图形无法在位图上绘制

Question

I'm writing a program that renders some Kinect data into small bitmaps (recorded gesture preview\\frames preview). I have a class that stores mapped Kinect data to screen (X = [0; 1], Y = [0, 1]); Now I want to draw the data on small bitmaps and display on my form. The problem is "created" bitmap... It's empty (transparent).

It's my mapped data class:

public class MappedJointData
{
    public JointType JointType { get; set; }
    public PointF MappedPosition { get; set; }
    public int Depth { get; set; }
    public JointTrackingState JointTrackingState { get; set; }
    public bool Seated { get; set; }
}

Then I wrote an extention class that should return bitmap from the data:

public static Bitmap ToBitmap(this RecordedSkeletonFrame frame, int width, int height)
{
    return DrawBonesAndJoints(frame.MappedJointData, width, height);
}

private static Bitmap DrawBonesAndJoints(List<MappedJointData> mappedJointData, int width, int height)
{
    Bitmap b = new Bitmap(width, height);
    using (Graphics g = Graphics.FromImage(b))
    {
        g.CompositingQuality = CompositingQuality.HighQuality;
        g.Clear(Color.Black);

        // (...)
        g.DrawEllipse(new Pen(drawBrush), joint.MappedPosition.X, joint.MappedPosition.Y, 3, 3);

        // (...)
        g.DrawLine(drawPen, joint0.MappedPosition.X, joint0.MappedPosition.Y, joint1.MappedPosition.X, joint1.MappedPosition.Y);
    }
    return b;
}

After successful recording I want to go through the mapped data and draw bitmaps:

foreach (RecordedSkeletonFrame frame in _gestureRecorder.Frames)
{
    FrameImages.Add(frame.ToBitmap(100, 75));
}

FrameImages is my ObservableCollection<Bitmap> that is bound to the ListView (binding should work, because I tested it using some already rendered images).

Why isn't it working? I tried to find something in the web, but ppl do this exactly like me. I don't know where's the problem. Even if my rendered data is bad (but isn't I set a breakpoint up and checked values of X and Y ), g.Clear(Color.Black); should make my bitmap black?

Answer 1

I'm sure your problem is not in the pasted code part. Somehow you lose/overwrite the data in FrameImages or something like that. The using and graphics part should definitely work.