Graph refresh and plot deleting

[olivier66]

Hi
I have an issue with a graph control I am using the code below to plot my data on the graph on timer events, but even if I set the attribute of the graph to not retain plot on the graph the graph does stack all plots, I have tried to delete plot half the time with my "deleteflag code" but it still does refresh too fast .
I want to keep the same timer event frequency tomake sure all points are plotted but I d like the graph to be smoothly refreshed


int CVICALLBACK GraphTimer_CB (int panel, int control, int event,
        void *callbackData, int eventData1, int eventData2)
{   
    double *Time;
    char *RampPatternString;
    double *Sum;
    double RampPattern[500];
    double *AnalogInputsArrayWithTickCountsVal;
    
                    if (deleteflag ==1)
                {
                    DeleteGraphPlot (dvdxt,DVDXT_SpeedTorqGraph ,-1 , VAL_DELAYED_DRAW); 
                    deleteflag = 0;
                }
                else deleteflag = 1;

    
    switch (event)
    {
        case EVENT_TIMER_TICK:
            
            if (StartTimerCallback!=0)
            {
                Sum=(double*)malloc(100*sizeof(double));
                RampPatternString=(char*)malloc(4440*sizeof(char));
                          
                SetCtrlAttribute(dvdxt, DVDXT_SpeedTorqGraph, ATTR_ACTIVE_YAXIS, VAL_LEFT_YAXIS);  
            
                //PlotY(dvdxt, DVDXT_SpeedTorqGraph,SpeedArray,500, VAL_DOUBLE, VAL_THIN_LINE, VAL_EMPTY_SQUARE, VAL_SOLID, 1, VAL_RED);
            
                PlotWaveform(dvdxt, DVDXT_SpeedTorqGraph, SpeedArray, 500, VAL_DOUBLE, 1, 0, 0, 0.0002, VAL_THIN_LINE, VAL_EMPTY_SQUARE, VAL_SOLID, 1, VAL_RED);
                
                SetCtrlAttribute(dvdxt, DVDXT_SpeedTorqGraph, ATTR_ACTIVE_YAXIS, VAL_RIGHT_YAXIS);
            
                //PlotY(dvdxt, DVDXT_SpeedTorqGraph,TorqueArray,500, VAL_DOUBLE, VAL_THIN_LINE, VAL_EMPTY_SQUARE, VAL_SOLID, 1, VAL_BLUE);
                
                PlotWaveform(dvdxt, DVDXT_SpeedTorqGraph, TorqueArray, 500, VAL_DOUBLE, 1, 0, 0, 0.0002, VAL_THIN_LINE, VAL_EMPTY_SQUARE, VAL_SOLID, 1, VAL_BLUE);
                
                SetCtrlVal(dvdxt, DVDXT_Pressure_indicator, PressureVal);
                
                Ramp(500, TimeIndex, TimeIndex + (500*0.0002),RampPattern);
                
                TimeIndex += 500*0.0002;
                
                SetCtrlVal(dvdxt, DVDXT_TimeIndex, TimeIndex);
                             
                
            
            }
            
            break;
    }
    return 0;
}

Thanks

Olivier

[LuisG]

Hello Olivier,

The reason the update isn't smooth is because when you plot the first array, the graph redraws at that point, and it redraws without the second plot. Then, a few milliseconds later, it draws again when you plot the second array. This creates flashiness. To avoid that, before plotting the first array, set the ATTR_REFRESH_GRAPH attribute to FALSE. Then, after plotting both arrays, set it back to TRUE. That should result in a single drawing operation, without any flashing.

And, of course, you need to continue passing VAL_DELAYED_DRAW to the DeleteGraphPlot function, otherwise it would redraw at deletion time as well.

Speaking of the delete operation, you really should move that code under the EVENT_TIMER_TICK case. Since this is a timer callback, it doesn't make a big difference (the only other event that is sent for timer controls is EVENT_DISCARD). But in the future, new events can always be added for a control, and then your code might start deleting plots unexpectedly.

Of course I might be assuming too much about how you want to delete the plots, given that you're only deleting every other iteration.

Luis