Introduction

Each pixel on a monitor holds a certain color. If you want, you can get that color and use it however you want. The following application shows how to retrieve the color of a pixel based on its (x, y) coordinate.

1. To create a new program, on the main menu, click File -> New -> Project...
2. In the Templates list, click Windows Forms Application
3. Set the Name to ColorSelector and click OK
4. Copy the following picture and paste it somewhere in your computer
    
   
5. Design the form as follows:
    

   Control Text Name Other Properties PictureBox   pbxColor Image: colorpal1.jpg Label Red:     TextBox   txtRed   Label Green:     TextBox   txtGreen   Label Blue:     TextBox   txtBlue   Panel   pnlPreview BorderStyle: FixedSingle Button Close btnClose

6. Right-click the form and click View Code
7. In the body of the class, declare a Boolean variable named IsSelecting:
   

   private:
   		/// <summary>
   		/// Required designer variable.
   		/// </summary>
   		System::ComponentModel::Container ^components;
   		bool isSelecting;

8. Return to the form and double-click an unoccupied area of its body
9. Implement the event as follows:
   

   System::Void Form1_Load(System::Object^  sender, System::EventArgs^  e)
   {
       isSelecting = false;
   }

10. Return to the form and click the picture box control on it
11. In the Properties window, click the Events button and double-click MouseDown
12. Implement the event as follows:
    

    System::Void pbxColor_MouseDown(System::Object^  sender,
    			 System::Windows::Forms::MouseEventArgs^  e)
    {
        isSelecting = true;
    }

13. Return to the form and click the picture box control on it
14. In the Events section of the Properties window, double-click MouseUp and implement the event as follows:
    

    System::Void pbxColor_MouseUp(System::Object^  sender,
    			System::Windows::Forms::MouseEventArgs^  e)
    {
        isSelecting = false;
    }

15. Return to the form and click the picture box control on it
16. In the Events section of the Properties window, double-click MouseMove and implement the event as follows:
    

    System::Void pbxColor_MouseMove(System::Object^  sender,
    			 System::Windows::Forms::MouseEventArgs^  e)
    {
        if( isSelecting == true )
        {
    	 Bitmap ^ bmpImage = static_cast<Bitmap ^>(pbxColor->Image);
    	 Color clr = bmpImage->GetPixel(e->X, e->Y);
    
    	 txtRed->Text = clr.R.ToString();
    	 txtGreen->Text = clr.G.ToString();
    	 txtBlue->Text = clr.B.ToString();
    
    	 pnlPreview->BackColor = clr;
        }
    }

17. Execute the application
18. Click the mouse on the picture mouse and drag to produce a color
     
    
19. Close the form