Drawing a single point

[rustyfancy]

Anyone know how to draw a single point in C#.NET??? I'm not good with GDI yet.

 

---Matt

[Volte]

Draw a 1x1 rectangle; oddly enough, there's no DrawPixel() function.

 

myGraphics.FillRectangle(Brushes.Red, x, y, 1, 1); // Draw a red point at (x, y)

[rustyfancy]

Hey Volte Face,

 

How do I set up the Graphics object??

[mutant]

You can create one, or you can use the one from paint event.

To create one do this:

Graphics gr = this.CreateGraphics(); //this refers to the form here

Now you will be able to draw to the form.

or use the one from Paint event:

e.Graphics.DrawRectangle(coordinates that you pick);

[Volte]

In the Paint event for whatever object you are painting:

Graphics g = e.Graphics; // e is the PaintEventArgs for the paint event, and the graphics object is passed into it

g.FillRectangle(Brushes.Red, x, y, 1, 1);

You should never do any drawing outside of the Paint event (not usually, anyway), as it will simply cause flickering and will require you to redraw more often, causing a potential performance hit.

[rustyfancy]

Guys,

Thanks for the help. I can GET a point to draw now. However, it isn't EXACTLY where my cursor is set. It's almost opposite coordinates of where I click. Ever have this occur?

[rustyfancy]

Here's my code...

 

Point p = Cursor.Position;

int x = p.X;

int y = p.Y;

textBox1.Text = "(" + x.ToString() + " , " + y.ToString()+")";

Graphics g = this.CreateGraphics();

g.FillRectangle(Brushes.Red, x,y, 1, 1);

[mutant]

You need to translate the cursor position to be relative to the form. Use the PointToClient() method of your form, and pass in the cursor coordinates to it. That will return the values that will corespond to the form.

[rustyfancy]

Mutant,

Thanks for the help, as always. What's the scope on this PointToClient method?? Is it a method of my form?? (i.e. form.PointToClient(Point p)) I need some code snippet here, sorry.

[Volte]

It is a method of your form.

 

Point screenPoint, formPoint;

screenPoint = Cursor.Location;
formPoint = this.PointToClient(screenPoint);

// use formPoint for your position