src/ui/keyboard/resources/elements/kb-modifier-key.html

   1 <!--
   2   -- Copyright 2013 The Chromium Authors. All rights reserved.
   3   -- Use of this source code is governed by a BSD-style license that can be
   4   -- found in the LICENSE file.
   5   -->
   6
   7 <polymer-element name="kb-modifier-key" class="unlocked dark" extends="kb-key"
   8     on-pointerout="out">
   9   <script>
  10     (function () {
  11
  12       /**
  13        * The possible states of the key.
  14        * @const
  15        * @type {Enum}
  16        */
  17       var KEY_STATES = {
  18         PRESSED: "pressed", // Key-down.
  19         UNLOCKED: "unlocked", // Default state.
  20         TAPPED: "tapped", // Key-down followed by key-up.
  21         CHORDING: "chording", // Chording mode.
  22       };
  23
  24       /**
  25        * A map of the state of all modifier keys.
  26        * @type {Object}
  27        */
  28       var states = {};
  29
  30       Polymer('kb-modifier-key', {
  31         up: function(event) {
  32           if (this.state == KEY_STATES.PRESSED)
  33             this.state = KEY_STATES.TAPPED;
  34           else
  35             this.state = KEY_STATES.UNLOCKED;
  36           this.super([event]);
  37         },
  38
  39         down: function(event) {
  40           // First transition state so that populateDetails generates
  41           // correct data.
  42           switch (this.state) {
  43             case KEY_STATES.UNLOCKED:
  44               this.state = KEY_STATES.PRESSED;
  45               break;
  46             case KEY_STATES.TAPPED:
  47               this.state = KEY_STATES.UNLOCKED;
  48               break;
  49             case KEY_STATES.PRESSED:
  50             case KEY_STATES.CHORDING:
  51               // We pressed another key at the same time,
  52               // so ignore second press.
  53               return;
  54             default:
  55               console.error("Undefined key state: " + state);
  56               break;
  57           }
  58           this.super([event]);
  59         },
  60
  61         /**
  62          * Returns whether the modifier for this key is active.
  63          * @return {boolean}
  64          */
  65         isActive: function() {
  66           return this.state != KEY_STATES.UNLOCKED;
  67         },
  68
  69         /**
  70          * Notifies key that a non-control keyed down.
  71          * A control key is defined as one of shift, control or alt.
  72          */
  73         onNonControlKeyDown: function() {
  74           switch(this.state) {
  75             case (KEY_STATES.PRESSED):
  76               this.state = KEY_STATES.CHORDING;
  77               break;
  78           }
  79         },
  80
  81         /**
  82          * Notifies key that a non-control keyed was typed.
  83          * A control key is defined as one of shift, control or alt.
  84          */
  85         onNonControlKeyTyped: function() {
  86            switch(this.state) {
  87              case (KEY_STATES.TAPPED):
  88                this.state = KEY_STATES.UNLOCKED;
  89                break;
  90            }
  91         },
  92
  93         /**
  94          * Called on a pointer-out event. Ends chording.
  95          * @param {event} event The pointer-out event.
  96          */
  97         out: function(event) {
  98           // TODO(rsadam): Add chording event so that we don't reset
  99           // when shift-chording.
 100           if (this.state == KEY_STATES.CHORDING) {
 101             this.state = KEY_STATES.UNLOCKED;
 102           }
 103         },
 104
 105         /*
 106          * Overrides the autoRelease function to enable chording.
 107          */
 108         autoRelease: function() {
 109         },
 110
 111         populateDetails: function(caller) {
 112           var detail = this.super([caller]);
 113           if (this.state != KEY_STATES.UNLOCKED)
 114             detail.activeModifier = this.charValue;
 115           return detail;
 116         },
 117
 118         /**
 119          *  Resets the modifier key state.
 120          */
 121         reset: function() {
 122           this.state = KEY_STATES.UNLOCKED;
 123         },
 124
 125         get state() {
 126           if (!this.innerText)
 127             console.error("innerText not defined for kb-modifier-key: "
 128                 + this);
 129           // All keys default to the unlock state.
 130           if (!(this.innerText in states))
 131             states[this.innerText] = KEY_STATES.UNLOCKED;
 132           return states[this.innerText];
 133         },
 134
 135         set state(value) {
 136           states[this.innerText] = value;
 137         }
 138       });
 139     })();
 140   </script>
 141 </polymer-element>