How to draw in console?

Question

Let's say I have a VB.net or C# console program that outputs its data to console. Is there a way to change color of a pixel? For example, my resolution is 1600x900. Can I paint pixel (800,600) red? Can I do the same for the active window (paint pixel (300,300) if the console is 400x400 - using coordinates relative to console)? What i want to do is to make a plot of some expression. I have multiple points and their coordinates and i want to draw them in the console by painting pixels. I'm really puzzled how to do this. Any suggestion and help is very much appreciated.

Answer 1

I know this answer is a little late, but in case you still want it, need it, or if someone else wants it, I found some tutorials and other things on stack overflow that led me to an answer. Here it is:

 [DllImport("kernel32.dll", EntryPoint = "GetConsoleWindow", SetLastError = true)]
    private static extern IntPtr GetConsoleHandle();

    IntPtr handler;
    Bitmap mainMap;

    void FinalDraw()
    {
        using (var graphics = Graphics.FromHwnd(handler))
            graphics.DrawImage(mainMap, new PointF(0, 0));
    }

Now just change the pixels inside the Bitmap mainMap, using mainMap.SetPixel(Color), and your all set, just call FinalDraw, and there you go. You will need to set mainMap to a new Bitmap and set the resolution. Finally make sure to install the System.Drawing.Common from the Manage NuGet window in Visual Studios. As well as add using System.Drawing; You may need to add a project reference as well. Good luck and have fun!

Edit:

Youll need to include System.Drawing, and System.Runtime.InteropServices. THe System.Drawing is for the graphics object, and the InteropServices is for the dll imports.

You can also make a reference to a graphics object, so you don't need to constantly use using.

So instead probably create a class that stores all your functions and the graphics object.

Example:

public class Canvas
{

    [DllImport("kernel32.dll", EntryPoint = "GetConsoleWindow", 
SetLastError = true)]
        private static extern IntPtr GetConsoleHandle();

        IntPtr handler;
    Graphics g;

    public Canvas()
    {
        using(var graphics = Graphics.FromHwnd(handler))
            g = graphics;
    }
}

Answer 2

Here a full example how to draw lines into console window. Build with .Net Framework 4.5.2 and VS-Studio 2015

using System;
using System.Drawing;
using System.Runtime.InteropServices;

namespace ConsoleDraw1
{
  class Program
  {
    [DllImport("kernel32.dll", EntryPoint = "GetConsoleWindow", SetLastError = true)]
    private static extern IntPtr GetConsoleHandle();


    [DllImport("user32.dll")]
    private static extern int GetWindowRect(IntPtr hwnd, out Rectangle rect);


    static void Main(string[] args)
    {
      Console.WindowHeight = 40;
      Console.WindowWidth  = 132;
      Console.CursorVisible = false;
      Console.Clear();

      IntPtr handle = GetConsoleHandle();
  
      Rectangle rect;
      GetWindowRect(handle, out rect);

      int width  = rect.Width;
      int height = rect.Height; 

      // using (var bmp = new Bitmap(600, 400))
      // using (var gfx = Graphics.FromImage(bmp))
      using (var gfx = Graphics.FromHwnd(handle))
      {
        gfx.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
        gfx.Clear(Color.Navy);

        Random rand = new Random(0);
        Pen pen = new Pen(Color.White);
        for (int i = 0; i < 10000; i++)
        {
          pen.Color = Color.FromArgb(rand.Next());
          Point pt1 = new Point(rand.Next(width), rand.Next(height));
          Point pt2 = new Point(rand.Next(width), rand.Next(height));
          gfx.DrawLine(pen, pt1, pt2);
        }
        // bmp.Save(@"C:\temp\demo.png");
      }
      
      Console.ReadKey(true);
    }
  }
}

Answer 3

You can change the Foreground and Background color as you write to the Console, but that's it. You need to use Winforms to accomplish what you want.

Answer 4

You cant draw a pixels, but you can use colored pseudographics. You can use Win32 functions like WriteConsoleOutput by p/invoking them. See Advanced Console IO in .NET for example.