gfx/src/CompositorHitTestInfo.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef MOZILLA_GFX_COMPOSITORHITTESTINFO_H_
   8 #define MOZILLA_GFX_COMPOSITORHITTESTINFO_H_
   9
  10 #include "mozilla/EnumSet.h"
  11 #include "mozilla/EnumTypeTraits.h"
  12
  13 namespace mozilla {
  14 namespace gfx {
  15
  16 // This set of flags is used to figure out what information a frame has
  17 // that is relevant to hit-testing in the compositor. The flags are
  18 // intentionally set up so that if all of them are 0 the item is effectively
  19 // invisible to hit-testing, and no information for this frame needs to be
  20 // sent to the compositor.
  21 // Each enumerator is annotated with the value it contributes to an
  22 // EnumSet (2 ^ <value of enumerator>), in hexadecimal.
  23 enum class CompositorHitTestFlags : uint8_t {
  24   // The frame participates in hit-testing
  25   eVisibleToHitTest = 0,  // 0x0001
  26
  27   // The frame may have odd shapes that requires the main thread to do accurate
  28   // hit-testing.
  29   eIrregularArea,  // 0x0002
  30   // The frame has APZ-aware listeners and so inputs targeted at this area
  31   // need to be handled by the main thread before APZ can use them, as they
  32   // might be prevent-defaulted.
  33   eApzAwareListeners,  // 0x0004
  34   // This is an inactive scrollframe or unlayerized scrollthumb. In this state
  35   // it cannot be used by APZ for async scrolling, so APZ will defer to the main
  36   // thread.
  37   eInactiveScrollframe,  // 0x0008
  38
  39   // The touch action flags are set up so that the default of
  40   // touch-action:auto on an element leaves all the flags as 0.
  41   eTouchActionPanXDisabled,           // 0x0010
  42   eTouchActionPanYDisabled,           // 0x0020
  43   eTouchActionPinchZoomDisabled,      // 0x0040
  44   eTouchActionAnimatingZoomDisabled,  // 0x0080
  45
  46   // The frame is a scrollbar or a subframe inside a scrollbar (including
  47   // scroll thumbs)
  48   eScrollbar,  // 0x0100
  49   // The frame is a scrollthumb. If this is set then eScrollbar will also be
  50   // set, unless gecko somehow generates a scroll thumb without a containing
  51   // scrollbar.
  52   eScrollbarThumb,  // 0x0200
  53   // If eScrollbar is set, this flag indicates if the scrollbar is a vertical
  54   // one (if set) or a horizontal one (if not set)
  55   eScrollbarVertical,  // 0x0400
  56
  57   // Events targeting this frame should only be processed if a target
  58   // confirmation is received from the main thread. If no such confirmation
  59   // is received within a timeout period, the event may be dropped.
  60   // Only meaningful in combination with eDispatchToContent.
  61   eRequiresTargetConfirmation,  // 0x0800
  62
  63   // Bits 0x1000, 0x2000, 0x4000, and 0x8000 are used by SideBitsPacked in
  64   // WebRenderAPI.cpp when we pack SideBits and CompositorHitTestInfo into a
  65   // uint16_t and pass in into webrender to store in the item tag.
  66
  67 };
  68
  69 using CompositorHitTestInfo = EnumSet<CompositorHitTestFlags, uint32_t>;
  70
  71 // A CompositorHitTestInfo with none of the flags set
  72 constexpr CompositorHitTestInfo CompositorHitTestInvisibleToHit;
  73
  74 // Mask to check for all the touch-action flags at once
  75 constexpr CompositorHitTestInfo CompositorHitTestTouchActionMask(
  76     CompositorHitTestFlags::eTouchActionPanXDisabled,
  77     CompositorHitTestFlags::eTouchActionPanYDisabled,
  78     CompositorHitTestFlags::eTouchActionPinchZoomDisabled,
  79     CompositorHitTestFlags::eTouchActionAnimatingZoomDisabled);
  80
  81 // Mask to check all the flags that involve APZ waiting for results from the
  82 // main thread
  83 constexpr CompositorHitTestInfo CompositorHitTestDispatchToContent(
  84     CompositorHitTestFlags::eIrregularArea,
  85     CompositorHitTestFlags::eApzAwareListeners,
  86     CompositorHitTestFlags::eInactiveScrollframe);
  87
  88 }  // namespace gfx
  89
  90 // Used for IPDL serialization. The 'value' have to be the biggest enum from
  91 // CompositorHitTestFlags.
  92 template <>
  93 struct MaxEnumValue<::mozilla::gfx::CompositorHitTestFlags> {
  94   static constexpr unsigned int value = static_cast<unsigned int>(
  95       gfx::CompositorHitTestFlags::eRequiresTargetConfirmation);
  96 };
  97
  98 namespace gfx {
  99
 100 // Checks if the CompositorHitTestFlags max enum value is less than N.
 101 template <int N>
 102 static constexpr bool DoesCompositorHitTestInfoFitIntoBits() {
 103   if (MaxEnumValue<CompositorHitTestInfo::valueType>::value < N) {
 104     return true;
 105   }
 106
 107   return false;
 108 }
 109 }  // namespace gfx
 110
 111 }  // namespace mozilla
 112
 113 #endif /* MOZILLA_GFX_COMPOSITORHITTESTINFO_H_ */