WPFExtensions ZoomControl-收缩缩放正在跳跃

我想在

WPFExtensions.Controls.ZoomControl

中使用夹点手势进行缩放

基于此-我知道如何检测捏手势。我将其用作成员

\u检测器
。我使用
ZoomControl.OperationDelta
进行缩放

所以我想我只是用
操纵delta
像这样缩放：

private void AssociatedObject_ManipulationDelta(object sender, System.Windows.Input.ManipulationDeltaEventArgs e)
{
    if (_detector.IsScalingAllowed) // this just tells me if it is a pinch gesture or not
    {
        if ((e.DeltaManipulation.Scale.X < 1)
            || (e.DeltaManipulation.Scale.X > 1))
        {
            //AssociatedObject is ZoomControl
            AssociatedObject.Zoom = Math.Max(e.DeltaManipulation.Scale.X, e.DeltaManipulation.Scale.Y);
        }
    }
}

public class ZoomBoxBehaviour : Behavior<ZoomControl>
{
    private GestureDetector _detector;

    protected override void OnAttached()
    {
        base.OnAttached();
        if (AssociatedObject != null)
        {
            _detector = new GestureDetector(AssociatedObject);

            if (!AssociatedObject.IsManipulationEnabled) AssociatedObject.IsManipulationEnabled = true;

            AssociatedObject.ManipulationDelta += AssociatedObject_ManipulationDelta;
        }
    }

    protected override void OnDetaching()
    {
        if (AssociatedObject != null)
        {
            AssociatedObject.ManipulationDelta -= AssociatedObject_ManipulationDelta;
        }

        base.OnDetaching();
    }

    private void AssociatedObject_ManipulationDelta(object sender, System.Windows.Input.ManipulationDeltaEventArgs e)
    {
        if (_detector.IsScalingAllowed) // this just tells me if it is a pinch gesture or not
        {
            if ((e.DeltaManipulation.Scale.X < 1)
                || (e.DeltaManipulation.Scale.X > 1))
            {
                AssociatedObject.Zoom = Math.Max(e.DeltaManipulation.Scale.X, e.DeltaManipulation.Scale.Y);
            }
        }
    }
}

您可以从第一个答案中获取
手势检测器

更新

我让它正确地缩放到中心

    private void AssociatedObject_ManipulationDelta(object sender, System.Windows.Input.ManipulationDeltaEventArgs e)
    {
        if (_detector.IsScalingAllowed) // this just tells me if it is a pinch gesture or not
        {
            if ((e.DeltaManipulation.Scale.X < 1)
                || (e.DeltaManipulation.Scale.X > 1))
            {
                AssociatedObject.Zoom = Math.Max(e.CumulativeManipulation.Scale.X, e.CumulativeManipulation.Scale.Y);

                //Size newSize = new Size(AssociatedObject.ZoomBox.Size.Width * e.CumulativeManipulation.Scale.X,
                //                        AssociatedObject.ZoomBox.Size.Height * e.CumulativeManipulation.Scale.Y);

                //AssociatedObject.ZoomTo(new Rect(new Point(0,0), newSize));
            }
        }


    }

private void associated object\u operation delta（对象发送方，System.Windows.Input.operation deltaeventargs e）
{
if（_detector.IsScalingAllowed）//这只是告诉我这是否是一个捏手势
{
if（（如DeltaManipulation.Scale.X<1）
||（e.DeltaManipulation.Scale.X>1）
{
AssociatedObject.Zoom=Math.Max（e.CumulativeManipulation.Scale.X，e.CumulativeManipulation.Scale.Y）；
//大小newSize=新大小（AssociatedObject.ZoomBox.Size.Width*e.CumulativeManipulation.Scale.X，
//AssociatedObject.ZoomBox.Size.Height*e.CumulativeManipulation.Scale.Y）；
//ZoomTo（新Rect（新点（0,0），newSize））；
}
}
}

但是现在我想放大到我手势的中心，但是这个注释的
code
只会放大到最大。。。。为什么？我解决了

public class ZoomBoxBehaviour : Behavior<ZoomControl>
    {
        private GestureDetector _detector;
        protected override void OnAttached()
        {
            base.OnAttached();
            if (AssociatedObject != null)
            {
                _detector = new GestureDetector(AssociatedObject);

                if (!AssociatedObject.IsManipulationEnabled) AssociatedObject.IsManipulationEnabled = true;

                AssociatedObject.ManipulationDelta += AssociatedObject_ManipulationDelta;
            }
        }


        protected override void OnDetaching()
        {
            if (AssociatedObject != null)
            {
                AssociatedObject.ManipulationDelta -= AssociatedObject_ManipulationDelta;
            }

            base.OnDetaching();
        }

        private void AssociatedObject_ManipulationStarting(object sender, ManipulationStartingEventArgs e)
        {
            e.ManipulationContainer = ((FrameworkElement)e.Source).Parent as FrameworkElement;
        }

        private void AssociatedObject_ManipulationDelta(object sender, System.Windows.Input.ManipulationDeltaEventArgs e)
        {
            if (_detector.IsPanningAllowed)
            {

                // Limit the X/Y translation extent to prevent the element from 'jumping' when using slow touchscreens, or many touch points.
                const double translationThreshold = 100.0;

                //Perform a translation(pan) tranformation
                if ((e.DeltaManipulation.Translation.X < translationThreshold &&
                     e.DeltaManipulation.Translation.X > -translationThreshold)
                )
                {
                    AssociatedObject.TranslateX += e.DeltaManipulation.Translation.X;
                }

                if ((e.DeltaManipulation.Translation.Y < translationThreshold &&
                     e.DeltaManipulation.Translation.Y > -translationThreshold))
                {
                    AssociatedObject.TranslateY += e.DeltaManipulation.Translation.Y;
                }
            }

            if (_detector.IsScalingAllowed) // this just tells me if it is a pinch gesture or not
            {
                if ((e.CumulativeManipulation.Scale.X < 1)
                    || (e.CumulativeManipulation.Scale.X > 1))
                {
                    AssociatedObject.Zoom = Math.Max(e.CumulativeManipulation.Scale.X, e.CumulativeManipulation.Scale.Y);
                }
            }

        }

    }

公共类ZoomBoxBehaviour:行为
{
私人手势检测器_检测器；
受保护的覆盖无效附加（）
{
base.onatached（）；
if（AssociatedObject！=null）
{
_检测器=新的手势检测器（关联对象）；
如果（！AssociatedObject.IsManipulationEnabled）AssociatedObject.IsManipulationEnabled=true；
AssociatedObject.OperationDelta+=AssociatedObject\u OperationDelta；
}
}
附加时受保护的覆盖无效（）
{
if（AssociatedObject！=null）
{
AssociatedObject.OperationDelta-=AssociatedObject\u OperationDelta；
}
base.OnDetaching（）；
}
private void Associated object_操纵开始（对象发送方，操纵开始事件参数e）
{
e、 操纵容器=（（FrameworkElement）e.Source）.Parent作为FrameworkElement；
}
private void Associated object_OperationDelta（对象发送方，System.Windows.Input.OperationDeltaEventArgs e）
{
如果（_检测器ispanning允许）
{
//限制X/Y平移范围，以防止在使用慢速触摸屏或多个触摸点时元素“跳跃”。
常数双平移阈值=100.0；
//执行翻译（pan）转换
if（（e.DeltaManipulation.Translation.X-translationThreshold）
)
{
AssociatedObject.TranslateX+=e.DeltaManipulation.Translation.X；
}
if（（e.DeltaManipulation.Translation.Y-translationThreshold）
{
AssociatedObject.TranslateY+=e.DeltaManipulation.Translate.Y；
}
}
if（_detector.IsScalingAllowed）//这只是告诉我这是否是一个捏手势
{
if（（如累积计算量表X<1）
||（e.累积计算.标度X>1）
{
AssociatedObject.Zoom=Math.Max（e.CumulativeManipulation.Scale.X，e.CumulativeManipulation.Scale.Y）；
}
}
}
}