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 7 /** 8 * This file defines the API to create a touch point or position where fingers 9 * makes contact with touch screen device. 10 */ 11 12 /** 13 * The <code>PP_TouchPoint</code> struct represents all information about a 14 * single touch point, such as position, id, rotation angle, and pressure. 15 */ 16 [assert_size(28), returnByValue] 17 struct PP_TouchPoint { 18 /** 19 * This value represents the identifier for this TouchPoint. The id 20 * corresponds to the order in which the points were pressed. For example, 21 * the first point to be pressed has an id of 0, the second has an id of 1, 22 * and so on. An id can be reused when a touch point is released. For 23 * example, if two fingers are down, with id 0 and 1, and finger 0 releases, 24 * the next finger to be pressed can be assigned to id 0. 25 */ 26 uint32_t id; 27 28 /** 29 * This value represents the x and y pixel position of this TouchPoint 30 * relative to the upper-left of the module instance receiving the event. 31 */ 32 PP_FloatPoint position; 33 34 /** 35 * This value represents the elliptical radii, in screen pixels, in the x 36 * and y direction of this TouchPoint. 37 */ 38 PP_FloatPoint radius; 39 40 /** 41 * This value represents the angle of rotation in degrees of the elliptical 42 * model of this TouchPoint clockwise from "up." 43 */ 44 float_t rotation_angle; 45 46 /** 47 * This value represents the pressure applied to this TouchPoint. This value 48 * is typically between 0 and 1, with 0 indicating no pressure and 1 49 * indicating some maximum pressure. Scaling differs depending on the 50 * hardware and the value is not guaranteed to stay within that range. 51 */ 52 float_t pressure; 53 }; 54 55 #inline c 56 /** 57 * @addtogroup Functions 58 * @{ 59 */ 60 61 /** 62 * PP_MakeTouchPoint() creates a <code>PP_TouchPoint</code>. 63 * 64 * @return A <code>PP_TouchPoint</code> structure. 65 */ 66 PP_INLINE struct PP_TouchPoint PP_MakeTouchPoint(void) { 67 struct PP_TouchPoint result = { 0, {0, 0}, {0, 0}, 0, 0 }; 68 return result; 69 } 70 /** 71 * @} 72 */ 73 74 #endinl 75
