I want to use qquickpainteditem class to draw graphics in QML, have implemented before drawing function

This time I slavish write again, I found it won't work, tried a lot of ways how to show never call paint () function,
Think because it is inherited qquickitem, I will rewrite updatepaintnode (), found that he had a call this function, rather than the I want to paint (), it makes me very strange

The code
ROI. H:

 
The class rectRoi: public QQuickPaintedItem 
{
Q_OBJECT 
Public: 
RectRoi (QQuickItem * parent=0); 
Virtual ~ rectRoi Q_DECL_OVERRIDE (); 
Protected: 
Void paint (QPainter * painter) Q_DECL_OVERRIDE; 
QRectF boundingRect () const Q_DECL_OVERRIDE; 
QSGNode * updatePaintNode (QSGNode * Node, UpdatePaintNodeData *) override. 
Private: 
QRectF the Rect, mBoundingRect; 
QPen PointPen LinePen; 
Void setRect (const int & amp; X, const int & amp; Y, const int & amp; W, const int & amp; H); 
}; 

ROI. CPP:

 
RectRoi: : rectRoi (QQuickItem * parent) 
: QQuickPaintedItem (parent) 
{
PointPen. SetColor (" red "); 
PointPen. SetWidth (9); 
LinePen. SetColor (" red "); 
LinePen. SetStyle (Qt: : SolidLine); 
LinePen. SetWidth (3); 
SetRect (300200200100); 
//setFlag (QQuickItem: : ItemHasContents); 
} 

RectRoi: : ~ rectRoi () 
{

} 

QSGNode * rectRoi: : updatePaintNode (QSGNode * Node, UpdatePaintNodeData *) 
{
QDebug () & lt; <"UpdatePaintNode"; 
Return the Node; 
} 

Void rectRoi: : paint (QPainter * painter) 
{
QDebug () & lt; & lt;" Paint "; 

Painter - & gt; SetRenderHint (QPainter: : Antialiasing, true); 

Painter - & gt; SetPen (PointPen); 
Painter - & gt; DrawPoint (the Rect topLeft ()); 
Painter - & gt; DrawPoint (the Rect topRight ()); 
Painter - & gt; DrawPoint (the Rect bottomLeft ()); 
Painter - & gt; DrawPoint (the Rect bottomRight ()); 

Painter - & gt; SetPen (LinePen); 
Painter - & gt; DrawLine (the Rect. TopLeft (), the Rect topRight ()); 
Painter - & gt; DrawLine (the Rect. TopRight (), the Rect bottomRight ()); 
Painter - & gt; DrawLine (the Rect. BottomRight (), the Rect bottomLeft ()); 
Painter - & gt; DrawLine (the Rect. BottomLeft (), the Rect topLeft ()); 
} 

Const QRectF rectRoi: : boundingRect () 
{
Return mBoundingRect; 
} 

Void rectRoi: : setRect (const int & amp; X, const int & amp; Y, const int & amp; W, const int & amp; H) 
{
The Rect=QRectF (x, y, w, h); 
MBoundingRect. Your setX (the Rect. X () - the Rect. Width ()/2); 
MBoundingRect. SetY (the Rect. Y () - the Rect. Height ()/2); 
MBoundingRect. SetWidth (the Rect. Width ()); 
MBoundingRect. SetHeight (the Rect. Height ()); 
QDebug () & lt; & lt;" BoundingRect: "& lt; The update (); 
QDebug () & lt; & lt;" SetRect "; 
} 

Welcome each great spirit to guide discussion

CodePudding user response:

I also encountered the same problem, finally I forced to modify the rectangle size is a function can enter the paint of paint