DBL_EPSILON和 FLT_EPSILON主要用于单精度和双精度的比较当中,归在c语言标准函数库 FLT_EPSILON用于float类型。 它是满足 x+1.0不等于1.0的最小的正数 也就是说,所有比FLT_EPSILON小的正数x,x+1.0==1.0都是成立的。 FLT_EPSILON 1.192092896e-07F DBL_EPSILON 2.2204460492503131e-016 这个FLT_MIN定义的是最小...
FLT_EPSILON来帮助我完成这类事情。#define fequal(a,b) (fabs((a) - (b)) < FLT_EPSILON) #...
1.1f);};CustomAnimationBlock shrinkBlock=^{self.bgview.transform=CGAffineTransformMakeScale(FLT_EPSILON,FLT_EPSILON);};CustomCompletionAnimationBlock completionBlock=^(BOOL done){[UIView animateWithDuration:0.5fanimations:shrinkBlock];};[UIView animateWithDuration:0.5fanimations:expandBlock...
CGRect imageRect = { CGPointZero, self.size }; UIImage *effectImage = self; BOOL hasBlur = blurRadius > __FLT_EPSILON__; BOOL hasSaturationChange = fabs(saturationDeltaFactor -1.) > __FLT_EPSILON__;if(hasBlur || hasSaturationChange) { UIGraphicsBeginImageContextWithOptions(self.size,...
UIImage*effectImage = self; BOOL hasBlur = blurRadius >__FLT_EPSILON__; BOOL hasSaturationChange= fabs(saturationDeltaFactor -1.) > __FLT_EPSILON__;if(hasBlur ||hasSaturationChange) { UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]); ...
// To support the minimum even when rounding errors occur, use an epsilon when comparing. We downcast to float because that's what we get for delayTime from ImageIO. if ([delayTime floatValue] < ((float)kFLAnimatedImageDelayTimeIntervalMinimum - FLT_EPSILON)) { ...
{CGPointZero,self.size};UIImage*effectImage=self;BOOLhasBlur=blurRadius>__FLT_EPSILON__;BOOLhasSaturationChange=fabs(saturationDeltaFactor-1.)>__FLT_EPSILON__;if(hasBlur||hasSaturationChange){UIGraphicsBeginImageContextWithOptions(self.size,NO,[[UIScreen mainScreen]scale]);CGContextRef effectIn...
FLT_EPSILON数值是1.192092896e-07F,最小的 float 型数,它使1.0+FLT_EPSILON !=1.0 2 为什么浮点数精度会丢失 十进制小数转化为二进制数:乘以2直到没有了小数为止。 举个例子,0.9 表示成二进制数。 0.9*2=1.8 取整数部分 1 0.8(1.8的小数部分)*2=1.6 取整数部分 1 ...
9、-1.) _FLT_EPSILON_; if(hasBlur | hasSaturati on Cha nge)UIGraphicsBeginlmageContextWithOptions(self.size, NO,UIScreen mainScreen scale);CGCon textRef effect InCon text =UIGraphicsGetCurre ntCon text(www.hu nanwan g. net);CGC on textScaleCTM(effectl nCon text,1.0,-1.0);CGC on ...
UIImage *effectImage = self; BOOL hasBlur = blurRadius > __FLT_EPSILON__; BOOL hasSaturationChange = fabs(saturationDeltaFactor - 1.) > __FLT_EPSILON__; if (hasBlur || hasSaturationChange) { UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]); ...