view src/events/SDL_mouse.c @ 1643:51038e80ae59

More general fix for bug #189 The clipping is done at a higher level, and the low level functions are passed clipped rectangles. Drivers which don't support source clipping have not been changed, so the image will be squished instead of clipped, but at least they will no longer crash when the destination rect was out of bounds.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 17 Apr 2006 06:47:23 +0000
parents 23a347cfbed8
children 782fd950bd46 c121d94672cb a1b03ba2fcd0
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* General mouse handling code for SDL */

#include "SDL_events.h"
#include "SDL_events_c.h"
#include "../video/SDL_cursor_c.h"
#include "../video/SDL_sysvideo.h"


/* These are static for our mouse handling code */
static Sint16 SDL_MouseX = 0;
static Sint16 SDL_MouseY = 0;
static Sint16 SDL_DeltaX = 0;
static Sint16 SDL_DeltaY = 0;
static Uint8  SDL_ButtonState = 0;


/* Public functions */
int SDL_MouseInit(void)
{
	/* The mouse is at (0,0) */
	SDL_MouseX = 0;
	SDL_MouseY = 0;
	SDL_DeltaX = 0;
	SDL_DeltaY = 0;
	SDL_ButtonState = 0;

	/* That's it! */
	return(0);
}
void SDL_MouseQuit(void)
{
}

/* We lost the mouse, so post button up messages for all pressed buttons */
void SDL_ResetMouse(void)
{
	Uint8 i;
	for ( i = 0; i < sizeof(SDL_ButtonState)*8; ++i ) {
		if ( SDL_ButtonState & SDL_BUTTON(i) ) {
			SDL_PrivateMouseButton(SDL_RELEASED, i, 0, 0);
		}
	}
}

Uint8 SDL_GetMouseState (int *x, int *y)
{
	if ( x ) {
		*x = SDL_MouseX;
	}
	if ( y ) {
		*y = SDL_MouseY;
	}
	return(SDL_ButtonState);
}

Uint8 SDL_GetRelativeMouseState (int *x, int *y)
{
	if ( x )
		*x = SDL_DeltaX;
	if ( y )
		*y = SDL_DeltaY;
	SDL_DeltaX = 0;
	SDL_DeltaY = 0;
	return(SDL_ButtonState);
}

static void ClipOffset(Sint16 *x, Sint16 *y)
{
	/* This clips absolute mouse coordinates when the apparent
	   display surface is smaller than the real display surface.
	 */
	if ( SDL_VideoSurface->offset ) {
		*y -= SDL_VideoSurface->offset/SDL_VideoSurface->pitch;
		*x -= (SDL_VideoSurface->offset%SDL_VideoSurface->pitch)/
				SDL_VideoSurface->format->BytesPerPixel;
	}
}

/* These are global for SDL_eventloop.c */
int SDL_PrivateMouseMotion(Uint8 buttonstate, int relative, Sint16 x, Sint16 y)
{
	int posted;
	Uint16 X, Y;
	Sint16 Xrel;
	Sint16 Yrel;

	/* Don't handle mouse motion if there's no cursor surface */
	if ( SDL_VideoSurface == NULL ) {
		return(0);
	}

	/* Default buttonstate is the current one */
	if ( ! buttonstate ) {
		buttonstate = SDL_ButtonState;
	}

	Xrel = x;
	Yrel = y;
	if ( relative ) {
		/* Push the cursor around */
		x = (SDL_MouseX+x);
		y = (SDL_MouseY+y);
	} else {
		/* Do we need to clip {x,y} ? */
		ClipOffset(&x, &y);
	}

	/* Mouse coordinates range from 0 - width-1 and 0 - height-1 */
	if ( x < 0 )
		X = 0;
	else
	if ( x >= SDL_VideoSurface->w )
		X = SDL_VideoSurface->w-1;
	else
		X = (Uint16)x;

	if ( y < 0 )
		Y = 0;
	else
	if ( y >= SDL_VideoSurface->h )
		Y = SDL_VideoSurface->h-1;
	else
		Y = (Uint16)y;

	/* If not relative mode, generate relative motion from clamped X/Y.
	   This prevents lots of extraneous large delta relative motion when
	   the screen is windowed mode and the mouse is outside the window.
	*/
	if ( ! relative ) {
		Xrel = X-SDL_MouseX;
		Yrel = Y-SDL_MouseY;
	}

	/* Drop events that don't change state */
	if ( ! Xrel && ! Yrel ) {
#if 0
printf("Mouse event didn't change state - dropped!\n");
#endif
		return(0);
	}

	/* Update internal mouse state */
	SDL_ButtonState = buttonstate;
	SDL_MouseX = X;
	SDL_MouseY = Y;
	SDL_DeltaX += Xrel;
	SDL_DeltaY += Yrel;
        SDL_MoveCursor(SDL_MouseX, SDL_MouseY);

	/* Post the event, if desired */
	posted = 0;
	if ( SDL_ProcessEvents[SDL_MOUSEMOTION] == SDL_ENABLE ) {
		SDL_Event event;
		SDL_memset(&event, 0, sizeof(event));
		event.type = SDL_MOUSEMOTION;
		event.motion.state = buttonstate;
		event.motion.x = X;
		event.motion.y = Y;
		event.motion.xrel = Xrel;
		event.motion.yrel = Yrel;
		if ( (SDL_EventOK == NULL) || (*SDL_EventOK)(&event) ) {
			posted = 1;
			SDL_PushEvent(&event);
		}
	}
	return(posted);
}

int SDL_PrivateMouseButton(Uint8 state, Uint8 button, Sint16 x, Sint16 y)
{
	SDL_Event event;
	int posted;
	int move_mouse;
	Uint8 buttonstate;

	SDL_memset(&event, 0, sizeof(event));

	/* Check parameters */
	if ( x || y ) {
		ClipOffset(&x, &y);
		move_mouse = 1;
		/* Mouse coordinates range from 0 - width-1 and 0 - height-1 */
		if ( x < 0 )
			x = 0;
		else
		if ( x >= SDL_VideoSurface->w )
			x = SDL_VideoSurface->w-1;

		if ( y < 0 )
			y = 0;
		else
		if ( y >= SDL_VideoSurface->h )
			y = SDL_VideoSurface->h-1;
	} else {
		move_mouse = 0;
	}
	if ( ! x )
		x = SDL_MouseX;
	if ( ! y )
		y = SDL_MouseY;

	/* Figure out which event to perform */
	buttonstate = SDL_ButtonState;
	switch ( state ) {
		case SDL_PRESSED:
			event.type = SDL_MOUSEBUTTONDOWN;
			buttonstate |= SDL_BUTTON(button);
			break;
		case SDL_RELEASED:
			event.type = SDL_MOUSEBUTTONUP;
			buttonstate &= ~SDL_BUTTON(button);
			break;
		default:
			/* Invalid state -- bail */
			return(0);
	}

	/* Update internal mouse state */
	SDL_ButtonState = buttonstate;
	if ( move_mouse ) {
		SDL_MouseX = x;
		SDL_MouseY = y;
		SDL_MoveCursor(SDL_MouseX, SDL_MouseY);
	}

	/* Post the event, if desired */
	posted = 0;
	if ( SDL_ProcessEvents[event.type] == SDL_ENABLE ) {
		event.button.state = state;
		event.button.button = button;
		event.button.x = x;
		event.button.y = y;
		if ( (SDL_EventOK == NULL) || (*SDL_EventOK)(&event) ) {
			posted = 1;
			SDL_PushEvent(&event);
		}
	}
	return(posted);
}