Seite 2

Cortana Bot

Published by Thomas Christof on 20. August 2018

A custom Cortana Bot can be developed and added pretty easily. The Bot can be used locally (local debugging), for a restricted audience (e.g.: to a specific Microsoft Account) or in public through the Microsoft App Store. Cortana only? An Azure Bot is not only bound to Cortana. Cortana is just one distribution channel. Other channels would …

Werewolf – Server Switch

Published by Thomas Christof on 11. August 2018

The Windows Phone Application Werewolf Online has a new server running on. (Thanks to MS Azure) The application has been rebuilt (IP-Address was static in code, but isn’t anymore) and will be in the store every minute. Enjoy

Browser + Razor = Blazor!

Published by Thomas Christof on 7. August 2018

Haven’t heard of WebAssemblies yet? Check some other articles to shortly educate yourself about WebAssemblies before continue reading. Ok, but what about C#? As far as my research did take place, there is currently Mono and Microsoft working on a project (Experimental). Since the Mono Project on GitHub lacks too much guidance and I haven’t the power …

Building a performant Hololens Project with Unity

Published by Thomas Christof on 4. Juni 2018

Building performant applications for embedded systems can be quite challenging. In case of the Hololens, we are dealing with a relatively small amount of RAM and GPU power. (Hololens Graphics) Unity is a great tool to build applications real quick without spending much time on the real basics. Hence, Unity already delivers a pre-defined set of …

Unity Code Extensions

Published by Thomas Christof on 26. Mai 2018

Unity already provides a bunch of methods to perform the most tasks a lot faster. However, still there is a gap for some useful extensions. The extensions I came up with are listed below. In addition, you can find the .cs file as an attachment.

AABB Collision Detection with Intersection Points (Incl. Rotation)

Published by Thomas Christof on 13. Januar 2018

    public struct Line
    {
        public Vector2 a;
        public Vector2 b;

        public Line(float x1, float y1,
            float x2, float y2)
        {
            a = new Vector2(x1, y1);
            b = new Vector2(x2, y2);
        }

        public void Rotate(float rad, Vector2 center)
        {
            Rotate(rad, ref a, center);
            Rotate(rad, ref b, center);
        }

        private void Rotate(float rad, ref Vector2 point, Vector2 center)
        {
            point = Vector2.Transform(point - center, Matrix.CreateRotationZ(rad)) + center;
        }

        public bool Intersect(Line line, out Vector2? intersectionPoint)
        {
            intersectionPoint = null;

            float a1 = b.Y - a.Y;
            float b1 = a.X - b.X;
            float c1 = a1 * a.X + b1 * a.Y;

            float a2 = line.b.Y - line.a.Y;
            float b2 = line.a.X - line.b.X;
            float c2 = a2 * line.a.X + b2 * line.a.Y;

            //If the lines are parallel, no collision possible.
            float det = a1 * b2 - a2 * b1;
            if (det == 0) return false;

            float x = (b2 * c1 - b1 * c2) / det;
            float y = (a1 * c2 - a2 * c1) / det;

            if (OnLine(this, x, y) && OnLine(line, x, y))
            {
                intersectionPoint = new Vector2(x, y);
                return true;
            }

            return false;
        }

        public static bool OnLine(Line line, float x, float y)
        {
            return Math.Min(line.a.X, line.b.X) <= x &&
                x <= Math.Max(line.a.X, line.b.X) &&
                Math.Min(line.a.Y, line.b.Y) <= y &&
                y <= Math.Max(line.a.Y, line.b.Y);
        }
    }

public struct Line

{

public Vector2 a;

public Vector2 b;

public Line(float x1, float y1,

float x2, float y2)

{

a = new Vector2(x1, y1);

b = new Vector2(x2, y2);

}

public void Rotate(float rad, Vector2 center)

{

Rotate(rad, ref a, center);

Rotate(rad, ref b, center);

}

private void Rotate(float rad, ref Vector2 point, Vector2 center)

{

point = Vector2.Transform(point - center, Matrix.CreateRotationZ(rad)) + center;

}

public bool Intersect(Line line, out Vector2? intersectionPoint)

{

intersectionPoint = null;

float a1 = b.Y - a.Y;

float b1 = a.X - b.X;

float c1 = a1 * a.X + b1 * a.Y;

float a2 = line.b.Y - line.a.Y;

float b2 = line.a.X - line.b.X;

float c2 = a2 * line.a.X + b2 * line.a.Y;

//If the lines are parallel, no collision possible.

float det = a1 * b2 - a2 * b1;

if (det == 0) return false;

float x = (b2 * c1 - b1 * c2) / det;

float y = (a1 * c2 - a2 * c1) / det;

if (OnLine(this, x, y) && OnLine(line, x, y))

{

intersectionPoint = new Vector2(x, y);

return true;

}

return false;

}

public static bool OnLine(Line line, float x, float y)

{

return Math.Min(line.a.X, line.b.X) <= x &&

x <= Math.Max(line.a.X, line.b.X) &&

Math.Min(line.a.Y, line.b.Y) <= y &&

y <= Math.Max(line.a.Y, line.b.Y);

}

    public struct SRectangle
    {
        public Line left;
        public Line top;
        public Line right;
        public Line bottom;

        public void Rotate(float rad, Vector2 center)
        {
            left.Rotate(rad, center);
            top.Rotate(rad, center);
            right.Rotate(rad, center);
            bottom.Rotate(rad, center);
        }

        public static SRectangle FromRectangle(Rectangle rectangle, Vector2 origin, float rotation)
        {
            Line left = new Line(rectangle.X, rectangle.Y, rectangle.X, rectangle.Y + rectangle.Height);
            Line top = new Line(rectangle.X, rectangle.Y, rectangle.X + rectangle.Width, rectangle.Y);
            Line right = new Line(rectangle.X + rectangle.Width, rectangle.Y, rectangle.X + rectangle.Width, rectangle.Y + rectangle.Height);
            Line bottom = new Line(rectangle.X, rectangle.Y + rectangle.Height, rectangle.X + rectangle.Width, rectangle.Y + rectangle.Height);

            left.a.X -= origin.X;
            left.a.Y -= origin.Y;
            left.b.X -= origin.X;
            left.b.Y -= origin.Y;
            top.a.X -= origin.X;
            top.a.Y -= origin.Y;
            top.b.X -= origin.X;
            top.b.Y -= origin.Y;
            right.a.X -= origin.X;
            right.a.Y -= origin.Y;
            right.b.X -= origin.X;
            right.b.Y -= origin.Y;
            bottom.a.X -= origin.X;
            bottom.a.Y -= origin.Y;
            bottom.b.X -= origin.X;
            bottom.b.Y -= origin.Y;

            origin.X += rectangle.X - rectangle.Width / 2;
            origin.Y += rectangle.Y - rectangle.Height / 2;

            left.Rotate(rotation, origin);
            right.Rotate(rotation, origin);
            top.Rotate(rotation, origin);
            bottom.Rotate(rotation, origin);

            return new SRectangle()
            {
                left = left,
                right = right,
                top = top,
                bottom = bottom
            };
        }
    }

public struct SRectangle

{

public Line left;

public Line top;

public Line right;

public Line bottom;

public void Rotate(float rad, Vector2 center)

{

left.Rotate(rad, center);

top.Rotate(rad, center);

right.Rotate(rad, center);

bottom.Rotate(rad, center);

}

public static SRectangle FromRectangle(Rectangle rectangle, Vector2 origin, float rotation)

{

Line left = new Line(rectangle.X, rectangle.Y, rectangle.X, rectangle.Y + rectangle.Height);

Line top = new Line(rectangle.X, rectangle.Y, rectangle.X + rectangle.Width, rectangle.Y);

Line right = new Line(rectangle.X + rectangle.Width, rectangle.Y, rectangle.X + rectangle.Width, rectangle.Y + rectangle.Height);

Line bottom = new Line(rectangle.X, rectangle.Y + rectangle.Height, rectangle.X + rectangle.Width, rectangle.Y + rectangle.Height);

left.a.X -= origin.X;

left.a.Y -= origin.Y;

left.b.X -= origin.X;

left.b.Y -= origin.Y;

top.a.X -= origin.X;

top.a.Y -= origin.Y;

top.b.X -= origin.X;

top.b.Y -= origin.Y;

right.a.X -= origin.X;

right.a.Y -= origin.Y;

right.b.X -= origin.X;

right.b.Y -= origin.Y;

bottom.a.X -= origin.X;

bottom.a.Y -= origin.Y;

bottom.b.X -= origin.X;

bottom.b.Y -= origin.Y;

origin.X += rectangle.X - rectangle.Width / 2;

origin.Y += rectangle.Y - rectangle.Height / 2;

left.Rotate(rotation, origin);

right.Rotate(rotation, origin);

top.Rotate(rotation, origin);

bottom.Rotate(rotation, origin);

return new SRectangle()

{

left = left,

right = right,

top = top,

bottom = bottom

};

}

        public static bool AABB_AABB(SmartRectangle x, SmartRectangle y, out Vector2[] collisionPoints)
        {
            List<Vector2> cp = new List<Vector2>();

            /* Left against y */
            if (x.left.Intersect(y.left, out Vector2? llcp)) cp.Add(llcp.Value);
            if (x.left.Intersect(y.top, out Vector2? ltcp)) cp.Add(ltcp.Value);
            if (x.left.Intersect(y.right, out Vector2? lrcp)) cp.Add(lrcp.Value);
            if (x.left.Intersect(y.bottom, out Vector2? lbcp)) cp.Add(lbcp.Value);
            /* Top against y */
            if (x.top.Intersect(y.left, out Vector2? tlcp)) cp.Add(tlcp.Value);
            if (x.top.Intersect(y.top, out Vector2? ttcp)) cp.Add(ttcp.Value);
            if (x.top.Intersect(y.right, out Vector2? trcp)) cp.Add(trcp.Value);
            if (x.top.Intersect(y.bottom, out Vector2? tbcp)) cp.Add(tbcp.Value);
            /* Right against y */
            if (x.right.Intersect(y.left, out Vector2? rlcp)) cp.Add(rlcp.Value);
            if (x.right.Intersect(y.top, out Vector2? rtcp)) cp.Add(rtcp.Value);
            if (x.right.Intersect(y.right, out Vector2? rrcp)) cp.Add(rrcp.Value);
            if (x.right.Intersect(y.bottom, out Vector2? rbcp)) cp.Add(rbcp.Value);
            /* Bottom against y */
            if (x.bottom.Intersect(y.left, out Vector2? blcp)) cp.Add(blcp.Value);
            if (x.bottom.Intersect(y.top, out Vector2? btcp)) cp.Add(btcp.Value);
            if (x.bottom.Intersect(y.right, out Vector2? brcp)) cp.Add(brcp.Value);
            if (x.bottom.Intersect(y.bottom, out Vector2? bbcp)) cp.Add(bbcp.Value);

            collisionPoints = cp.ToArray();
            return cp.Count > 0;
        }

public static bool AABB_AABB(SmartRectangle x, SmartRectangle y, out Vector2[] collisionPoints)

{

List<Vector2> cp = new List<Vector2>();

/* Left against y */

if (x.left.Intersect(y.left, out Vector2? llcp)) cp.Add(llcp.Value);

if (x.left.Intersect(y.top, out Vector2? ltcp)) cp.Add(ltcp.Value);

if (x.left.Intersect(y.right, out Vector2? lrcp)) cp.Add(lrcp.Value);

if (x.left.Intersect(y.bottom, out Vector2? lbcp)) cp.Add(lbcp.Value);

/* Top against y */

if (x.top.Intersect(y.left, out Vector2? tlcp)) cp.Add(tlcp.Value);

if (x.top.Intersect(y.top, out Vector2? ttcp)) cp.Add(ttcp.Value);

if (x.top.Intersect(y.right, out Vector2? trcp)) cp.Add(trcp.Value);

if (x.top.Intersect(y.bottom, out Vector2? tbcp)) cp.Add(tbcp.Value);

/* Right against y */

if (x.right.Intersect(y.left, out Vector2? rlcp)) cp.Add(rlcp.Value);

if (x.right.Intersect(y.top, out Vector2? rtcp)) cp.Add(rtcp.Value);

if (x.right.Intersect(y.right, out Vector2? rrcp)) cp.Add(rrcp.Value);

if (x.right.Intersect(y.bottom, out Vector2? rbcp)) cp.Add(rbcp.Value);

/* Bottom against y */

if (x.bottom.Intersect(y.left, out Vector2? blcp)) cp.Add(blcp.Value);

if (x.bottom.Intersect(y.top, out Vector2? btcp)) cp.Add(btcp.Value);

if (x.bottom.Intersect(y.right, out Vector2? brcp)) cp.Add(brcp.Value);

if (x.bottom.Intersect(y.bottom, out Vector2? bbcp)) cp.Add(bbcp.Value);

collisionPoints = cp.ToArray();

return cp.Count > 0;

}

Supported Frameworks

Published by Thomas Christof on 22. Oktober 2017

Full Functional Range Support .NET Framework >= 4.6 No Bluetooth Support .NET Core >= 2.0 Mono >= 5.4 Xamarin.iOS >= 10.14 Xamarin.MAC >= 3.8 Xamarin.Android >= 8.0 UWP >= 10.0.16299 .NET Standard 2.0

Switching to Linux – Roadmap 🎬 1

Published by Thomas Christof on 18. Oktober 2017

Since Window 8.0 has been released I thought about switching to Linux due many different reasons, whichever I won’t cover in this article. However, the idea to try Linux was always present and the desire to do so, grew from day to day. Long story short, due Driver problems Nearly none-existing games Lacking productivity tools Missing …

WPF ObservableCollection – Add millions of data within milliseconds

Published by Thomas Christof on 26. März 2017

Adding huge amount of Data to an ObservableCollection can cause GUI freezes. Even if operating on another thread, the process of adding items is pretty slow. But why?

WPF Scrollable + Zoomable + Dragable Control

Published by Thomas Christof on 21. März 2017

Unluckily there is no standard control to zoom, drag and scroll your content. My implementation is based on following tutorial. With this implementation you are able to zoom, drag and scroll arbitrary controls. Showcase ScrollDragZoomControl.xaml

<UserControl x:Class="MinimalMonitoringClient.Controls.ScrollDragZoomControl"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             Background="Transparent">

    <UserControl.Template>
        <ControlTemplate TargetType="UserControl">
            <ScrollViewer x:Name="scrollViewer"
                  Loaded="scrollViewer_Loaded"
                  HorizontalScrollBarVisibility="Visible"
                  VerticalScrollBarVisibility="Visible">

                <Grid Name="grid" RenderTransformOrigin="0.5,0.5">
                    <Grid.LayoutTransform>
                        <TransformGroup>
                            <ScaleTransform x:Name="scaleTransform" />
                        </TransformGroup>
                    </Grid.LayoutTransform>
                    <Viewbox>
                        <!-- Present the actual stuff the user wants to display -->
                        <ContentPresenter />
                    </Viewbox>
                </Grid>
            </ScrollViewer>
        </ControlTemplate>
    </UserControl.Template>
</UserControl>

<UserControl x:Class="MinimalMonitoringClient.Controls.ScrollDragZoomControl"

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Background="Transparent">

<UserControl.Template>

<ScrollViewer x:Name="scrollViewer"

Loaded="scrollViewer_Loaded"

HorizontalScrollBarVisibility="Visible"

VerticalScrollBarVisibility="Visible">

<Grid.LayoutTransform>

</TransformGroup>

</Grid.LayoutTransform>

</Viewbox>

</Grid>

</ScrollViewer>

</ControlTemplate>

</UserControl.Template>

</UserControl>

ScrollDragZoomControl.xaml.cs

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace NAMESPACE
{
    /// <summary>
    /// Interaktionslogik für ScrollDragZoomControl.xaml
    /// </summary>
    public partial class ScrollDragZoomControl : UserControl
    {
        private int zoomLevel = 1;

        private ScaleTransform scaleTransform;
        private ScrollViewer scrollViewer;
        private Grid grid;

        Point? lastCenterPositionOnTarget;
        Point? lastMousePositionOnTarget;
        Point? lastDragPoint;

        public ScrollDragZoomControl()
        {
            InitializeComponent();
        }

        private void scrollViewer_Loaded(object sender, RoutedEventArgs e)
        {
            scaleTransform = (ScaleTransform)Template.FindName("scaleTransform", this);
            scrollViewer = (ScrollViewer)Template.FindName("scrollViewer", this);
            grid = (Grid)Template.FindName("grid", this);

            scrollViewer.ScrollChanged += OnScrollViewerScrollChanged;
            scrollViewer.MouseLeftButtonUp += OnMouseLeftButtonUp;
            scrollViewer.PreviewMouseLeftButtonUp += OnMouseLeftButtonUp;
            scrollViewer.PreviewMouseWheel += OnPreviewMouseWheel;
            scrollViewer.PreviewMouseLeftButtonDown += OnMouseLeftButtonDown;
            scrollViewer.MouseMove += OnMouseMove;
        }

        void OnMouseMove(object sender, MouseEventArgs e)
        {
            if (lastDragPoint.HasValue)
            {
                Point posNow = e.GetPosition(scrollViewer);

                double dX = posNow.X - lastDragPoint.Value.X;
                double dY = posNow.Y - lastDragPoint.Value.Y;

                lastDragPoint = posNow;

                scrollViewer.ScrollToHorizontalOffset(scrollViewer.HorizontalOffset - dX);
                scrollViewer.ScrollToVerticalOffset(scrollViewer.VerticalOffset - dY);
            }
        }

        void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            var mousePos = e.GetPosition(scrollViewer);
            if (mousePos.X <= scrollViewer.ViewportWidth && mousePos.Y <
                scrollViewer.ViewportHeight) //make sure we still can use the scrollbars
            {
                scrollViewer.Cursor = Cursors.SizeAll;
                lastDragPoint = mousePos;
                Mouse.Capture(scrollViewer);
            }
        }

        void OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)
        {
            lastMousePositionOnTarget = Mouse.GetPosition(grid);

            if (e.Delta > 0)
                zoomLevel++;
            else if (e.Delta < 0)
                zoomLevel--;

            zoomLevel = zoomLevel < 1 ? 1 : zoomLevel;

            scaleTransform.ScaleX = zoomLevel;
            scaleTransform.ScaleY = zoomLevel;

            var centerOfViewport = new Point(scrollViewer.ViewportWidth / 2, scrollViewer.ViewportHeight / 2);
            lastCenterPositionOnTarget = scrollViewer.TranslatePoint(centerOfViewport, grid);

            e.Handled = true;
        }

        void OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            scrollViewer.Cursor = Cursors.Arrow;
            scrollViewer.ReleaseMouseCapture();
            lastDragPoint = null;
        }

        void OnScrollViewerScrollChanged(object sender, ScrollChangedEventArgs e)
        {
            if (e.ExtentHeightChange != 0 || e.ExtentWidthChange != 0)
            {
                Point? targetBefore = null;
                Point? targetNow = null;

                if (!lastMousePositionOnTarget.HasValue)
                {
                    if (lastCenterPositionOnTarget.HasValue)
                    {
                        var centerOfViewport = new Point(scrollViewer.ViewportWidth / 2,
                                                         scrollViewer.ViewportHeight / 2);
                        Point centerOfTargetNow =
                              scrollViewer.TranslatePoint(centerOfViewport, grid);

                        targetBefore = lastCenterPositionOnTarget;
                        targetNow = centerOfTargetNow;
                    }
                }
                else
                {
                    targetBefore = lastMousePositionOnTarget;
                    targetNow = Mouse.GetPosition(grid);

                    lastMousePositionOnTarget = null;
                }

                if (targetBefore.HasValue)
                {
                    double dXInTargetPixels = targetNow.Value.X - targetBefore.Value.X;
                    double dYInTargetPixels = targetNow.Value.Y - targetBefore.Value.Y;

                    double multiplicatorX = e.ExtentWidth / grid.Width;
                    double multiplicatorY = e.ExtentHeight / grid.Height;

                    double newOffsetX = scrollViewer.HorizontalOffset -
                                        dXInTargetPixels * multiplicatorX;
                    double newOffsetY = scrollViewer.VerticalOffset -
                                        dYInTargetPixels * multiplicatorY;

                    if (double.IsNaN(newOffsetX) || double.IsNaN(newOffsetY))
                    {
                        return;
                    }

                    scrollViewer.ScrollToHorizontalOffset(newOffsetX);
                    scrollViewer.ScrollToVerticalOffset(newOffsetY);
                }
            }
        }
    }
}

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using System.Windows;

using System.Windows.Controls;

using System.Windows.Input;

using System.Windows.Media;

namespace NAMESPACE

{

/// <summary>

/// Interaktionslogik für ScrollDragZoomControl.xaml

/// </summary>

public partial class ScrollDragZoomControl : UserControl

{

private int zoomLevel = 1;

private ScaleTransform scaleTransform;

private ScrollViewer scrollViewer;

private Grid grid;

Point? lastCenterPositionOnTarget;

Point? lastMousePositionOnTarget;

Point? lastDragPoint;

public ScrollDragZoomControl()

{

InitializeComponent();

}

private void scrollViewer_Loaded(object sender, RoutedEventArgs e)

{

scaleTransform = (ScaleTransform)Template.FindName("scaleTransform", this);

scrollViewer = (ScrollViewer)Template.FindName("scrollViewer", this);

grid = (Grid)Template.FindName("grid", this);

scrollViewer.ScrollChanged += OnScrollViewerScrollChanged;

scrollViewer.MouseLeftButtonUp += OnMouseLeftButtonUp;

scrollViewer.PreviewMouseLeftButtonUp += OnMouseLeftButtonUp;

scrollViewer.PreviewMouseWheel += OnPreviewMouseWheel;

scrollViewer.PreviewMouseLeftButtonDown += OnMouseLeftButtonDown;

scrollViewer.MouseMove += OnMouseMove;

}

void OnMouseMove(object sender, MouseEventArgs e)

{

if (lastDragPoint.HasValue)

{

Point posNow = e.GetPosition(scrollViewer);

double dX = posNow.X - lastDragPoint.Value.X;

double dY = posNow.Y - lastDragPoint.Value.Y;

lastDragPoint = posNow;

scrollViewer.ScrollToHorizontalOffset(scrollViewer.HorizontalOffset - dX);

scrollViewer.ScrollToVerticalOffset(scrollViewer.VerticalOffset - dY);

}

void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)

{

var mousePos = e.GetPosition(scrollViewer);

if (mousePos.X <= scrollViewer.ViewportWidth && mousePos.Y <

scrollViewer.ViewportHeight) //make sure we still can use the scrollbars

{

scrollViewer.Cursor = Cursors.SizeAll;

lastDragPoint = mousePos;

Mouse.Capture(scrollViewer);

}

void OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)

{

lastMousePositionOnTarget = Mouse.GetPosition(grid);

if (e.Delta > 0)

zoomLevel++;

else if (e.Delta < 0)

zoomLevel--;

zoomLevel = zoomLevel < 1 ? 1 : zoomLevel;

scaleTransform.ScaleX = zoomLevel;

scaleTransform.ScaleY = zoomLevel;

var centerOfViewport = new Point(scrollViewer.ViewportWidth / 2, scrollViewer.ViewportHeight / 2);

lastCenterPositionOnTarget = scrollViewer.TranslatePoint(centerOfViewport, grid);

e.Handled = true;

}

void OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)

{

scrollViewer.Cursor = Cursors.Arrow;

scrollViewer.ReleaseMouseCapture();

lastDragPoint = null;

}

void OnScrollViewerScrollChanged(object sender, ScrollChangedEventArgs e)

{

if (e.ExtentHeightChange != 0 || e.ExtentWidthChange != 0)

{

Point? targetBefore = null;

Point? targetNow = null;

if (!lastMousePositionOnTarget.HasValue)

{

if (lastCenterPositionOnTarget.HasValue)

{

var centerOfViewport = new Point(scrollViewer.ViewportWidth / 2,

scrollViewer.ViewportHeight / 2);

Point centerOfTargetNow =

scrollViewer.TranslatePoint(centerOfViewport, grid);

targetBefore = lastCenterPositionOnTarget;

targetNow = centerOfTargetNow;

}

else

{

targetBefore = lastMousePositionOnTarget;

targetNow = Mouse.GetPosition(grid);

lastMousePositionOnTarget = null;

}

if (targetBefore.HasValue)

{

double dXInTargetPixels = targetNow.Value.X - targetBefore.Value.X;

double dYInTargetPixels = targetNow.Value.Y - targetBefore.Value.Y;

double multiplicatorX = e.ExtentWidth / grid.Width;

double multiplicatorY = e.ExtentHeight / grid.Height;

double newOffsetX = scrollViewer.HorizontalOffset -

dXInTargetPixels * multiplicatorX;

double newOffsetY = scrollViewer.VerticalOffset -

dYInTargetPixels * multiplicatorY;

if (double.IsNaN(newOffsetX) || double.IsNaN(newOffsetY))

{

return;

}

scrollViewer.ScrollToHorizontalOffset(newOffsetX);

scrollViewer.ScrollToVerticalOffset(newOffsetY);

}

Usage Add the “ScrollDragZoomControl” to your project and use it as follows:

    <controls:ScrollDragZoomControl>
        <!-- Your Content to present -->
    </controls:ScrollDragZoomControl>

<controls:ScrollDragZoomControl>

</controls:ScrollDragZoomControl>