react-native/Libraries/NativeAnimation/Drivers/RCTFrameAnimation.m

140 lines
4.3 KiB
Objective-C

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
#import "RCTFrameAnimation.h"
#import <UIKit/UIKit.h>
#import <React/RCTConvert.h>
#import <React/RCTDefines.h>
#import "RCTAnimationUtils.h"
#import "RCTValueAnimatedNode.h"
const double SINGLE_FRAME_INTERVAL = 1.0 / 60.0;
@interface RCTFrameAnimation ()
@property (nonatomic, strong) NSNumber *animationId;
@property (nonatomic, strong) RCTValueAnimatedNode *valueNode;
@property (nonatomic, assign) BOOL animationHasBegun;
@property (nonatomic, assign) BOOL animationHasFinished;
@end
@implementation RCTFrameAnimation
{
NSArray<NSNumber *> *_frames;
CGFloat _toValue;
CGFloat _fromValue;
NSTimeInterval _animationStartTime;
NSTimeInterval _animationCurrentTime;
RCTResponseSenderBlock _callback;
}
- (instancetype)initWithId:(NSNumber *)animationId
config:(NSDictionary *)config
forNode:(RCTValueAnimatedNode *)valueNode
callBack:(nullable RCTResponseSenderBlock)callback;
{
if ((self = [super init])) {
NSNumber *toValue = [RCTConvert NSNumber:config[@"toValue"]] ?: @1;
NSArray<NSNumber *> *frames = [RCTConvert NSNumberArray:config[@"frames"]];
_animationId = animationId;
_toValue = toValue.floatValue;
_fromValue = valueNode.value;
_valueNode = valueNode;
_frames = [frames copy];
_callback = [callback copy];
}
return self;
}
RCT_NOT_IMPLEMENTED(- (instancetype)init)
- (void)startAnimation
{
_animationStartTime = _animationCurrentTime = -1;
_animationHasBegun = YES;
}
- (void)stopAnimation
{
_valueNode = nil;
if (_callback) {
_callback(@[@{
@"finished": @(_animationHasFinished)
}]);
}
}
- (void)stepAnimationWithTime:(NSTimeInterval)currentTime
{
if (!_animationHasBegun || _animationHasFinished || _frames.count == 0) {
// Animation has not begun or animation has already finished.
return;
}
if (_animationStartTime == -1) {
_animationStartTime = _animationCurrentTime = currentTime;
}
_animationCurrentTime = currentTime;
NSTimeInterval currentDuration = _animationCurrentTime - _animationStartTime;
// Determine how many frames have passed since last update.
// Get index of frames that surround the current interval
NSUInteger startIndex = floor(currentDuration / SINGLE_FRAME_INTERVAL);
NSUInteger nextIndex = startIndex + 1;
if (nextIndex >= _frames.count) {
// We are at the end of the animation
// Update value and flag animation has ended.
NSNumber *finalValue = _frames.lastObject;
[self updateOutputWithFrameOutput:finalValue.doubleValue];
_animationHasFinished = YES;
return;
}
// Do a linear remap of the two frames to safegaurd against variable framerates
NSNumber *fromFrameValue = _frames[startIndex];
NSNumber *toFrameValue = _frames[nextIndex];
NSTimeInterval fromInterval = startIndex * SINGLE_FRAME_INTERVAL;
NSTimeInterval toInterval = nextIndex * SINGLE_FRAME_INTERVAL;
// Interpolate between the individual frames to ensure the animations are
//smooth and of the proper duration regardless of the framerate.
CGFloat frameOutput = RCTInterpolateValue(currentDuration,
fromInterval,
toInterval,
fromFrameValue.doubleValue,
toFrameValue.doubleValue,
EXTRAPOLATE_TYPE_EXTEND,
EXTRAPOLATE_TYPE_EXTEND);
[self updateOutputWithFrameOutput:frameOutput];
}
- (void)updateOutputWithFrameOutput:(CGFloat)frameOutput
{
CGFloat outputValue = RCTInterpolateValue(frameOutput,
0,
1,
_fromValue,
_toValue,
EXTRAPOLATE_TYPE_EXTEND,
EXTRAPOLATE_TYPE_EXTEND);
_valueNode.value = outputValue;
[_valueNode setNeedsUpdate];
}
@end