Colour Common Dialog Box Example

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The Colour Dialog Box is created by initialising a CHOOSECOLOR structure and passing the structure to the ChooseColor function.

The syntax of the ChooseColour function is

BOOL ChooseColor(LPCHOOSECOLOR lpcc );

Where lpcc is a Pointer to the LPCHOOSECOLOR structure that contains information used to initialise the dialog box. When ChooseColor function returns, this structure also contains information about the user's colour selection.

#include <windows.h>
#include <commdlg.h>

#define ID_BUTTON 1

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
COLORREF ShowColorDialog(HWND);

COLORREF gColor = RGB(255,255,255);
HBRUSH hBrush = NULL;

int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
    MSG msg;
    WNDCLASS wc;

    ZeroMemory(&wc, sizeof(wc));

    wc.lpszClassName = TEXT("ColorDialog");
    wc.hInstance = hInstance;
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    wc.lpfnWndProc = WndProc;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);

    RegisterClass(&wc);

    CreateWindow(
        TEXT("ColorDialog"),
        TEXT("Choose Colour Example"),
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        100,
        100,
        500,
        300,
        NULL,
        NULL,
        hInstance,
        NULL);

    while(GetMessage(&msg,NULL,0,0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd,
                         UINT msg,
                         WPARAM wParam,
                         LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    RECT rc;

    switch(msg)
    {
        case WM_CREATE:

            CreateWindow(
                TEXT("BUTTON"),
                TEXT("Choose Colour"),
                WS_CHILD | WS_VISIBLE,
                20,
                20,
                120,
                30,
                hwnd,
                (HMENU)ID_BUTTON,
                NULL,
                NULL);

            hBrush = CreateSolidBrush(gColor);

            return 0;

        case WM_COMMAND:

            if(LOWORD(wParam)==ID_BUTTON)
            {
                gColor = ShowColorDialog(hwnd);

                DeleteObject(hBrush);
                hBrush = CreateSolidBrush(gColor);

                InvalidateRect(hwnd,NULL,TRUE);
            }

            return 0;

        case WM_ERASEBKGND:

            hdc = (HDC)wParam;

            GetClientRect(hwnd,&rc);

            FillRect(hdc,&rc,hBrush);

            return 1;

        case WM_PAINT:

            hdc = BeginPaint(hwnd,&ps);
            EndPaint(hwnd,&ps);

            return 0;

        case WM_DESTROY:

            DeleteObject(hBrush);

            PostQuitMessage(0);

            return 0;
    }

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

COLORREF ShowColorDialog(HWND hwnd)
{
    CHOOSECOLOR cc;
    static COLORREF customColours[16];

    ZeroMemory(&cc,sizeof(CHOOSECOLOR));

    cc.lStructSize = sizeof(CHOOSECOLOR);
    cc.hwndOwner = hwnd;
    cc.lpCustColors = customColours;
    cc.rgbResult = gColor;
    cc.Flags = CC_FULLOPEN | CC_RGBINIT;

    if(ChooseColor(&cc))
        return cc.rgbResult;

    return gColor;
}