从相册或者摄像头照相取头像作为头像时偶尔出现全黑问题的解决办法，以及头像旋转等问题的解决办法

标签：blog   http   io   color   ar   for   sp   文件   on   

试了网上的很多方法，都没解决！其宗旨是一致的，就是根据图片的方向orientation 作相应的角度旋转，达到我们想要的效果！！

直接来看代码吧，我是用imagePickerController来获取头像的

#pragma mark - UIImagePickerControllerDelegate methods
//当选择一张图片后进入这里
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    //照片的处理在这里
  //  NSString *type = [info objectForKey:UIImagePickerControllerMediaType];
//*
    UIImage *originalImage = [info objectForKey:UIImagePickerControllerOriginalImage];
    UIImageOrientation orientation = originalImage.imageOrientation;
    if (orientation == UIImageOrientationUp) {
        [self dismissViewControllerAnimated:YES completion:nil];
        _memberIconView.image = originalImage;
    }else if(orientation == UIImageOrientationRight){
        [self dismissViewControllerAnimated:YES completion:nil];
        _memberIconView.image = [originalImage imageRotatedByDegrees:90.0];
    }
}
 

-(UIImage *)fixOrientation
{
    if (self.imageOrientation == UIImageOrientationUp) {
        return self;
    }
    CGAffineTransform transform;
    NSLog(@"%i",self.imageOrientation);
    switch (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
        {
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
        }
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        {
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
        }
        case UIImageOrientationRight:
        {
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        }
        case UIImageOrientationRightMirrored:
        {
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        }
        default:
            break;
    }
    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
    }
    
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
                                             CGImageGetBitsPerComponent(self.CGImage), 0,
                                             CGImageGetColorSpace(self.CGImage),
                                             CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}

最后我综合了其他方法，一起来填充UIImage的类扩展，来最终解决问题：

方法：其实他也是根据方向做出角度旋转，但是他管用

- (UIImage *)imageRotatedByRadians:(CGFloat)radians {
    return [self imageRotatedByDegrees:radiansToDegrees(radians)];
}
- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees {
    // calculate the size of the rotated view's containing box for our drawing space
    UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,self.size.width, self.size.height)];
    CGAffineTransform t = CGAffineTransformMakeRotation(degreesToRadians(degrees));
    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, degreesToRadians(degrees));
    // Now, draw the rotated/scaled image into the context
    CGContextScaleCTM(bitmap, 1.0, -1.0);
    CGContextDrawImage(bitmap, CGRectMake(-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), [self CGImage]);
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

先是头文件：UIImage+fixOrientation.h

#import <UIKit/UIKit.h>

@interface UIImage (fixOrientation)
- (UIImage *)fixOrientation;
- (UIImage *)imageRotatedByRadians:(CGFloat)radians;
- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees;

@end

再来.m文件：UIImage+fixOrientation.m

#import "UIImage+fixOrientation.h"

CGFloat degreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;};
CGFloat radiansToDegrees(CGFloat radians) {return radians * 180/M_PI;};
@implementation UIImage (fixOrientation)

-(UIImage *)fixOrientation
{
    if (self.imageOrientation == UIImageOrientationUp) {
        return self;
    }
    CGAffineTransform transform;
    NSLog(@"%i",self.imageOrientation);
    switch (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
        {
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
        }
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        {
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
        }
        case UIImageOrientationRight:
        {
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        }
        case UIImageOrientationRightMirrored:
        {
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        }
        default:
            break;
    }
    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
    }
    
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
                                             CGImageGetBitsPerComponent(self.CGImage), 0,
                                             CGImageGetColorSpace(self.CGImage),
                                             CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}


- (UIImage *)imageRotatedByRadians:(CGFloat)radians {
    return [self imageRotatedByDegrees:radiansToDegrees(radians)];
}
- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees {
    // calculate the size of the rotated view's containing box for our drawing space
    UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,self.size.width, self.size.height)];
    CGAffineTransform t = CGAffineTransformMakeRotation(degreesToRadians(degrees));
    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, degreesToRadians(degrees));
    // Now, draw the rotated/scaled image into the context
    CGContextScaleCTM(bitmap, 1.0, -1.0);
    CGContextDrawImage(bitmap, CGRectMake(-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), [self CGImage]);
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}
@end

从相册或者摄像头照相取头像作为头像时偶尔出现全黑问题的解决办法，以及头像旋转等问题的解决办法

标签：blog   http   io   color   ar   for   sp   文件   on   

原文地址：http://blog.csdn.net/feixiang_song/article/details/40711245