ios 图片尺寸的等比压缩

//图片的尺寸等比压缩（压缩之后图片容量也相应变化）

- (UIImage*) scaleImage : (UIImage *)image toScale:(float)scaleSize {

    UIGraphicsBeginImageContext(CGSizeMake(image.size.width * scaleSize, image.size.height * scaleSize));

    [image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height * scaleSize)];

    UIImage *scaleImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return scaleImage;

}

//图片的自定义尺寸压缩（压缩之后图片容量也相应变化）

- (UIImage *) reSizeImage:(UIImage *)image toSize:(CGSize)reSize {

    UIGraphicsBeginImageContext(CGSizeMake(reSize.width, reSize.height));

    [image drawInRect:CGRectMake(0, 0, reSize.width, reSize.height)];

    UIImage *reSizeImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return reSizeImage;

}