如何在使用 ZoomToFactor 增加按钮单击时的缩放级别时在滚动查看器中缩放

Question

我正在使用滚动查看器来缩放设置为 Grid.When 背景的图像，我在使用 scrollViewer.ZoomToFactor(zoomFactor) 图像设置按钮点击时的缩放系数值是从左上角开始放大，而不是从中心位置开始。

请从下面link或下面的代码片段中获取示例以供参考。 Link: https://github.com/ragulsv/ScrollViewer

代码片段[C#]:

    float count = 1;
    private void Clr_Click(object sender, RoutedEventArgs e)
    {
        count = 1;
         viewer.ZoomToFactor(count);
        viewer.RenderTransformOrigin = new Point(0.5, 0.5);
    }
    private void Btn_Click(object sender, RoutedEventArgs e)
    {
         viewer.ZoomToFactor(count);
        viewer.RenderTransformOrigin = new Point(0.5, 0.5);
        count += 1;
    }

代码片段[Xaml]:

   <Grid x:Name="grid1">
    <Grid.RowDefinitions>
        <RowDefinition Height="0.1*">

        </RowDefinition>
        <RowDefinition Height="0.1*">

        </RowDefinition>
        <RowDefinition Height="0.8*">

        </RowDefinition>
    </Grid.RowDefinitions>
    <Button x:Name="btn" Grid.Row="0"></Button>
    <Button x:Name="clr" Grid.Row="1"></Button>
    <ScrollViewer x:Name="viewer" Grid.Row="2" ZoomMode="Enabled">
        <Grid>
          <Image Source="Assets\EditedImage.jpg" Height="190" Width="190"/>
        </Grid>
    </ScrollViewer>
</Grid>

Answer 1

How to zoom at center in scroll viewer while using ZoomToFactor to increase zoom level in button click

对于这种情况，可以设置图片的parentGridVerticalAlignment="Center" HorizontalAlignment="Center"，使图片始终固定在ScrollViewer的中心，然后调用ChangeView方法进行编辑ZoomFactor.

private void Btn_Click(object sender, RoutedEventArgs e)
{
    viewer.ChangeView(0, 0, (viewer.ZoomFactor + 1f));       
}

如何在使用 ZoomToFactor 增加按钮单击时的缩放级别时在滚动查看器中缩放

How to zoom at center in scroll viewer while using ZoomToFactor to increase zoom level in button click

c#

xaml

scrollviewer

zooming

uwp