缩放单元格的图像

Question

我正在尝试将图像添加到单元格中，但是可以正常使用，但是缩放比例并没有真正起作用，图像被缩放到一定的大小，并保持该大小，我输入到scale函数中的数字不会改变任何事情。自动缩放到某个恒定大小）

 NSURL *url = [NSURL URLWithString:icon];
        NSData *data = [NSData dataWithContentsOfURL:url];
        UIImage *logo=[UIImage imageWithData:data scale:4];
        cell.imageView.layer.masksToBounds = YES;
        cell.imageView.layer.cornerRadius = 10.0;
        cell.imageView.image=logo;

Answer 1

实现此方法并使用它：

/*! Returns a UIImage which is resized image of the image provided.
    @param image
        The image to be resized.
    @param size
        The size of the image to be resized.
*/
+ (UIImage*)resizeImage:(UIImage *)image imageSize:(CGSize)size {
    CGFloat imageWidth = image.size.width;
    CGFloat imageHeight = image.size.height;
    CGFloat requiredWidth = (imageWidth * size.height) / imageHeight;

    UIGraphicsBeginImageContextWithOptions(CGSizeMake(requiredWidth, size.height), NO, [UIScreen mainScreen].scale);
    [image drawInRect:CGRectMake(0, 0, requiredWidth, size.height)];
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    //here is the scaled image which has been changed to the size specified
    UIGraphicsEndImageContext();
    return newImage;
}

Answer 2

只需在如下声明的自定义单元类方法中编写掩蔽函数即可。

- (void)setSelected:(BOOL)selected animated:(BOOL)animated
{
    [super setSelected:selected animated:animated];

    // Configure the view for the selected state

    [self.imageView.layer setCornerRadius:10.0];
    self.imageView.layer.masksToBounds = YES;
}

Answer 3

使用此功能可以根据需要缩放图像。

- (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {
    //UIGraphicsBeginImageContext(newSize);
    float theScaleFactor = 0.0f;
    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
        if ([[UIScreen mainScreen] scale] == 2.0) {
            theScaleFactor = 2.0f;
        } else {
            theScaleFactor = 0.0f;
        }
    } else {
        theScaleFactor = 0.0f;
    }

    UIGraphicsBeginImageContextWithOptions(newSize, NO, theScaleFactor);
    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

希望这会帮助你。