I have found this question (as a few others), but this is the one I have implemented so far:
Crosshair cursor with additional lines in C#
As it states, I can use a stock cursor "cross" directly in the IDE. This is a really good way to do things. The answer specified in the answer above draws a cross on the screen at the given width / height. Eg:
private Cursor crossCursor(Pen pen, Brush brush, int x, int y)
{
var pic = new Bitmap(x, y);
Graphics gr = Graphics.FromImage(pic);
var pathX = new GraphicsPath();
var pathY = new GraphicsPath();
pathX.AddLine(0, y / 2, x, y / 2);
pathY.AddLine(x / 2, 0, x / 2, y);
gr.DrawPath(pen, pathX);
gr.DrawPath(pen, pathY);
IntPtr ptr = pic.GetHicon();
var c = new Cursor(ptr);
return c;
}
My issue is that I want my cross hairs to extend to the Bounds of the viewing area. To provide context here, I have:
//Form
//TableLayoutPanel
//UserControl (fills the TableLayoutPanel visible area)
So how can I adjust my cursor so that the lines extend (much like in CAD pacakages)?
Thanks.
Update: I have tried calling the method from here:
protected override void OnLoad(System.EventArgs e)
{
Cursor = crossCursor(Pens.WhiteSmoke, Brushes.WhiteSmoke, Bounds.Width, Bounds.Height);
}
But it is not Ok because at this point in time Bounds is returning a dimension of 150 by 150 which is not the size of the TableLayoutPanel
.
Update: I have adjuted it to use the Resize handler instead and it does improve things:
protected override void OnResize(EventArgs e)
{
base.OnResize(e);
Cursor = crossCursor(Pens.WhiteSmoke, Brushes.WhiteSmoke, Bounds.Width, Bounds.Height);
}
The only problem now (and it kind of makes sense I suppose) is that the cursor will only take the full width and height of the view when it is central to the view. As soon as I move about in the view that cursor does not adjust. I always want a horizontal/vertical line through the mouse position (not just the initial cross).
See:
The crosshairs need extending (the thicker red lines). Either I need to constantly create the cursor as the mouse moves or construct the two lines another way. What to do?
I came across this:
https://social.msdn.microsoft.com/Forums/vstudio/en-US/7bdbad6d-1f65-461b-8f0c-6ef4f243fa6b/crosshair-cursor-using-c?forum=csharpgeneral
So, instead of changing the cursor object I now draw lines in the controls MouseMove handler:
Region r = new Region();
r.Union(new Rectangle(0, lastY, this.Width, 1));
r.Union(new Rectangle(lastX, 0, 1, this.Height));
this.Invalidate(r);
this.Update();
Graphics g = Graphics.FromHwnd(this.Handle);
g.DrawLine(Pens.White, 0, e.Y, this.Width, e.Y);
g.DrawLine(Pens.White, e.X, 0, e.X, this.Height);
int intDiameter = 20;//the diameter of this circle
g.DrawEllipse(Pens.White, e.X - intDiameter / 2, e.Y - intDiameter / 2, 20, 20);
//to draw the circle
lastX = e.X;
lastY = e.Y;
It works, but I get noticiable screen flicker doing it this way.