//intercept invalidation and render next frame
protected override void OnInvalidated(InvalidateEventArgs e)
{
base.OnInvalidated(e);
//if there's no rendering region or the invalid rect is not touching it, return here.
if (Region == null || !DisplayRectangle.IntersectsWith(e.InvalidRect))
{
return;
}
Graphics bufferGraphics = RenderingBufferedGraphics.GetNewGraphicsContext();
bufferGraphics.Clear(Color.Transparent);
PreRendering(bufferGraphics);
bufferGraphics.Dispose();
}
/// <summary>
/// Gets coordinates in client space of indicator triangle to last marked tile.
/// </summary>
/// <param name="pointerHeight">Height of indicator, in pixels.</param>
/// <param name="pointerWidth">Width of indicator, in pixels.</param>
/// <returns>Returns table of 3 points making indicator triangle or null if last
/// marked tile is in viewport and indicator is not needed.</returns>
public Point[] GetIndicatorPointsToLastMarkedTile(int pointerHeight, int pointerWidth)
{
if (lastMarked == new Point(-1, -1))
{
return(null);
}
Rectangle lastMarkedTile = new Rectangle(GetTilePositionInClientSpace(lastMarked), TileSizeInViewport);
if (DisplayRectangle.IntersectsWith(lastMarkedTile))
{
return(null);
}
Point[] result = new Point[3];
result[1] = new Point(-pointerHeight, pointerWidth / 2);
result[2] = new Point(-pointerHeight, -pointerWidth / 2);
Point viewToTileVector = new Point(lastMarkedTile.X + lastMarkedTile.Width / 2 - Width / 2,
lastMarkedTile.Y + lastMarkedTile.Height / 2 - Height / 2);
double viewToTileLength =
Math.Sqrt(viewToTileVector.X * viewToTileVector.X + viewToTileVector.Y * viewToTileVector.Y);
double xAxisAngleCos = viewToTileVector.X / viewToTileLength;
double xAxisAngleSin = viewToTileVector.Y / viewToTileLength;
// rotate points
for (int i = 1; i < result.Length; ++i)
{
result[i] = new Point((int)(result[i].X * xAxisAngleCos - result[i].Y * xAxisAngleSin),
(int)(result[i].X * xAxisAngleSin + result[i].Y * xAxisAngleCos));
}
const int boundDistance = 20;
int[] vecProductsSigns =
{
CrossProductSign(viewToTileVector, new Point(Width / 2, Height / 2)),
CrossProductSign(viewToTileVector, new Point(-Width / 2, Height / 2)),
CrossProductSign(viewToTileVector, new Point(-Width / 2, -Height / 2)),
CrossProductSign(viewToTileVector, new Point(Width / 2, -Height / 2))
};
Point indicatorLineBeg, indicatorLineDir;
if (vecProductsSigns[0] < 0 && vecProductsSigns[1] >= 0 &&
vecProductsSigns[2] > 0 && vecProductsSigns[3] < 0)
{
indicatorLineBeg = new Point(boundDistance, Height - boundDistance);
indicatorLineDir = new Point(1, 0);
}
else if (vecProductsSigns[0] < 0 && vecProductsSigns[1] < 0 &&
vecProductsSigns[2] >= 0 && vecProductsSigns[3] > 0)
{
indicatorLineBeg = new Point(boundDistance, boundDistance);
indicatorLineDir = new Point(0, 1);
}
else if (vecProductsSigns[0] > 0 && vecProductsSigns[1] < 0 &&
vecProductsSigns[2] < 0 && vecProductsSigns[3] >= 0)
{
indicatorLineBeg = new Point(boundDistance, boundDistance);
indicatorLineDir = new Point(1, 0);
}
else
{
indicatorLineBeg = new Point(Width - boundDistance, boundDistance);
indicatorLineDir = new Point(0, 1);
}
int mainDeterminant = viewToTileVector.X * indicatorLineDir.Y -
viewToTileVector.Y * indicatorLineDir.X;
int tDeterminant = (indicatorLineBeg.X - Width / 2) * indicatorLineDir.Y -
(indicatorLineBeg.Y - Height / 2) * indicatorLineDir.X;
double t0 = (double)tDeterminant / mainDeterminant;
result[0] = new Point((int)(Width / 2 + viewToTileVector.X * t0),
(int)(Height / 2 + viewToTileVector.Y * t0));
for (int i = 1; i < result.Length; ++i)
{
result[i].X += result[0].X;
result[i].Y += result[0].Y;
}
return(result);
}