+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Simple camera control for user, as the method `accept_scroll_and_zoom`
+module camera_control
+
+import gamnit
+import cameras
+
+import camera_control_linux is conditional(linux)
+import camera_control_android is conditional(android)
+
+redef class EulerCamera
+ # Zoom and scroll this camera from user input
+ #
+ # Scrolling is accomplished by moving the camera on the XY plane and
+ # zooming by moving it on the Z axis.
+ #
+ # This method has distinct implementations per platform.
+ # On desktop computers, the mouse wheel changes the zoom level, and
+ # holding down the middle mouse button scrolls the camera.
+ # On Android, a two finger pinch and slide gesture zoom and scroll.
+ #
+ # Returns `true` if the event is used.
+ #
+ # Should be called from `App::accept_event` before accepting pointer events:
+ #
+ # ~~~nitish
+ # redef class App
+ # redef fun accept_event(event)
+ # do
+ # if world_camera.accept_scroll_and_zoom(event) then return true
+ #
+ # # Handle other events...
+ # return false
+ # end
+ # end
+ # ~~~
+ fun accept_scroll_and_zoom(event: InputEvent): Bool do return false
+end