entry.bits;
+}
+
+QDataStream &operator>>(QDataStream &stream, QPaintBufferCacheEntryV2 &entry)
+{
+    return stream >> entry.bits;
+}
+
 static int qRegisterPaintBufferMetaTypes()
 {
     qRegisterMetaType<QPaintBufferCacheEntry>();
     qRegisterMetaTypeStreamOperators<QPaintBufferCacheEntry>("QPaintBufferCacheEntry");
+    qRegisterMetaType<QPaintBufferCacheEntryV2>();
+    qRegisterMetaTypeStreamOperators<QPaintBufferCacheEntryV2>("QPaintBufferCacheEntryV2");
 
     return 0; // something
 }
@@ -1823,6 +1895,9 @@ Q_CONSTRUCTOR_FUNCTION(qRegisterPaintBufferMetaTypes)
 
 QDataStream &operator<<(QDataStream &stream, const QPaintBuffer &buffer)
 {
+    QHash<qint64, uint> pixmapKeys;
+    QHash<qint64, uint> imageKeys;
+
     QHash<qint64, QPixmap> pixmaps;
     QHash<qint64, QImage> images;
 
@@ -1831,19 +1906,33 @@ QDataStream &operator<<(QDataStream &stream, const QPaintBuffer &buffer)
         const QVariant &v = variants.at(i);
         if (v.type() == QVariant::Image) {
             const QImage image(v.value<QImage>());
-            images[image.cacheKey()] = image;
 
-            QPaintBufferCacheEntry entry;
-            entry.type = QVariant::Image;
-            entry.cacheKey = image.cacheKey();
+            QPaintBufferCacheEntryV2 entry;
+            entry.flags.type = QPaintBufferCacheEntryV2::ImageKey;
+
+            QHash<qint64, uint>::iterator it = imageKeys.find(image.cacheKey());
+            if (it != imageKeys.end()) {
+                entry.flags.key = *it;
+            } else {
+                imageKeys[image.cacheKey()] = entry.flags.key = images.size();
+                images[images.size()] = image;
+            }
+
             variants[i] = QVariant::fromValue(entry);
         } else if (v.type() == QVariant::Pixmap) {
             const QPixmap pixmap(v.value<QPixmap>());
-            pixmaps[pixmap.cacheKey()] = pixmap;
 
-            QPaintBufferCacheEntry entry;
-            entry.type = QVariant::Pixmap;
-            entry.cacheKey = pixmap.cacheKey();
+            QPaintBufferCacheEntryV2 entry;
+            entry.flags.type = QPaintBufferCacheEntryV2::PixmapKey;
+
+            QHash<qint64, uint>::iterator it = pixmapKeys.find(pixmap.cacheKey());
+            if (it != pixmapKeys.end()) {
+                entry.flags.key = *it;
+            } else {
+                pixmapKeys[pixmap.cacheKey()] = entry.flags.key = pixmaps.size();
+                pixmaps[pixmaps.size()] = pixmap;
+            }
+
             variants[i] = QVariant::fromValue(entry);
         }
     }
@@ -1885,6 +1974,15 @@ QDataStream &operator>>(QDataStream &stream, QPaintBuffer &buffer)
                 variants[i] = QVariant(images.value(entry.cacheKey));
             else
                 variants[i] = QVariant(pixmaps.value(entry.cacheKey));
+        } else if (v.canConvert<QPaintBufferCacheEntryV2>()) {
+            QPaintBufferCacheEntryV2 entry = v.value<QPaintBufferCacheEntryV2>();
+
+            if (entry.flags.type == QPaintBufferCacheEntryV2::ImageKey)
+                variants[i] = QVariant(images.value(entry.flags.key));
+            else if (entry.flags.type == QPaintBufferCacheEntryV2::PixmapKey)
+                variants[i] = QVariant(pixmaps.value(entry.flags.key));
+            else
+                qWarning() << "operator<<(QDataStream &stream, QPaintBuffer &buffer): unrecognized cache entry type:" << entry.flags.type;
         }
     }
 
diff --git a/src/gui/painting/qpaintbuffer_p.h b/src/gui/painting/qpaintbuffer_p.h
index 41a26c5..8c2bb6b 100644
--- a/src/gui/painting/qpaintbuffer_p.h
+++ b/src/gui/painting/qpaintbuffer_p.h
@@ -184,6 +184,7 @@ public:
         Cmd_DrawTiledPixmap,
 
         Cmd_SystemStateChanged,
+        Cmd_Translate,
 
         Cmd_LastCommand
     };
diff --git a/src/plugins/graphicssystems/trace/qgraphicssystem_trace.cpp b/src/plugins/graphicssystems/trace/qgraphicssystem_trace.cpp
index 13044f4..6bf9d6b 100644
--- a/src/plugins/graphicssystems/trace/qgraphicssystem_trace.cpp
+++ b/src/plugins/graphicssystems/trace/qgraphicssystem_trace.cpp
@@ -82,8 +82,13 @@ QTraceWindowSurface::~QTraceWindowSurface()
         QFile outputFile(QString(QLatin1String("qtgraphics-%0.trace")).arg(winId));
         if (outputFile.open(QIODevice::WriteOnly)) {
             QDataStream out(&outputFile);
-            out.writeBytes("qttrace", 7);
-            out << *buffer << updates;
+            out.setFloatingPointPrecision(QDataStream::SinglePrecision);
+
+            out.writeBytes("qttraceV2", 9);
+
+            uint version = 1;
+
+            out << version << *buffer << updates;
         }
         delete buffer;
     }