content/renderer/input/synchronous_input_handler_proxy.h

   1 // Copyright 2015 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_RENDERER_INPUT_SYNCHRONOUS_INPUT_HANDLER_PROXY_H_
   6 #define CONTENT_RENDERER_INPUT_SYNCHRONOUS_INPUT_HANDLER_PROXY_H_
   7
   8 #include "base/time/time.h"
   9
  10 namespace gfx {
  11 class ScrollOffset;
  12 class SizeF;
  13 }
  14
  15 namespace content {
  16
  17 class CONTENT_EXPORT SynchronousInputHandler {
  18  public:
  19   // Informs the Android WebView embedder that a fling animation is running, and
  20   // that it should call SynchronouslyAnimate() if it wants to execute that
  21   // animation. The embedder/app may choose to override and ignore the
  22   // request for animation.
  23   virtual void SetNeedsSynchronousAnimateInput() = 0;
  24
  25   // Informs the Android WebView embedder of the current root scroll and page
  26   // scale state.
  27   virtual void UpdateRootLayerState(
  28       const gfx::ScrollOffset& total_scroll_offset,
  29       const gfx::ScrollOffset& max_scroll_offset,
  30       const gfx::SizeF& scrollable_size,
  31       float page_scale_factor,
  32       float min_page_scale_factor,
  33       float max_page_scale_factor) = 0;
  34 };
  35
  36 // Android WebView requires synchronous scrolling from the WebView application.
  37 // This interface provides support for that behaviour. The WebView embedder will
  38 // act as the InputHandler for controlling the timing of input (fling)
  39 // animations.
  40 class CONTENT_EXPORT SynchronousInputHandlerProxy {
  41  public:
  42   // Tell the proxy that we will control the timing of root fling animations
  43   // from the SynchronousInputHandler. Once this is set, the InputHandler is
  44   // not requested to Animate() the InputHandlerProxy for root layer flings.
  45   // Instead, requests for animation will go to the SynchronousInputHandler and
  46   // animation ticks will only come back through SynchronouslyAnimate().
  47   // Non-root flings are not affected.
  48   virtual void SetOnlySynchronouslyAnimateRootFlings(
  49       SynchronousInputHandler* synchronous_input_handler) = 0;
  50
  51   // Tick input (fling) animations. This may happen out of phase with the frame
  52   // timing, or not at all, as it is controlled by the WebView application. When
  53   // it returns, it expects the animation scroll offsets to be visible to the
  54   // application.
  55   virtual void SynchronouslyAnimate(base::TimeTicks time) = 0;
  56
  57   // Called when the synchronous input handler wants to change the root scroll
  58   // offset. Since it has the final say, this overrides values from compositor-
  59   // controlled behaviour. After the offset is applied, the
  60   // SynchronousInputHandler should be given back the result in case it differs
  61   // from what was sent.
  62   virtual void SynchronouslySetRootScrollOffset(
  63       const gfx::ScrollOffset& root_offset) = 0;
  64 };
  65
  66 }  // namespace content
  67
  68 #endif  // CONTENT_RENDERER_INPUT_SYNCHRONOUS_INPUT_HANDLER_PROXY_H_