Optimize QQuickTextEdit for larger documents.

The rationale is to not end up re-processing the whole document on each update
Since we know where the editing takes place, we can break down the text edit's
contents in several text nodes and only re-create the affected text nodes upon
editing.

This requires ripping out the SelectionEngine helper class from QQuickTextNode
so that QQuickTextEdit can tap into its functionality directly.

A positive side-effect of this exercise is that it should be much harder to
to come across GlyphNodes packing more than 16300 glyphs or so.

Task-number: QTBUG-29596
Change-Id: Id29b0709baa43f5b29c44ab02398ba996be3e28a
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/quick/items/qquicktextnode_p.h b/src/quick/items/qquicktextnode_p.h
index dcc4ebe22f..16da3ce685 100644
--- a/src/quick/items/qquicktextnode_p.h
+++ b/src/quick/items/qquicktextnode_p.h
@@ -49,6 +49,7 @@
 #include <QtGui/qcolor.h>
 #include <QtGui/qtextlayout.h>
 #include <QtCore/qvarlengtharray.h>
+#include <QtCore/qscopedpointer.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -62,6 +63,8 @@ class QSGSimpleRectNode;
 class QSGClipNode;
 class QSGTexture;
 
+class QQuickTextNodeEngine;
+
 class QQuickTextNode : public QSGTransformNode
 {
 public:
@@ -104,13 +107,17 @@ public:
     void setUseNativeRenderer(bool on) { m_useNativeRenderer = on; }
 
 private:
-    void mergeFormats(QTextLayout *textLayout, QVarLengthArray<QTextLayout::FormatRange> *mergedFormats);
+    void initEngine(const QColor &textColor, const QColor &selectedTextColor, const QColor &selectionColor, const QColor& anchorColor = QColor());
+
 
     QSGContext *m_context;
     QSGSimpleRectNode *m_cursorNode;
     QList<QSGTexture *> m_textures;
     QQuickItem *m_ownerElement;
     bool m_useNativeRenderer;
+    QScopedPointer<QQuickTextNodeEngine> m_engine;
+
+    friend class QQuickTextEdit;
 };
 
 QT_END_NAMESPACE