view src/video/wincommon/SDL_sysmouse.c @ 1287:15a89a0c52bf

Date: Tue, 15 Feb 2005 21:28:48 +0900 (JST) From: "Michael Leonhard" Subject: [SDL] resize bug on Win32 and patch This is my first post to this mailing list. In this email I will detail a bug in the behavior of resizable SDL windows on Win32. Then I will explain the solution and provide a patch. Symptoms: Under Windows, an SDL display created with the SDL_RESIZABLE flag exhibits quirky behavior when being maximized. The window is resized to the proper size, but it is shifted upwards about half the height of the title bar. Similarly, a window whose origin is above the top of the screen will spontaneously move its upper-left origin upon being resized. After two such resize-induced moves, the title bar will be entirely off the top edge of the screen. Subsequently, when the mouse is clicked and released on the window border, the window will shrink its height spontaneously. This height shrinkage occurs even if the user did not resize the border. To observe this curious situation, please invoke: SDL-1.2.8/test/testwm.exe -resize Cause: A pair of integers, SDL_windowX and SDL_windowY, are defined in video/wincommon/SDL_sysevents.c. They are used by the DirectX video driver and the DIB video driver: video/windx5/SDL_dx5video.c video/windib/SDL_dibvideo.c As I understand the source code, the primary use of these variables is to create a rectangle that represents the surface area in CLIENT SPACE. Client space refers to a coordinate system that originates at the upper left corner of a Win32 Window's drawable area. This is just inside the window border and title bar. This client space rectangle, called bounds, is subsequently converted to screen space with a call to AdjustWindowRectEx. The problem is found in SDL's handling of the WM_WINDOWPOSCHANGED message. According to MSDN, "The WM_WINDOWPOSCHANGED message is sent to a window whose size, position, or place in the Z order has changed as a result of a call to the SetWindowPos function or another window-management function." I have confirmed that this message is indeed being sent to the SDL window when the mouse is clicked on the window border, even if the window border is not dragged. In video/wincommon/SDL_sysevents.c, on line 464, in response to the WM_WINDOWPOSCHANGED message, the (potentially) new client rectangle is obtained. This rectangle is translated into screen coordinates and THEN assigned to the SDL_windowX and Y variables. Thus screen coordinates are being assigned to client coordinate variables. Once this is understood, the solution is apparent: assign SDL_windowX and Y before translating the rectangle to screen coordinates. This is accomplished by the following patch. -Mike_L
author Sam Lantinga <slouken@libsdl.org>
date Sun, 29 Jan 2006 08:50:06 +0000
parents 86d0d01290ea
children c9b51268668f
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997, 1998, 1999  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@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

#include <stdlib.h>
#include <windows.h>

#include "SDL_error.h"
#include "SDL_mouse.h"
#include "SDL_sysmouse_c.h"
#include "SDL_events_c.h"
#include "SDL_cursor_c.h"
#include "SDL_lowvideo.h"

#ifdef _WIN32_WCE
#define USE_STATIC_CURSOR
#endif

HCURSOR	SDL_hcursor = NULL;		/* Exported for SDL_eventloop.c */

/* The implementation dependent data for the window manager cursor */
/* For some reason when creating a windows cursor, the ands and xors memory
   is not copied, so we need to keep track of it and free it when we are done
   with the cursor.  If we free the memory prematurely, the app crashes. :-}
*/
struct WMcursor {
	HCURSOR curs;
#ifndef USE_STATIC_CURSOR
	Uint8 *ands;
	Uint8 *xors;
#endif
};

/* Convert bits to padded bytes */
#define PAD_BITS(bits)	((bits+7)/8)

#ifdef CURSOR_DEBUG
static void PrintBITMAP(FILE *out, char *bits, int w, int h)
{
	int i;
	unsigned char ch;

	while ( h-- > 0 ) {
		for ( i=0; i<w; ++i ) {
			if ( (i%8) == 0 )
				ch = *bits++;
			if ( ch&0x80 )
				fprintf(out, "X");
			else
				fprintf(out, " ");
			ch <<= 1;
		}
		fprintf(out, "\n");
	}
}
#endif

#ifndef USE_STATIC_CURSOR
/* Local functions to convert the SDL cursor mask into Windows format */
static void memnot(Uint8 *dst, Uint8 *src, int len)
{
	while ( len-- > 0 )
		*dst++ = ~*src++;
}
static void memxor(Uint8 *dst, Uint8 *src1, Uint8 *src2, int len)
{
	while ( len-- > 0 )
		*dst++ = (*src1++)^(*src2++);
}
#endif /* !USE_STATIC_CURSOR */

void WIN_FreeWMCursor(_THIS, WMcursor *cursor)
{
#ifndef USE_STATIC_CURSOR
	if ( cursor->curs == GetCursor() )
		SetCursor(NULL);
	if ( cursor->curs != NULL )
		DestroyCursor(cursor->curs);
	if ( cursor->ands != NULL )
		free(cursor->ands);
	if ( cursor->xors != NULL )
		free(cursor->xors);
#endif /* !USE_STATIC_CURSOR */
	free(cursor);
}

WMcursor *WIN_CreateWMCursor(_THIS,
		Uint8 *data, Uint8 *mask, int w, int h, int hot_x, int hot_y)
{
#ifdef USE_STATIC_CURSOR
	WMcursor *cursor;

	/* Allocate the cursor */
	cursor = (WMcursor *)malloc(sizeof(*cursor));
	if ( cursor ) {
		cursor->curs = LoadCursor(NULL, IDC_ARROW);
	}
	return(cursor);
#else
	WMcursor *cursor;
	int allowed_x;
	int allowed_y;
	int run, pad, i;
	Uint8 *aptr, *xptr;

	/* Check to make sure the cursor size is okay */
	allowed_x = GetSystemMetrics(SM_CXCURSOR);
	allowed_y = GetSystemMetrics(SM_CYCURSOR);
	if ( (w > allowed_x) || (h > allowed_y) ) {
		SDL_SetError("Only cursors of dimension (%dx%d) are allowed",
							allowed_x, allowed_y);
		return(NULL);
	}

	/* Allocate the cursor */
	cursor = (WMcursor *)malloc(sizeof(*cursor));
	if ( cursor == NULL ) {
		SDL_SetError("Out of memory");
		return(NULL);
	}
	cursor->curs = NULL;
	cursor->ands = NULL;
	cursor->xors = NULL;

	/* Pad out to the normal cursor size */
	run = PAD_BITS(w);
	pad = PAD_BITS(allowed_x)-run;
	aptr = cursor->ands = (Uint8 *)malloc((run+pad)*allowed_y);
	xptr = cursor->xors = (Uint8 *)malloc((run+pad)*allowed_y);
	if ( (aptr == NULL) || (xptr == NULL) ) {
		WIN_FreeWMCursor(NULL, cursor);
		SDL_OutOfMemory();
		return(NULL);
	}
	for ( i=0; i<h; ++i ) {
		memxor(xptr, data, mask, run);
		xptr += run;
		data += run;
		memnot(aptr, mask, run);
		mask += run;
		aptr += run;
		memset(xptr,  0, pad);
		xptr += pad;
		memset(aptr, ~0, pad);
		aptr += pad;
	}
	pad += run;
	for ( ; i<allowed_y; ++i ) {
		memset(xptr,  0, pad);
		xptr += pad;
		memset(aptr, ~0, pad);
		aptr += pad;
	}

	/* Create the cursor */
	cursor->curs = CreateCursor(
			(HINSTANCE)GetWindowLong(SDL_Window, GWL_HINSTANCE),
					hot_x, hot_y, allowed_x, allowed_y, 
						cursor->ands, cursor->xors);
	if ( cursor->curs == NULL ) {
		WIN_FreeWMCursor(NULL, cursor);
		SDL_SetError("Windows couldn't create the requested cursor");
		return(NULL);
	}
	return(cursor);
#endif /* USE_STATIC_CURSOR */
}

int WIN_ShowWMCursor(_THIS, WMcursor *cursor)
{
	POINT mouse_pos;

	/* The fullscreen cursor must be done in software with DirectInput */
	if ( !this->screen || DDRAW_FULLSCREEN() ) {
		return(0);
	}

	/* Set the window cursor to our cursor, if applicable */
	if ( cursor != NULL ) {
		SDL_hcursor = cursor->curs;
	} else {
		SDL_hcursor = NULL;
	}
	GetCursorPos(&mouse_pos);
	if ( PtInRect(&SDL_bounds, mouse_pos) ) {
		SetCursor(SDL_hcursor);
	}
	return(1);
}

void WIN_WarpWMCursor(_THIS, Uint16 x, Uint16 y)
{
	if ( DDRAW_FULLSCREEN() ) {
		SDL_PrivateMouseMotion(0, 0, x, y);
	} else if ( mouse_relative) {
		/*	RJR: March 28, 2000
			leave physical cursor at center of screen if
			mouse hidden and grabbed */
		SDL_PrivateMouseMotion(0, 0, x, y);
	} else {
		POINT pt;
		pt.x = x;
		pt.y = y;
		ClientToScreen(SDL_Window, &pt);
		SetCursorPos(pt.x, pt.y);
	}
}

/* Update the current mouse state and position */
void WIN_UpdateMouse(_THIS)
{
	RECT rect;
	POINT pt;

	if ( ! DDRAW_FULLSCREEN() ) {
		GetClientRect(SDL_Window, &rect);
		GetCursorPos(&pt);
		MapWindowPoints(NULL, SDL_Window, &pt, 1);
		if (PtInRect(&rect, pt) && (WindowFromPoint(pt) == SDL_Window)){
			SDL_PrivateAppActive(1, SDL_APPMOUSEFOCUS);
			SDL_PrivateMouseMotion(0,0, (Sint16)pt.x, (Sint16)pt.y);
		} else {
			SDL_PrivateAppActive(0, SDL_APPMOUSEFOCUS);
		}
	}
}

/* Check to see if we need to enter or leave mouse relative mode */
void WIN_CheckMouseMode(_THIS)
{
#ifndef _WIN32_WCE 
        /* If the mouse is hidden and input is grabbed, we use relative mode */
        if ( !(SDL_cursorstate & CURSOR_VISIBLE) &&
             (this->input_grab != SDL_GRAB_OFF) ) {
                mouse_relative = 1;
        } else {
                mouse_relative = 0;
        }
#else
		mouse_relative =  0; 
#endif
}