tdenetwork/krfb/libvncserver/cursor.c

/*
 * cursor.c - support for cursor shape updates.
 */

/*
 *  Copyright (C) 2000, 2001 Const Kaplinsky.  All Rights Reserved.
 *  Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
 *
 *  This is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This software is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this software; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 *  USA.
 */

#include "rfb.h"

/*
 * Send cursor shape either in X-style format or in client pixel format.
 */

Bool
rfbSendCursorShape(cl)
    rfbClientPtr cl;
{
    rfbCursorPtr pCursor;
    rfbFramebufferUpdateRectHeader rect;
    rfbXCursorColors colors;
    int saved_ublen;
    int bitmapRowBytes, maskBytes, dataBytes;
    int i, j;
    CARD8 *bitmapData;
    CARD8 bitmapByte;

    pCursor = cl->screen->getCursorPtr(cl);
    /*if(!pCursor) return TRUE;*/

    if (cl->useRichCursorEncoding) {
      if(pCursor && !pCursor->richSource)
	MakeRichCursorFromXCursor(cl->screen,pCursor);
      rect.encoding = Swap32IfLE(rfbEncodingRichCursor);
    } else {
       if(pCursor && !pCursor->source)
	 MakeXCursorFromRichCursor(cl->screen,pCursor);
       rect.encoding = Swap32IfLE(rfbEncodingXCursor);
    }

    /* If there is no cursor, send update with empty cursor data. */

    if ( pCursor && pCursor->width == 1 &&
	 pCursor->height == 1 &&
	 pCursor->mask[0] == 0 ) {
	pCursor = NULL;
    }

    if (pCursor == NULL) {
	if (cl->ublen + sz_rfbFramebufferUpdateRectHeader > UPDATE_BUF_SIZE ) {
	    if (!rfbSendUpdateBuf(cl))
		return FALSE;
	}
	rect.r.x = rect.r.y = 0;
	rect.r.w = rect.r.h = 0;
	memcpy(&cl->updateBuf[cl->ublen], (char *)&rect,
	       sz_rfbFramebufferUpdateRectHeader);
	cl->ublen += sz_rfbFramebufferUpdateRectHeader;

	cl->rfbCursorBytesSent += sz_rfbFramebufferUpdateRectHeader;
	cl->rfbCursorUpdatesSent++;

	if (!rfbSendUpdateBuf(cl))
	    return FALSE;

	return TRUE;
    }

    /* Calculate data sizes. */

    bitmapRowBytes = (pCursor->width + 7) / 8;
    maskBytes = bitmapRowBytes * pCursor->height;
    dataBytes = (cl->useRichCursorEncoding) ?
	(pCursor->width * pCursor->height *
	 (cl->format.bitsPerPixel / 8)) : maskBytes;

    /* Send buffer contents if needed. */

    if ( cl->ublen + sz_rfbFramebufferUpdateRectHeader +
	 sz_rfbXCursorColors + maskBytes + dataBytes > UPDATE_BUF_SIZE ) {
	if (!rfbSendUpdateBuf(cl))
	    return FALSE;
    }

    if ( cl->ublen + sz_rfbFramebufferUpdateRectHeader +
	 sz_rfbXCursorColors + maskBytes + dataBytes > UPDATE_BUF_SIZE ) {
	return FALSE;		/* FIXME. */
    }

    saved_ublen = cl->ublen;

    /* Prepare rectangle header. */

    rect.r.x = Swap16IfLE(pCursor->xhot);
    rect.r.y = Swap16IfLE(pCursor->yhot);
    rect.r.w = Swap16IfLE(pCursor->width);
    rect.r.h = Swap16IfLE(pCursor->height);

    memcpy(&cl->updateBuf[cl->ublen], (char *)&rect,sz_rfbFramebufferUpdateRectHeader);
    cl->ublen += sz_rfbFramebufferUpdateRectHeader;

    /* Prepare actual cursor data (depends on encoding used). */

    if (!cl->useRichCursorEncoding) {
	/* XCursor encoding. */
	colors.foreRed   = (char)(pCursor->foreRed   >> 8);
	colors.foreGreen = (char)(pCursor->foreGreen >> 8);
	colors.foreBlue  = (char)(pCursor->foreBlue  >> 8);
	colors.backRed   = (char)(pCursor->backRed   >> 8);
	colors.backGreen = (char)(pCursor->backGreen >> 8);
	colors.backBlue  = (char)(pCursor->backBlue  >> 8);

	memcpy(&cl->updateBuf[cl->ublen], (char *)&colors, sz_rfbXCursorColors);
	cl->ublen += sz_rfbXCursorColors;

	bitmapData = (CARD8 *)pCursor->source;

	for (i = 0; i < pCursor->height; i++) {
	    for (j = 0; j < bitmapRowBytes; j++) {
		bitmapByte = bitmapData[i * bitmapRowBytes + j];
		cl->updateBuf[cl->ublen++] = (char)bitmapByte;
	    }
	}
    } else {
	/* RichCursor encoding. */
       int bpp1=cl->screen->rfbServerFormat.bitsPerPixel/8,
	 bpp2=cl->format.bitsPerPixel/8;
       (*cl->translateFn)(cl->translateLookupTable,
		       &(cl->screen->rfbServerFormat),
                       &cl->format, pCursor->richSource,
		       &cl->updateBuf[cl->ublen],
                       pCursor->width*bpp1, pCursor->width, pCursor->height);

       cl->ublen += pCursor->width*bpp2*pCursor->height;
    }

    /* Prepare transparency mask. */

    bitmapData = (CARD8 *)pCursor->mask;

    for (i = 0; i < pCursor->height; i++) {
	for (j = 0; j < bitmapRowBytes; j++) {
	    bitmapByte = bitmapData[i * bitmapRowBytes + j];
	    cl->updateBuf[cl->ublen++] = (char)bitmapByte;
	}
    }

    /* Send everything we have prepared in the cl->updateBuf[]. */

    cl->rfbCursorBytesSent += (cl->ublen - saved_ublen);
    cl->rfbCursorUpdatesSent++;

    if (!rfbSendUpdateBuf(cl))
	return FALSE;

    return TRUE;
}

/*
 * Send soft cursor state and possibly image
 */

Bool
rfbSendSoftCursor(rfbClientPtr cl, Bool cursorWasChanged)
{
    rfbCursorPtr pCursor;
    rfbSoftCursorSetImage setImage;
    rfbSoftCursorMove moveMsg;
    rfbFramebufferUpdateRectHeader rect;
    int saved_ublen, i, scOindex, scNindex, nlen, imgLen;

    pCursor = cl->screen->getCursorPtr(cl);
    if (cursorWasChanged && cl->softSource) {
	free(cl->softSource);
	cl->softSource = 0;
    }
    if (!cl->softSource)
	MakeSoftCursor(cl, pCursor);

    imgLen = cl->softSourceLen;

    /* If there is no cursor, send update with empty cursor data. */

    if ( pCursor && pCursor->width <= 1 &&
	 pCursor->height <= 1 &&
	 pCursor->mask[0] == 0 ) {
	pCursor = NULL;
    }

    setImage.imageLength = Swap16IfLE(imgLen);

    scOindex = -1;
    scNindex = -1;
    for (i = 0; i < rfbSoftCursorMaxImages; i++) {
	rfbSoftCursorSetImage *scsi = cl->softCursorImages[i];
	if (!scsi) {
	    scNindex = i;
	    break;
	}
	
	setImage.imageIndex = scsi->imageIndex;
	if (!memcmp((char*)scsi, (char*)&setImage, sizeof(setImage))) {
	    if (imgLen && !memcmp(((char*)scsi)+sizeof(rfbSoftCursorSetImage),
				  cl->softSource,
				  imgLen)) {
		scOindex = i;
		break;
	    }
	}
    }

    nlen = 0;
    if (scOindex < 0) {
	if (scNindex < 0) {
	    scNindex = cl->nextUnusedSoftCursorImage;
	    cl->nextUnusedSoftCursorImage = (cl->nextUnusedSoftCursorImage+1) 
		% rfbSoftCursorMaxImages;
	    free(cl->softCursorImages[scNindex]);
	}

	scOindex = scNindex;
	setImage.imageIndex = scNindex + rfbSoftCursorSetIconOffset;
	nlen = sizeof(setImage) + imgLen;
	cl->softCursorImages[scNindex] = calloc(1, nlen);
	memcpy((char*)cl->softCursorImages[scNindex], (char*)&setImage, 
	       sizeof(setImage));
	if (imgLen)
	    memcpy(((char*)cl->softCursorImages[scNindex])+sizeof(setImage), 
		   (char*)cl->softSource, imgLen);
    }

    /* Send buffer contents if needed. */

    if ( cl->ublen + sizeof(rfbSoftCursorMove) + 
	 ((scNindex >= 0 && cursorWasChanged) ? 
	 (sizeof(rfbSoftCursorSetImage) + imgLen) : 0) > UPDATE_BUF_SIZE) {
			    
	if (!rfbSendUpdateBuf(cl))
	    return FALSE;
    }

    saved_ublen = cl->ublen;

    if (scNindex >= 0 && cursorWasChanged) {
	rect.encoding = Swap32IfLE(rfbEncodingSoftCursor);
	if (pCursor) {
	    rect.r.x = Swap16IfLE(pCursor->xhot);
	    rect.r.y = Swap16IfLE(pCursor->yhot);
	    rect.r.w = Swap16IfLE(pCursor->width);
	    rect.r.h = Swap16IfLE(pCursor->height);
	}
	else {
	    rect.r.x = 0;
	    rect.r.y = 0;
	    rect.r.w = 0;
	    rect.r.h = 0;
	}

	memcpy(&cl->updateBuf[cl->ublen], 
	       (char *)&rect,sz_rfbFramebufferUpdateRectHeader);
	cl->ublen += sz_rfbFramebufferUpdateRectHeader;
	memcpy(&cl->updateBuf[cl->ublen], (char*)cl->softCursorImages[scNindex], nlen);
	cl->ublen += nlen;
	cl->rfbCursorUpdatesSent++;
    }

    rect.encoding = Swap32IfLE(rfbEncodingSoftCursor);
    rect.r.x = 0;
    rect.r.y = 0;
    rect.r.w = Swap16IfLE(cl->screen->cursorX);
    rect.r.h = Swap16IfLE(cl->screen->cursorY);
    moveMsg.imageIndex = scOindex;
    moveMsg.buttonMask = 0; /* todo */
    memcpy(&cl->updateBuf[cl->ublen], 
	   (char *)&rect,sz_rfbFramebufferUpdateRectHeader);
    cl->ublen += sz_rfbFramebufferUpdateRectHeader;
    memcpy(&cl->updateBuf[cl->ublen], (char*)&moveMsg, sizeof(moveMsg));
    cl->ublen += sizeof(moveMsg);

    /* Send everything we have prepared in the cl->updateBuf[]. */

    cl->rfbCursorBytesSent += (cl->ublen - saved_ublen);
    cl->rfbCursorUpdatesSent++;

    return rfbSendUpdateBuf(cl);
}

/* conversion routine for predefined cursors in LSB order */
unsigned char rfbReverseByte[0x100] = {
  /* copied from Xvnc/lib/font/util/utilbitmap.c */
	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
	0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
	0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
	0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
	0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
	0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
	0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
	0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
	0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
	0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
	0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
	0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
	0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
	0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
	0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
	0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
	0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
	0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
	0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
	0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
	0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
	0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
	0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
	0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
	0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
	0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
	0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
	0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
	0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
	0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
	0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
	0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
};

void rfbConvertLSBCursorBitmapOrMask(int width,int height,unsigned char* bitmap)
{
   int i,t=(width+7)/8*height;
   for(i=0;i<t;i++)
     bitmap[i]=rfbReverseByte[(int)bitmap[i]];
}

/* Cursor creation. You "paint" a cursor and let these routines do the work */

rfbCursorPtr rfbMakeXCursor(int width,int height,char* cursorString,char* maskString)
{
   int i,j,w=(width+7)/8;
   rfbCursorPtr cursor = (rfbCursorPtr)calloc(1,sizeof(rfbCursor));
   char* cp;
   unsigned char bit;

   cursor->width=width;
   cursor->height=height;
   /*cursor->backRed=cursor->backGreen=cursor->backBlue=0xffff;*/
   cursor->foreRed=cursor->foreGreen=cursor->foreBlue=0xffff;
   
   cursor->source = (unsigned char*)calloc(w,height);
   for(j=0,cp=cursorString;j<height;j++)
      for(i=0,bit=0x80;i<width;i++,bit=(bit&1)?0x80:bit>>1,cp++)
	if(*cp!=' ') ((char*)(cursor->source))[j*w+i/8]|=bit;

   if(maskString) {
      cursor->mask = (unsigned char*)calloc(w,height);
      for(j=0,cp=maskString;j<height;j++)
	for(i=0,bit=0x80;i<width;i++,bit=(bit&1)?0x80:bit>>1,cp++)
	  if(*cp!=' ') ((char*)(cursor->mask))[j*w+i/8]|=bit;
   } else
     cursor->mask = (unsigned char*)rfbMakeMaskForXCursor(width,height,(char*)(cursor->source));

   return(cursor);
}

char* rfbMakeMaskForXCursor(int width,int height,char* source)
{
   int i,j,w=(width+7)/8;
   char* mask=(char*)calloc(w,height);
   unsigned char c;
   
   for(j=0;j<height;j++)
     for(i=w-1;i>=0;i--) {
	c=source[j*w+i];
	if(j>0) c|=source[(j-1)*w+i];
	if(j<height-1) c|=source[(j+1)*w+i];
	
	if(i>0 && (c&0x80))
	  mask[j*w+i-1]|=0x01;
	if(i<w-1 && (c&0x01))
	  mask[j*w+i+1]|=0x80;
	
	mask[j*w+i]|=(c<<1)|c|(c>>1);
     }
   
   return(mask);
}

void rfbFreeCursor(rfbCursorPtr cursor)
{
   if(cursor) {
      if(cursor->richSource)
	 free(cursor->richSource);
      free((char*)(cursor->source));
      free((char*)(cursor->mask));
      free(cursor);
   }
   
}

/* background and foregroud colour have to be set beforehand */
void MakeXCursorFromRichCursor(rfbScreenInfoPtr rfbScreen,rfbCursorPtr cursor)
{
   rfbPixelFormat* format=&rfbScreen->rfbServerFormat;
   int i,j,w=(cursor->width+7)/8,bpp=format->bitsPerPixel/8,
     width=cursor->width*bpp;
   CARD32 background;
   char *back=(char*)&background;
   unsigned char bit;
   
   cursor->source=(unsigned char*)calloc(w,cursor->height);
   
   if(format->bigEndian)
      back+=4-bpp;

   background=cursor->backRed<<format->redShift|
     cursor->backGreen<<format->greenShift|cursor->backBlue<<format->blueShift;

   for(j=0;j<cursor->height;j++)
     for(i=0,bit=0x80;i<cursor->width;i++,bit=(bit&1)?0x80:bit>>1)
       if(memcmp(cursor->richSource+j*width+i*bpp,back,bpp))
	 ((char*)(cursor->source))[j*w+i/8]|=bit;
}

void MakeRichCursorFromXCursor(rfbScreenInfoPtr rfbScreen,rfbCursorPtr cursor)
{
   rfbPixelFormat* format=&rfbScreen->rfbServerFormat;
   int i,j,w=(cursor->width+7)/8,bpp=format->bitsPerPixel/8;
   CARD32 background,foreground;
   char *back=(char*)&background,*fore=(char*)&foreground;
   unsigned char *cp;
   unsigned char bit;

   cp=cursor->richSource=(unsigned char*)calloc(cursor->width*bpp,cursor->height);
   
   if(format->bigEndian) {
      back+=4-bpp;
      fore+=4-bpp;
   }

   background=cursor->backRed<<format->redShift|
     cursor->backGreen<<format->greenShift|cursor->backBlue<<format->blueShift;
   foreground=cursor->foreRed<<format->redShift|
     cursor->foreGreen<<format->greenShift|cursor->foreBlue<<format->blueShift;
   
   for(j=0;j<cursor->height;j++)
     for(i=0,bit=0x80;i<cursor->height;i++,bit=(bit&1)?0x80:bit>>1,cp+=bpp)
       if(cursor->source[j*w+i/8]&bit) memcpy(cp,fore,bpp);
       else memcpy(cp,back,bpp);
}

void MakeSoftCursor(rfbClientPtr cl, rfbCursorPtr cursor)
{
    int w = (cursor->width+7)/8;
    int bpp = cl->format.bitsPerPixel/8;
    int sbpp= cl->screen->rfbServerFormat.bitsPerPixel/8;
    unsigned char *cp, *sp, *translatedCursor;
    int state; /* 0 = transparent, 1 otherwise */
    CARD8 *counter;
    unsigned char bit;
    int i,j;
    
    if ((!cursor) || (cl->softSource)) {
	cl->softSourceLen = 0;
	return;
    }
    
    if (!cursor->richSource)
	MakeRichCursorFromXCursor(cl->screen, cursor);

    sp = malloc(cursor->width*bpp*cursor->height);

    (*cl->translateFn)(cl->translateLookupTable,
		       &(cl->screen->rfbServerFormat),
                       &cl->format, cursor->richSource,
		       sp, cursor->width*sbpp, 
		       cursor->width, cursor->height);

    translatedCursor = sp;
    cp=cl->softSource=(unsigned char*)calloc(cursor->width*(bpp+2),cursor->height);
    
    state = 0;
    counter = cp++;
    *counter = 0;
    
    for(j=0;j<cursor->height;j++)
	for(i=0,bit=0x80;i<cursor->width;i++,bit=(bit&1)?0x80:bit>>1)
	    if(cursor->mask[j*w+i/8]&bit) {
		if (state) {
		    memcpy(cp,sp,bpp);
		    cp += bpp;
		    sp += bpp;
		    (*counter)++;
		    if (*counter == 255) {
			state = 0;
			counter = cp++;
			*counter = 0;
		    }
		}
		else {
		    state = 1;
		    counter = cp++;
		    *counter = 1;
		    memcpy(cp,sp,bpp);
		    cp += bpp;
		    sp += bpp;
		}
	    }
	    else {
		if (!state) {
		    (*counter)++;
		    if (*counter == 255) {
			state = 1;
			counter = cp++;
			*counter = 0;
		    }
		}
		else {
		    state = 0;
		    counter = cp++;
		    *counter = 1;
		}
		sp += bpp;
	    }

    free(translatedCursor);
    cl->softSourceLen = cp - cl->softSource;
}


/* functions to draw/hide cursor directly in the frame buffer */

void rfbUndrawCursor(rfbScreenInfoPtr s)
{
   rfbCursorPtr c=s->cursor;
   int j,x1,x2,y1,y2,bpp=s->rfbServerFormat.bitsPerPixel/8,
     rowstride=s->paddedWidthInBytes;
   LOCK(s->cursorMutex);
   if(!s->cursorIsDrawn) {
     UNLOCK(s->cursorMutex);
     return;
   }
   
   /* restore what is under the cursor */
   x1=s->cursorX-c->xhot;
   x2=x1+c->width;
   if(x1<0) x1=0;
   if(x2>=s->width) x2=s->width-1;
   x2-=x1; if(x2<=0) {
     UNLOCK(s->cursorMutex);
     return;
   }
   y1=s->cursorY-c->yhot;
   y2=y1+c->height;
   if(y1<0) y1=0;
   if(y2>=s->height) y2=s->height-1;
   y2-=y1; if(y2<=0) {
     UNLOCK(s->cursorMutex);
     return;
   }

   /* get saved data */
   for(j=0;j<y2;j++)
     memcpy(s->frameBuffer+(y1+j)*rowstride+x1*bpp,
	    s->underCursorBuffer+j*x2*bpp,
	    x2*bpp);
   
   rfbMarkRectAsModified(s,x1,y1,x1+x2,y1+y2);
   s->cursorIsDrawn = FALSE;
   UNLOCK(s->cursorMutex);
}

void rfbDrawCursor(rfbScreenInfoPtr s)
{
   rfbCursorPtr c=s->cursor;
   int i,j,x1,x2,y1,y2,i1,j1,bpp=s->rfbServerFormat.bitsPerPixel/8,
     rowstride=s->paddedWidthInBytes,
     bufSize,w;
   if(!c) return;
   LOCK(s->cursorMutex);
   if(s->cursorIsDrawn) {
     /* is already drawn */
     UNLOCK(s->cursorMutex);
     return;
   }
   bufSize=c->width*c->height*bpp;
   w=(c->width+7)/8;
   if(s->underCursorBufferLen<bufSize) {
      if(s->underCursorBuffer!=NULL)
	free(s->underCursorBuffer);
      s->underCursorBuffer=malloc(bufSize);
      s->underCursorBufferLen=bufSize;
   }
   /* save what is under the cursor */
   i1=j1=0; /* offset in cursor */
   x1=s->cursorX-c->xhot;
   x2=x1+c->width;
   if(x1<0) { i1=-x1; x1=0; }
   if(x2>=s->width) x2=s->width-1;
   x2-=x1; if(x2<=0) {
     UNLOCK(s->cursorMutex);
     return; /* nothing to do */
   }
   y1=s->cursorY-c->yhot;
   y2=y1+c->height;
   if(y1<0) { j1=-y1; y1=0; }
   if(y2>=s->height) y2=s->height-1;
   y2-=y1; if(y2<=0) {
     UNLOCK(s->cursorMutex);
     return; /* nothing to do */
   }

   /* save data */
   for(j=0;j<y2;j++)
     memcpy(s->underCursorBuffer+j*x2*bpp,
	    s->frameBuffer+(y1+j)*rowstride+x1*bpp,
	    x2*bpp);
   
   if(!c->richSource)
     MakeRichCursorFromXCursor(s,c);
   
   /* now the cursor has to be drawn */
   for(j=0;j<y2;j++)
     for(i=0;i<x2;i++)
       if((c->mask[(j+j1)*w+(i+i1)/8]<<((i+i1)&7))&0x80)
	 memcpy(s->frameBuffer+(j+y1)*rowstride+(i+x1)*bpp,
		c->richSource+(j+j1)*c->width*bpp+(i+i1)*bpp,bpp);


   rfbMarkRectAsModified(s,x1,y1,x1+x2,y1+y2);
   s->cursorIsDrawn = TRUE;
   UNLOCK(s->cursorMutex);
}

/* for debugging */

void rfbPrintXCursor(rfbCursorPtr cursor)
{
   int i,i1,j,w=(cursor->width+7)/8;
   unsigned char bit;
   for(j=0;j<cursor->height;j++) {
      for(i=0,i1=0,bit=0x80;i1<cursor->width;i1++,i+=(bit&1)?1:0,bit=(bit&1)?0x80:bit>>1)
	if(cursor->source[j*w+i]&bit) putchar('#'); else putchar(' ');
      putchar(':');
      for(i=0,i1=0,bit=0x80;i1<cursor->width;i1++,i+=(bit&1)?1:0,bit=(bit&1)?0x80:bit>>1)
	if(cursor->mask[j*w+i]&bit) putchar('#'); else putchar(' ');
      putchar('\n');
   }
}

extern void rfbSetCursor(rfbScreenInfoPtr rfbScreen,rfbCursorPtr c,Bool freeOld)
{
  LOCK(rfbScreen->cursorMutex);
  while(rfbScreen->cursorIsDrawn) {
    UNLOCK(rfbScreen->cursorMutex);
    rfbUndrawCursor(rfbScreen);
    LOCK(rfbScreen->cursorMutex);
  }

  if(freeOld && rfbScreen->cursor)
    rfbFreeCursor(rfbScreen->cursor);

  rfbScreen->cursor = c;

  UNLOCK(rfbScreen->cursorMutex);
}