[XFree86] XDrawLine problem with XFree86.4.2.0

[ktang <keith.tang@xxxxxxxxxxxxxxxxxxxx>]

I apologize for not reporting this using Bugzilla.  I wasn't having much
luck getting returns on my queries.

I recently installed Mandrake 8.2 on a system and attemped to use an application
that I wrote which acquires and displays waveforms.  It was immediately obvious
that there was a problem with the XDrawLine call used in the plotting function.

The installation used the XFree86.4.2.0 release.  The videao card is an S3
Trio64 (generic 86C764/765).  Installing the XFree86.3.3.6 release cured
the problem.  The basic problem is the second point on the line is not in
the correct position.

I am attaching a small program (psrc.c) which exibits the problem.  The program
uses the xforms library for the API.  The call to draw the lines, "fl_line",
is simply a call to XDrawLine function.  I have tried both calls with exactly
the same results.  The second line in the psrc.c file is the command line
for compiling the sample program.

I am including snap shots of the correct display using 3.3.6 release and
an incorrect display from the 4.2.0 release.

I have also notice another detrimental difference between 3.3.6 and the
4.x.x releases. Graphics  drawn using 3.3.6 will be retained after being
covered by another window.  These are lost when using the 4.xx releases I
have tried.  This is an anoying problem for my applications.  There may be
a simple solution to this, but I have not discovered it.

Here is the correct display using the 3.3.6 release.  The upper right end
of the green diagonals are in the little black rectangles.

Here is the incorrect display using the 4.2.0 release.  The red horizontal
line and the black rectangles are correct.  The green diagonals are not.

I would like to know if this has been previously encountered by other developers.

Thank you,

Keith Tang
Marathon Electric Co.
Wausau, WI

715 675-3359 ext 4292

/*
gcc psrc.c -o psrc -L /usr/X11/lib -lforms -lX11 -lm
*/

	#include <stdlib.h>
	#include <unistd.h>

	#include "forms.h"

/*	#include "ptst.h"*/

/**********************/
/** Header file generated with fdesign on Wed Nov  5 08:03:50 2003.**/

#ifndef FD_ptst0_h_
#define FD_ptst0_h_

/** Callbacks, globals and object handlers **/


/**** Forms and Objects ****/
typedef struct
{
	FL_FORM *ptst0;
	void *vdata;
	char *cdata;
	long  ldata;
}
FD_ptst0;

extern FD_ptst0 * create_form_ptst0(void);

#endif /* FD_ptst0_h_ */
/**********************/

void plot(void);



int main(int argc, char *argv[])
{
	int i;
	FD_ptst0 *myfdui;
	FL_OBJECT *but;
	
	printf("1\n");
	fl_initialize(&argc, argv, "psrc", 0, 0);
	printf("2\n");
	myfdui = create_form_ptst0();
	printf("3\n");
	fl_show_form(myfdui->ptst0,FL_PLACE_CENTER,FL_FULLBORDER,"psrc");
	printf("4\n");

	plot();

	while (1)
	{
		but=fl_do_forms();
		plot();
		printf("5\n");
		usleep(100000);
	}
}


void plot(void)
{
	long i, y, j;
	
	for (j = 0; j < 25; ++j)
	{
		y = 675-24*j;

		printf("y:%d\n", y);

		/* draw the little rectangle at xy point	*/
		fl_rect(408, y-2, 4, 4, FL_BLACK);

		/* draw from origin to the xy point */
		fl_line(50, 675, 410, y, FL_GREEN);

		/* draw horizontal line at the y position	*/
		fl_line(50, y, 410, y, FL_RED);
	}

}



FD_ptst0 *create_form_ptst0(void)
{
  FL_OBJECT *obj;
  FD_ptst0 *fdui = (FD_ptst0 *) fl_calloc(1, sizeof(*fdui));

  fdui->ptst0 = fl_bgn_form(FL_NO_BOX, 500, 700);
  obj = fl_add_box(FL_UP_BOX,0,0,500,700,"");
  obj = fl_add_button(FL_NORMAL_BUTTON,10,10,70,20,"replot");
  fl_end_form();

  fdui->ptst0->fdui = fdui;

  return fdui;
}