/// <summary>
/// <para>Moves the Camera in a viewport toward a fixed point</para>
/// </summary>
public static bool Move(this ViewportInfo viewport, CGSize viewSize, double magnifcationFactor, CGPoint fixedScreenPoint)
{
if (viewport.IsCameraLocationLocked)
{
return(false);
}
var screenWidth = viewSize.Width;
var screenHeight = viewSize.Height;
if (1 > screenWidth || 1 > screenHeight)
{
return(false);
}
// move camera toward target to magnify
if (magnifcationFactor > 0)
{
// if the screen point is not in the viewport, then ignore it.
if (!fixedScreenPoint.IsEmpty)
{
if (fixedScreenPoint.X <= 0 || fixedScreenPoint.X >= screenWidth - 1 || fixedScreenPoint.Y <= 0 || fixedScreenPoint.Y >= screenHeight - 1)
{
fixedScreenPoint.X = 0;
fixedScreenPoint.Y = 0;
}
}
double frustumNear = viewport.FrustumNear;
double frustumWidth = viewport.FrustumWidth;
double frustumHeight = viewport.FrustumHeight;
double d = 0.0;
// dolly camera location and the target location...
if (viewport.IsPerspectiveProjection)
{
const double miniumumTargetDistance = 0.000001;
var cameraZ = viewport.CameraZ;
var cameraLocation = viewport.CameraLocation;
var target = viewport.TargetPoint;
var v0 = target - cameraLocation;
double targetDistance = (cameraLocation - target) * cameraZ;
if (targetDistance >= 0.0)
{
double delta = (1.0 - (1.0 / magnifcationFactor)) * targetDistance;
if (targetDistance - delta > miniumumTargetDistance)
{
v0.Unitize();
var l = delta * v0;
var newLocation = cameraLocation + l;
var newTarget = target + l;
viewport.SetTarget(newTarget, newLocation, Rhino.Geometry.Vector3d.ZAxis);
if (!fixedScreenPoint.IsEmpty)
{
d = (targetDistance / 2) / frustumNear;
frustumWidth *= d;
frustumHeight *= d;
d = ((targetDistance / 2) - delta) / (targetDistance / 2);
}
}
}
}
if (!fixedScreenPoint.IsEmpty && Math.Abs(d) > Double.Epsilon)
{
// lateral dolly to keep fixed_screen_point in same location on screen
Rhino.Geometry.Vector3d scale = new Rhino.Geometry.Vector3d(1.0, 1.0, 1.0);
scale.X = viewport.ViewScale.Width;
scale.Y = viewport.ViewScale.Height;
double fx = ((double)fixedScreenPoint.X / (double)screenWidth);
double fy = ((double)fixedScreenPoint.Y / (double)screenHeight);
double dx = ((0.5 - fx) * (1.0 - d) * frustumWidth) / scale.X;
double dy = ((fy - 0.5) * (1.0 - d) * frustumHeight) / scale.Y;
Rhino.Geometry.Vector3d dollyVector = dx * viewport.CameraX + dy * viewport.CameraY;
var cameraLocation = viewport.CameraLocation;
var target = viewport.TargetPoint;
viewport.TargetPoint = target - dollyVector;
viewport.SetCameraLocation(cameraLocation - dollyVector);
}
}
return(true);
}