content/common/input/synthetic_gesture_params.h

   1 // Copyright 2013 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 #ifndef CONTENT_COMMON_INPUT_SYNTHETIC_GESTURE_PARAMS_H_
   6 #define CONTENT_COMMON_INPUT_SYNTHETIC_GESTURE_PARAMS_H_
   7
   8 #include "base/memory/scoped_ptr.h"
   9 #include "content/common/content_export.h"
  10
  11 namespace content {
  12
  13 // Base class for storing parameters of synthetic gestures. Sending an object
  14 // over IPC is handled by encapsulating it in a SyntheticGesturePacket object.
  15 //
  16 // The subclasses of this class only store data on synthetic gestures.
  17 // The logic for dispatching input events that implement the gesture lives
  18 // in separate classes in content/browser/renderer_host/input/.
  19 //
  20 // Adding new gesture types involves the following steps:
  21 //   1) Create a new sub-type of SyntheticGestureParams with the parameters
  22 //      needed for the new gesture.
  23 //   2) Use IPC macros to create serialization methods for the new type in
  24 //      content/common/input_messages.h.
  25 //   3) Extend ParamTraits<content::SyntheticGesturePacket>::Write/Read/Log in
  26 //      content/common/input/input_param_traits.cc.
  27 //   4) Add a new unit test to make sure that sending the type over IPC works
  28 //      correctly.
  29 // The details of each step should become clear when looking at other types.
  30 struct CONTENT_EXPORT SyntheticGestureParams {
  31   SyntheticGestureParams();
  32   SyntheticGestureParams(const SyntheticGestureParams& other);
  33   virtual ~SyntheticGestureParams();
  34
  35   // Describes which type of input events synthetic gesture objects should
  36   // generate. When specifying DEFAULT_INPUT the platform will be queried for
  37   // the preferred input event type.
  38   enum GestureSourceType {
  39     DEFAULT_INPUT,
  40     TOUCH_INPUT,
  41     MOUSE_INPUT,
  42     GESTURE_SOURCE_TYPE_MAX = MOUSE_INPUT
  43   };
  44   GestureSourceType gesture_source_type;
  45
  46   enum GestureType {
  47     SMOOTH_SCROLL_GESTURE,
  48     SMOOTH_DRAG_GESTURE,
  49     PINCH_GESTURE,
  50     TAP_GESTURE,
  51     SYNTHETIC_GESTURE_TYPE_MAX = TAP_GESTURE
  52   };
  53   virtual GestureType GetGestureType() const = 0;
  54
  55   // Returns true if the specific gesture source type is supported on this
  56   // platform.
  57   static bool IsGestureSourceTypeSupported(
  58       GestureSourceType gesture_source_type);
  59 };
  60
  61 }  // namespace content
  62
  63 #endif  // CONTENT_COMMON_INPUT_SYNTHETIC_GESTURE_PARAMS_H_