Winforms smooth animations

Question

So I'm attempting to make some animations with Winforms, and more specifically, a left to right animation. However, I've ran into multiple problems. Firstly, the System.Windows.Forms.Timer and even the other Timer classes like System.Threading.Timer are not nearly fast enough for the animation I want. To compensate, I could increase the amount of pixels by which I add to the left right animation. However, this results in a choppy-animation, which is not what I'm going for. To fix this, I'm using my own timer (on another thread), which is much more accurate:

long frequency = Stopwatch.Frequency;
long prevTicks = 0;
while (true)
{
    double interval = ((double)frequency) / Interval;
    long ticks = Stopwatch.GetTimestamp();
    if (ticks >= prevTicks + interval)
    {
        prevTicks = ticks;
        Tick?.Invoke(this, EventArgs.Empty);
    }
}

This however has its own drawbacks. First, this puts a heavy load on the CPU. Secondly, I cannot redraw fast enough if I want to increase the left-right animation by 1 pixel at a time for a smooth animation. The solution to this is to directly draw on the graphics provided by CreateGraphics, and it works fairly well, except when we go to transparent brushes. Then, things slow down. The solution to all of this is to just increase the amount of pixels I draw at a time on the left-right animation, but this would result in a lack of smoothness for the animation. Here is some test code:

private int index;
private Graphics g;
private Brush brush;
private void FastTimer_Tick(object sender, EventArgs e)
{
    index++;
    if (g == null)
    {
        g = CreateGraphics();
    }
    if (brush == null)
    {
        brush = new SolidBrush(Color.FromArgb(120, Color.Black));
    }
    g.FillRectangle(brush, index, 0, 1, Height);
}

I've heard the GDI is much faster as it's hardware accelerated, but I'm not sure how to use it. Does anybody have a solution to this while sticking to winforms? Thanks.

EDIT: Here's an example video: https://www.youtube.com/watch?v=gcOttFFCUz8&feature=youtu.be When the form is minimized, it's very smooth. However, when the form is maximized, I have to compensate smoothness for speed. I'm looking to know how to redraw faster (possibly using GDI) so that I can still use +1px animations, for a smooth experience.

Answer 1

There is a lot of stuff to improve/change in your code,
Here is a suggestion, please see comments inside the code:

private void button1_Click(object sender, EventArgs e)
{
    // optional: most animations are made in another thread to keep the GUI free, please see Invoke() to update GUI in StartAnimation()
    System.Threading.Thread t1 = new System.Threading.Thread(StartAnimation);
    t1.Start();
}
    
private void StartAnimation()
{
    // Use a stop watch
    if (st == null)
    {
        st = new Stopwatch();
        st.Start();
    }

    long prevTicks = 0;
    // a bool field to control the start and stop of the animation is better practice the While(true)
    while (IsAnimationActive)
    {
        double interval = 100000;
        long ticks = st.ElapsedTicks;

        if (ticks >= prevTicks + interval)
        {
            prevTicks = ticks;
            // Execture animation using invoke to prevent cross threading exception while updating the gui 
            pictureBox1.Invoke(new MethodInvoker(() =>
            {
                pictureBox1.Refresh();
            }));
        }
    }

    st.Stop();
}

private int index;
private int Height = 5;
// Use the Paint event of the control and not CreateGraphics()
// note: picture box is a control that is most suitable for animations and graphics
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
    if (index >= pictureBox1.Width)
        index = 0;

    index++;
    Graphics g = e.Graphics;
    // set HighQuality  fot the SmoothingMode property
    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
    g.FillRectangle(Brushes.Black, 0, 0, index, Height);
}

Answer 2

If you want it to go as fast as possible, the pop that code into a loop wrapped in an async/await method?

private void button1_Click(object sender, EventArgs e)
{
    button1.Enabled = false;
    SweepRight(Color.Black);
    button1.Enabled = true;
}

private async void SweepRight(Color c)
{
    using (Graphics g = CreateGraphics())
    {
        using (SolidBrush brush = new SolidBrush(Color.FromArgb(120, c)))
        {
            await Task.Run(() =>
            {
                for (int i = 0; i <= Width; i++)
                {
                    g.FillRectangle(brush, i, 0, 1, Height);
                }
            });
        }
    }
}