QPainter Event help

[vivekyuvan]

[ATTACH=CONFIG]12572
Hi Wysota

Thanks For the reply. I have done graph plotting using qtpaint event. I want to Freeze Graph on my button Click. I googled this info but no luck. is there any method to achieve Grpah freeze method using Qt paintevent
I don't have a Idea To freeze Graph like a screen shot.

[

Here is my code :

This paint event triggered by timer


void GraphArea_Single_ECG_1::paintEvent(QPaintEvent *Mypaint)
{
Q_UNUSED(Mypaint);
QPainter Single_ECG_1_Painter(this);

if(Screen_Empty_Flag == false)
{
QPen Pen_Single_ECG_1(Qt::green);
Pen_Single_ECG_1.setWidth(2);
Single_ECG_1_Painter.setPen(Pen_Single_ECG_1);
Single_ECG_1_Painter.setRenderHint(QPainter::Antia liasing,true);

Single_ECG_1_Painter.drawLine(X_Position, (127 - Single_ECG_1_Previous_Graph_data) +075, X_Position+1, (127 - Single_ECG_1_Current_Graph_data) +075);

QPen gap (Qt::black);
Single_ECG_1_Painter.setPen(gap);
Single_ECG_1_Painter.drawRect(X_Position+ 5, 0, 1, 1000);
Single_ECG_1_Painter.drawRect(X_Position+10, 0, 1, 1000);
Single_ECG_1_Painter.drawRect(X_Position+15, 0, 1, 1000);

Single_ECG_1_Previous_Graph_data = Single_ECG_1_Current_Graph_data;
}

else
{
QBrush brush(Qt::black, Qt::SolidPattern);
Single_ECG_1_Painter.fillRect(0, 0, 2000, 1000, brush);
X_Position = 0;
Screen_Empty_Flag = false;
}
}


/****Qt paint Event Trigger Function ******/

void GraphArea_Single_ECG_1::Timer_Single_ECG_1_Timeout ()
{
if(!Array_ECG_1_Data.isEmpty())
{
Single_ECG_1_Current_Graph_data = Array_ECG_1_Data.takeFirst() + 100;
}

X_Position++;
if(X_Position > Graph_Width)
X_Position=0;

this->update();
}

/**********Timer Inialization**********/

void GraphArea_Single_ECG_1::Timer_Initialization_Singl e_ECG_1()
{
Timer_Single_ECG_1 = new QTimer(this);
Timer_Single_ECG_1->setInterval(6);
connect(Timer_Single_ECG_1, SIGNAL(timeout()), this, SLOT(Timer_Single_ECG_1_Timeout()));

}]

[wysota]

Could you explain what you mean by "graph freeze"?

[high_flyer]

@wysota I think he means that when a button is clicked that graph which is otherwise moving on the time axist stops to advance hence "freeze", and I imagine, once "released" the graph should continue from its current position (as if it continued to move in the background).

@OP
One way might be that when you want to "freeze" you can simply set a flag, and check that flag in Timer_Single_ECG_1_Timeout ().
Like this:

void GraphArea_Single_ECG_1::Timer_Single_ECG_1_Timeout ()
{
if(!m_bFreeze){  //m_bFreeze is a bool which gets true when you pressed a button for freeze or some other way to trigger freeze.
if( !Array_ECG_1_Data.isEmpty()) 
{
Single_ECG_1_Current_Graph_data = Array_ECG_1_Data.takeFirst() + 100;
}
 
X_Position++;
if(X_Position > Graph_Width)
X_Position=0;
}
 
this->update();
}

void GraphArea_Single_ECG_1::Timer_Single_ECG_1_Timeout ()
{
if(!m_bFreeze){  //m_bFreeze is a bool which gets true when you pressed a button for freeze or some other way to trigger freeze.
if( !Array_ECG_1_Data.isEmpty()) 
{
Single_ECG_1_Current_Graph_data = Array_ECG_1_Data.takeFirst() + 100;
}

X_Position++;
if(X_Position > Graph_Width)
X_Position=0;
}

this->update();
}

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[vivekyuvan]

@wysota I think he means that when a button is clicked that graph which is otherwise moving on the time axist stops to advance hence "freeze", and I imagine, once "released" the graph should continue from its current position (as if it continued to move in the background).

@OP
One way might be that when you want to "freeze" you can simply set a flag, and check that flag in Timer_Single_ECG_1_Timeout ().
Like this:

void GraphArea_Single_ECG_1::Timer_Single_ECG_1_Timeout ()
{
if(!m_bFreeze){  //m_bFreeze is a bool which gets true when you pressed a button for freeze or some other way to trigger freeze.
if( !Array_ECG_1_Data.isEmpty()) 
{
Single_ECG_1_Current_Graph_data = Array_ECG_1_Data.takeFirst() + 100;
}
 
X_Position++;
if(X_Position > Graph_Width)
X_Position=0;
}
 
this->update();
}

void GraphArea_Single_ECG_1::Timer_Single_ECG_1_Timeout ()
{
if(!m_bFreeze){  //m_bFreeze is a bool which gets true when you pressed a button for freeze or some other way to trigger freeze.
if( !Array_ECG_1_Data.isEmpty()) 
{
Single_ECG_1_Current_Graph_data = Array_ECG_1_Data.takeFirst() + 100;
}

X_Position++;
if(X_Position > Graph_Width)
X_Position=0;
}

this->update();
}

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@high_flyer Thanks for Your Reply.You got my point Exactly, I will Try this method.

[vivekyuvan]

@high_flyer I followed your instruction now my problem is solved. thanks for the reply.