调整的UIImage和改变的UIImageView的大小(Resize UIImage and ch

我有这样UIImageView和我有它的最大高度和最大宽度的数值。 我想实现的是，我要带图像（与任何方面比任何分辨率），我想它适合在边界，所以画面不超过他们，但因为它希望它可以缩小他们。 （标记在图像红色）：

眼下图像正确贴合所需的大小，但我有2个忧虑：1. UIImageView不等于调整后的图像的大小，从而留下红色的背景（我不希望出现这种情况）2.如果图像较小我的高度UIImageView它不是调整大小要小一些，它保持相同的高度。

这里是我的代码，我知道它错了：

UIImage *actualImage = [attachmentsArray lastObject];
UIImageView *attachmentImageNew = [[UIImageView alloc] initWithFrame:CGRectMake(5.5, 6.5, 245, 134)];
attachmentImageNew.image = actualImage;
attachmentImageNew.backgroundColor = [UIColor redColor];
attachmentImageNew.contentMode = UIViewContentModeScaleAspectFit;

那么，如何动态改变大小不仅的UIImageView.image ，但整体UIImageView ，从而使得它的尺寸完全可调的内容。 任何帮助将不胜感激，谢谢！

Answer 1:

当你得到一个调整后的图像的宽度和高度获取UIViewContentModeScaleAspectFit经过调整后的图像的宽度 ，你可以调整你的ImageView：

imageView.frame = CGRectMake(0, 0, resizedWidth, resizedHeight);
imageView.center = imageView.superview.center;

如果它工作我没有检查，但我觉得都应该是OK

Answer 2:

- (UIImage *)image:(UIImage*)originalImage scaledToSize:(CGSize)size
{
    //avoid redundant drawing
    if (CGSizeEqualToSize(originalImage.size, size))
    {
        return originalImage;
    }

    //create drawing context
    UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f);

    //draw
    [originalImage drawInRect:CGRectMake(0.0f, 0.0f, size.width, size.height)];

    //capture resultant image
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    //return image
    return image;
}

Answer 3:

这是斯威夫特等效Rajneesh071的答案，使用扩展

UIImage {
  func scaleToSize(aSize :CGSize) -> UIImage {
    if (CGSizeEqualToSize(self.size, aSize)) {
      return self
    }

    UIGraphicsBeginImageContextWithOptions(aSize, false, 0.0)
    self.drawInRect(CGRectMake(0.0, 0.0, aSize.width, aSize.height))
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
  }
}

用法：

let image = UIImage(named: "Icon")
item.icon = image?.scaleToSize(CGSize(width: 30.0, height: 30.0))

Answer 4:

使用以下分类，然后从石英申请边境进入你的形象：

[yourimage.layer setBorderColor:[[UIColor whiteColor] CGColor]];
[yourimage.layer setBorderWidth:2];

类别：UIImage的+ AutoScaleResize.h

#import <Foundation/Foundation.h>

@interface UIImage (AutoScaleResize)

- (UIImage *)imageByScalingAndCroppingForSize:(CGSize)targetSize;

@end

的UIImage + AutoScaleResize.m

#import "UIImage+AutoScaleResize.h"

@implementation UIImage (AutoScaleResize)

- (UIImage *)imageByScalingAndCroppingForSize:(CGSize)targetSize
{
    UIImage *sourceImage = self;
    UIImage *newImage = nil;
    CGSize imageSize = sourceImage.size;
    CGFloat width = imageSize.width;
    CGFloat height = imageSize.height;
    CGFloat targetWidth = targetSize.width;
    CGFloat targetHeight = targetSize.height;
    CGFloat scaleFactor = 0.0;
    CGFloat scaledWidth = targetWidth;
    CGFloat scaledHeight = targetHeight;
    CGPoint thumbnailPoint = CGPointMake(0.0,0.0);

    if (CGSizeEqualToSize(imageSize, targetSize) == NO)
    {
        CGFloat widthFactor = targetWidth / width;
        CGFloat heightFactor = targetHeight / height;

        if (widthFactor > heightFactor)
        {
            scaleFactor = widthFactor; // scale to fit height
        }
        else
        {
            scaleFactor = heightFactor; // scale to fit width
        }

        scaledWidth  = width * scaleFactor;
        scaledHeight = height * scaleFactor;

        // center the image
        if (widthFactor > heightFactor)
        {
            thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
        }
        else
        {
            if (widthFactor < heightFactor)
            {
                thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
            }
        }
    }

    UIGraphicsBeginImageContext(targetSize); // this will crop

    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = thumbnailPoint;
    thumbnailRect.size.width  = scaledWidth;
    thumbnailRect.size.height = scaledHeight;

    [sourceImage drawInRect:thumbnailRect];

    newImage = UIGraphicsGetImageFromCurrentImageContext();

    if(newImage == nil)
    {
        NSLog(@"could not scale image");
    }

    //pop the context to get back to the default
    UIGraphicsEndImageContext();

    return newImage;
}

@end

Answer 5:

如果你有图像的大小，你为什么不设置frame.size图像视图成为这种规模的？

编辑 - -

好了，看到你的评论，我建议这样的：

UIImageView *imageView;
//so let's say you're image view size is set to the maximum size you want

CGFloat maxWidth = imageView.frame.size.width;
CGFloat maxHeight = imageView.frame.size.height;

CGFloat viewRatio = maxWidth / maxHeight;
CGFloat imageRatio = image.size.height / image.size.width;

if (imageRatio > viewRatio) {
    CGFloat imageViewHeight = round(maxWidth * imageRatio);
    imageView.frame = CGRectMake(0, ceil((self.bounds.size.height - imageViewHeight) / 2.f), maxWidth, imageViewHeight);
}
else if (imageRatio < viewRatio) {
    CGFloat imageViewWidth = roundf(maxHeight / imageRatio);
    imageView.frame = CGRectMake(ceil((maxWidth - imageViewWidth) / 2.f), 0, imageViewWidth, maxHeight);
} else {
    //your image view is already at the good size
}

此代码将调整图片大小，以便将其图像比例，并且图像视图还定位到同一中心作为你的“默认”的位置。

PS：我希望你设置imageView.layer.shouldRasterise = YES和imageView.layer.rasterizationScale = [UIScreen mainScreen].scale;

如果你使用的CALayer阴影效果;）这将大大提高你的用户界面的性能。

Answer 6:

我想你想要的是一个不同的content mode 。 尝试使用UIViewContentModeScaleToFill 。 这将通过缩放如果需要改变内容的纵横比，以适应乌尔的UIImageView的大小的内容。

看一看在content mode上的官方文档部分，可获取不同的内容模式（它说明与图片）的一个更好的主意。

Answer 7:

   if([[SDWebImageManager sharedManager] diskImageExistsForURL:[NSURL URLWithString:@"URL STRING1"]])
   {
       NSString *key = [[SDWebImageManager sharedManager] cacheKeyForURL:[NSURL URLWithString:@"URL STRING1"]];

       UIImage *tempImage=[self imageWithImage:[[SDImageCache sharedImageCache] imageFromDiskCacheForKey:key] scaledToWidth:cell.imgview.bounds.size.width];
       cell.imgview.image=tempImage;

   }
   else
   {
       [cell.imgview sd_setImageWithURL:[NSURL URLWithString:@"URL STRING1"] placeholderImage:nil completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL)
        {
            UIImage *tempImage=[self imageWithImage:image scaledToWidth:cell.imgview.bounds.size.width];
            cell.imgview.image=tempImage;
//                [tableView beginUpdates];
//                [tableView endUpdates];

        }];
   }

文章来源: Resize UIImage and change the size of UIImageView