--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/SDL_cursor.c	Thu Apr 26 16:45:43 2001 +0000
@@ -0,0 +1,743 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library 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
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public
+    License along with this library; if not, write to the Free
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Sam Lantinga
+    slouken@devolution.com
+*/
+
+#ifdef SAVE_RCSID
+static char rcsid =
+ "@(#) $Id$";
+#endif
+
+/* General cursor handling code for SDL */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "SDL_mutex.h"
+#include "SDL_error.h"
+#include "SDL_video.h"
+#include "SDL_mouse.h"
+#include "SDL_blit.h"
+#include "SDL_events_c.h"
+#include "SDL_sysvideo.h"
+#include "SDL_sysevents.h"
+#include "SDL_cursor_c.h"
+#include "SDL_pixels_c.h"
+#include "default_cursor.h"
+
+/* These are static for our cursor handling code */
+volatile int SDL_cursorstate = CURSOR_VISIBLE;
+SDL_Cursor *SDL_cursor = NULL;
+static SDL_Cursor *SDL_defcursor = NULL;
+SDL_mutex *SDL_cursorlock = NULL;
+
+/* Public functions */
+void SDL_CursorQuit(void)
+{
+	if ( SDL_cursor != NULL ) {
+		SDL_Cursor *cursor;
+
+		SDL_cursorstate &= ~CURSOR_VISIBLE;
+		if ( SDL_cursor != SDL_defcursor ) {
+			SDL_FreeCursor(SDL_cursor);
+		}
+		SDL_cursor = NULL;
+		if ( SDL_defcursor != NULL ) {
+			cursor = SDL_defcursor;
+			SDL_defcursor = NULL;
+			SDL_FreeCursor(cursor);
+		}
+	}
+	if ( SDL_cursorlock != NULL ) {
+		SDL_DestroyMutex(SDL_cursorlock);
+		SDL_cursorlock = NULL;
+	}
+}
+int SDL_CursorInit(Uint32 multithreaded)
+{
+	/* We don't have mouse focus, and the cursor isn't drawn yet */
+	SDL_cursorstate = CURSOR_VISIBLE;
+
+	/* Create the default cursor */
+	if ( SDL_defcursor == NULL ) {
+		SDL_defcursor = SDL_CreateCursor(default_cdata, default_cmask,
+					DEFAULT_CWIDTH, DEFAULT_CHEIGHT,
+						DEFAULT_CHOTX, DEFAULT_CHOTY);
+		SDL_SetCursor(SDL_defcursor);
+	}
+
+	/* Create a lock if necessary */
+	if ( multithreaded ) {
+		SDL_cursorlock = SDL_CreateMutex();
+	}
+
+	/* That's it! */
+	return(0);
+}
+
+/* Multi-thread support for cursors */
+#ifndef SDL_LockCursor
+void SDL_LockCursor(void)
+{
+	if ( SDL_cursorlock ) {
+		SDL_mutexP(SDL_cursorlock);
+	}
+}
+#endif
+#ifndef SDL_UnlockCursor
+void SDL_UnlockCursor(void)
+{
+	if ( SDL_cursorlock ) {
+		SDL_mutexV(SDL_cursorlock);
+	}
+}
+#endif
+
+/* Software cursor drawing support */
+SDL_Cursor * SDL_CreateCursor (Uint8 *data, Uint8 *mask, 
+					int w, int h, int hot_x, int hot_y)
+{
+	SDL_VideoDevice *video = current_video;
+	int savelen;
+	int i;
+	SDL_Cursor *cursor;
+
+	/* Make sure the width is a multiple of 8 */
+	w = ((w+7)&~7);
+
+	/* Sanity check the hot spot */
+	if ( (hot_x < 0) || (hot_y < 0) || (hot_x >= w) || (hot_y >= h) ) {
+		SDL_SetError("Cursor hot spot doesn't lie within cursor");
+		return(NULL);
+	}
+
+	/* Allocate memory for the cursor */
+	cursor = (SDL_Cursor *)malloc(sizeof *cursor);
+	if ( cursor == NULL ) {
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+	savelen = (w*4)*h;
+	cursor->area.x = 0;
+	cursor->area.y = 0;
+	cursor->area.w = w;
+	cursor->area.h = h;
+	cursor->hot_x = hot_x;
+	cursor->hot_y = hot_y;
+	cursor->data = (Uint8 *)malloc((w/8)*h*2);
+	cursor->mask = cursor->data+((w/8)*h);
+	cursor->save[0] = (Uint8 *)malloc(savelen*2);
+	cursor->save[1] = cursor->save[0] + savelen;
+	cursor->wm_cursor = NULL;
+	if ( ! cursor->data || ! cursor->save[0] ) {
+		SDL_FreeCursor(cursor);
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+	for ( i=((w/8)*h)-1; i>=0; --i ) {
+		cursor->data[i] = data[i];
+		cursor->mask[i] = mask[i] | data[i];
+	}
+	memset(cursor->save[0], 0, savelen*2);
+
+	/* If the window manager gives us a good cursor, we're done! */
+	if ( video->CreateWMCursor ) {
+		cursor->wm_cursor = video->CreateWMCursor(video, data, mask,
+							w, h, hot_x, hot_y);
+	} else {
+		cursor->wm_cursor = NULL;
+	}
+	return(cursor);
+}
+
+/* SDL_SetCursor(NULL) can be used to force the cursor redraw,
+   if this is desired for any reason.  This is used when setting
+   the video mode and when the SDL window gains the mouse focus.
+ */
+void SDL_SetCursor (SDL_Cursor *cursor)
+{
+	SDL_VideoDevice *video = current_video;
+	SDL_VideoDevice *this  = current_video;
+
+	/* Make sure that the video subsystem has been initialized */
+	if ( ! video ) {
+		return;
+	}
+
+	/* Prevent the event thread from moving the mouse */
+	SDL_LockCursor();
+
+	/* Set the new cursor */
+	if ( cursor && (cursor != SDL_cursor) ) {
+		/* Erase the current mouse position */
+		if ( SHOULD_DRAWCURSOR(SDL_cursorstate) ) {
+			SDL_EraseCursor(SDL_VideoSurface);
+		} else if ( video->MoveWMCursor ) {
+			/* If the video driver is moving the cursor directly,
+			   it needs to hide the old cursor before (possibly)
+			   showing the new one.  (But don't erase NULL cursor)
+			 */
+			if ( SDL_cursor ) {
+				video->ShowWMCursor(this, NULL);
+			}
+		}
+		SDL_cursor = cursor;
+	}
+
+	/* Draw the new mouse cursor */
+	if ( SDL_cursor && (SDL_cursorstate&CURSOR_VISIBLE) ) {
+		/* Use window manager cursor if possible */
+		if ( SDL_cursor->wm_cursor && 
+	             video->ShowWMCursor(this, SDL_cursor->wm_cursor) )
+			SDL_cursorstate &= ~CURSOR_USINGSW;
+		else {
+			SDL_cursorstate |= CURSOR_USINGSW;
+			if ( video->ShowWMCursor ) {
+				video->ShowWMCursor(this, NULL);
+			}
+			{ int x, y;
+				SDL_GetMouseState(&x, &y);
+				SDL_cursor->area.x = (x - SDL_cursor->hot_x);
+				SDL_cursor->area.y = (y - SDL_cursor->hot_y);
+			}
+			SDL_DrawCursor(SDL_VideoSurface);
+		}
+	} else {
+		/* Erase window manager mouse (cursor not visible) */
+		if ( SDL_cursor && (SDL_cursorstate & CURSOR_USINGSW) ) {
+			SDL_EraseCursor(SDL_VideoSurface);
+		} else {
+			if ( video ) {
+				video->ShowWMCursor(this, NULL);
+			}
+		}
+	}
+	SDL_UnlockCursor();
+}
+
+SDL_Cursor * SDL_GetCursor (void)
+{
+	return(SDL_cursor);
+}
+
+void SDL_FreeCursor (SDL_Cursor *cursor)
+{
+	if ( cursor ) {
+		if ( cursor == SDL_cursor ) {
+			SDL_SetCursor(SDL_defcursor);
+		}
+		if ( cursor != SDL_defcursor ) {
+			if ( cursor->data ) {
+				free(cursor->data);
+			}
+			if ( cursor->save[0] ) {
+				free(cursor->save[0]);
+			}
+			if ( cursor->wm_cursor ) {
+				SDL_VideoDevice *video = current_video;
+				SDL_VideoDevice *this  = current_video;
+				video->FreeWMCursor(this, cursor->wm_cursor);
+			}
+			free(cursor);
+		}
+	}
+}
+
+int SDL_ShowCursor (int toggle)
+{
+	int showing;
+
+	showing = (SDL_cursorstate & CURSOR_VISIBLE);
+	if ( toggle >= 0 ) {
+		SDL_LockCursor();
+		if ( toggle ) {
+			SDL_cursorstate |= CURSOR_VISIBLE;
+		} else {
+			SDL_cursorstate &= ~CURSOR_VISIBLE;
+		}
+		SDL_UnlockCursor();
+		if ( (SDL_cursorstate & CURSOR_VISIBLE) != showing ) {
+			SDL_VideoDevice *video = current_video;
+			SDL_VideoDevice *this  = current_video;
+
+			SDL_SetCursor(NULL);
+			if ( video && video->CheckMouseMode ) {
+				video->CheckMouseMode(this);
+			}
+		}
+	} else {
+		/* Query current state */ ;
+	}
+	return(showing ? 1 : 0);
+}
+
+void SDL_WarpMouse (Uint16 x, Uint16 y)
+{
+	SDL_VideoDevice *video = current_video;
+	SDL_VideoDevice *this  = current_video;
+
+	/* This generates a mouse motion event */
+	if ( video->WarpWMCursor ) {
+		video->WarpWMCursor(this, x, y);
+	} else {
+		x += (this->screen->offset % this->screen->pitch) /
+		      this->screen->format->BytesPerPixel;
+		y += (this->screen->offset / this->screen->pitch);
+		SDL_PrivateMouseMotion(0, 0, x, y);
+	}
+}
+
+void SDL_MoveCursor(int x, int y)
+{
+	SDL_VideoDevice *video = current_video;
+
+	/* Erase and update the current mouse position */
+	if ( SHOULD_DRAWCURSOR(SDL_cursorstate) ) {
+		/* Erase and redraw mouse cursor in new position */
+		SDL_LockCursor();
+		SDL_EraseCursor(SDL_VideoSurface);
+		SDL_cursor->area.x = (x - SDL_cursor->hot_x);
+		SDL_cursor->area.y = (y - SDL_cursor->hot_y);
+		SDL_DrawCursor(SDL_VideoSurface);
+		SDL_UnlockCursor();
+	} else if ( video->MoveWMCursor ) {
+		video->MoveWMCursor(video, x, y);
+	}
+}
+
+/* Keep track of the current cursor colors */
+static int palette_changed = 1;
+static Uint32 pixels8[2];
+
+void SDL_CursorPaletteChanged(void)
+{
+	palette_changed = 1;
+}
+
+void SDL_MouseRect(SDL_Rect *area)
+{
+	int clip_diff;
+
+	*area = SDL_cursor->area;
+	if ( area->x < 0 ) {
+		area->w += area->x;
+		area->x = 0;
+	}
+	if ( area->y < 0 ) {
+		area->h += area->y;
+		area->y = 0;
+	}
+	clip_diff = (area->x+area->w)-SDL_VideoSurface->w;
+	if ( clip_diff > 0 ) {
+		area->w -= clip_diff;
+	}
+	clip_diff = (area->y+area->h)-SDL_VideoSurface->h;
+	if ( clip_diff > 0 ) {
+		area->h -= clip_diff;
+	}
+}
+
+static void SDL_DrawCursorFast(SDL_Surface *screen, SDL_Rect *area)
+{
+	const Uint32 pixels[2] = { 0xFFFFFFFF, 0x00000000 };
+	int i, w, h;
+	Uint8 *data, datab;
+	Uint8 *mask, maskb;
+
+	data = SDL_cursor->data + area->y * SDL_cursor->area.w/8;
+	mask = SDL_cursor->mask + area->y * SDL_cursor->area.w/8;
+	switch (screen->format->BytesPerPixel) {
+
+	    case 1: {
+		Uint8 *dst;
+		int dstskip;
+
+		if ( palette_changed ) {
+			pixels8[0] = SDL_MapRGB(screen->format, 255, 255, 255);
+			pixels8[1] = SDL_MapRGB(screen->format, 0, 0, 0);
+			palette_changed = 0;
+		}
+		dst = (Uint8 *)screen->pixels +
+                       (SDL_cursor->area.y+area->y)*screen->pitch +
+                       SDL_cursor->area.x;
+		dstskip = screen->pitch-area->w;
+
+		for ( h=area->h; h; h-- ) {
+			for ( w=area->w/8; w; w-- ) {
+				maskb = *mask++;
+				datab = *data++;
+				for ( i=0; i<8; ++i ) {
+					if ( maskb & 0x80 ) {
+						*dst = pixels8[datab>>7];
+					}
+					maskb <<= 1;
+					datab <<= 1;
+					dst++;
+				}
+			}
+			dst += dstskip;
+		}
+	    }
+	    break;
+
+	    case 2: {
+		Uint16 *dst;
+		int dstskip;
+
+		dst = (Uint16 *)screen->pixels +
+                       (SDL_cursor->area.y+area->y)*screen->pitch/2 +
+                       SDL_cursor->area.x;
+		dstskip = (screen->pitch/2)-area->w;
+
+		for ( h=area->h; h; h-- ) {
+			for ( w=area->w/8; w; w-- ) {
+				maskb = *mask++;
+				datab = *data++;
+				for ( i=0; i<8; ++i ) {
+					if ( maskb & 0x80 ) {
+						*dst = pixels[datab>>7];
+					}
+					maskb <<= 1;
+					datab <<= 1;
+					dst++;
+				}
+			}
+			dst += dstskip;
+		}
+	    }
+	    break;
+
+	    case 3: {
+		Uint8 *dst;
+		int dstskip;
+
+		dst = (Uint8 *)screen->pixels +
+                       (SDL_cursor->area.y+area->y)*screen->pitch +
+                       SDL_cursor->area.x*3;
+		dstskip = screen->pitch-area->w*3;
+
+		for ( h=area->h; h; h-- ) {
+			for ( w=area->w/8; w; w-- ) {
+				maskb = *mask++;
+				datab = *data++;
+				for ( i=0; i<8; ++i ) {
+					if ( maskb & 0x80 ) {
+						memset(dst,pixels[datab>>7],3);
+					}
+					maskb <<= 1;
+					datab <<= 1;
+					dst += 3;
+				}
+			}
+			dst += dstskip;
+		}
+	    }
+	    break;
+
+	    case 4: {
+		Uint32 *dst;
+		int dstskip;
+
+		dst = (Uint32 *)screen->pixels +
+                       (SDL_cursor->area.y+area->y)*screen->pitch/4 +
+                       SDL_cursor->area.x;
+		dstskip = (screen->pitch/4)-area->w;
+
+		for ( h=area->h; h; h-- ) {
+			for ( w=area->w/8; w; w-- ) {
+				maskb = *mask++;
+				datab = *data++;
+				for ( i=0; i<8; ++i ) {
+					if ( maskb & 0x80 ) {
+						*dst = pixels[datab>>7];
+					}
+					maskb <<= 1;
+					datab <<= 1;
+					dst++;
+				}
+			}
+			dst += dstskip;
+		}
+	    }
+	    break;
+	}
+}
+
+static void SDL_DrawCursorSlow(SDL_Surface *screen, SDL_Rect *area)
+{
+	const Uint32 pixels[2] = { 0xFFFFFF, 0x000000 };
+	int h;
+	int x, minx, maxx;
+	Uint8 *data, datab = 0;
+	Uint8 *mask, maskb = 0;
+	Uint8 *dst;
+	int dstbpp, dstskip;
+
+	data = SDL_cursor->data + area->y * SDL_cursor->area.w/8;
+	mask = SDL_cursor->mask + area->y * SDL_cursor->area.w/8;
+	dstbpp = screen->format->BytesPerPixel;
+	dst = (Uint8 *)screen->pixels +
+                       (SDL_cursor->area.y+area->y)*screen->pitch +
+                       SDL_cursor->area.x*dstbpp;
+	dstskip = screen->pitch-SDL_cursor->area.w*dstbpp;
+
+	minx = area->x;
+	maxx = area->x+area->w;
+	if ( screen->format->BytesPerPixel == 1 ) {
+		if ( palette_changed ) {
+			pixels8[0] = SDL_MapRGB(screen->format, 255, 255, 255);
+			pixels8[1] = SDL_MapRGB(screen->format, 0, 0, 0);
+			palette_changed = 0;
+		}
+		for ( h=area->h; h; h-- ) {
+			for ( x=0; x<SDL_cursor->area.w; ++x ) {
+				if ( (x%8) == 0 ) {
+					maskb = *mask++;
+					datab = *data++;
+				}
+				if ( (x >= minx) && (x < maxx) ) {
+					if ( maskb & 0x80 ) {
+						memset(dst, pixels8[datab>>7], dstbpp);
+					}
+				}
+				maskb <<= 1;
+				datab <<= 1;
+				dst += dstbpp;
+			}
+			dst += dstskip;
+		}
+	} else {
+		for ( h=area->h; h; h-- ) {
+			for ( x=0; x<SDL_cursor->area.w; ++x ) {
+				if ( (x%8) == 0 ) {
+					maskb = *mask++;
+					datab = *data++;
+				}
+				if ( (x >= minx) && (x < maxx) ) {
+					if ( maskb & 0x80 ) {
+						memset(dst, pixels[datab>>7], dstbpp);
+					}
+				}
+				maskb <<= 1;
+				datab <<= 1;
+				dst += dstbpp;
+			}
+			dst += dstskip;
+		}
+	}
+}
+
+/* This handles the ugly work of converting the saved cursor background from
+   the pixel format of the shadow surface to that of the video surface.
+   This is only necessary when blitting from a shadow surface of a different
+   pixel format than the video surface, and using a software rendered cursor.
+*/
+static void SDL_ConvertCursorSave(SDL_Surface *screen, int w, int h)
+{
+	SDL_BlitInfo info;
+	SDL_loblit RunBlit;
+
+	/* Make sure we can steal the blit mapping */
+	if ( screen->map->dst != SDL_VideoSurface ) {
+		return;
+	}
+
+	/* Set up the blit information */
+	info.s_pixels = SDL_cursor->save[1];
+	info.s_width = w;
+	info.s_height = h;
+	info.s_skip = 0;
+	info.d_pixels = SDL_cursor->save[0];
+	info.d_width = w;
+	info.d_height = h;
+	info.d_skip = 0;
+	info.aux_data = screen->map->sw_data->aux_data;
+	info.src = screen->format;
+	info.table = screen->map->table;
+	info.dst = SDL_VideoSurface->format;
+	RunBlit = screen->map->sw_data->blit;
+
+	/* Run the actual software blit */
+	RunBlit(&info);
+}
+
+void SDL_DrawCursorNoLock(SDL_Surface *screen)
+{
+	SDL_Rect area;
+
+	/* Get the mouse rectangle, clipped to the screen */
+	SDL_MouseRect(&area);
+	if ( (area.w == 0) || (area.h == 0) ) {
+		return;
+	}
+
+	/* Copy mouse background */
+	{ int w, h, screenbpp;
+	  Uint8 *src, *dst;
+
+	  /* Set up the copy pointers */
+	  screenbpp = screen->format->BytesPerPixel;
+	  if ( (screen == SDL_VideoSurface) ||
+	          FORMAT_EQUAL(screen->format, SDL_VideoSurface->format) ) {
+		dst = SDL_cursor->save[0];
+	  } else {
+		dst = SDL_cursor->save[1];
+	  }
+	  src = (Uint8 *)screen->pixels + area.y * screen->pitch +
+                                          area.x * screenbpp;
+
+	  /* Perform the copy */
+	  w = area.w*screenbpp;
+	  h = area.h;
+	  while ( h-- ) {
+		  memcpy(dst, src, w);
+		  dst += w;
+		  src += screen->pitch;
+	  }
+	}
+
+	/* Draw the mouse cursor */
+	area.x -= SDL_cursor->area.x;
+	area.y -= SDL_cursor->area.y;
+	if ( (area.x == 0) && (area.w == SDL_cursor->area.w) ) {
+		SDL_DrawCursorFast(screen, &area);
+	} else {
+		SDL_DrawCursorSlow(screen, &area);
+	}
+}
+
+void SDL_DrawCursor(SDL_Surface *screen)
+{
+	/* Lock the screen if necessary */
+	if ( screen == NULL ) {
+		return;
+	}
+	if ( SDL_MUSTLOCK(screen) ) {
+		if ( SDL_LockSurface(screen) < 0 ) {
+			return;
+		}
+	}
+
+	SDL_DrawCursorNoLock(screen);
+
+	/* Unlock the screen and update if necessary */
+	if ( SDL_MUSTLOCK(screen) ) {
+		SDL_UnlockSurface(screen);
+	}
+	if ( (screen == SDL_VideoSurface) &&
+	     ((screen->flags & SDL_HWSURFACE) != SDL_HWSURFACE) ) {
+		SDL_VideoDevice *video = current_video;
+		SDL_VideoDevice *this  = current_video;
+		SDL_Rect area;
+
+		SDL_MouseRect(&area);
+
+		/* This can be called before a video mode is set */
+		if ( video->UpdateRects ) {
+			video->UpdateRects(this, 1, &area);
+		}
+	}
+}
+
+void SDL_EraseCursorNoLock(SDL_Surface *screen)
+{
+	SDL_Rect area;
+
+	/* Get the mouse rectangle, clipped to the screen */
+	SDL_MouseRect(&area);
+	if ( (area.w == 0) || (area.h == 0) ) {
+		return;
+	}
+
+	/* Copy mouse background */
+	{ int w, h, screenbpp;
+	  Uint8 *src, *dst;
+
+	  /* Set up the copy pointers */
+	  screenbpp = screen->format->BytesPerPixel;
+	  if ( (screen == SDL_VideoSurface) ||
+	          FORMAT_EQUAL(screen->format, SDL_VideoSurface->format) ) {
+		src = SDL_cursor->save[0];
+	  } else {
+		src = SDL_cursor->save[1];
+	  }
+	  dst = (Uint8 *)screen->pixels + area.y * screen->pitch +
+                                          area.x * screenbpp;
+
+	  /* Perform the copy */
+	  w = area.w*screenbpp;
+	  h = area.h;
+	  while ( h-- ) {
+		  memcpy(dst, src, w);
+		  src += w;
+		  dst += screen->pitch;
+	  }
+
+	  /* Perform pixel conversion on cursor background */
+	  if ( src > SDL_cursor->save[1] ) {
+		SDL_ConvertCursorSave(screen, area.w, area.h);
+	  }
+	}
+}
+
+void SDL_EraseCursor(SDL_Surface *screen)
+{
+	/* Lock the screen if necessary */
+	if ( screen == NULL ) {
+		return;
+	}
+	if ( SDL_MUSTLOCK(screen) ) {
+		if ( SDL_LockSurface(screen) < 0 ) {
+			return;
+		}
+	}
+
+	SDL_EraseCursorNoLock(screen);
+
+	/* Unlock the screen and update if necessary */
+	if ( SDL_MUSTLOCK(screen) ) {
+		SDL_UnlockSurface(screen);
+	}
+	if ( (screen == SDL_VideoSurface) &&
+	     ((screen->flags & SDL_HWSURFACE) != SDL_HWSURFACE) ) {
+		SDL_VideoDevice *video = current_video;
+		SDL_VideoDevice *this  = current_video;
+		SDL_Rect area;
+
+		SDL_MouseRect(&area);
+		video->UpdateRects(this, 1, &area);
+	}
+}
+
+/* Reset the cursor on video mode change
+   FIXME:  Keep track of all cursors, and reset them all.
+ */
+void SDL_ResetCursor(void)
+{
+	int savelen;
+
+	if ( SDL_cursor ) {
+		savelen = SDL_cursor->area.w*4*SDL_cursor->area.h;
+		SDL_cursor->area.x = 0;
+		SDL_cursor->area.y = 0;
+		memset(SDL_cursor->save[0], 0, savelen);
+	}
+}