How to clear the curve in the Pttrend ?

QNX DEVELOPERS GUI Programming
1

If the length of Pttrend is 100,first I draw the curve full of Pttrend,now I only want to clear some data in the Pttrend,for example I only want to draw the curve whose length is 80,how to do?

2

I have never used that widget, but I am guessing you will have to track the data points yourself and massage what the Trend widget actually sees to behave the way you want. Basically providing a higher-level API to the widget.

3

sorry,I don’t understand what you say,can you tell me how to do step by step?

4

Step-by-step? No, I don’t think I will do that. ;)

Basically you need to manage your data yourself. Instead of trying to have the widget manage it for you. Then you can just keep the widget in-sync with the data you are managing.

5

oh,my god!

6

You need set another points number the same way as you draw PtTrend first time. Or zerro points to clear it. Or PtUnrealizeWidget() to delete it from the screen

7

PtSetArg( &arg, Pt_ARG_TREND_DATA, NULL, 0 );
PtSetResources( trend_widget_prt, 1, &arg );

8

That’s a unique reaction :slight_smile:

9

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