ios - 如何将图像旋转90度并保存

Question

我想从文档目录中获取图像，然后旋转并将更改反映到文档目录中的同一图像文件。

我通过像这样使用图像路径来获取图像

[UIImage imageWithContentsOfFile:imgURL];

我想将此图像旋转 90 度并以相同的图像名称保存在相同的路径中。

Answer 1

  UIImage *image = [UIImage imageWithContentsOfFile:imgURL];
    UIImage *newImage=[image imageRotatedByDegrees:90.0]; // i guess "image" is your orginal image
[[NSFileManager defaultManager] removeItemAtPath:imgURL];
    [UIImageJPEGRepresentation(newImage) writeToFile:imgURL atomically:YES];

Answer 2

试试这个代码：

UIImageView *starimage=[[UIImageView alloc] initWithImage:[UIImage imageWithContentsOfFile: imgURL]];
starimage.transform=CGAffineTransformMakeRotation(3.14159265/2 * -1); //For Left rotation

starimage.transform=CGAffineTransformMakeRotation(3.14159265/2 * 1); //For Right rotation

NSData *imagedata=UIImagePNGRepresentation(starimage.image);

//--------现在将图像数据写入文件--------

NSString *fileName = [NSString stringWithFormat:@"test.png"];

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *saveDirectory = [paths objectAtIndex:0];
NSString *saveFileName = fileName;
NSString *documentPath = [saveDirectory stringByAppendingPathComponent:saveFileName];
// [imagedata writeToFile:documentPath atomically:YES encoding:NSUTF8StringEncoding error:nil];
[imagedata writeToFile:documentPath atomically:YES];