图丫ios

A. iOS项目中几个常用的图片处理方法

第一个：压缩图片
当我们上传图片到服务器时，需要压缩一下图片的质量。方法如下：
/*
*压缩图片
*/+ (UIImage *)resizeImageWithImage:(UIImage *)image targetSize:(CGSize)targetSize;
+ (UIImage *)resizeImageWithImage:(UIImage *)image targetSize:(CGSize)targetSize
{ CGSize size = image.size; CGFloat widthRatio = targetSize.width / image.size.width; CGFloat heightRatio = targetSize.height / image.size.height; CGSize newSize; if (widthRatio > heightRatio) newSize = CGSizeMake(size.width * heightRatio, size.height * heightRatio); else newSize = CGSizeMake(size.width * widthRatio, size.height * widthRatio); CGRect rect = CGRectMake(0, 0, newSize.width, newSize.height); (newSize, NO, 1.0);
[image drawInRect:rect]; UIImage *newImage = (); UIGraphicsEndImageContext(); return newImage;
}

第二个，截取人脸部图片
拍摄身份证或者其他有人脸部的图片时，我们可能只需要人脸部分的头像图片。裁剪的方法如下：
/*
*获取脸部图片
*/+ (CGRect)adjustFaceImageWithRect:(CGRect)rect sourceImage:(UIImage *)sourceImage;
+ (CGRect)adjustFaceImageWithRect:(CGRect)rect sourceImage:(UIImage *)sourceImage
{ CGRect faceRect; CGFloat widthMargin = rect.size.width/2;; CGFloat heightMargin = rect.size.height/2;
faceRect.origin.x = MAX(rect.origin.x - widthMargin, 0);
faceRect.origin.y = MAX(rect.origin.y - heightMargin - heightMargin/2, 0) + 20;
faceRect.size.width = MIN(rect.size.width + 2*widthMargin, (CGFloat)(sourceImage.size.width - faceRect.origin.x - 1));
faceRect.size.height = MIN(rect.size.height + 2*heightMargin + heightMargin/2, (CGFloat)(sourceImage.size.height - faceRect.origin.y - 1)); return faceRect;
}

第三个,从一张图片上截取一部分图片
根据坐标信息，从一张大的图片上裁剪出我们需要的那一部分图片区域，具体如下：
/*
*在一张图片上根据坐标范围裁剪图片
*/+ (UIImage *)cutImageWithRect:(CGRect)rect image:(UIImage *)cutImage;
+ (UIImage *)cutImageWithRect:(CGRect)rect image:(UIImage *)cutImage
{ CGImageRef cgRef = cutImage.CGImage; CGImageRef imageRef = CGImageCreateWithImageInRect(cgRef, rect); UIImage *thumbScale = [UIImage imageWithCGImage:imageRef]; CGImageRelease(imageRef); return thumbScale;
}

第四个，保存图片到本地
- (void)saveImageToPhotos:(UIImage*)savedImage
{ (savedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
}
- (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo
{ NSString *msg = nil ; if(error != NULL) msg = @"保存图片失败" ; else msg = @"保存图片成功" ; UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示"
message:msg
delegate:self
cancelButtonTitle:@"确定"
otherButtonTitles:nil];
[alert show];
}

作者：ZYiDa
链接：https://www.jianshu.com/p/198b2ab8f5f8
来源：简书
简书著作权归作者所有，任何形式的转载都请联系作者获得授权并注明出处。