ppapi/c/pp_touch_point.h

   1 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2  * Use of this source code is governed by a BSD-style license that can be
   3  * found in the LICENSE file.
   4  */
   5
   6 /* From pp_touch_point.idl modified Thu Mar 28 10:13:07 2013. */
   7
   8 #ifndef PPAPI_C_PP_TOUCH_POINT_H_
   9 #define PPAPI_C_PP_TOUCH_POINT_H_
  10
  11 #include "ppapi/c/pp_macros.h"
  12 #include "ppapi/c/pp_point.h"
  13 #include "ppapi/c/pp_stdint.h"
  14
  15 /**
  16  * @file
  17  * This file defines the API to create a touch point or position where fingers
  18  * makes contact with touch screen device.
  19  */
  20
  21
  22 /**
  23  * @addtogroup Structs
  24  * @{
  25  */
  26 /**
  27  * The <code>PP_TouchPoint</code> struct represents all information about a
  28  * single touch point, such as position, id, rotation angle, and pressure.
  29  */
  30 struct PP_TouchPoint {
  31   /**
  32    * This value represents the identifier for this TouchPoint. The id
  33    * corresponds to the order in which the points were pressed. For example,
  34    * the first point to be pressed has an id of 0, the second has an id of 1,
  35    * and so on. An id can be reused when a touch point is released.  For
  36    * example, if two fingers are down, with id 0 and 1, and finger 0 releases,
  37    * the next finger to be pressed can be assigned to id 0.
  38    */
  39   uint32_t id;
  40   /**
  41    * This value represents the x and y pixel position of this TouchPoint
  42    * relative to the upper-left of the module instance receiving the event.
  43    */
  44   struct PP_FloatPoint position;
  45   /**
  46    * This value represents the elliptical radii, in screen pixels, in the x
  47    * and y direction of this TouchPoint.
  48    */
  49   struct PP_FloatPoint radius;
  50   /**
  51    * This value represents the angle of rotation in degrees of the elliptical
  52    * model of this TouchPoint clockwise from "up."
  53    */
  54   float rotation_angle;
  55   /**
  56    * This value represents the pressure applied to this TouchPoint.  This value
  57    * is typically between 0 and 1, with 0 indicating no pressure and 1
  58    * indicating some maximum pressure. Scaling differs depending on the
  59    * hardware and the value is not guaranteed to stay within that range.
  60    */
  61   float pressure;
  62 };
  63 PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_TouchPoint, 28);
  64 /**
  65  * @}
  66  */
  67
  68 /**
  69  * @addtogroup Functions
  70  * @{
  71  */
  72
  73 /**
  74  * PP_MakeTouchPoint() creates a <code>PP_TouchPoint</code>.
  75  *
  76  * @return A <code>PP_TouchPoint</code> structure.
  77  */
  78 PP_INLINE struct PP_TouchPoint PP_MakeTouchPoint(void) {
  79   struct PP_TouchPoint result = { 0, {0, 0}, {0, 0}, 0, 0 };
  80   return result;
  81 }
  82 /**
  83  * @}
  84  */
  85
  86 #endif  /* PPAPI_C_PP_TOUCH_POINT_H_ */
  87