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Thomas W.


Date of registration: Jun 2nd 2015

Posts: 40


Tuesday, November 28th 2017, 1:26pm

GRAPH widget for MPP tracking application

Hi there,

I want to use the GRAPH widget in XY mode in order to display an MPPT curve in real time (like in the attached image). Therefore I want to indicate the maximum power point and the corresponding current value with a marker (cross or circle). I was already able to modify the example WIDGET_GraphXY.c in order to get the expected behavior with the aid of a owner draw callback function (see attached source file).
Unfortunately I am not completely satisfied with my solution and therefore I have the following questions:

1. Is it possible to update a single graph data object without calling GRAPH_DATA_XY_Clear() and GRAPH_DATA_XY_AddPoint()? I was looking for an invalidation function like WM_InvalidateWindow() but without success...

2. Is it possible to get the index of the currently drawn point in the user defined owner draw callback function? I would like to look for the "MPP" value in the data array before I draw the graph and then I want to draw the indicator at the corresponding point index in the user defined owner draw callback function.

3. Is there a WM message or notification which informs me if the graph data object is cleared, updated or if a point is added?

I also found this thread How to make marker on graph widget in the forum, but I think that my solution with the owner draw callback function would be more elegant.

Furthermore I noticed that there are some undocumented function declarations in GRAPH.h...

Hope you can help me.

regards Thomas
Thomas W. has attached the following image:
  • MPPT.jpg
Thomas W. has attached the following file:
  • WIDGET_GraphXY.txt (21.61 kB - 102 times downloaded - Last download: Yesterday, 11:20am)

This post has been edited 2 times, last edit by "Thomas W." (Nov 28th 2017, 1:33pm)