public ImageQuadranglePicker()
{
Canvas.KeyDown += Canvas_KeyDown;
var lostFocus = Observable.FromEventPattern <EventArgs>(Canvas, "LostFocus").Select(e => e.EventArgs);
var mouseUp = Observable.FromEventPattern <MouseEventArgs>(Canvas, "MouseUp").Select(e => e.EventArgs);
var mouseDown = Observable.FromEventPattern <MouseEventArgs>(Canvas, "MouseDown").Select(e => e.EventArgs);
var mouseMove = Observable.FromEventPattern <MouseEventArgs>(Canvas, "MouseMove").Select(e => e.EventArgs);
var mouseLeftButtonUp = mouseUp.Where(evt => evt.Button == MouseButtons.Left);
var mouseLeftButtonDown = mouseDown.Where(evt => evt.Button == MouseButtons.Left);
var mouseRightButtonDown = mouseDown.Where(evt => evt.Button == MouseButtons.Right &&
!MouseButtons.HasFlag(MouseButtons.Left));
var mouseDrag = mouseLeftButtonDown.SelectMany(downEvt =>
{
var image = Image;
var downPoint = ImagePoint(downEvt.X, downEvt.Y, image);
var cornerIndex = CornerIndex(downPoint);
commandExecutor.BeginCompositeCommand();
commandExecutor.Execute(() => { }, UpdateQuadrangle);
UpdatePoint(cornerIndex, quadrangle[cornerIndex]);
return(mouseMove
.TakeUntil(mouseLeftButtonUp.Merge(lostFocus))
.Select(evt => ImagePoint(evt.X, evt.Y, image))
.Do(point =>
{
quadrangle[cornerIndex] = point;
UpdateQuadrangle();
})
.TakeLast(1)
.Do(point =>
{
UpdatePoint(cornerIndex, point);
commandExecutor.Execute(UpdateQuadrangle, () => { });
})
.Finally(commandExecutor.EndCompositeCommand));
});
mouseDrag.Subscribe();
mouseRightButtonDown.Subscribe(evt =>
{
var image = Image;
if (image != null)
{
InitializeQuadrangle(
new Point2f(0, 0),
new Point2f(0, image.Height),
new Point2f(image.Width, image.Height),
new Point2f(image.Width, 0));
}
else
{
InitializeQuadrangle(
new Point2f(-1, -1),
new Point2f(-1, 1),
new Point2f(1, 1),
new Point2f(1, -1));
}
});
}