IOS 改变图片尺寸和大小方法

最新推荐文章于 2023-11-05 14:32:07 发布

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本文介绍了两种针对UIImage的操作方法：一是如何按指定尺寸缩放UIImage；二是如何将UIImage转换为PNG或JPEG格式的数据，并可调整压缩质量，适用于图片上传等场景。

一、改变size

- (UIImage *)image:(UIImage*)image byScalingToSize:(CGSize)targetSize {
    UIImage *sourceImage = image;
    UIImage *newImage = nil;

    UIGraphicsBeginImageContext(targetSize);

    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = CGPointZero;
    thumbnailRect.size.width  = targetSize.width;
    thumbnailRect.size.height = targetSize.height;

    [sourceImage drawInRect:thumbnailRect];

    newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage ;
}

二、改变字节(多用于上传至服务器时)

UIKIT_EXTERN NSData *UIImagePNGRepresentation(UIImage *image);                               
UIKIT_EXTERN NSData *UIImageJPEGRepresentation(UIImage *image, CGFloat compressionQuality);