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Diffstat (limited to 'dom/animation/KeyframeUtils.h')
| -rw-r--r-- | dom/animation/KeyframeUtils.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/dom/animation/KeyframeUtils.h b/dom/animation/KeyframeUtils.h new file mode 100644 index 000000000..dbaed97f5 --- /dev/null +++ b/dom/animation/KeyframeUtils.h @@ -0,0 +1,151 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this file, + * You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef mozilla_KeyframeUtils_h +#define mozilla_KeyframeUtils_h + +#include "nsTArrayForwardDeclare.h" // For nsTArray +#include "js/RootingAPI.h" // For JS::Handle +#include "mozilla/KeyframeEffectParams.h" // SpacingMode + +struct JSContext; +class JSObject; +class nsIDocument; +class nsStyleContext; + +namespace mozilla { +struct AnimationProperty; +enum class CSSPseudoElementType : uint8_t; +class ErrorResult; +struct Keyframe; +struct PropertyStyleAnimationValuePair; + +namespace dom { +class Element; +} // namespace dom +} // namespace mozilla + + +namespace mozilla { + +// Represents the set of property-value pairs on a Keyframe converted to +// computed values. +using ComputedKeyframeValues = nsTArray<PropertyStyleAnimationValuePair>; + +/** + * Utility methods for processing keyframes. + */ +class KeyframeUtils +{ +public: + /** + * Converts a JS value representing a property-indexed keyframe or a sequence + * of keyframes to an array of Keyframe objects. + * + * @param aCx The JSContext that corresponds to |aFrames|. + * @param aDocument The document to use when parsing CSS properties. + * @param aFrames The JS value, provided as an optional IDL |object?| value, + * that is the keyframe list specification. + * @param aRv (out) Out-param to hold any error returned by this function. + * Must be initially empty. + * @return The set of processed keyframes. If an error occurs, aRv will be + * filled-in with the appropriate error code and an empty array will be + * returned. + */ + static nsTArray<Keyframe> + GetKeyframesFromObject(JSContext* aCx, + nsIDocument* aDocument, + JS::Handle<JSObject*> aFrames, + ErrorResult& aRv); + + /** + * Calculate the StyleAnimationValues of properties of each keyframe. + * This involves expanding shorthand properties into longhand properties, + * removing the duplicated properties for each keyframe, and creating an + * array of |property:computed value| pairs for each keyframe. + * + * These computed values are used *both* when computing the final set of + * per-property animation values (see GetAnimationPropertiesFromKeyframes) as + * well when applying paced spacing. By returning these values here, we allow + * the result to be re-used in both operations. + * + * @param aKeyframes The input keyframes. + * @param aElement The context element. + * @param aStyleContext The style context to use when computing values. + * @return The set of ComputedKeyframeValues. The length will be the same as + * aFrames. + */ + static nsTArray<ComputedKeyframeValues> + GetComputedKeyframeValues(const nsTArray<Keyframe>& aKeyframes, + dom::Element* aElement, + nsStyleContext* aStyleContext); + + /** + * Fills in the mComputedOffset member of each keyframe in the given array + * using the specified spacing mode. + * + * https://w3c.github.io/web-animations/#spacing-keyframes + * + * @param aKeyframes The set of keyframes to adjust. + * @param aSpacingMode The spacing mode to apply. + * @param aProperty The paced property. Only used when |aSpacingMode| is + * SpacingMode::paced. In all other cases it is ignored and hence may be + * any value, e.g. eCSSProperty_UNKNOWN. + * @param aComputedValues The set of computed keyframe values as returned by + * GetComputedKeyframeValues. Only used when |aSpacingMode| is + * SpacingMode::paced. In all other cases this parameter is unused and may + * be any value including an empty array. + * @param aStyleContext The style context used for calculating paced spacing + * on transform. + */ + static void ApplySpacing(nsTArray<Keyframe>& aKeyframes, + SpacingMode aSpacingMode, + nsCSSPropertyID aProperty, + nsTArray<ComputedKeyframeValues>& aComputedValues, + nsStyleContext* aStyleContext); + + /** + * Wrapper for ApplySpacing to simplify using distribute spacing. + * + * @param aKeyframes The set of keyframes to adjust. + */ + static void ApplyDistributeSpacing(nsTArray<Keyframe>& aKeyframes); + + /** + * Converts an array of Keyframe objects into an array of AnimationProperty + * objects. This involves creating an array of computed values for each + * longhand property and determining the offset and timing function to use + * for each value. + * + * @param aKeyframes The input keyframes. + * @param aComputedValues The computed keyframe values (as returned by + * GetComputedKeyframeValues) used to fill in the individual + * AnimationPropertySegment objects. Although these values could be + * calculated from |aKeyframes|, passing them in as a separate parameter + * allows the result of GetComputedKeyframeValues to be re-used both + * here and in ApplySpacing. + * @param aStyleContext The style context to calculate the style difference. + * @return The set of animation properties. If an error occurs, the returned + * array will be empty. + */ + static nsTArray<AnimationProperty> GetAnimationPropertiesFromKeyframes( + const nsTArray<Keyframe>& aKeyframes, + const nsTArray<ComputedKeyframeValues>& aComputedValues, + nsStyleContext* aStyleContext); + + /** + * Check if the property or, for shorthands, one or more of + * its subproperties, is animatable. + * + * @param aProperty The property to check. + * @return true if |aProperty| is animatable. + */ + static bool IsAnimatableProperty(nsCSSPropertyID aProperty); +}; + +} // namespace mozilla + +#endif // mozilla_KeyframeUtils_h |