🚀 go-pugleaf

A developer of sunview-based software has run into an anomaly using
sunview.  The problem is explained in the header comment of the following
small program that demonstrates the problem.

Any information or insight regarding this would be appreciated.

Thanks,
Rob Jaksa

/*  This small program illustrates what I take to be a bug in
	the SUNVIEW software system.  The program creates a canvas
	window within a Frame.  The canvas handler simply calls the
	draw_and_erase routine, which draws a line segment within the
	canvas using two points input by two LEFT mouse clicks.  A
	third mouse click should erase the line.  The program works as
	expected on Sun3 terminals and on Color Sparc stations.  However,
	on Monochrome Sparc stations the line segment is not always
	completely erased.  Line segments that are more than about
	45 degrees to the horizontal are only partially erased;
	sometimes most and sometimes very little of the line is
	removed.

	Compilation: cc  demo.c -lsuntool -lsunwindow -lpixrect

*/


#include <stdio.h>
#include <suntool/sunview.h>
#include <suntool/canvas.h>

Frame   base_frame;
Canvas  canvas;
Pixwin *canvas_pw;
Rect   *canvas_rect;


static void
canvas_handler(canvas, event, arg)
  Canvas  canvas;
  Event  *event;
  caddr_t arg;
{
  if (!((event_id(event) == LOC_STILL) &&
	(event_id(event) == LOC_MOVE))) {
    draw_and_erase();
  }

}

draw_and_erase()
{
  int     x1,
          y1,
          x2,
          y2;

  Event   event;

  printf("\n enter draw and erase ");

/* wait for left click for first endpoint */
  do {
    window_read_event(canvas, &event);
    if ((event_id(&event) == LOC_RGNEXIT) ||
	(event_id(&event) == LOC_WINEXIT)) {
      printf(" leave window \n");
      return;
    }
  } while (event_id(&event) != MS_LEFT);

  x1 = event_x(&event);
  y1 = event_y(&event);

/* wait for left click for second endpoint */
  do {
    window_read_event(canvas, &event);
    if ((event_id(&event) == LOC_RGNEXIT) ||
	(event_id(&event) == LOC_WINEXIT)) {
      printf(" leave window \n");
      return;
    }
  } while (event_id(&event) != MS_LEFT);

  x2 = event_x(&event);
  y2 = event_y(&event);

/* draw edge */
  pw_vector(canvas_pw, x1, y1, x2, y2, PIX_SRC, 1);

/* wait for left click to erase edge  */
  do {
    window_read_event(canvas, &event);
    if ((event_id(&event) == LOC_RGNEXIT) ||
	(event_id(&event) == LOC_WINEXIT)) {
      printf(" leave window \n");
      return;
    }
  } while (event_id(&event) != MS_LEFT);

/* erase edge  */
  pw_vector(canvas_pw, x1, y1, x2, y2, PIX_NOT(PIX_SRC) & PIX_DST, 1);
}

main()
{
  base_frame =
    window_create(0, FRAME,
		  WIN_X, 100,
		  WIN_Y, 100,
		  WIN_WIDTH, 500,
		  WIN_HEIGHT, 500,
		  FRAME_SUBWINDOWS_ADJUSTABLE, FALSE, 0);

  canvas =
    window_create(base_frame, CANVAS,
		  WIN_EVENT_PROC, canvas_handler,
		  WIN_WIDTH, 500,
		  WIN_HEIGHT, 500,
		  WIN_IGNORE_PICK_EVENTS, WIN_UP_EVENTS, 0,
		  WIN_IGNORE_KBD_EVENT, WIN_NO_EVENTS,
		  CANVAS_FIXED_IMAGE, TRUE,
		  CANVAS_FAST_MONO, TRUE,
		  0);
  window_set(canvas, WIN_CONSUME_PICK_EVENTS, LOC_STILL, LOC_RGNENTER, LOC_RGNEXIT, 0);
  canvas_pw = canvas_pixwin(canvas);
  canvas_rect = (Rect *) window_get(canvas, WIN_RECT);
  window_main_loop(base_frame);
  exit(0);
}