Question

我使用尺寸为80X80的imagview来显示大图像（1024 X 780）。

将大图像放入图像视图时，图像看起来被压缩，压缩的东西不像质量图像。

我的问题是，如何将大图像制作成与原始图像一样好的小图像？

Answer 1

在图片视图中，请将 imageview.mode 设为中心，而不是缩放以适合或任何其他。我相信这会将你的任何缩放图像放在80x80维度的最好的质量中。

Answer 2

在这种情况下，您应该对想要在ImageView中显示的图像进行适当的缩放

- (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize 
{
    UIImage *sourceImage = chosenImage;
    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;
        else
            scaleFactor = heightFactor;

        scaledWidth  = width * scaleFactor*1;
        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);

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

    [sourceImage drawInRect:thumbnailRect];

    newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage ;
}

Answer 3

[imageView setContentMode:UIViewContentModeScaleAspectFill];

但是，您应该考虑调整图像大小并将其保存在磁盘上，如果您想再使用它一次。要调整图像大小：

The simplest way to resize an UIImage?

UIImage resize (Scale proportion)

UIImage: Resize, then Crop

等。

Answer 4

从1034x780到80x80几乎不可能保持质量，因为没有足够的空间来捕捉所有细节。

您可以尝试缩放它：

+ (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize;
{
    UIGraphicsBeginImageContext( newSize );
    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;
}

Answer 5

您可以设置图片模式[imageView setContentMode:UIViewContentModeScaleAspectFill]; imageView.autoresizingMask =（UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight）; [imageView setClipsToBounds：YES];

如何将大图像制作成与原始图像一样好的小图像？

5 个答案: