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SDL_touchscreen.h
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SDL_touchscreen.h
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/*
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
*/
/**
* \file SDL_touchscreen.h
*
* Include file for SDL touchscreen event handling
*/
#ifndef _SDL_touchscreen_h
#define _SDL_touchscreen_h
#include "SDL_stdinc.h"
#include "SDL_error.h"
#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
extern "C" {
/* *INDENT-ON* */
#endif
/* In order to use these functions, SDL_Init() must have been called
with the SDL_INIT_TOUCHSCREEN flag. This causes SDL to scan the system
for touchscreens, and load appropriate drivers.
*/
/* The touchscreen structure used to identify an SDL touchscreen */
struct _SDL_Touchscreen;
typedef struct _SDL_Touchscreen SDL_Touchscreen;
/* Function prototypes */
/*
* Count the number of touchscreens attached to the system
*/
extern DECLSPEC int SDLCALL SDL_NumTouchscreens(void);
/*
* Get the implementation dependent name of a touchscreen.
* This can be called before any touchscreens are opened.
* If no name can be found, this function returns NULL.
*/
extern DECLSPEC const char *SDLCALL SDL_TouchscreenName(int device_index);
/*
* Open a touchscreen for use - the index passed as an argument refers to
* the N'th touchscreen on the system. This index is the value which will
* identify this touchscreen in future touchscreen events.
*
* This function returns a touchscreen identifier, or NULL if an error occurred.
*/
extern DECLSPEC SDL_Touchscreen *SDLCALL SDL_TouchscreenOpen(int device_index);
/*
* Returns 1 if the touchscreen has been opened, or 0 if it has not.
*/
extern DECLSPEC int SDLCALL SDL_TouchscreenOpened(int device_index);
/*
* Get the device index of an opened touchscreen.
*/
extern DECLSPEC int SDLCALL SDL_TouchscreenIndex(SDL_Touchscreen * touchscreen);
/*
* Get the number of points a touchscreen can register at a time
* (single or multi-touch.)
*/
extern DECLSPEC int SDLCALL SDL_TouchscreenMaxPoints(SDL_Touchscreen * touchscreen);
/*
* Update the current state of the open touchscreens.
* This is called automatically by the event loop if any touchscreen
* events are enabled.
*/
extern DECLSPEC void SDLCALL SDL_TouchscreenUpdate(void);
/*
* Enable/disable touchscreen event polling.
* If touchscreen events are disabled, you must call SDL_TouchscreenUpdate()
* yourself and check the state of the touchscreen when you want touchscreen
* information.
* The state can be one of SDL_QUERY, SDL_ENABLE or SDL_IGNORE.
*/
extern DECLSPEC int SDLCALL SDL_TouchscreenEventState(int state);
/*
* Get the current X,Y position of the indicated point on the touchscreen.
*
* If not NULL, *x is set to an integer in the range [-32768,32767]
* where -32768 is the left edge, 0 is center, 32767 is right edge.
* Similarly with *y, for the top, center, and bottom, respectively.
* The returned value is an unsigned integer in the range [1,32767]
* that represents the pressure of the touch.
* If not being touched, 0 is returned and *x and *y are unmodified.
*
* The touch point indices start at index 0.
* If given a negative value for point, all the X,Y, and pressures
* for all the currently touched points on a multitouch device
* should be averaged and used for *x, *y, and the return value.
* If the value of point exceeds the number of points currently touched,
* 0 should be returned, and *x, *y should be left unmodified.
*
* On error, -1 is returned.
*/
extern DECLSPEC int SDLCALL SDL_TouchscreenGetXY(SDL_Touchscreen *touchscreen,
int point, int *x, int *y);
/*
* Get the number of currently touched points on a touchscreen.
* This is either 0 or 1 for a single-touch device.
* On error, -1 is returned.
*/
extern DECLSPEC int SDLCALL SDL_TouchscreenGetPoints(SDL_Touchscreen * touchscreen);
/*
* Close a touchscreen previously opened with SDL_TouchscreenOpen()
*/
extern DECLSPEC void SDLCALL SDL_TouchscreenClose(SDL_Touchscreen * touchscreen);
/* Ends C function definitions when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
}
/* *INDENT-ON* */
#endif
#include "close_code.h"
#endif /* _SDL_touchscreen_h */
/* vi: set ts=4 sw=4 expandtab: */