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      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  * This file defines the API used to handle mouse and keyboard input events.
      8  */
      9 
     10 /**
     11  * The <code>PP_InputEvent_Key</code> struct represents a key up or key down
     12  * event.
     13  *
     14  * Key up and key down events correspond to physical keys on the keyboard. The
     15  * actual character that the user typed (if any) will be delivered in a
     16  * "character" event.
     17  *
     18  * If the user loses focus on the module while a key is down, a key up
     19  * event might not occur. For example, if the module has focus and the user
     20  * presses and holds the shift key, the module will see a "shift down" message.
     21  * Then if the user clicks elsewhere on the web page, the module's focus will
     22  * be lost and no more input events will be delivered.
     23  *
     24  * If your module depends on receiving key up events, it should also handle
     25  * "lost focus" as the equivalent of "all keys up."
     26  */
     27 [assert_size(8)]
     28 struct PP_InputEvent_Key {
     29   /** This value is a bit field combination of the EVENT_MODIFIER flags. */
     30   uint32_t modifier;
     31 
     32   /**
     33    * This value reflects the DOM KeyboardEvent <code>keyCode</code> field.
     34    * Chrome populates this with the Windows-style Virtual Key code of the key.
     35    */
     36 
     37   uint32_t key_code;
     38 };
     39 
     40 /**
     41  * The <code>PP_InputEvent_Character</code> struct represents a typed character
     42  * event.
     43  *
     44  * Normally, the program will receive a key down event, followed by a character
     45  * event, followed by a key up event. The character event will have any
     46  * modifier keys applied. Obvious examples are symbols, where Shift-5 gives you
     47  * a '%'. The key down and up events will give you the scan code for the "5"
     48  * key, and the character event will give you the '%' character.
     49  *
     50  * You may not get a character event for all key down events if the key doesn't
     51  * generate a character. Likewise, you may actually get multiple character
     52  * events in a row. For example, some locales have an accent key that modifies
     53  * the next character typed. You might get this stream of events: accent down,
     54  * accent up (it didn't generate a character), letter key down, letter with
     55  * accent character event (it was modified by the previous accent key), letter
     56  * key up.  If the letter can't be combined with the accent, like an umlaut and
     57  * an 'R', the system might send umlaut down, umlaut up, 'R' key down, umlaut
     58  * character (can't combine it with 'R', so just send the raw umlaut so it
     59  * isn't lost"), 'R' character event, 'R' key up.
     60  */
     61 [assert_size(12)]
     62 struct PP_InputEvent_Character {
     63   /** A combination of the <code>PP_InputEvent_Modifier</code> flags. */
     64   uint32_t modifier;
     65 
     66   /**
     67    * This value represents the typed character as a single null-terminated UTF-8
     68    * character. Any unused bytes will be filled with null bytes. Since the
     69    * maximum UTF-8 character is 4 bytes, there will always be at least one null
     70    * at the end so you can treat this as a null-terminated UTF-8 string.
     71    */
     72   char[5] text;
     73 };
     74 
     75 /**
     76  * The <code>PP_InputEvent_Mouse</code> struct represents all mouse events
     77  * except mouse wheel events.
     78  */
     79 [assert_size(20)]
     80 struct PP_InputEvent_Mouse {
     81   /**
     82    * This value is a bit field combination of the
     83    * <code>PP_InputEvent_Modifier</code> flags.
     84    */
     85   uint32_t modifier;
     86 
     87   /**
     88    * This value represents the button that changed for mouse down or up events.
     89    * This value will be <code>PP_EVENT_MOUSEBUTTON_NONE</code> for mouse move,
     90    * enter, and leave events.
     91    */
     92   PP_InputEvent_MouseButton button;
     93 
     94   /**
     95    * This values represents the x coordinate of the mouse when the event
     96    * occurred.
     97    *
     98    * In most, but not all, cases these coordinates will just be integers.
     99    * For example, the plugin element might be arbitrarily scaled or transformed
    100    * in the DOM, and translating a mouse event into the coordinate space of the
    101    * plugin will give non-integer values.
    102    */
    103   float_t x;
    104   /**
    105    * This values represents the y coordinate of the mouse when the event
    106    * occurred.
    107    *
    108    * In most, but not all, cases these coordinates will just be integers.
    109    * For example, the plugin element might be arbitrarily scaled or transformed
    110    * in the DOM, and translating a mouse event into the coordinate space of the
    111    * plugin will give non-integer values.
    112    */
    113   float_t y;
    114 
    115   /* TODO(brettw) figure out exactly what this means.*/
    116   int32_t click_count;
    117 };
    118 
    119 /**
    120  * The <code>PP_InputEvent_Wheel</code> struct represents all mouse wheel
    121  * events.
    122  */
    123 [assert_size(24)] struct PP_InputEvent_Wheel {
    124   /**
    125    * This value represents a combination of the <code>EVENT_MODIFIER</code>
    126    * flags.
    127    */
    128   uint32_t modifier;
    129 
    130   /**
    131    * The mouse wheel's horizontal scroll amount. A scroll to the right
    132    * (where the content moves left) is represented as positive values,
    133    * and a scroll to the left (where the content moves right) is
    134    * represented as negative values.
    135    *
    136    * The units are either in pixels (when scroll_by_page is false) or pages
    137    * (when scroll_by_page is true). For example, delta_y = -3 means scroll up 3
    138    * pixels when scroll_by_page is false, and scroll up 3 pages when
    139    * scroll_by_page is true.
    140    *
    141    * This amount is system dependent and will take into account the user's
    142    * preferred scroll sensitivity and potentially also nonlinear acceleration
    143    * based on the speed of the scrolling.
    144    *
    145    * Devices will be of varying resolution. Some mice with large detents will
    146    * only generate integer scroll amounts. But fractional values are also
    147    * possible, for example, on some trackpads and newer mice that don't have
    148    * "clicks".
    149    */
    150   float_t delta_x;
    151 
    152   /**
    153    * The mouse wheel's vertical scroll amount. A scroll down (where the
    154    * content moves up) is represented as positive values, and a scroll up
    155    * (where the content moves down) is represented as negative values.
    156    *
    157    * The units are either in pixels (when scroll_by_page is false) or pages
    158    * (when scroll_by_page is true). For example, delta_y = -3 means scroll up 3
    159    * pixels when scroll_by_page is false, and scroll up 3 pages when
    160    * scroll_by_page is true.
    161    *
    162    * This amount is system dependent and will take into account the user's
    163    * preferred scroll sensitivity and potentially also nonlinear acceleration
    164    * based on the speed of the scrolling.
    165    *
    166    * Devices will be of varying resolution. Some mice with large detents will
    167    * only generate integer scroll amounts. But fractional values are also
    168    * possible, for example, on some trackpads and newer mice that don't have
    169    * "clicks".
    170    */
    171   float_t delta_y;
    172 
    173   /**
    174    * The number of "clicks" of the scroll wheel that have produced the
    175    * event. The value may have system-specific acceleration applied to it,
    176    * depending on the device. The positive and negative meanings are the same
    177    * as for <code>delta_x</code> and <code>delta_y</code>.
    178    *
    179    * If you are scrolling, you probably want to use the delta values above.
    180    * These tick events can be useful if you aren't doing actual scrolling and
    181    * don't want or pixel values. An example may be cycling between different
    182    * items in a game.
    183    *
    184    * You may receive fractional values for the wheel ticks if the mouse wheel
    185    * is high resolution or doesn't have "clicks". If your program wants
    186    * discrete events (as in the "picking items" example) you should accumulate
    187    * fractional click values from multiple messages until the total value
    188    * reaches positive or negative one. This should represent a similar amount
    189    * of scrolling as for a mouse that has a discrete mouse wheel.
    190    */
    191   float_t wheel_ticks_x;
    192 
    193   /** This value represents */
    194   float_t wheel_ticks_y;
    195 
    196   /**
    197    * Indicates if the scroll <code>delta_x</code>/<code>delta_y</code>
    198    * indicates pages or lines to scroll by. When true, the user is requesting
    199    * to scroll by pages.
    200    */
    201   PP_Bool scroll_by_page;
    202 };
    203 
    204