我已经阅读了许多与此相关的答案,但我仍然无法让它发挥作用.
我有一个用户可以在其中签名的视图.以下是它的外观:http://d.pr/i/McuE
我可以成功检索此图像并将其保存到文件系统,但我需要在保存前将其旋转90度,以便签名从左到右读取.
// Grab the image UIGraphicsBeginImageContext(self.signArea.bounds.size); [self.signArea drawRect: self.signArea.bounds]; UIImage *signatureImage = UIGraphicsGetImageFromCurrentImageContext(); //-- ? -- Rotate the image (this doesn't work) -- ? -- CGContextRef context = UIGraphicsGetCurrentContext(); CGContextRotateCTM(context, M_PI_2); UIGraphicsEndImageContext(); //Save the image as a PNG in Documents folder [UIImagePNGRepresentation(signatureImage) writeToFile:[[PPHelpers documentsPath] stringByAppendingPathComponent:@"signature-temp.png"] atomically:YES];
如何在保存之前旋转图像?
在此先感谢您的帮助.我使用iOS 7 SDK在Xcode 5上.
我终于使用这篇文章中的一个答案来解决这个问题:如何将UIImage旋转90度?
我用这个方法:
- (UIImage *)imageRotatedByDegrees:(UIImage*)oldImage deg:(CGFloat)degrees{ //Calculate the size of the rotated view's containing box for our drawing space UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,oldImage.size.width, oldImage.size.height)]; CGAffineTransform t = CGAffineTransformMakeRotation(degrees * M_PI / 180); rotatedViewBox.transform = t; CGSize rotatedSize = rotatedViewBox.frame.size; //Create the bitmap context UIGraphicsBeginImageContext(rotatedSize); CGContextRef bitmap = UIGraphicsGetCurrentContext(); //Move the origin to the middle of the image so we will rotate and scale around the center. CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2); //Rotate the image context CGContextRotateCTM(bitmap, (degrees * M_PI / 180)); //Now, draw the rotated/scaled image into the context CGContextScaleCTM(bitmap, 1.0, -1.0); CGContextDrawImage(bitmap, CGRectMake(-oldImage.size.width / 2, -oldImage.size.height / 2, oldImage.size.width, oldImage.size.height), [oldImage CGImage]); UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return newImage; }
然后这样叫:
//Rotate it UIImage *rotatedImage = [self imageRotatedByDegrees:signatureImage deg:90];
感谢大家.