如何在AspectFit比率之后调整UIImageView的大小

Question

如何在将内容模式设置为UIViewContentModeScaleAspectFit后重新调整UIImageView的大小，以便我可以从顶部和顶部删除空格。下面。 请参阅附图

提前致谢：）

Answer 1

希望这对其他人也有帮助，如果在某些条件下会破坏，请发表评论:)

- (CGRect)frameForImageattribute:(CGSize)image inImageViewAspectFit:(UIImageView *)imageView {
        float imageRatio = image.width / image.height;
        float viewRatio = imageView.frame.size.width / imageView.frame.size.height;
        if (imageRatio < viewRatio) {
            float scale = imageView.frame.size.height / image.height;
            float width = scale * image.width;
            return CGRectMake(kLeftPading, kTopPading, width, imageView.frame.size.height);
        }
        else {
            float scale = imageView.frame.size.width / image.width;
            float height = scale * image.height;  
            return CGRectMake(kLeftPading, kTopPading, imageView.frame.size.width, height);
        }
}

Answer 2

您需要获取图像视图的比例因子。它可以通过

获得

float scaleFactor = MAX(image.size.width/imageView.bounds.size.width, image.size.height/imageView.bounds.size.height);

然后做

CGRect ivFrame = imageView.frame;
ivframe.size.height = image.size.height/scalefactor;
ivFrame.size.width = image.size.width/scalefactor;
imageView.frame = ivFrame;

theres可能是一个自动执行此操作的类别。

编辑：以下是一个用于比例因子计算，它甚至尊重mageView的内容模式：

how can I get the scale factor of a UIImageView who's mode is AspectFit?

Answer 3

如果您只知道图像视图的宽度以及图像的高度是动态的，那么您需要根据给定的宽度缩放图像的高度，以删除UIViewContentModeScaleAspectFit中图像上方和下方的空白区域模式。使用here中的以下方法根据屏幕的标准宽度缩放图像的高度。

-(UIImage*)imageWithImage: (UIImage*) sourceImage scaledToWidth: (float) i_width
{
    float oldWidth = sourceImage.size.width;
    float scaleFactor = i_width / oldWidth;

    float newHeight = sourceImage.size.height * scaleFactor;
    float newWidth = oldWidth * scaleFactor;

    UIGraphicsBeginImageContext(CGSizeMake(newWidth, newHeight));
    [sourceImage drawInRect:CGRectMake(0, 0, newWidth, newHeight)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    
    UIGraphicsEndImageContext();
    return newImage;
}

从你的cellForRowAtIndexPath：方法中调用它：

UIImage *img = [dictImages objectForKey:yourImageKey]; // loaded the image
cell.imgView.image = [self imageWithImage:img scaledToWidth:self.view.frame.size.width];