/// <summary>
/// Adds missing flakes on canvas
/// </summary>
/// <param name="top">true if flakes appear on top of canvas, false if random Y position</param>
private void SetFlakes(bool top = false)
{
int halfCanvasWidth = (int)canvas.ActualWidth / 2;
Random rand = new Random();
Image flake = null;
SnowInfo info = null;
for (int i = flakes.Count; i < maxFlakes; i++)
{
//Flake creation
flake = new Image();
//Randomly selecting image
flake.Source = CreateImage(flakeImages[rand.Next(0, flakeImages.Count)]);
flake.Stretch = Stretch.Uniform;
info = new SnowInfo(flake, verticalSpeedRatio * rand.Next(minStartingSpeed, maxStartingSpeed), rand.Next(minRadius, maxRadius));
// Placing image
Canvas.SetLeft(flake, halfCanvasWidth + rand.Next(-halfCanvasWidth, halfCanvasWidth));
if (!top)
{
Canvas.SetTop(flake, rand.Next(0, (int)canvas.ActualHeight));
}
else
{
Canvas.SetTop(flake, -info.Radius * 2);
}
canvas.Children.Add(flake);
info.VelocityX = rand.Next(minHorizontalSpeed, maxHorizontalSpeed);
flakes.Add(info);
}
}
/// <summary>
/// Render snow
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void CompositionTarget_Rendering(object sender, EventArgs e)
{
Random random = new Random();
SnowInfo info = null;
double left = 0;
double top = 0;
if (!IsWorking)
{
return;
}
//Add missing flakes
if (flakes.Count < maxFlakes)
{
SetFlakes(true);
return;
}
//Setting position of all flakes
for (int i = flakes.Count - 1; i >= 0; i--)
{
info = flakes[i];
left = Canvas.GetLeft(info.Flake);
top = Canvas.GetTop(info.Flake);
//.5 is magic number. Don't use magic numbers! :)
flakes[i].VelocityX += .5 * HorizontalSpeedRatio;
Canvas.SetLeft(flakes[i].Flake, left + Math.Cos(flakes[i].VelocityX));
Canvas.SetTop(info.Flake, top + 1 * info.VelocityY);
//Remove image from canvas when it leaves canvas
if (top >= (canvas.ActualHeight + info.Radius * 2))
{
flakes.Remove(info);
canvas.Children.Remove(info.Flake);
}
}
}