third_party/WebKit/Source/platform/graphics/CompositingReasons.h

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CompositingReasons_h
#define CompositingReasons_h

#include "platform/PlatformExport.h"
#include "wtf/Allocator.h"
#include "wtf/text/WTFString.h"
#include <stdint.h>

namespace blink {

const uint64_t CompositingReasonNone = 0;
const uint64_t CompositingReasonAll = ~static_cast<uint64_t>(0);

// Intrinsic reasons that can be known right away by the layer
const uint64_t CompositingReason3DTransform = UINT64_C(1) << 0;
const uint64_t CompositingReasonVideo = UINT64_C(1) << 1;
const uint64_t CompositingReasonCanvas = UINT64_C(1) << 2;
const uint64_t CompositingReasonPlugin = UINT64_C(1) << 3;
const uint64_t CompositingReasonIFrame = UINT64_C(1) << 4;
const uint64_t CompositingReasonBackfaceVisibilityHidden = UINT64_C(1) << 5;
const uint64_t CompositingReasonActiveAnimation = UINT64_C(1) << 6;
const uint64_t CompositingReasonTransitionProperty = UINT64_C(1) << 7;
const uint64_t CompositingReasonScrollDependentPosition = UINT64_C(1) << 8;
const uint64_t CompositingReasonOverflowScrollingTouch = UINT64_C(1) << 9;
const uint64_t CompositingReasonOverflowScrollingParent = UINT64_C(1) << 10;
const uint64_t CompositingReasonOutOfFlowClipping = UINT64_C(1) << 11;
const uint64_t CompositingReasonVideoOverlay = UINT64_C(1) << 12;
const uint64_t CompositingReasonWillChangeCompositingHint = UINT64_C(1) << 13;
const uint64_t CompositingReasonBackdropFilter = UINT64_C(1) << 14;

// Overlap reasons that require knowing what's behind you in paint-order before
// knowing the answer.
const uint64_t CompositingReasonAssumedOverlap = UINT64_C(1) << 15;
const uint64_t CompositingReasonOverlap = UINT64_C(1) << 16;
const uint64_t CompositingReasonNegativeZIndexChildren = UINT64_C(1) << 17;
const uint64_t CompositingReasonSquashingDisallowed = UINT64_C(1) << 18;

// Subtree reasons that require knowing what the status of your subtree is
// before knowing the answer.
const uint64_t CompositingReasonTransformWithCompositedDescendants = UINT64_C(1)
                                                                     << 19;
const uint64_t CompositingReasonOpacityWithCompositedDescendants = UINT64_C(1)
                                                                   << 20;
const uint64_t CompositingReasonMaskWithCompositedDescendants = UINT64_C(1)
                                                                << 21;
const uint64_t CompositingReasonReflectionWithCompositedDescendants =
    UINT64_C(1) << 22;
const uint64_t CompositingReasonFilterWithCompositedDescendants = UINT64_C(1)
                                                                  << 23;
const uint64_t CompositingReasonBlendingWithCompositedDescendants = UINT64_C(1)
                                                                    << 24;
const uint64_t CompositingReasonClipsCompositingDescendants = UINT64_C(1) << 25;
const uint64_t CompositingReasonPerspectiveWith3DDescendants = UINT64_C(1)
                                                               << 26;
const uint64_t CompositingReasonPreserve3DWith3DDescendants = UINT64_C(1) << 27;
const uint64_t CompositingReasonReflectionOfCompositedParent = UINT64_C(1)
                                                               << 28;
const uint64_t CompositingReasonIsolateCompositedDescendants = UINT64_C(1)
                                                               << 29;
const uint64_t CompositingReasonPositionFixedWithCompositedDescendants =
    UINT64_C(1) << 30;

// The root layer is a special case. It may be forced to be a layer, but it also
// needs to be a layer if anything else in the subtree is composited.
const uint64_t CompositingReasonRoot = UINT64_C(1) << 31;

// CompositedLayerMapping internal hierarchy reasons
const uint64_t CompositingReasonLayerForAncestorClip = UINT64_C(1) << 32;
const uint64_t CompositingReasonLayerForDescendantClip = UINT64_C(1) << 33;
const uint64_t CompositingReasonLayerForPerspective = UINT64_C(1) << 34;
const uint64_t CompositingReasonLayerForHorizontalScrollbar = UINT64_C(1) << 35;
const uint64_t CompositingReasonLayerForVerticalScrollbar = UINT64_C(1) << 36;
const uint64_t CompositingReasonLayerForOverflowControlsHost = UINT64_C(1)
                                                               << 37;
const uint64_t CompositingReasonLayerForScrollCorner = UINT64_C(1) << 38;
const uint64_t CompositingReasonLayerForScrollingContents = UINT64_C(1) << 39;
const uint64_t CompositingReasonLayerForScrollingContainer = UINT64_C(1) << 40;
const uint64_t CompositingReasonLayerForSquashingContents = UINT64_C(1) << 41;
const uint64_t CompositingReasonLayerForSquashingContainer = UINT64_C(1) << 42;
const uint64_t CompositingReasonLayerForForeground = UINT64_C(1) << 43;
const uint64_t CompositingReasonLayerForBackground = UINT64_C(1) << 44;
const uint64_t CompositingReasonLayerForMask = UINT64_C(1) << 45;
const uint64_t CompositingReasonLayerForClippingMask = UINT64_C(1) << 46;
const uint64_t CompositingReasonLayerForAncestorClippingMask = UINT64_C(1)
                                                               << 47;
const uint64_t CompositingReasonLayerForScrollingBlockSelection = UINT64_C(1)
                                                                  << 48;
// Composited layer painted on top of all other layers as decoration
const uint64_t CompositingReasonLayerForDecoration = UINT64_C(1) << 49;

// Composited elements with inline transforms trigger assumed overlap so that
// we can update their transforms quickly.
const uint64_t CompositingReasonInlineTransform = UINT64_C(1) << 50;

const uint64_t CompositingReasonCompositorProxy = UINT64_C(1) << 51;

// Various combinations of compositing reasons are defined here also, for more
// intutive and faster bitwise logic.
const uint64_t CompositingReasonComboAllDirectReasons =
    CompositingReason3DTransform | CompositingReasonVideo |
    CompositingReasonCanvas | CompositingReasonPlugin |
    CompositingReasonIFrame | CompositingReasonBackfaceVisibilityHidden |
    CompositingReasonActiveAnimation | CompositingReasonTransitionProperty |
    CompositingReasonScrollDependentPosition |
    CompositingReasonOverflowScrollingTouch |
    CompositingReasonOverflowScrollingParent |
    CompositingReasonOutOfFlowClipping | CompositingReasonVideoOverlay |
    CompositingReasonWillChangeCompositingHint |
    CompositingReasonCompositorProxy | CompositingReasonBackdropFilter;

const uint64_t CompositingReasonComboAllDirectStyleDeterminedReasons =
    CompositingReason3DTransform | CompositingReasonBackfaceVisibilityHidden |
    CompositingReasonActiveAnimation | CompositingReasonTransitionProperty |
    CompositingReasonWillChangeCompositingHint |
    CompositingReasonCompositorProxy | CompositingReasonBackdropFilter;

const uint64_t CompositingReasonComboCompositedDescendants =
    CompositingReasonTransformWithCompositedDescendants |
    CompositingReasonIsolateCompositedDescendants |
    CompositingReasonOpacityWithCompositedDescendants |
    CompositingReasonMaskWithCompositedDescendants |
    CompositingReasonFilterWithCompositedDescendants |
    CompositingReasonBlendingWithCompositedDescendants |
    CompositingReasonReflectionWithCompositedDescendants |
    CompositingReasonClipsCompositingDescendants |
    CompositingReasonPositionFixedWithCompositedDescendants;

const uint64_t CompositingReasonCombo3DDescendants =
    CompositingReasonPreserve3DWith3DDescendants |
    CompositingReasonPerspectiveWith3DDescendants;

const uint64_t CompositingReasonComboAllStyleDeterminedReasons =
    CompositingReasonComboAllDirectStyleDeterminedReasons |
    CompositingReasonComboCompositedDescendants |
    CompositingReasonCombo3DDescendants | CompositingReasonInlineTransform;

const uint64_t CompositingReasonComboReasonsThatRequireOwnBacking =
    CompositingReasonComboAllDirectReasons | CompositingReasonOverlap |
    CompositingReasonAssumedOverlap | CompositingReasonNegativeZIndexChildren |
    CompositingReasonSquashingDisallowed |
    CompositingReasonTransformWithCompositedDescendants |
    CompositingReasonOpacityWithCompositedDescendants |
    CompositingReasonMaskWithCompositedDescendants |
    CompositingReasonFilterWithCompositedDescendants |
    CompositingReasonBlendingWithCompositedDescendants |
    CompositingReasonIsolateCompositedDescendants |
    CompositingReasonPreserve3DWith3DDescendants |  // preserve-3d has to create
                                                    // a backing store to ensure
                                                    // that 3d-transformed
                                                    // elements intersect.
    CompositingReasonBackdropFilter |
    CompositingReasonPositionFixedWithCompositedDescendants;

const uint64_t CompositingReasonComboSquashableReasons =
    CompositingReasonOverlap | CompositingReasonAssumedOverlap |
    CompositingReasonOverflowScrollingParent;

typedef uint64_t CompositingReasons;

// Any reasons other than overlap or assumed overlap will require the layer to
// be separately compositing.
inline bool requiresCompositing(CompositingReasons reasons) {
  return reasons & ~CompositingReasonComboSquashableReasons;
}

// If the layer has overlap or assumed overlap, but no other reasons, then it
// should be squashed.
inline bool requiresSquashing(CompositingReasons reasons) {
  return !requiresCompositing(reasons) &&
         (reasons & CompositingReasonComboSquashableReasons);
}

struct CompositingReasonStringMap {
  STACK_ALLOCATED();
  CompositingReasons reason;
  const char* shortName;
  const char* description;
};

PLATFORM_EXPORT extern const CompositingReasonStringMap
    kCompositingReasonStringMap[];
PLATFORM_EXPORT extern const size_t kNumberOfCompositingReasons;
PLATFORM_EXPORT String compositingReasonsAsString(CompositingReasons);

}  // namespace blink

#endif  // CompositingReasons_h