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/. */
7 #ifndef DOM_SMIL_SMILCOMPOSITOR_H_
8 #define DOM_SMIL_SMILCOMPOSITOR_H_
12 #include "PLDHashTable.h"
13 #include "SMILTargetIdentifier.h"
14 #include "mozilla/SMILAnimationFunction.h"
15 #include "mozilla/SMILCompositorTable.h"
16 #include "mozilla/UniquePtr.h"
17 #include "nsCSSPropertyID.h"
19 #include "nsTHashtable.h"
25 //----------------------------------------------------------------------
28 // Performs the composition of the animation sandwich by combining the results
29 // of a series animation functions according to the rules of SMIL composition
30 // including prioritising animations.
32 class SMILCompositor
: public PLDHashEntryHdr
{
34 using KeyType
= SMILTargetIdentifier
;
35 using KeyTypeRef
= const KeyType
&;
36 using KeyTypePointer
= const KeyType
*;
38 explicit SMILCompositor(KeyTypePointer aKey
)
39 : mKey(*aKey
), mForceCompositing(false) {}
40 SMILCompositor(SMILCompositor
&& toMove
) noexcept
41 : PLDHashEntryHdr(std::move(toMove
)),
42 mKey(std::move(toMove
.mKey
)),
43 mAnimationFunctions(std::move(toMove
.mAnimationFunctions
)),
44 mForceCompositing(false) {}
46 // PLDHashEntryHdr methods
47 KeyTypeRef
GetKey() const { return mKey
; }
48 bool KeyEquals(KeyTypePointer aKey
) const;
49 static KeyTypePointer
KeyToPointer(KeyTypeRef aKey
) { return &aKey
; }
50 static PLDHashNumber
HashKey(KeyTypePointer aKey
);
51 enum { ALLOW_MEMMOVE
= false };
53 // Adds the given animation function to this Compositor's list of functions
54 void AddAnimationFunction(SMILAnimationFunction
* aFunc
);
56 // Composes the attribute's current value with the list of animation
57 // functions, and assigns the resulting value to this compositor's target
58 // attribute. If a change is made that might produce style updates,
59 // aMightHavePendingStyleUpdates is set to true. Otherwise it is not modified.
60 void ComposeAttribute(bool& aMightHavePendingStyleUpdates
);
62 // Clears animation effects on my target attribute
63 void ClearAnimationEffects();
65 // Cycle-collection support
66 void Traverse(nsCycleCollectionTraversalCallback
* aCallback
);
68 // Toggles a bit that will force us to composite (bypassing early-return
69 // optimizations) when we hit ComposeAttribute.
70 void ToggleForceCompositing() { mForceCompositing
= true; }
72 // Transfers |aOther|'s mCachedBaseValue to |this|
73 void StealCachedBaseValue(SMILCompositor
* aOther
) {
74 mCachedBaseValue
= std::move(aOther
->mCachedBaseValue
);
78 // Create a SMILAttr for my target, on the heap.
80 // @param aBaseComputedStyle An optional ComputedStyle which, if set, will be
81 // used when fetching the base style.
82 UniquePtr
<SMILAttr
> CreateSMILAttr(const ComputedStyle
* aBaseComputedStyle
);
84 // Returns the CSS property this compositor should animate, or
85 // eCSSProperty_UNKNOWN if this compositor does not animate a CSS property.
86 nsCSSPropertyID
GetCSSPropertyToAnimate() const;
88 // Returns true if we might need to refer to base styles (i.e. we are
89 // targeting a CSS property and have one or more animation functions that
90 // don't just replace the underlying value).
92 // This might return true in some cases where we don't actually need the base
93 // style since it doesn't build up the animation sandwich to check if the
94 // functions that appear to need the base style are actually replaced by
95 // a function further up the stack.
96 bool MightNeedBaseStyle() const;
98 // Finds the index of the first function that will affect our animation
99 // sandwich. Also toggles the 'mForceCompositing' flag if it finds that any
100 // (used) functions have changed.
101 uint32_t GetFirstFuncToAffectSandwich();
103 // If the passed-in base value differs from our cached base value, this
104 // method updates the cached value (and toggles the 'mForceCompositing' flag)
105 void UpdateCachedBaseValue(const SMILValue
& aBaseValue
);
107 // The hash key (tuple of element and attributeName)
110 // Hash Value: List of animation functions that animate the specified attr
111 nsTArray
<SMILAnimationFunction
*> mAnimationFunctions
;
113 // Member data for detecting when we need to force-recompose
114 // ---------------------------------------------------------
115 // Flag for tracking whether we need to compose. Initialized to false, but
116 // gets flipped to true if we detect that something has changed.
117 bool mForceCompositing
;
119 // Cached base value, so we can detect & force-recompose when it changes
120 // from one sample to the next. (SMILAnimationController moves this
121 // forward from the previous sample's compositor by calling
122 // StealCachedBaseValue.)
123 SMILValue mCachedBaseValue
;
126 } // namespace mozilla
128 #endif // DOM_SMIL_SMILCOMPOSITOR_H_