protected override void OnMouseWheel(MouseWheelEventArgs args)
{
base.OnMouseWheel(args);
// If there is a mouse op in progress, forward the event
var op = MouseOperations.Active;
if (op != null && !op.Cancelled)
{
op.MouseWheel(args);
if (args.Handled)
{
return;
}
}
var location = args.GetPosition(this);
var along_ray = Options.MouseCentredZoom || Keyboard.Modifiers.HasFlag(ModifierKeys.Alt);
var chart_pt = ClientToChart(location);
var hit = HitTestZoneCS(location, Keyboard.Modifiers, args.ToMouseBtns());
// Batch mouse wheel events into 100ms groups
var defer_nav_checkpoint = DeferNavCheckpoints();
Dispatcher_.BeginInvokeDelayed(() =>
{
Util.Dispose(ref defer_nav_checkpoint !);
SaveNavCheckpoint();
}, TimeSpan.FromMilliseconds(100));
var scale = 0.001f;
if (Keyboard.Modifiers.HasFlag(ModifierKeys.Shift))
{
scale *= 0.1f;
}
if (Keyboard.Modifiers.HasFlag(ModifierKeys.Alt))
{
scale *= 0.01f;
}
var delta = Math_.Clamp(args.Delta * scale, -0.999f, 0.999f);
var chg = (string?)null;
// If zooming is allowed on both axes, translate the camera
if (hit.Zone == EZone.Chart && XAxis.AllowZoom && YAxis.AllowZoom)
{
// Translate the camera along a ray through 'point'
var loc = Gui_.MapPoint(this, Scene, location);
Scene.Window.MouseNavigateZ(loc.ToPointF(), args.ToMouseBtns(Keyboard.Modifiers), args.Delta, along_ray);
chg = nameof(SetRangeFromCamera);
}
// Otherwise, zoom on the allowed axis only
else if (hit.Zone == EZone.XAxis || (hit.Zone == EZone.Chart && !YAxis.AllowZoom))
{
if (hit.ModifierKeys.HasFlag(ModifierKeys.Control) && XAxis.AllowScroll)
{
// Scroll the XAxis
XAxis.Shift(XAxis.Span * delta);
chg = nameof(SetCameraFromRange);
}
else if (!hit.ModifierKeys.HasFlag(ModifierKeys.Control) && XAxis.AllowZoom)
{
// Change the aspect ratio by zooming on the XAxis
var x = along_ray ? chart_pt.X : XAxis.Centre;
var left = (XAxis.Min - x) * (1f - delta);
var rite = (XAxis.Max - x) * (1f - delta);
XAxis.Set(x + left, x + rite);
if (Options.LockAspect != null)
{
YAxis.Span *= (1f - delta);
}
chg = nameof(SetCameraFromRange);
}
}
else if (hit.Zone == EZone.YAxis || (hit.Zone == EZone.Chart && !XAxis.AllowZoom))
{
if (hit.ModifierKeys.HasFlag(ModifierKeys.Control) && YAxis.AllowScroll)
{
// Scroll the YAxis
YAxis.Shift(YAxis.Span * delta);
chg = nameof(SetCameraFromRange);
}
else if (!hit.ModifierKeys.HasFlag(ModifierKeys.Control) && YAxis.AllowZoom)
{
// Change the aspect ratio by zooming on the YAxis
var y = along_ray ? chart_pt.Y : YAxis.Centre;
var left = (YAxis.Min - y) * (1f - delta);
var rite = (YAxis.Max - y) * (1f - delta);
YAxis.Set(y + left, y + rite);
if (Options.LockAspect != null)
{
XAxis.Span *= (1f - delta);
}
chg = nameof(SetCameraFromRange);
}
}
switch (chg)
{
// Update the axes from the camera position
case nameof(SetRangeFromCamera):
SetRangeFromCamera();
NotifyPropertyChanged(nameof(ValueAtPointer));
Invalidate();
break;
// Set the camera position from the new axis ranges
case nameof(SetCameraFromRange):
SetCameraFromRange();
NotifyPropertyChanged(nameof(ValueAtPointer));
Invalidate();
break;
}
}