COLORREF GetPixel(); Help

This is a discussion on COLORREF GetPixel(); Help within the C++ Programming forums, part of the General Programming Boards category; [UPDATE] Ok can some one help me get this code working im using Dev-C++ and windows XP Code: #include <iostream.h> ...

  1. #1
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    Question COLORREF GetPixel(); Help

    [UPDATE]
    Ok can some one help me get this code working im using Dev-C++ and windows XP

    Code:
    #include <iostream.h>
    #include <stdlib.h>
    #include <windows.h>
    int main()
    {
    DWORD color = GetPixel(hdc, x, y);
    unsigned int r = GetRValue(color);
    unsigned int g = GetGValue(color);
    unsigned int b = GetBValue(color);
    
    cout << "red: " << r << endl;
    cout << "green: " << g << endl;
    cout << "blue: " << b << endl;
    system("pause");
    return 0;
    }
    Last edited by JordanCason; 11-19-2007 at 08:59 PM.

  2. #2
    Hardware Engineer
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    First, you need to tell us what computer, operating system, and compiler you are using. (There is no color or graphics in Standard ANSI/ISO C++, so it depends on your platform.)

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    All right than thanks ill remember that well I’m using Dev-C++ on windows XP.

    Found this at msdn and it works just cant get it all to work to gather to make something like that which I explained before.
    http://msdn2.microsoft.com/en-us/library/ms532282.aspx
    Last edited by JordanCason; 11-19-2007 at 04:12 PM.

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    Thumbs up

    bumb because of UPDATE and dident wont to start a new thread

  5. #5
    int x = *((int *) NULL); Cactus_Hugger's Avatar
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    You need to defined hdc, x, and y, and set each to valid values, otherwise your code won't even compile. What are you trying to do?
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    I’m kind of working on making something like a little color picker for the CMD not a real purpose for it besides making a goal for me to work for. Works best that way for me but I am also fallowing a book at the same time. But ya I tried that it didn’t work properly because of my mistake but I will try again. O yes and what exactly is hdc that would help to. Thanks ill let you know if I get the code working thanks.

    ya I think if some one could clear up what hdc is that I will beable to get this working thaks
    Last edited by JordanCason; 11-19-2007 at 10:17 PM.

  7. #7
    Algorithm Dissector iMalc's Avatar
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    You use GetPixel to get the colour of the pixel in some Device Context at some location.
    What Device Context do you want to get a pixel's colour from, and where on it?

    Or would you simply like a random colour?
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  8. #8
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    Thumbs up

    Thank you for your Reply but I have figured it out I was havening a link error "undefined reference to getpixel@12" and I fixed it by going to project > Project options > load object file and loading "libgdi32.a".

    Here is my code for any one els trying to get this stuff to work took me for ever lol.
    Code:
    #include <iostream>
    #include <stdlib.h>
    #include <windows.h>
    int main()
    {
    int x,y;
        cout << "Enter coordanets: ";
             cin >> x;
             cin >> y;
                 HDC hdc = GetDC(NULL);
                 DWORD color = GetPixel(hdc, x, y);
                 unsigned int r = GetRValue(color);
                 unsigned int g = GetGValue(color);
                 unsigned int b = GetBValue(color);
        cout << "red: " << r << endl;
        cout << "green: " << g << endl;
        cout << "blue: " << b << endl;
    cin.get();
    cin.ignore();
    return 0;
    }
    I do have a new task if any of you would like to help me. I’m working on making the mouse move to a color pixel bye using this code if you could help with that it would be grate thanks.


    Also im stuck with this one see if any of you guys can help
    Code:
    #include <iostream>
    #include <windows.h>
    #include <stdlib.h>
    
    
    using namespace std;
    
    int main(int x, int y)
    {
    HANDLE mouseup = mouse_event(MOUSEEVENTF_LEFTUP, x, y, 0, 0);
    WaitForSingleObject(mouseup, INFINITE);
    cout << "should never appeared";
    }
    the goal im trying to reach with this is to wait untill the left buttin on the mouse lifts up.
    Last edited by JordanCason; 11-20-2007 at 07:27 AM.

  9. #9
    Its hard... But im here swgh's Avatar
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    Drop the .h from iostream thats an old header. Use
    Code:
    #include <iostream>
    Also do not use system() calls unless you really need to. They are unsafe. Use

    Code:
    cin.get();
    cin.ignore()
    In place to act the same as system("pause");
    I'm just trying to be a better person - My Name Is Earl

  10. #10
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    Thanks! and I updated it : )

  11. #11
    Algorithm Dissector iMalc's Avatar
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    Quote Originally Posted by JordanCason View Post
    Code:
    int main(int x, int y)
    I don't believe that is a valid function signature for main.
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    Linus Torvalds: "But it clearly is the only right way. The fact that everybody else does it some other way only means that they are wrong"

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