[scilab-Users] Question on using plot in call_scilab module

[Mike Page]

Hi Norm,

Sorry if this response is too late for you, but it may help somebody else...

I came across your post while looking for help on another issue related to
plotting with SendScilabJob.  Here is some example code that runs the
plotting in a separate thread under WinXp.  It works for me and I think it
would do what you wanted.  Sorry it's a bit short on comments ;-)

To build this, you need to also include the /include directories from:
SCI/modules/call_scilab
SCI/modules/api_scilab
SCI/modules/core

You also need to set the library path to include SCI/bin and include the
libraries:
api_scilab.lib
call_scilab.lib
MALLOC.lib
LibScilab.lib

When running, /SCI/bin needs to be in your path so Scilab can find the DLLs.

HTH.
Mike.

/*--------------------------------------------------------------------------
*/
#include <windows.h>
#include <stdio.h>
#include <process.h>
#include "call_scilab.h"
#include "api_scilab.h"


HANDLE	PlotCmd[2];
HANDLE	Reply;
double	x[100];
double	y[100];


/*--------------------------------------------------------------------------
*/
static void SciPlot (void* Params)
{
	DWORD	Event;
	BOOL	Exit = FALSE;

	if (StartScilab (NULL, NULL, 0) == FALSE)
	{
		printf ("Error : StartScilab\n");
	}

	Reply = CreateEvent (NULL, FALSE, FALSE, NULL);

	while (!Exit)
	{
		Event = WaitForMultipleObjects (2, PlotCmd, FALSE, INFINITE);

		switch (Event)
		{
			case	(WAIT_OBJECT_0 + 0):
			{
				createNamedMatrixOfDouble (pvApiCtx, "x", 1, 100, x);
				createNamedMatrixOfDouble (pvApiCtx, "y", 1, 100, y);
				SendScilabJob ("delete (e);");
				SendScilabJob ("plot2d(x,y);");
				SendScilabJob ("e = gce ();");
				printf ("...Plot started\n");
				SetEvent (Reply);
				break;
			}
			case	(WAIT_OBJECT_0 + 1):
			{
				Exit = TRUE;
				break;
			}
		}
	}

	if (TerminateScilab (NULL) == FALSE)
	{
		printf ("Error : TerminateScilab\n");
	}

	SetEvent (Reply);
}

/*--------------------------------------------------------------------------
*/
int main(void)
{
	int	i, j;

	printf ("Starting\n");
	PlotCmd[0] = CreateEvent (NULL, FALSE, FALSE, NULL);
	PlotCmd[1] = CreateEvent (NULL, FALSE, FALSE, NULL);
	_beginthread (SciPlot, 0, NULL);
	Sleep (1000);

	for (j=1; j<100; j++)
	{
		x[j] = j;
	}

	for (i=0; i<10; i++)
	{
		for (j=1; j<100; j++)
		{
			y[j] = (2.0 *(double)rand () / (double)RAND_MAX) - 1.0;
		}
		printf ("Update Plot\n");
		SetEvent (PlotCmd[0]);
		WaitForSingleObject (Reply, INFINITE);
		Sleep (1000);
	}
	printf ("Terminate Plot\n");
	SetEvent (PlotCmd[1]);
	WaitForSingleObject (Reply, INFINITE);
	CloseHandle (PlotCmd[0]);
	CloseHandle (PlotCmd[1]);
	return 0;
}
/*--------------------------------------------------------------------------
*/



-----Original Message-----
From: Norman Beamish [mailto:norman.beamish at m4s.be]
Sent: 03 June 2010 11:13
To: users at lists.scilab.org
Subject: [scilab-Users] Question on using plot in call_scilab module


Hi,

I'm using the call_scilab module to access scilab functions from within
a C program.  I'm using MS Visual C++ 2008 on MS Vista.

Everything that just writes its output to the console works ok.  However
when I use the scilab plot command
      SendScilabJob("plot(x,y, style);")
I find that the plot window freezes and the plot menu options are
unavailable unless I run the following loop: -
    while( ScilabHaveAGraph() )
    {
        ScilabDoOneEvent();
    }
Of course this loop stops my program from doing anything else.

My question:
I believe this problem arises because everything is operating in a
single thread.  Is there a way to make the plot command start out in a
separate thread so that it can still monitor for user events such as
mouse clicks while the rest of my program continues.

thanks,
Norm

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