/// <summary>
/// Set ArbgPixel at given point.
/// </summary>
/// <param name="x">X.</param>
/// <param name="y">Y.</param>
/// <param name="waveColor">Color.</param>
internal void SetAt(int x, int y, ArbgPixel waveColor)
{
System.Diagnostics.Debug.Assert(_base != null);
System.Diagnostics.Debug.Assert(_width > 0);
ArbgPixel* pixel = (ArbgPixel*)(_base + (y * _width) + (x * sizeof(ArbgPixel)));
*pixel = waveColor;
}
private Bitmap DrawWaveform(int sampleOffset, int sampleLength, Rectangle clip)
{
ArbgPixel waveColor = new ArbgPixel(255, 0, 255, 0);
if (_waveFile == null)
{
return null;
}
if (clip.Width == 0 || clip.Height == 0)
{
return null;
}
Bitmap waveform = new Bitmap(clip.Width, clip.Height);
using (UnsafeBitmap unsafeMap = new UnsafeBitmap(waveform))
{
Graphics graphics = Graphics.FromImage(unsafeMap.Bitmap);
graphics.FillRectangle(Brushes.WhiteSmoke, graphics.VisibleClipBounds);
unsafeMap.LockBitmap();
float stepY = (float)clip.Height / 2 / short.MaxValue;
float stepX = (float)clip.Width / sampleLength;
//// #region Draw middle line
int middleY = (int)clip.Height / 2;
for (int x = 0; x < clip.Width; x++)
{
unsafeMap.SetAt(x, middleY, 0, 255, 0, 0);
}
//// #endregion
short[] data = _waveFile.DataIn16Bits;
int sampleEndIndex = sampleOffset + sampleLength;
Point prevPoint = new Point(0, middleY);
Point currPoint = new Point(0, middleY);
int prevY = int.MinValue;
for (int sampleIndex = sampleOffset; sampleIndex < sampleEndIndex; sampleIndex++)
{
currPoint.X = (int)(((sampleIndex - sampleOffset) * stepX) + 0.5);
currPoint.Y = middleY - (int)((data[sampleIndex] * stepY) + 0.5);
unsafeMap.SetAt((int)currPoint.X, (int)currPoint.Y, waveColor);
if (currPoint.X != prevPoint.X)
{
// connect two points in line
float tag = (float)(currPoint.Y - prevPoint.Y) / (currPoint.X - prevPoint.X);
for (int interX = prevPoint.X; interX < currPoint.X; interX++)
{
int interY = (int)(((interX - prevPoint.X) * tag) + 0.5) + prevPoint.Y;
if (prevY != interY && prevY != int.MinValue)
{
int insertDirect = Math.Sign(interY - prevY);
int insertLength = Math.Abs(interY - prevY);
for (int insertY = 1; insertY < insertLength; insertY++)
{
unsafeMap.SetAt(interX, prevY + (insertY * insertDirect), waveColor);
}
}
unsafeMap.SetAt(interX, interY, waveColor);
prevY = interY;
}
}
else
{
if (prevPoint.Y != currPoint.Y)
{
int insertDirect = Math.Sign(currPoint.Y - prevPoint.Y);
int insertLength = Math.Abs(currPoint.Y - prevPoint.Y);
for (int insertY = 1; insertY < insertLength; insertY++)
{
unsafeMap.SetAt(prevPoint.X, prevPoint.Y + (insertY * insertDirect),
waveColor);
}
}
}
prevPoint = currPoint;
}
unsafeMap.UnlockBitmap();
waveform = unsafeMap.Detach();
}
return waveform;
}
