1 # This file is part of NIT (http://www.nitlanguage.org).
3 # Licensed under the Apache License, Version 2.0 (the "License");
4 # you may not use this file except in compliance with the License.
5 # You may obtain a copy of the License at
7 # http://www.apache.org/licenses/LICENSE-2.0
9 # Unless required by applicable law or agreed to in writing, software
10 # distributed under the License is distributed on an "AS IS" BASIS,
11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 # See the License for the specific language governing permissions and
13 # limitations under the License.
15 # Simple service keeping track of which keys are currently pressed
17 # This service revolves around `app.pressed_keys`, a `Set` of the names of currently pressed keys.
18 # As a `Set`, `app.pressed_keys` can be iterated and queried with `has`.
20 # Limitations: The keys names are platform dependent.
24 # redef fun accept_event(event)
26 # # First, pass the event to `super`, `pressed_keys` must see all
27 # # events but it doesn't intercept any of them.
28 # if super then return true
32 # redef fun update(dt)
34 # for key in pressed_keys do
35 # if k == "left" or k == "a" then
36 # # Act on key pressed down
37 # print "left or a is pressed down"
49 # Currently pressed keys
50 var pressed_keys
= new Set[String] is lazy
52 # Register `event` to update `app.pressed_keys`
53 private fun register_key_event
(event
: KeyEvent)
57 app
.pressed_keys
.add key
58 else if app
.pressed_keys
.has
(key
) then
59 app
.pressed_keys
.remove key
63 redef fun accept_event
(event
)
65 if event
isa KeyEvent then register_key_event event