popup.c Example C Language Program

/*
popup.c:
Demonstrates "how to write your own popup menu" routine
s.
Use LEFTMOUSE instead of RIGHTMOUSE to pop up the me
nus.
*/

#include <gl/gl.h>
#include <gl/device.h>

#define LINE 1

#define POINTS 2

#define CIRCLE 3

#define RECT 4

#define RECTF 5

#define QUIT 6

typedef struct {
  short type;
  char *text;
} popupentry;

popupentry mainmenu[] = {
  {LINE, "Line"},
  {POINTS, "100 points"},
  {CIRCLE, "Filled circle"},
  {RECT, "Outlined rectangle"},
  {RECTF, "Filled rectangle"},
  {QUIT, "Quit"},
  {0, 0}
};
/* mark end of menu */

main()
{
  long win;
  short val, command;

  prefposition(0,XMAXSCREEN,0,YMAXSCREEN);
  win = winopen("popup");
  ortho2(-1.0, 1.0, -1.0, 1.0);
  overlay(2);
  gconfig();

  drawmode(OVERDRAW);
  mapcolor(0, 0, 0, 0);        /* background only */
  mapcolor(1, 120, 120, 120);  /* popup background */
  mapcolor(2, 255, 255, 255);  /* popup text only */
  drawmode(NORMALDRAW);
  qdevice(RIGHTMOUSE);
  qdevice(LEFTMOUSE);
  tie(LEFTMOUSE, MOUSEX, MOUSEY);
  color(0);
  clear();

  while (TRUE) {
    switch(qread(&val)) {
    case REDRAW:
      reshapeviewport();
      drawstuff(command);
      break;
    case LEFTMOUSE:
      drawstuff(command = popup(mainmenu));
    default:
      break;
    }
  }

}

drawstuff(command)
short command;
{
  register i, j;

  color(0);
  clear();
  color(GREEN);
  switch(command) {
  case LINE:
    move2(-1.0, -1.0);
    draw2(1.0, 1.0);
    break;
  case POINTS:
    for (i =  0; i < 10; i++)
      for (j = 0; j < 10; j++)
        pnt2(i/20.0, j/20.0);
    break;
  case CIRCLE:
    circf(0.0, 0.0, 0.5);
    break;
  case RECT:
    rect(-0.5, -0.5, 0.5, 0.5);
    break;
  case RECTF:
    rectf(-0.5, -0.5, 0.5, 0.5);
    break;
  case QUIT:
    greset();
    gexit();
    exit(0);
  default:
    break;
  }

}

popup(names)
popupentry names[];
{
  register short i, menucount;
  short menutop, menubottom, menuleft, menuright;
  short lasthighlight = -1, highlight;
  short dummy, x, y;
  menucount = 0;
  qread(&x);
  qread(&y);
  pushmatrix();
  drawmode(OVERDRAW);
  ortho2(-0.5, 1279.5, -0.5, 1023.5);
  while (names[menucount].type)
    menucount++;
  menutop = y + menucount*8;
  menubottom = y - menucount*8;
  if (menutop > YMAXSCREEN) {
    menutop = YMAXSCREEN;
    menubottom = menutop - menucount*16;
  }

  if (menubottom < 0) {
    menubottom = 0;
    menutop = menubottom + menucount*16;
  }

  menuleft = x - 100;
  menuright = x + 100;
  if (menuleft < 0) {
    menuleft = 0;
    menuright = menuleft + 200;
  }

  if (menuright > XMAXSCREEN) {
    menuright = XMAXSCREEN;
    menuleft = menuright - 200;
  }
  color(0);
  clear();

  color(1);                /* menu background */
  rectfi(menuleft, menubottom, menuright, menutop);

  color(2);                /* menu text */
  move2i(menuleft, menubottom);
  draw2i(menuleft, menutop);
  draw2i(menuright, menutop);
  draw2i(menuright, menubottom);

  for (i = 0; i < menucount; i++) {
    move2i(menuleft, menutop - (i+1)*16);
    draw2i(menuright, menutop - (i+1)*16);
    cmov2i(menuleft + 10, menutop - 14 - i*16);
    charstr(names[i].text);
  }

  while (!qtest()) {
    x = getvaluator(MOUSEX);
    y = getvaluator(MOUSEY);
    if (menuleft < x && x < menuright && 
        menubottom < y && y < menutop)
    {
      highlight = (menutop - y)/16;
      if (lasthighlight != -1 && lasthighlight != highlight) {
        color(1);
        rectfi(menuleft+1, 
            menutop - lasthighlight*16 - 15,
            menuright-1, menutop - lasthighlight*16 - 1);
        color(2);
        cmov2i(menuleft + 10, 
            menutop - 14 - lasthighlight*16);
        charstr(names[lasthighlight].text);
      }

      if (lasthighlight != highlight) {
        color(2);
        rectfi(menuleft+1, menutop - highlight*16 - 15,
            menuright-1, menutop - highlight*16 - 1);
        color(1);
        cmov2i(menuleft + 10, 
            menutop - 14 - highlight*16);
        charstr(names[highlight].text);
      }

      lasthighlight = highlight;
    }

    else /* the cursor is outside the menu */ 
    {
      if (lasthighlight != -1)
      {
        color(1);
        rectfi(menuleft+1, 
            menutop - lasthighlight*16 - 15,
            menuright-1, menutop - lasthighlight*16 - 1);
        color(2);
        cmov2i(menuleft + 10, 
            menutop - 14 - lasthighlight*16);
        charstr(names[lasthighlight].text);
        lasthighlight = -1;
      }

    }

  }

  qread(&dummy);
  qread(&x);
  qread(&y);
  color(0);
  rectfi(menuleft, menubottom, menuright, menutop);
  if (menuleft<x && x<menuright && menubottom<y && y<menutop)
    x = (menutop - y)/16;
  else
    x = 0;
  drawmode(NORMALDRAW);
  popmatrix();
  return names[x].type;
}

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