/** * 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 "RCTAnimationUtils.h" #import static NSUInteger _RCTFindIndexOfNearestValue(CGFloat value, NSArray *range) { NSUInteger index; NSUInteger rangeCount = range.count; for (index = 1; index < rangeCount - 1; index++) { NSNumber *inputValue = range[index]; if (inputValue.doubleValue >= value) { break; } } return index - 1; } /** * Interpolates value by remapping it linearly fromMin->fromMax to toMin->toMax */ CGFloat RCTInterpolateValue(CGFloat value, CGFloat inputMin, CGFloat inputMax, CGFloat outputMin, CGFloat outputMax, NSString *extrapolateLeft, NSString *extrapolateRight) { if (value < inputMin) { if ([extrapolateLeft isEqualToString:EXTRAPOLATE_TYPE_IDENTITY]) { return value; } else if ([extrapolateLeft isEqualToString:EXTRAPOLATE_TYPE_CLAMP]) { value = inputMin; } else if ([extrapolateLeft isEqualToString:EXTRAPOLATE_TYPE_EXTEND]) { // noop } else { RCTLogError(@"Invalid extrapolation type %@ for left extrapolation", extrapolateLeft); } } if (value > inputMax) { if ([extrapolateRight isEqualToString:EXTRAPOLATE_TYPE_IDENTITY]) { return value; } else if ([extrapolateRight isEqualToString:EXTRAPOLATE_TYPE_CLAMP]) { value = inputMax; } else if ([extrapolateRight isEqualToString:EXTRAPOLATE_TYPE_EXTEND]) { // noop } else { RCTLogError(@"Invalid extrapolation type %@ for right extrapolation", extrapolateRight); } } return outputMin + (value - inputMin) * (outputMax - outputMin) / (inputMax - inputMin); } /** * Interpolates value by mapping it from the inputRange to the outputRange. */ CGFloat RCTInterpolateValueInRange(CGFloat value, NSArray *inputRange, NSArray *outputRange, NSString *extrapolateLeft, NSString *extrapolateRight) { NSUInteger rangeIndex = _RCTFindIndexOfNearestValue(value, inputRange); CGFloat inputMin = inputRange[rangeIndex].doubleValue; CGFloat inputMax = inputRange[rangeIndex + 1].doubleValue; CGFloat outputMin = outputRange[rangeIndex].doubleValue; CGFloat outputMax = outputRange[rangeIndex + 1].doubleValue; return RCTInterpolateValue(value, inputMin, inputMax, outputMin, outputMax, extrapolateLeft, extrapolateRight); } CGFloat RCTRadiansToDegrees(CGFloat radians) { return radians * 180.0 / M_PI; } CGFloat RCTDegreesToRadians(CGFloat degrees) { return degrees / 180.0 * M_PI; }