iosUIImage图片反响旋转（内存消耗超大基本应用不到项目中，有大神能解决求告知）

warning 图片旋转的时候，特别的消耗内存

- (UIImage )image:(UIImage )image rotation:(UIImageOrientation)orientation

{

long double rotate = 0.0;

CGRect rect;

float translateX = 0;

float translateY = 0;

float scaleX = 1.0;

float scaleY = 1.0;

switch (orientation) {

case UIImageOrientationLeft:

rotate = M_PI_2;

rect = CGRectMake(0, 0, image.size.height, image.size.width);

translateX = 0;

translateY = -rect.size.width;

scaleY = rect.size.width/rect.size.height;

scaleX = rect.size.height/rect.size.width;

break;

case UIImageOrientationRight:

rotate = 3 M_PI_2;

rect = CGRectMake(0, 0, image.size.height, image.size.width);

translateX = -rect.size.height;

translateY = 0;

scaleY = rect.size.width/rect.size.height;

scaleX = rect.size.height/rect.size.width;

break;

case UIImageOrientationDown:

rotate = M_PI;

rect = CGRectMake(0, 0, image.size.width, image.size.height);

translateX = -rect.size.width;

translateY = -rect.size.height;

break;

default:

rotate = 0.0;

rect = CGRectMake(0, 0, image.size.width, image.size.height);

translateX = 0;

translateY = 0;

break;

}

UIGraphicsBeginImageContext(rect.size);

CGContextRef context = UIGraphicsGetCurrentContext();

//做CTM变换

CGContextTranslateCTM(context, 0.0, rect.size.height);

CGContextScaleCTM(context, 1.0, -1.0);

CGContextRotateCTM(context, rotate);

CGContextTranslateCTM(context, translateX, translateY);

CGContextScaleCTM(context, scaleX, scaleY);

//绘制图片

CGContextDrawImage(context, CGRectMake(0, 0, rect.size.width, rect.size.height), image.CGImage);

UIImage newPic = UIGraphicsGetImageFromCurrentImageContext();

return newPic;

}