Drawing a line

This is a discussion on Drawing a line within the Windows Programming forums, part of the Platform Specific Boards category; How do I do this? I can draw a rectangle but not a line x.x Also how would I go ...

  1. #1
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    Drawing a line

    How do I do this? I can draw a rectangle but not a line x.x Also how would I go about drawing half of a circle.

    EDIT:

    Also, how would I make my embedded bitmap rotate x.x
    Last edited by Homunculus; 03-18-2006 at 09:10 PM.

  2. #2
    Registered User Bajanine's Avatar
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    Are you using the GDI?

    Link

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    Favorite Quote:

    >For that reason someone invented C++.
    BLASPHEMY! Begone from my C board, you foul lover of objects, before the gods of C cast you into the void as punishment for your weakness! There is no penance for saying such things in my presence. You are henceforth excommunicated. Never return to this house, filthy heretic!



  3. #3
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    thx

    Ok, now using the POINT structure, how would I specify current position?

    If you know a good set of tutorials on doing this stuff , please direct me=P im programming in pure win32 api. Meaning no MFC etc.

  4. #4
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    Set your starting point:-
    MoveToEx(hdc, x, y, NULL);

    GO!
    LineTo(hdc, x2, y2);

  5. #5
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    ok thanks =P, now how do I make my embedded bitmap rotate? would I have to mix opengl and bind textures and crap?

  6. #6
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    also

    I have want to have it draw when I click a button, I will show what I've done:

    Code:
                     switch(GET_WM_COMMAND_ID(wParam,lParam))
                     {
                         case BUTTON123:
                              {
                                   HDC hdc;
                                   PAINTSTRUCT ps;
                                   HPEN hPen;
                                   
                                   hdc = BeginPaint(Phys,&ps);
                                   hPen = CreatePen(PS_DASHDOTDOT,1,RGB(0,0,0));
                                   
                                   LineTo(hdc,200,200);
                                   
                                   EndPaint(Phys,&ps);
                              }
                         break;
                     }
    This is in a child window >.<

    It doesn't do anything when the button is clicked... I tried sending a wm_paint message and having it paint that when the message is handled. and in that having a variable that gets cordinates, but nothing works

  7. #7
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    Try not to call BeginPaint/EndPaint outside of a WM_PAINT response, you'll achieve nothing.

    Replace them with
    hdc = GetDC(hwnd);
    ReleaseDC(hwnd, hdc);

    hwnd being the variable you're using for your window handle.

    Also, creating a pen is all well and good, but you'll need to select it into the dc to use it. So, after your CreatePen bit:-
    hOld = SelectObject(hdc, hPen);

    Make hOld another HPEN.
    Then, after your line drawing and before ReleaseDC:-
    SelectObject(hdc, hOld);
    DeleteObject(hPen);

    This stops you from potentially running out of GDI handles (it stops working, as does most of Windows).

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