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WINAPI Buttons and Shapes

ashtonr132 (18)
Why doesn't this work? i am trying to make the button make the circle red.

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 #include <windows.h>
#include "main.h"

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);                                           //Declaring the windows Procedure Function that handle the events

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLine, int nShowCmd)
{
    static char name[] = "My Window Class";                                                     //Declaring the Windows Class Name
    WNDCLASSEX wc;                                                                              //Declaring the Windows Class Structure
    HWND hwnd;                                                                                  //Declaring the Main Window Handle
    MSG Msg;                                                                                    //Declaring the Message Structure

    //Step 1: Registering the Window Class
    wc.cbSize        = sizeof(WNDCLASSEX);                                                      //The size of the Windows class always set it to sizeof(WNDCLASSEX);
    wc.style         = CS_HREDRAW | CS_VREDRAW;                                                 //The Windows style, this is how it will look.
    wc.lpfnWndProc   = WndProc;                                                                 //Needs a pointer to WndProc
    wc.cbClsExtra    = 0;                                                                       //How many extra bytes to assign to the Class and the Window
    wc.cbWndExtra    = 0;
    wc.hInstance     = hInstance;                                                               //The instance handle being passed to WinMain
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);                                         //A handle to the application icon
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);                                             //A handle to the cursor the program will use
    wc.hbrBackground = (HBRUSH) CreateSolidBrush(RGB(0, 0, 0));                                 //The colour of the Window background
    wc.lpszMenuName  = NULL;                                                                    //A handle t the menu, havn't used one so set to 0
    wc.lpszClassName = name;                                                                    //The declared class name
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);                                         //A handle to the small top left icon

    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Registration Failure", MB_ICONEXCLAMATION | MB_OK);    //Registering the class, will display a message if it fails
        return 0;
    }

    // Step 2: Creating the Window //This will return the handle of the main window    (TheExtendedWindowsStyle, ClassName, WindowName, WindowStyle, XWindowPos, YWindowPos, WindowWidth, WindowHeight, ParentWindowHandle, MenuHandle, InstanceHandle, WM_CREATEPointer)
    hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, name, "Practice Window", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 400, 400, NULL, NULL, hInstance, NULL);

    ShowWindow(hwnd, nShowCmd);                                                                 //Display the window
    UpdateWindow(hwnd);                                                                         //Handles messages sent by Windows to my program

    // Step 3: The Message Loop
    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return (int)Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    int x = 0;
    int y = 0;
    int z = 0;

    switch(msg)
    {

    case WM_CREATE:
        hCloseBTN = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", "Colour",
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 20, 50, 80, 30, hwnd, NULL,
        GetModuleHandle(NULL), NULL);
        break;
    case WM_COMMAND:

    switch(LOWORD(wParam))
    {
    case BN_CLICKED:
        if(hCloseBTN == (HWND)lParam)
        {
            if(hCloseBTN == (HWND)lParam)
            {
                x = 255;
            }
        }
    }
    break;

    case WM_PAINT:
        {
            HDC hdc;
            PAINTSTRUCT ps;
            hdc = BeginPaint(hwnd, &ps);

            HGDIOBJ original = NULL;
            original = SelectObject(hdc,GetStockObject(DC_BRUSH));
            SelectObject(hdc, GetStockObject(DC_BRUSH));
            SetDCBrushColor(hdc, RGB(x,y,z));

            Ellipse(hdc, 100, 100, 160, 160);

            EndPaint(hwnd, &ps);
        }
        break;

    case WM_CLOSE:
        DestroyWindow(hwnd);
        break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    }

    return DefWindowProc(hwnd, msg, wParam, lParam);
}
Last edited on
coder777 (8444)
The first reason is that x,y,z are local variables. You get one msg per call. Hence x,y,z is always 0 when msg -> WM_PAINT. Solution: Make the variables global.

The second problem is that you need to invalidate the rect/ellipse that you want to redraw:

http://msdn.microsoft.com/en-us/library/windows/desktop/dd145002%28v=vs.85%29.aspx

Otherwise you might not get a WM_PAINT msg.
ashtonr132 (18)
Thankyou very much i have managed to make that work, Would you happen to know how to check for more than one button click?

For context i tried to change the;
x = 255;
into
x =+ 10;

So it would become more red the more it was clicked, but it only seemes to do the first click, thanks again.
ashtonr132 (18)
Bump?

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#include <windows.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);                                           //Declaring the windows Procedure Function that handle the events

    int x = 0;
    int y = 0;
    int z = 0;

    HWND hCloseBTN;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLine, int nShowCmd)
{



    static char name[] = "My Window Class";                                                     //Declaring the Windows Class Name
    WNDCLASSEX wc;                                                                              //Declaring the Windows Class Structure
    HWND hwnd;                                                                                  //Declaring the Main Window Handle
    MSG Msg;                                                                                    //Declaring the Message Structure

    //Step 1: Registering the Window Class
    wc.cbSize        = sizeof(WNDCLASSEX);                                                      //The size of the Windows class always set it to sizeof(WNDCLASSEX);
    wc.style         = CS_HREDRAW | CS_VREDRAW;                                                 //The Windows style, this is how it will look.
    wc.lpfnWndProc   = WndProc;                                                                 //Needs a pointer to WndProc
    wc.cbClsExtra    = 0;                                                                       //How many extra bytes to assign to the Class and the Window
    wc.cbWndExtra    = 0;
    wc.hInstance     = hInstance;                                                               //The instance handle being passed to WinMain
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);                                         //A handle to the application icon
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);                                             //A handle to the cursor the program will use
    wc.hbrBackground = (HBRUSH) CreateSolidBrush(RGB(0, 0, 0));                                 //The colour of the Window background
    wc.lpszMenuName  = NULL;                                                                    //A handle t the menu, havn't used one so set to 0
    wc.lpszClassName = name;                                                                    //The declared class name
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);                                         //A handle to the small top left icon

    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Registration Failure", MB_ICONEXCLAMATION | MB_OK);    //Registering the class, will display a message if it fails
        return 0;
    }

    // Step 2: Creating the Window //This will return the handle of the main window    (TheExtendedWindowsStyle, ClassName, WindowName, WindowStyle, XWindowPos, YWindowPos, WindowWidth, WindowHeight, ParentWindowHandle, MenuHandle, InstanceHandle, WM_CREATEPointer)
    hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, name, "Practice Window", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 400, 400, NULL, NULL, hInstance, NULL);

    ShowWindow(hwnd, nShowCmd);                                                                 //Display the window
    UpdateWindow(hwnd);                                                                         //Handles messages sent by Windows to my program

    // Step 3: The Message Loop
    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return (int)Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{

    switch(msg)
    {

    case WM_CREATE:
        hCloseBTN = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", "Colour",
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 20, 50, 80, 30, hwnd, NULL,
        GetModuleHandle(NULL), NULL);
        break;
    case WM_COMMAND:

    switch(LOWORD(wParam))
    {
    case BN_CLICKED:
        if(hCloseBTN == (HWND)lParam)
        {
            if(hCloseBTN == (HWND)lParam)
            {
                x =+ 10;
                InvalidateRect(hwnd, NULL, TRUE);

            }
        }
    }
    break;

    case WM_PAINT:
        {
            HDC hdc;
            PAINTSTRUCT ps;
            hdc = BeginPaint(hwnd, &ps);

            HGDIOBJ original = NULL;
            original = SelectObject(hdc,GetStockObject(DC_BRUSH));
            SelectObject(hdc, GetStockObject(DC_BRUSH));
            SetDCBrushColor(hdc, RGB(x,y,z));

            Ellipse(hdc, 100, 100, 160, 160);

            EndPaint(hwnd, &ps);
        }
        break;

    case WM_CLOSE:
        DestroyWindow(hwnd);
        break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    }

    return DefWindowProc(hwnd, msg, wParam, lParam);
}
coder777 (8444)
Well: It is x += 10; // Note: += not =+
ashtonr132 (18)
Idiocy strikes again, thankyou!
ashtonr132 (18)
How can i use a button to change the shape? because this doesn't work.
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#include <windows.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);                                           //Declaring the windows Procedure Function that handle the events

    int x = 0;
    int y = 0;
    int z = 0;
    int s = 0;

    HWND hRedBTN;
    HWND hBlueBTN;
    HWND hGreenBTN;
    HWND hBlackBTN;
    HWND hShapeBTN;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLine, int nShowCmd)
{
    static char name[] = "My Window Class";                                                     //Declaring the Windows Class Name
    WNDCLASSEX wc;                                                                              //Declaring the Windows Class Structure
    HWND hwnd;                                                                                  //Declaring the Main Window Handle
    MSG Msg;                                                                                    //Declaring the Message Structure

    //Step 1: Registering the Window Class
    wc.cbSize        = sizeof(WNDCLASSEX);                                                      //The size of the Windows class always set it to sizeof(WNDCLASSEX);
    wc.style         = CS_HREDRAW | CS_VREDRAW;                                                 //The Windows style, this is how it will look.
    wc.lpfnWndProc   = WndProc;                                                                 //Needs a pointer to WndProc
    wc.cbClsExtra    = 0;                                                                       //How many extra bytes to assign to the Class and the Window
    wc.cbWndExtra    = 0;
    wc.hInstance     = hInstance;                                                               //The instance handle being passed to WinMain
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);                                         //A handle to the application icon
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);                                             //A handle to the cursor the program will use
    wc.hbrBackground = (HBRUSH) CreateSolidBrush(RGB(255, 255, 255));                                 //The colour of the Window background
    wc.lpszMenuName  = NULL;                                                                    //A handle t the menu, havn't used one so set to 0
    wc.lpszClassName = name;                                                                    //The declared class name
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);                                         //A handle to the small top left icon

    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Registration Failure", MB_ICONEXCLAMATION | MB_OK);    //Registering the class, will display a message if it fails
        return 0;
    }

    // Step 2: Creating the Window //This will return the handle of the main window    (TheExtendedWindowsStyle, ClassName, WindowName, WindowStyle, XWindowPos, YWindowPos, WindowWidth, WindowHeight, ParentWindowHandle, MenuHandle, InstanceHandle, WM_CREATEPointer)
    hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, name, "Practice Window", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 460, 400, NULL, NULL, hInstance, NULL);

    ShowWindow(hwnd, nShowCmd);                                                                 //Display the window
    UpdateWindow(hwnd);                                                                         //Handles messages sent by Windows to my program

    // Step 3: The Message Loop
    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return (int)Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{

    switch(msg)
    {

    case WM_CREATE:

        hRedBTN = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", "R + 10",
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 20, 50, 80, 30, hwnd, NULL,
        GetModuleHandle(NULL), NULL);

        hBlueBTN = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", "B + 10",
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 100, 50, 80, 30, hwnd, NULL,
        GetModuleHandle(NULL), NULL);

        hGreenBTN = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", "G + 10",
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 180, 50, 80, 30, hwnd, NULL,
        GetModuleHandle(NULL), NULL);

        hBlackBTN = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", "RGB, 0, 0, 0",
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 260, 50, 80, 30, hwnd, NULL,
        GetModuleHandle(NULL), NULL);

        hShapeBTN = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", "Shape",
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 340, 50, 80, 30, hwnd, NULL,
        GetModuleHandle(NULL), NULL);

        break;

    case WM_COMMAND:

    switch(LOWORD(wParam))
    {
    case BN_CLICKED:
        if(hRedBTN == (HWND)lParam)
        {
            if(hRedBTN == (HWND)lParam)
            {
                x += 10;
                if(x > 255){
                    x = 0;
                }
            InvalidateRect(hwnd, NULL, TRUE);
            }
        }
        if(hBlueBTN == (HWND)lParam)
        {
            if(hBlueBTN == (HWND)lParam)
            {
                z += 10;
                if(z > 255){
                    z = 0;
                }
            InvalidateRect(hwnd, NULL, TRUE);
            }
        }
        if(hGreenBTN == (HWND)lParam)
        {
            if(hGreenBTN == (HWND)lParam)
            {
                y += 10;
                if(y > 255){
                    y = 0;
                }
            InvalidateRect(hwnd, NULL, TRUE);
            }
        }
        if(hBlackBTN == (HWND)lParam)
        {
            if(hBlackBTN == (HWND)lParam)
                {
                    z = 0;
                    y = 0;
                    x = 0;
                }
                InvalidateRect(hwnd, NULL, TRUE);
        }
        if(hShapeBTN == (HWND)lParam)
        {
            if(hShapeBTN == (HWND)lParam)
                {
                    if(s = 1){
                        s -= 1;}
                    else{
                    s += 1;
                    }

                }
                InvalidateRect(hwnd, NULL, TRUE);
        }

    }
    break;

    case WM_PAINT:
        {
            HDC hdc;
            PAINTSTRUCT ps;
            hdc = BeginPaint(hwnd, &ps);

            HGDIOBJ original = NULL;
            original = SelectObject(hdc,GetStockObject(DC_BRUSH));
            SelectObject(hdc, GetStockObject(DC_BRUSH));
            SetDCBrushColor(hdc, RGB(x,y,z));

            if(s = 0){
            Ellipse(hdc, 100, 100, 160, 160);
            }
            else{
            Rectangle(hdc, 100, 100, 160, 160);
            }

            EndPaint(hwnd, &ps);
        }
        break;

    case WM_CLOSE:
        DestroyWindow(hwnd);
        break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    }

    return DefWindowProc(hwnd, msg, wParam, lParam);
}


Also, why am i getting a warning for the OR staments, i googled it and its somthing to do with the difference between = and == but i'm afraid i don't understand it.
"Suggest parentheses around assignment used as truth value"
wildblue (1505)
"Suggest parentheses around assignment used as truth value"


check line 140
ashtonr132 (18)
Thanks, just for anyone witha similar problem, = is the assignment opereator I.E. s = 1; and == is the equality operator, so if(s == 1){}. Hint, dont use = in if's.
coder777 (8444)
Thanks, just for anyone witha similar problem, = is the assignment opereator I.E. s = 1; and == is the equality operator, so if(s == 1){}. Hint, dont use = in if's.
Yes, to avoid problem with this put the constant value on the left side, i.e. if(1 == s)
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