SDL  2.0
SDL_touch.h
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
4 
5  This software is provided 'as-is', without any express or implied
6  warranty. In no event will the authors be held liable for any damages
7  arising from the use of this software.
8 
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12 
13  1. The origin of this software must not be misrepresented; you must not
14  claim that you wrote the original software. If you use this software
15  in a product, an acknowledgment in the product documentation would be
16  appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18  misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20 */
21 
22 /**
23  * \file SDL_touch.h
24  *
25  * Include file for SDL touch event handling.
26  */
27 
28 #ifndef SDL_touch_h_
29 #define SDL_touch_h_
30 
31 #include "SDL_stdinc.h"
32 #include "SDL_error.h"
33 #include "SDL_video.h"
34 
35 #include "begin_code.h"
36 /* Set up for C function definitions, even when using C++ */
37 #ifdef __cplusplus
38 extern "C" {
39 #endif
40 
43 
44 typedef enum
45 {
47  SDL_TOUCH_DEVICE_DIRECT, /* touch screen with window-relative coordinates */
48  SDL_TOUCH_DEVICE_INDIRECT_ABSOLUTE, /* trackpad with absolute device coordinates */
49  SDL_TOUCH_DEVICE_INDIRECT_RELATIVE /* trackpad with screen cursor-relative coordinates */
51 
52 typedef struct SDL_Finger
53 {
55  float x;
56  float y;
57  float pressure;
58 } SDL_Finger;
59 
60 /* Used as the device ID for mouse events simulated with touch input */
61 #define SDL_TOUCH_MOUSEID ((Uint32)-1)
62 
63 /* Used as the SDL_TouchID for touch events simulated with mouse input */
64 #define SDL_MOUSE_TOUCHID ((Sint64)-1)
65 
66 
67 /**
68  * Get the number of registered touch devices.
69  *
70  * On some platforms SDL first sees the touch device if it was actually used.
71  * Therefore SDL_GetNumTouchDevices() may return 0 although devices are
72  * available. After using all devices at least once the number will be
73  * correct.
74  *
75  * This was fixed for Android in SDL 2.0.1.
76  *
77  * \returns the number of registered touch devices.
78  *
79  * \since This function is available since SDL 2.0.0.
80  *
81  * \sa SDL_GetTouchDevice
82  */
83 extern DECLSPEC int SDLCALL SDL_GetNumTouchDevices(void);
84 
85 /**
86  * Get the touch ID with the given index.
87  *
88  * \param index the touch device index
89  * \returns the touch ID with the given index on success or 0 if the index is
90  * invalid; call SDL_GetError() for more information.
91  *
92  * \since This function is available since SDL 2.0.0.
93  *
94  * \sa SDL_GetNumTouchDevices
95  */
96 extern DECLSPEC SDL_TouchID SDLCALL SDL_GetTouchDevice(int index);
97 
98 /**
99  * Get the type of the given touch device.
100  *
101  * \since This function is available since SDL 2.0.10.
102  */
103 extern DECLSPEC SDL_TouchDeviceType SDLCALL SDL_GetTouchDeviceType(SDL_TouchID touchID);
104 
105 /**
106  * Get the number of active fingers for a given touch device.
107  *
108  * \param touchID the ID of a touch device
109  * \returns the number of active fingers for a given touch device on success
110  * or 0 on failure; call SDL_GetError() for more information.
111  *
112  * \since This function is available since SDL 2.0.0.
113  *
114  * \sa SDL_GetTouchFinger
115  */
116 extern DECLSPEC int SDLCALL SDL_GetNumTouchFingers(SDL_TouchID touchID);
117 
118 /**
119  * Get the finger object for specified touch device ID and finger index.
120  *
121  * The returned resource is owned by SDL and should not be deallocated.
122  *
123  * \param touchID the ID of the requested touch device
124  * \param index the index of the requested finger
125  * \returns a pointer to the SDL_Finger object or NULL if no object at the
126  * given ID and index could be found.
127  *
128  * \since This function is available since SDL 2.0.0.
129  *
130  * \sa SDL_RecordGesture
131  */
132 extern DECLSPEC SDL_Finger * SDLCALL SDL_GetTouchFinger(SDL_TouchID touchID, int index);
133 
134 /* Ends C function definitions when using C++ */
135 #ifdef __cplusplus
136 }
137 #endif
138 #include "close_code.h"
139 
140 #endif /* SDL_touch_h_ */
141 
142 /* vi: set ts=4 sw=4 expandtab: */
int64_t Sint64
Definition: SDL_stdinc.h:227
Sint64 SDL_TouchID
Definition: SDL_touch.h:41
Sint64 SDL_FingerID
Definition: SDL_touch.h:42
SDL_TouchDeviceType
Definition: SDL_touch.h:45
@ SDL_TOUCH_DEVICE_INDIRECT_ABSOLUTE
Definition: SDL_touch.h:48
@ SDL_TOUCH_DEVICE_DIRECT
Definition: SDL_touch.h:47
@ SDL_TOUCH_DEVICE_INDIRECT_RELATIVE
Definition: SDL_touch.h:49
@ SDL_TOUCH_DEVICE_INVALID
Definition: SDL_touch.h:46
int SDL_GetNumTouchDevices(void)
SDL_TouchID SDL_GetTouchDevice(int index)
SDL_TouchDeviceType SDL_GetTouchDeviceType(SDL_TouchID touchID)
SDL_Finger * SDL_GetTouchFinger(SDL_TouchID touchID, int index)
int SDL_GetNumTouchFingers(SDL_TouchID touchID)
float y
Definition: SDL_touch.h:56
float pressure
Definition: SDL_touch.h:57
SDL_FingerID id
Definition: SDL_touch.h:54
float x
Definition: SDL_touch.h:55