sprite.c

数据挖掘中de一个算法 hamster的实例

/*----------------------------------------------------------------------
  File    : sprite.c
  Contents: sprite management, single color (X11 version)
  Author  : Christian Borgelt
  History : 30.10.1997 file created
            31.10.1997 first version completed
            01.11.1997 event processing in function spr_move added
            02.11.1997 NOFLICKER version hardcoded
            04.11.1997 move function changed to timeout procedure
            06.11.1997 callback function added to function spr_move
            16.06.1998 switching to new sprite image improved
----------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "sprite.h"
#include <X11/Xutil.h>

/*----------------------------------------------------------------------
  Auxiliary Functions
----------------------------------------------------------------------*/

static void move (XtPointer data, XtIntervalId *iid)
{                               /* --- move sprite one step */
  SPRITE *spr = data;           /* sprite to be moved */

  if (spr->cnt <= 0) return;    /* if stopped, abort function */
  XSetClipOrigin(spr->display, spr->gc,       /* duplicate */
    spr->xext -spr->xoff, -spr->yoff);        /* background */
  XCopyArea(spr->display, spr->buffer, spr->buffer, spr->gc,
    0, 0, spr->xext, spr->yext, spr->xext, 0);
  spr->xnew += spr->di *spr->xext; /* get offset for new image */
  XSetClipOrigin(spr->display, spr->gc,       /* draw new image */
    spr->dx -spr->xnew, spr->dy -spr->ynew);  /* into buffer */
  XFillRectangle(spr->display, spr->buffer, spr->gc,
    spr->dx, spr->dy, spr->xext, spr->yext);
  XSetClipOrigin(spr->display, spr->gc,       /* undraw sprite */
    spr->xpos -spr->xoff, spr->ypos -spr->yoff);
  XCopyArea(spr->display, spr->buffer, spr->window, spr->gc,
    0, 0, spr->xext, spr->yext, spr->xpos, spr->ypos);
  spr->xpos += spr->dx;         /* move sprite to */
  spr->ypos += spr->dy;         /* new position */
  XSetClipOrigin(spr->display, spr->gc,       /* copy background */
    -spr->xnew, -spr->ynew);                  /* into buffer */
  XCopyArea(spr->display, spr->window, spr->buffer, spr->gc,
    spr->xpos, spr->ypos, spr->xext, spr->yext, 0, 0);
  XSetClipOrigin(spr->display, spr->gc,       /* complete background */
    -spr->dx -spr->xoff, -spr->dy -spr->yoff);/* from duplicate */
  XCopyArea(spr->display, spr->buffer, spr->buffer, spr->gc,
    spr->xext, 0, spr->xext, spr->yext, -spr->dx, -spr->dy);
  /* It is necessary to complete the background with the */
  /* background data from the duplicate in the second buffer, */
  /* since we drew the new sprite image into the background */
  /* buffer and copied this modified background to the screen. */
  /* Hence, if the new and the old sprite image overlap, */
  /* we cannot get the complete background from the screen, */
  /* but only the part that is not obscured by the overlap. */
  /* The obscured part we get from the buffered duplicate. */
  XSetClipOrigin(spr->display, spr->gc,  /* draw sprite */
    spr->xpos -spr->xnew, spr->ypos -spr->ynew);
  XFillRectangle(spr->display, spr->window, spr->gc,
    spr->xpos, spr->ypos, spr->xext, spr->yext);
  XFlush(spr->display);         /* flush buffered drawing commands */
  spr->xoff = spr->xnew;        /* transfer offsets for new image */
  spr->yoff = spr->ynew;        /* to offsets for current image */
  if (--spr->cnt > 0)           /* if not done, reregister function */
    spr->iid = XtAppAddTimeOut(spr->appctx, spr->delay, move, spr);
  else if (spr->cback)          /* otherwise call callback function */
    spr->cback(spr->widget, spr->data, (XtPointer)spr);
}  /* move() */

/*----------------------------------------------------------------------
  Main Functions
----------------------------------------------------------------------*/

SPRITE* spr_create (Widget widget, int xext, int yext,
                    Pixmap bitmap, unsigned long color)
{                               /* --- create a sprite */
  SPRITE *spr;                  /* created sprite */
  int    depth;                 /* color depth of display */

  spr = (SPRITE*)malloc(sizeof(SPRITE));
  if (!spr) return NULL;        /* allocate sprite body */
  spr->xext    = xext;          /* and initialize fields */
  spr->yext    = yext;          /* note sprite extensions */
  spr->xoff    = spr->yoff = 0; /* select first image of first series */
  spr->xnew    = spr->ynew = 0; /* for the current and the new image */
  spr->xpos    = spr->ypos = 0; /* initialize position */
  spr->drawn   = spr->cnt  = 0; /* sprite is not drawn and not moving */
  spr->appctx  = XtWidgetToApplicationContext(widget);
  spr->widget  = widget;        /* note app. context and widget */
  spr->display = XtDisplay(widget);  /* get display and */
  spr->window  = XtWindow(widget);   /* window of widget */

  /* --- create window graphic context --- */
  spr->gc = XCreateGC(spr->display, spr->window, 0, NULL);
  if (!spr->gc) { free(spr); return NULL; }
  XSetForeground(spr->display, spr->gc, color);   /* set color */
  XSetClipMask  (spr->display, spr->gc, bitmap);  /* and bitmap */

  /* --- create background buffer --- */
  depth = XDefaultDepth(spr->display, XDefaultScreen(spr->display));
  spr->buffer = XCreatePixmap(spr->display, spr->window,
                              2 *xext, yext, depth);
  if (spr->buffer == None) { spr_delete(spr); return NULL; }
  /* The reason why the background buffer is allocated with */
  /* double sprite width can be seen in the function spr_move. */

  return spr;                   /* return created sprite */
}  /* spr_create() */

/*--------------------------------------------------------------------*/

void spr_delete (SPRITE *spr)
{                               /* --- delete a sprite */
  if (spr->drawn)          spr_undraw(spr);
  if (spr->buffer != None) XFreePixmap(spr->display, spr->buffer);
  if (spr->gc)             XFreeGC(spr->display, spr->gc);
  free(spr);                    /* delete buffer, gcs and sprite body */
}  /* spr_delete() */

/*--------------------------------------------------------------------*/

void spr_select (SPRITE *spr, int series, int index)
{                               /* --- select a sprite image */
  spr->xnew = (index  > 0) ? index  *spr->xext : 0;
  spr->ynew = (series > 0) ? series *spr->yext : 0;
}  /* spr_select() */

/*--------------------------------------------------------------------*/

int spr_draw (SPRITE *spr, int x, int y)
{                               /* --- draw a sprite */
  if (spr->drawn) {             /* if sprite is drawn */
    if (((x == INT_MIN) || (x == spr->xpos))
    &&  ((y == INT_MIN) || (y == spr->ypos))
    &&  (spr->xoff == spr->xnew)
    &&  (spr->yoff == spr->ynew))
      return 0;                 /* if sprite is already drawn at the */
    spr_undraw(spr);            /* correct position, abort function, */
    spr->xoff = spr->xnew;      /* otherwise undraw sprite */
    spr->yoff = spr->ynew;      /* and get the offsets for */
  }                             /* the new sprite image */
  if (x > INT_MIN) spr->xpos = x;  /* if new coordinates given, */
  if (y > INT_MIN) spr->ypos = y;  /* use coordinates */
  XSetClipOrigin(spr->display, spr->gc,
    -spr->xoff, -spr->yoff);    /* save background in buffer */
  XCopyArea(spr->display, spr->window, spr->buffer, spr->gc,
    spr->xpos, spr->ypos, spr->xext, spr->yext, 0, 0);
  XSetClipOrigin(spr->display, spr->gc,
    spr->xpos -spr->xoff, spr->ypos -spr->yoff);
  XFillRectangle(spr->display, spr->window, spr->gc,
    spr->xpos, spr->ypos, spr->xext, spr->yext);
  XFlush(spr->display);         /* draw sprite */
  spr->drawn = 1;               /* note that sprite is drawn */
  return 0;                     /* return 'ok' */
}  /* spr_draw() */

/*--------------------------------------------------------------------*/

int spr_undraw (SPRITE *spr)
{                               /* --- undraw a sprite */
  if (!spr->drawn) return -1;   /* if sprite is not drawn, abort */
  XCopyArea(spr->display, spr->buffer, spr->window, spr->gc,
    0, 0, spr->xext, spr->yext, spr->xpos, spr->ypos);
  XFlush(spr->display);         /* copy background back to window */
  spr->drawn = 0;               /* note that sprite is not drawn */
  return 0;                     /* return 'ok' */
}  /* spr_undraw() */

/*--------------------------------------------------------------------*/

int spr_move (SPRITE *spr, int dx, int dy, int di, int cnt, float delay,
              XtCallbackProc callback, XtPointer data)
{                               /* --- animate a sprite */
  if (spr->cnt > 0) return -1;  /* if sprite is (still) moving, abort */
  if (!spr->drawn)              /* if sprite is not drawn, */
    spr_draw(spr, INT_MIN, INT_MIN);            /* draw it */
  if (cnt <= 0) return 0;       /* if not to move, abort function */
  spr->dx    = dx; spr->dy = dy; spr->di = di;
  spr->cnt   = cnt;             /* note parameters */
  spr->delay = (unsigned int)(delay *1000);
  spr->cback = callback;        /* note callback function */
  spr->data  = data;            /* and client data */
  spr->iid   = XtAppAddTimeOut(spr->appctx, spr->delay, move, spr);
  return 0;                     /* register function and return 'ok' */
}  /* spr_move() */

/*--------------------------------------------------------------------*/

void spr_stop (SPRITE *spr)
{                               /* --- stop moving sprite */
  if (spr->cnt <= 0) return;    /* if sprite is not moving, abort */
  XtRemoveTimeOut(spr->iid);    /* remove timer procedure */
  spr->cnt = 0;                 /* and clear number of steps */
}  /* spr_stop() */