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0a0dd30c6a
Summary:
Combining 2 animated values via addition, multiplication, and modulo are already supported, and this adds another one: division.
There are some cases where an animated value needs to invert (1 / x) another animated value for calculation. An example is inverting a scale (2x --> 0.5x), e.g.:
```
const a = Animated.Value(1);
const b = Animated.divide(1, a);
Animated.spring(a, {
toValue: 2,
}).start();
```
`b` will then follow `a`'s spring animation and produce the value of `1 / a`.
The basic usage is like this:
```
<Animated.View style={{transform: [{scale: a}]}}>
<Animated.Image style={{transform: [{scale: b}]}} />
<Animated.View>
```
In this example, the inner image won't get stretched at all because the parent's scaling gets cancelled out.
Also added this to native animated implementation.
Reviewed By: foghina, mmmulani
Differential Revision: D3922891
fbshipit-source-id: 32508956c4b65b2deb7574d50a10c85b4809b961
35 lines
1.0 KiB
Objective-C
35 lines
1.0 KiB
Objective-C
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*/
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#import "RCTDivisionAnimatedNode.h"
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#import "RCTLog.h"
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@implementation RCTDivisionAnimatedNode
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- (void)performUpdate
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{
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[super performUpdate];
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NSArray<NSNumber *> *inputNodes = self.config[@"input"];
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if (inputNodes.count > 1) {
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RCTValueAnimatedNode *parent1 = (RCTValueAnimatedNode *)self.parentNodes[inputNodes[0]];
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RCTValueAnimatedNode *parent2 = (RCTValueAnimatedNode *)self.parentNodes[inputNodes[1]];
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if ([parent1 isKindOfClass:[RCTValueAnimatedNode class]] &&
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[parent2 isKindOfClass:[RCTValueAnimatedNode class]]) {
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if (parent2.value == 0) {
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RCTLogError(@"Detected a division by zero in Animated.divide node");
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return;
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}
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self.value = parent1.value / parent2.value;
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}
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}
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}
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@end
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