12,748,323 members (42,192 online)

Email

Password

Sign in with

I can't understand why it is.

Here is some code of mine:

This is the overridden OnMouseMove method for the customized Label (my arrow):

```
protected override void OnMouseMove(MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
//Check if mouse holds down on the middle of the arrow then just move it or translate it, not rotate.
if (downPoint == MouseDownPoint.Middle)
{
Left += e.X - oldPos.X;
Top += e.Y - oldPos.Y;
}
else //if mouse holds down on one of the two heads of the arrow then start rotating.
{
if (downPoint == MouseDownPoint.First)
{
if (a != ArrowType.LastToFirst)
TurnTailPointTo(Parent.PointToClient(PointToScreen(e.Location)));
else TurnHeadPointTo(Parent.PointToClient(PointToScreen(e.Location)));
}
else if (a != ArrowType.LastToFirst)
TurnHeadPointTo(Parent.PointToClient(PointToScreen(e.Location)));
else TurnTailPointTo(Parent.PointToClient(PointToScreen(e.Location)));
}
Invalidate();
first = Parent.PointToClient(PointToScreen(localFirst));
last = Parent.PointToClient(PointToScreen(localLast));
}
base.OnMouseMove(e);
}
```

Here are the code for

```
void TurnPointTo(Point Tip, Point p)
{
if (Parent != null) Parent.SuspendLayout();
Size = new Size(2 * Math.Abs(Tip.X - p.X) + 10 + fontHeight, 2 * Math.Abs(Tip.Y - p.Y) + 10 + fontHeight);
turning = true;
Location = new Point(Math.Min(p.X, Tip.X) - Width / 2, Math.Min(p.Y, Tip.Y) - Height / 2);
turning = false;
if (Parent != null) Parent.ResumeLayout();
}
public void TurnHeadPointTo(Point p)
{
if (a != ArrowType.LastToFirst)
{
TurnPointTo(first, p);
localLast = new Point(p.X - Location.X, p.Y - Location.Y);
localFirst = new Point(first.X - Location.X, first.Y - Location.Y);
last = p;
}
else
{
TurnPointTo(last, p);
localFirst = new Point(p.X - Location.X, p.Y - Location.Y);
localLast = new Point(last.X - Location.X, last.Y - Location.Y);
first = p;
}
Invalidate();
}
public void TurnTailPointTo(Point p)
{
if (a != ArrowType.LastToFirst)
{
TurnPointTo(last, p);
localLast = new Point(last.X - Location.X, last.Y - Location.Y);
localFirst = new Point(p.X - Location.X, p.Y - Location.Y);
first = p;
}
else
{
TurnPointTo(first, p);
localLast = new Point(p.X - Location.X, p.Y - Location.Y);
localFirst = new Point(first.X - Location.X, first.Y - Location.Y);
last = p;
}
Invalidate();
}
```

My idea is each time the rotating action happens, I will resize the customized label to the new size which can contain the 2 points of 2 heads of the arrow, and relocate it, update the

Here is the code for the OnPaint method of the customized Label:

```
protected override void OnPaint(PaintEventArgs e)
{
GraphicsPath gp = new GraphicsPath();
Point tail = a == ArrowType.FirstToLast || a == ArrowType.None ?
```**localFirst** : **localLast**;
Point head = a == ArrowType.FirstToLast || a == ArrowType.None ? **localLast** : **localFirst**;
int h = Math.Max(tail.Y, head.Y) - Math.Min(tail.Y, head.Y);
int w = Math.Max(tail.X, head.X) - Math.Min(tail.X, head.X);
float alpha = (float)Math.Atan((float)h / w);
int dx = (int)((thick / 2) * Math.Sin(alpha));
int dy = (int)((thick / 2) * Math.Cos(alpha));
int signDx = 1, signDy = 1, signHeadX = 1, signHeadY = 1;
if (tail.X >= head.X && tail.Y >= head.Y)
{
signDx = -1;
}
else if (tail.X <= head.X && tail.Y <= head.Y)
{
signDy = -1;
signHeadX = signHeadY = -1;
}
else if (tail.Y >= head.Y)
{
signDx = signDy = -1;
signHeadX = -1;
}
else
{
signHeadY = -1;
}
Point p1 = new Point(tail.X + signDx * dx, tail.Y + signDy * dy);
Point p2 = new Point(tail.X - signDx * dx, tail.Y - signDy * dy);
Point p3 = new Point(head.X + signDx * dx, head.Y + signDy * dy);
Point p4 = new Point(head.X - signDx * dx, head.Y - signDy * dy);
if (a == ArrowType.None)//Just shape a line
{
gp.AddLines(new Point[] { p1, p2, p4, p3 });
}
else//Shape an arrow
{
Point k = new Point((int)(head.X + signHeadX * 10 * Math.Cos(alpha)), (int)(head.Y + signHeadY * 10 * Math.Sin(alpha)));
p3 = new Point(k.X + signDx * dx, k.Y + signDy * dy);
p4 = new Point(k.X - signDx * dx, k.Y - signDy * dy);
k = new Point((int)Math.Round((head.X + signHeadX * 20 * Math.Cos(alpha))), (int)Math.Round((head.Y + signHeadY * 20 * Math.Sin(alpha))));
dx = (int)(2 * thick * Math.Sin(alpha));
dy = (int)(2 * thick * Math.Cos(alpha));
Point p5 = new Point(k.X + signDx * dx, k.Y + signDy * dy);
Point p6 = new Point(k.X - signDx * dx, k.Y - signDy * dy);
gp.AddLines(new Point[] { p1, p2, p4, p6, head, p5, p3 });
}
gp.AddPath(val, true);
Region = new Region(gp);
base.OnPaint(e);
}

Please don't suggest me the idea using

I also tried overriding CreateParams of the form and add the ExStyle with 0x02000000 as many other sites discussed about preventing flicker. I think my problem is some kind of flicker.

Hope you understand my idea as well as my code to help me out!

Your help would be highly appreciated! Thanks!

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CodeProject,
503-250 Ferrand Drive Toronto Ontario, M3C 3G8 Canada
+1 416-849-8900 x 100