Draw on the screen itself

Hello,
Is there a way to draw a pixel or a graphic out side of my form

so maybe even though my form (200px by 200px in size) is placed on 400,400 on the screen...
But maybe I would like to draw a pixel on 10,10 on the screen, NOT the form...

so that the pixel will be OUT of the form..
If any answers are available, it would be very appriciated!
Thank You
Keehun Nam

Answer this question

Draw on the screen itself

Deuce Loosely
why not
does it stay even after the program finishes

does it slow down my computer, or is it just not
a good way to draw pixels out of my form
If it isn't, is there a "better" way

Thank You for your replie though!

elargento

Yes there is, but I would discourage you to use it.

Use a p/invoke to GetDC with NULL as parameter. Like this

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace DrawScreen
{
    public partial class Form1 : Form
    {
        [DllImport( "User32.dll" )]
        public extern static IntPtr GetDC( IntPtr hWnd );
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Paint( object sender, PaintEventArgs e )
        {
            IntPtr hDC = GetDC( new IntPtr( 0 ) );
            if( hDC != IntPtr.Zero )
            {
                using( Graphics g = Graphics.FromHdc( hDC ) )
                {
                    g.DrawLine( Pens.Black, 0, 0, 500, 500 );
                }
            }
        }
    }
}

but really... I mean... this is not really good practise.

fariborz

It is C# code. Convert it to VB by pasting using this code, it contains a converter:

http://www.carlosag.net/Tools/CodeTranslator/Default.aspx
nitinbourai

May I ask you what you are trying to accomplish

p.s.: please try to start new threads instead of replying to old 'answered' threads.
QXUE
jvanderbeek wrote:

2. If you need to paint over other windows, make your own form transparent. An article on how to do this can be found here.

This is what I'm trying to do; I'd like to paint a rotatable Direct3D mesh on a transparent form and see the user's desktop behind it. Each time through the render loop, I'm calling the Device.Clear method, which repaints the background to a solid color. The linked article above demonstrates how to make a control on a form transparent, but not how to make the form itself transparent and render objects on top of it. Is there a relatively easy way to do this

Matt
shadow_woman
Thank you!
Well, I have one more question to make....
Will the bmp be "click-proof" because if I was to
put the bmp on the screen on the icon of the start button,
will the user be able to click through the bmp that I placed on the start
button

Thank You!

Keehun Nam
vikrant

Ok, here are some reasons why not to paint on the screen itself:

The Windows operating system manages the windows and their visibility. It also manages invalidation of rectangles, so that only those portions get updated that need to be updated. The OS hands canvases to the applications that need them. You can paint on them and the OS will take care of managing them. When painting on the screen canvas, you are sabotaging the system. For instance, top-level windows will suddenly be painted over. Another example is that the taskbar with the start button could be painted over. Now that's not really good practise, is it

I'm also not quite sure whether you can get it to work glitch-free.

Here are my suggestions (in addition to eligazit's):

1. If you need a real fullscreen surface to paint on, use DirectX.

2. If you need to paint over other windows, make your own form transparent. An article on how to do this can be found here.

3. If you just need a very large, almost fullscreen canvas, just maximize your form without borders...

Don't forget to mark correct replies as answers!
bill_csharper
This code seem to have problems on Visual Basic Express Edition

I am close to editing and making it work though..
But it would be better if you like translate it...
I don't have a clue of what this code is from...
C C# C++ J

Thank You!
Keehun Nam
Anthony at Beckman
I have a form with multiple panels. I'd like to draw a line across different panels. How can I get the mousedown/mousemove/mouseover event hooked up

Thanks.
Alan
GapToN
Thank you!
I just have one question...
Lets predend that I have resolution of 1280X800
then my client has resolution of 800X600 or 2400X1800
then if I tell the program to pain on 0,1280
then it will be on MY left-bottom corner...
But for my clients, 800X600, will it be out of their screen
and also for the client 2400X1800 will the pixel be like
in 3/4th down the screen, or does the program make the
dot relative to my screen

Thank You anyway!
Keehun Nam
Brent McCulloch

Maybe you can use a new form that is region is set to a bitmap. that way you can create your outsize-of-form drawing at runtime by customizing the Bmp.

There are a lot of examples for this manner on the code project.
Draw on the screen itself

Answer this question