generating animated line

Question

(x,y) =(10,20),(50,30),(20,20),(40,22),(45,20),(50,35),.........

I want to create an animation with .Net.Normally I am using windows form. But if needed, i can use WPF.

It starts with (10,20) point.Actually a line starts from (10,20) then goes to (50,30) point with 10ms delay. then, from (50,30) to (20,20) after 10ms and so on.

This values will be read from a text file. I can simply make two ArrayList x&y, to put values from the text file.I just Have to know how could i generate the animated line from this x,y with 10 ms delay from each node to another?

If my question is difficult to understand, please let me know. I will try to make it easier.

Thanks in Advance.

Answer 1

If I understand you correctly, you want to animate the line as it would be just drawn. Here is a simple example with your values.

<Window x:Class="WpfApplication1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">

    <Canvas Name="lineCanvas" MouseLeftButtonDown="lineCanvas_MouseLeftButtonDown" Background="White" />
</Window>

The event handler will start the animation later. First, we'll define the data:

List<Point> Points = new List<Point>();
Storyboard sb;

public MainWindow()
{
    InitializeComponent();

    Points.Add(new Point(10, 20));
    Points.Add(new Point(50, 30));
    Points.Add(new Point(20, 20));
    Points.Add(new Point(40, 22));
    Points.Add(new Point(45, 20));
    Points.Add(new Point(50, 35));

    InitAnimation();
}

sb is the Storyboard that will contain the animation. Points can easily be filled with the values from a file.

Let's initialize the animation. A new line will be added for each segment. Then the endpoint of the line will be animated.

public void InitAnimation()
{
    sb = new Storyboard();

    for (int i = 0; i < Points.Count - 1; ++i)
    {
        //new line for current line segment
        var l = new Line();
        l.Stroke = Brushes.Black;
        l.StrokeThickness = 2;

        //data from list
        var startPoint = Points[i];
        var endPoint = Points[i + 1];

        //set startpoint = endpoint will result in the line not being drawn
        l.X1 = startPoint.X;
        l.Y1 = startPoint.Y;
        l.X2 = startPoint.X;
        l.Y2 = startPoint.Y;
        lineCanvas.Children.Add(l);

        //Initialize the animations with duration of 1 second for each segment
        var daX = new DoubleAnimation(endPoint.X, new Duration(TimeSpan.FromMilliseconds(1000)));
        var daY = new DoubleAnimation(endPoint.Y, new Duration(TimeSpan.FromMilliseconds(1000)));
        //Define the begin time. This is sum of durations of earlier animations + 10 ms delay for each
        daX.BeginTime = TimeSpan.FromMilliseconds(i * 1010);
        daY.BeginTime = TimeSpan.FromMilliseconds(i * 1010);

        sb.Children.Add(daX);
        sb.Children.Add(daY);

        //Set the targets for the animations
        Storyboard.SetTarget(daX, l);
        Storyboard.SetTarget(daY, l);
        Storyboard.SetTargetProperty(daX, new PropertyPath(Line.X2Property));
        Storyboard.SetTargetProperty(daY, new PropertyPath(Line.Y2Property));
    }
}

The duration of the animations can easily be changed according to the length of the line to make it look nicer.

Last task, show the animation:

private void lineCanvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    sb.Begin(this);
}