how to get UIView 's angle after CGAffineTransform?-白红宇

how to get UIView 's angle after CGAffineTransform?

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发布时间：2019-06-23

本文共 3669 字，大约阅读时间需要 12 分钟。

CGFloat radians = atan2f(self.view.transform.b, self.view.transform.a);

CGFloat degrees = radians * (180 / M_PI);

NSLog(@"%f %f %f", acos (MyView.transform.a), asin (MyView.transform.b), atan2(MyView.transform.b,MyView.transform.a));

- (CGImageRef)CGImageRotatedByAngle:(CGImageRef)imgRef angle:(CGFloat)angle {
     CGFloat angleInRadians = angle * (M_PI / 180);   CGFloat width = CGImageGetWidth(imgRef);   CGFloat height = CGImageGetHeight(imgRef);   CGRect imgRect = CGRectMake(0, 0, width, height);   CGAffineTransform transform = CGAffineTransformMakeRotation(angleInRadians);   CGRect rotatedRect = CGRectApplyAffineTransform(imgRect, transform);   CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();   CGContextRef bmContext = CGBitmapContextCreate(NULL,                                                  rotatedRect.size.width,                                                  rotatedRect.size.height, 8, 0,                                                  colorSpace,                                                  kCGImageAlphaPremultipliedFirst);   CGContextSetAllowsAntialiasing(bmContext, FALSE);   CGContextSetInterpolationQuality(bmContext, kCGInterpolationNone);   CGColorSpaceRelease(colorSpace);   CGContextTranslateCTM(bmContext,                         +(rotatedRect.size.width/2),                         +(rotatedRect.size.height/2));   CGContextRotateCTM(bmContext, angleInRadians);   CGContextTranslateCTM(bmContext,                         -(rotatedRect.size.width/2),                         -(rotatedRect.size.height/2));   CGContextDrawImage(bmContext, CGRectMake(0, 0,                                            rotatedRect.size.width,                                            rotatedRect.size.height),                      imgRef);   CGImageRef rotatedImage = CGBitmapContextCreateImage(bmContext);   CFRelease(bmContext);   [(id)rotatedImage autorelease]; return rotatedImage; }

- (CGImageRef)CGImageRotatedByAngle:(CGImageRef)imgRef angle:(CGFloat)angle {
     CGFloat angleInRadians = angle * (M_PI / 180);   CGFloat width = CGImageGetWidth(imgRef);   CGFloat height = CGImageGetHeight(imgRef);   CGRect imgRect = CGRectMake(0, 0, width, height);   CGAffineTransform transform = CGAffineTransformMakeRotation(angleInRadians);   CGRect rotatedRect = CGRectApplyAffineTransform(imgRect, transform);   CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();   CGContextRef bmContext = CGBitmapContextCreate(NULL,                                                  rotatedRect.size.width,                                                  rotatedRect.size.height, 8, 0,                                                  colorSpace,                                                  kCGImageAlphaPremultipliedFirst);   CGContextSetAllowsAntialiasing(bmContext, FALSE);   CGContextSetInterpolationQuality(bmContext, kCGInterpolationNone);   CGColorSpaceRelease(colorSpace);   CGContextTranslateCTM(bmContext,                         +(rotatedRect.size.width/2),                         +(rotatedRect.size.height/2));   CGContextRotateCTM(bmContext, angleInRadians);   CGContextTranslateCTM(bmContext,                         -(rotatedRect.size.width/2),                         -(rotatedRect.size.height/2));   CGContextDrawImage(bmContext, CGRectMake(0, 0,                                            rotatedRect.size.width,                                            rotatedRect.size.height),                      imgRef);   CGImageRef rotatedImage = CGBitmapContextCreateImage(bmContext);   CFRelease(bmContext);   [(id)rotatedImage autorelease]; return rotatedImage; }

转载于:https://www.cnblogs.com/pengyingh/articles/2381253.html

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