Question

im试图创建一个包含“浏览”按钮以加载图像文件和“ +”按钮以放大图像的窗口。浏览按钮及其打开的对话框将图像成功加载到Image aka中。当我按下“ +”按钮时，它不会放大加载的图像，但会使其模糊。怎么了？

原始加载的图像被命名为OriginalSizedImage。 zoomedIn图像命名为

private void ZoomInButton_Click(object sender, RoutedEventArgs e)
        {
            BitmapImage newZoomedInImage = new BitmapImage();
            newZoomedInImage.BeginInit();
            newZoomedInImage.DecodePixelWidth = originalSizedImage.DecodePixelWidth + 20 ;
            newZoomedInImage.DecodePixelHeight = originalSizedImage.DecodePixelHeight + 20;
            newZoomedInImage.UriSource = originalSizedImage.UriSource;
            newZoomedInImage.EndInit();
            imageView.Source = newZoomedInImage ;
        }

Answer 1

每次更改缩放系数时，创建新的BitmapImage都是不必要且效率低下的。

最好将Image元素放置在对其进行裁剪的父元素中

<Grid ClipToBounds="True">
    <Image x:Name="imageView" RenderTransformOrigin="0.5,0.5">
        <Image.RenderTransform>
            <ScaleTransform/>
        </Image.RenderTransform>
    </Image>            
</Grid>

，然后修改分配给其ScaleTransform（可能还有其RenderTransform）的RenderTransformOrigin：

private void ZoomInButtonClick(object sender, RoutedEventArgs e)
{
    var transform = (ScaleTransform)imageView.RenderTransform;
    transform.ScaleX *= 1.1;
    transform.ScaleY *= 1.1;
}

private void ZoomOutButtonClick(object sender, RoutedEventArgs e)
{
    var transform = (ScaleTransform)imageView.RenderTransform;
    transform.ScaleX /= 1.1;
    transform.ScaleY /= 1.1;
}

使用C＃WPF放大imageView图像

1 个答案: