Fixes: NB#216969 - [TASK] MLabelView rendering speed is too slow

RevBy: Peter Penz
Details: Added data caching and precalculation based on the performance graphs in the bug report.

3 files changed, 35 insertions, 26 deletions

diff --git a/src/views/mlabelview.cpp b/src/views/mlabelview.cpp
index cac920e6..885c9bf8 100644
--- a/src/views/mlabelview.cpp
+++ b/src/views/mlabelview.cpp
@@ -88,6 +88,8 @@ void MLabelView::applyStyle()
     Q_D(MLabelView);
     d->impl->markDirty();
     d->impl->applyStyle();
+    const MLabelStyle* labelStyle = d->style();
+    d->paddedSize = size() - QSizeF(labelStyle->paddingLeft() + labelStyle->paddingRight(), labelStyle->paddingTop() + labelStyle->paddingBottom());
     updateGeometry();
 }
 
@@ -98,13 +100,12 @@ void MLabelView::drawContents(QPainter *painter, const QStyleOptionGraphicsItem
 
     //Opacity for the label
     qreal oldOpacity = painter->opacity();
-    if (style()->textOpacity() >= 0.0)
-        painter->setOpacity(d->controller->effectiveOpacity() * style()->textOpacity());
+    const MLabelStyle* labelStyle = d->style();
+    if (labelStyle->textOpacity() >= 0.0)
+        painter->setOpacity(d->controller->effectiveOpacity() * labelStyle->textOpacity());
 
     //give size adjusted with padding to the actual implementation class
-    QSizeF padding(style()->paddingLeft() + style()->paddingRight(),
-                   style()->paddingTop() + style()->paddingBottom());
-    d->impl->drawContents(painter, size() - padding);
+    d->impl->drawContents(painter, d->paddedSize);
 
     painter->setOpacity(oldOpacity);
 }
@@ -115,12 +116,13 @@ void MLabelView::resizeEvent(QGraphicsSceneResizeEvent *event)
 
     Q_D(MLabelView);
     d->impl->markDirty();
-
-    QSizeF padding(style()->paddingLeft() + style()->paddingRight(),
-                   style()->paddingTop() + style()->paddingBottom());
+    const MLabelStyle* labelStyle = d->style();
+    QSizeF padding(labelStyle->paddingLeft() + labelStyle->paddingRight(),
+                   labelStyle->paddingTop() + labelStyle->paddingBottom());
+    d->paddedSize = event->newSize() - QSizeF(labelStyle->paddingLeft() + labelStyle->paddingRight(), labelStyle->paddingTop() + labelStyle->paddingBottom());
 
     event->setOldSize(event->oldSize() - padding);
-    event->setNewSize(event->newSize() - padding);
+    event->setNewSize(d->paddedSize);
 
     if (d->impl->resizeEvent(event))  {
         updateGeometry();
diff --git a/src/views/mlabelview_p.h b/src/views/mlabelview_p.h
index 9e6fb4d7..a67e1561 100644
--- a/src/views/mlabelview_p.h
+++ b/src/views/mlabelview_p.h
@@ -49,7 +49,7 @@ public:
     virtual void longPressEvent(QGestureEvent *event, QTapAndHoldGesture* gesture);
     virtual void orientationChangeEvent(MOrientationChangeEvent *event);
     virtual void applyStyle();
-    void initializeStaticText();
+    void initializeTextProperties();
 
     /**
      * \param width Available width in pixels for the text.
@@ -107,6 +107,10 @@ public:
     bool dirty;
     QStaticText staticText;
     QString unconstraintText;
+    
+    bool clip;
+    QPen pen;
+    QFont font;
 };
 
 class MLabelViewRich : public MLabelViewSimple
@@ -229,6 +233,8 @@ public:
 
     MLabelViewSimple *impl;
     QTextOption textOptions;
+
+    QSizeF paddedSize;
 };
 
 #endif
diff --git a/src/views/mlabelview_simple.cpp b/src/views/mlabelview_simple.cpp
index 85c10b5c..dc4a1311 100644
--- a/src/views/mlabelview_simple.cpp
+++ b/src/views/mlabelview_simple.cpp
@@ -37,7 +37,7 @@
 
 
 MLabelViewSimple::MLabelViewSimple(MLabelViewPrivate *viewPrivate) :
-    viewPrivate(viewPrivate), preferredSize(-1, -1), textOffset(), paintingRect(), dirty(true), staticText()
+    viewPrivate(viewPrivate), preferredSize(-1, -1), textOffset(), paintingRect(), dirty(true), staticText(), clip(false)
 {
     staticText.setTextFormat(Qt::PlainText);
 }
@@ -50,23 +50,15 @@ void MLabelViewSimple::drawContents(QPainter *painter, const QSizeF &size)
 {
     Q_UNUSED(size);
 
-    initializeStaticText();
+    initializeTextProperties();
     if (staticText.text().isEmpty() || paintingRect.isEmpty()) {
         return;
     }
 
-    const MLabelModel *model = viewPrivate->model();
-    const MLabelStyle *style = viewPrivate->style();
-
-    painter->setPen(model->color().isValid() ? model->color() : style->color());
-    painter->setFont(viewPrivate->controller->font());
+    painter->setPen(pen);
+    painter->setFont(font);
     painter->setRenderHint(QPainter::TextAntialiasing);
-    painter->setLayoutDirection(model->textDirection());
-
-    const bool clip =    textOffset.x() < paintingRect.x()
-                      || textOffset.y() < paintingRect.y()
-                      || textOffset.x() + staticText.size().width()  > paintingRect.right()
-                      || textOffset.y() + staticText.size().height() > paintingRect.bottom();
+    painter->setLayoutDirection(viewPrivate->model()->textDirection());
 
     if (clip) {
         painter->save();
@@ -223,7 +215,7 @@ void MLabelViewSimple::applyStyle()
         const_cast<MLabelModel*>(viewPrivate->model())->setAlignment(viewPrivate->style()->horizontalAlignment() | viewPrivate->style()->verticalAlignment());
 }
 
-void MLabelViewSimple::initializeStaticText()
+void MLabelViewSimple::initializeTextProperties()
 {
     if (!dirty) {
         return;
@@ -247,6 +239,15 @@ void MLabelViewSimple::initializeStaticText()
     staticText.prepare(QTransform(), viewPrivate->controller->font());
 
     adjustTextOffset();
+    
+    clip =  textOffset.x() < paintingRect.x()
+           || textOffset.y() < paintingRect.y()
+           || textOffset.x() + staticText.size().width()  > paintingRect.right()
+           || textOffset.y() + staticText.size().height() > paintingRect.bottom();
+
+    const QColor& color = viewPrivate->model()->color();
+    pen = QPen(color.isValid() ? color : style->color());
+    font = QFont(viewPrivate->controller->font());
 }
 
 QString MLabelViewSimple::textToRender(qreal width) const
@@ -360,7 +361,7 @@ QSizeF MLabelViewSimple::sizeForWidth(qreal width) const
         width = -1.0;
     }
 
-    const_cast<MLabelViewSimple*>(this)->initializeStaticText();
+    const_cast<MLabelViewSimple*>(this)->initializeTextProperties();
 
     const bool equalWidth = (width < 0.0 && staticText.textWidth() < 0.0) || width == staticText.textWidth();
     if (equalWidth && staticText.text() == unconstraintText) {
@@ -373,7 +374,7 @@ QSizeF MLabelViewSimple::sizeForWidth(qreal width) const
     if (staticText2.text() != unconstraintText) {
         staticText2.setText(unconstraintText);
     }
-    staticText2.prepare(QTransform(), viewPrivate->controller->font());
+    staticText2.prepare(QTransform(), font);
 
     return staticText2.size();
 }