128 lines
3.2 KiB
Objective-C
128 lines
3.2 KiB
Objective-C
/**
|
|
* Copyright (c) 2015-present, Facebook, Inc.
|
|
*
|
|
* This source code is licensed under the MIT license found in the
|
|
* LICENSE file in the root directory of this source tree.
|
|
*/
|
|
|
|
#import "RCTDecayAnimation.h"
|
|
|
|
#import <UIKit/UIKit.h>
|
|
#import <React/RCTConvert.h>
|
|
|
|
#import "RCTValueAnimatedNode.h"
|
|
|
|
@interface RCTDecayAnimation ()
|
|
|
|
@property (nonatomic, strong) NSNumber *animationId;
|
|
@property (nonatomic, strong) RCTValueAnimatedNode *valueNode;
|
|
@property (nonatomic, assign) BOOL animationHasBegun;
|
|
@property (nonatomic, assign) BOOL animationHasFinished;
|
|
|
|
@end
|
|
|
|
@implementation RCTDecayAnimation
|
|
{
|
|
CGFloat _velocity;
|
|
CGFloat _deceleration;
|
|
NSTimeInterval _frameStartTime;
|
|
CGFloat _fromValue;
|
|
CGFloat _lastValue;
|
|
NSInteger _iterations;
|
|
NSInteger _currentLoop;
|
|
RCTResponseSenderBlock _callback;
|
|
}
|
|
|
|
- (instancetype)initWithId:(NSNumber *)animationId
|
|
config:(NSDictionary *)config
|
|
forNode:(RCTValueAnimatedNode *)valueNode
|
|
callBack:(nullable RCTResponseSenderBlock)callback;
|
|
{
|
|
if ((self = [super init])) {
|
|
_callback = [callback copy];
|
|
_animationId = animationId;
|
|
_valueNode = valueNode;
|
|
_fromValue = 0;
|
|
_lastValue = 0;
|
|
_velocity = [RCTConvert CGFloat:config[@"velocity"]]; // initial velocity
|
|
[self resetAnimationConfig:config];
|
|
}
|
|
return self;
|
|
}
|
|
|
|
- (void)resetAnimationConfig:(NSDictionary *)config
|
|
{
|
|
NSNumber *iterations = [RCTConvert NSNumber:config[@"iterations"]] ?: @1;
|
|
_fromValue = _lastValue;
|
|
_deceleration = [RCTConvert CGFloat:config[@"deceleration"]];
|
|
_iterations = iterations.integerValue;
|
|
_currentLoop = 1;
|
|
_animationHasFinished = iterations.integerValue == 0;
|
|
}
|
|
|
|
RCT_NOT_IMPLEMENTED(- (instancetype)init)
|
|
|
|
- (void)startAnimation
|
|
{
|
|
_frameStartTime = -1;
|
|
_animationHasBegun = YES;
|
|
}
|
|
|
|
- (void)stopAnimation
|
|
{
|
|
_valueNode = nil;
|
|
if (_callback) {
|
|
_callback(@[@{
|
|
@"finished": @(_animationHasFinished)
|
|
}]);
|
|
}
|
|
}
|
|
|
|
- (void)stepAnimationWithTime:(NSTimeInterval)currentTime
|
|
{
|
|
if (!_animationHasBegun || _animationHasFinished) {
|
|
// Animation has not begun or animation has already finished.
|
|
return;
|
|
}
|
|
|
|
if (_frameStartTime == -1) {
|
|
// Since this is the first animation step, consider the start to be on the previous frame.
|
|
_frameStartTime = currentTime - RCTSingleFrameInterval;
|
|
if (_fromValue == _lastValue) {
|
|
// First iteration, assign _fromValue based on _valueNode.
|
|
_fromValue = _valueNode.value;
|
|
} else {
|
|
// Not the first iteration, reset _valueNode based on _fromValue.
|
|
[self updateValue:_fromValue];
|
|
}
|
|
_lastValue = _valueNode.value;
|
|
}
|
|
|
|
CGFloat value = _fromValue +
|
|
(_velocity / (1 - _deceleration)) *
|
|
(1 - exp(-(1 - _deceleration) * (currentTime - _frameStartTime) * 1000.0));
|
|
|
|
[self updateValue:value];
|
|
|
|
if (fabs(_lastValue - value) < 0.1) {
|
|
if (_iterations == -1 || _currentLoop < _iterations) {
|
|
// Set _frameStartTime to -1 to reset instance variables on the next runAnimationStep.
|
|
_frameStartTime = -1;
|
|
_currentLoop++;
|
|
} else {
|
|
_animationHasFinished = true;
|
|
return;
|
|
}
|
|
}
|
|
|
|
_lastValue = value;
|
|
}
|
|
|
|
- (void)updateValue:(CGFloat)outputValue
|
|
{
|
|
_valueNode.value = outputValue;
|
|
[_valueNode setNeedsUpdate];
|
|
}
|
|
|
|
@end
|