DO declare
 
#DEFINE CC_RGBINIT 1
#DEFINE CC_FULLOPEN 2
#DEFINE CC_PREVENTFULLOPEN 4
#DEFINE CC_SHOWHELP 8
#DEFINE CC_SOLIDCOLOR 128
#DEFINE CC_ANYCOLOR 256
#DEFINE CC_WIDE 32
 
*| typedef struct { 
*|   DWORD        lStructSize;      0:4
*|   HWND         hwndOwner;        4:4
*|   HWND         hInstance;        8:4
*|   COLORREF     rgbResult;       12:4
*|   COLORREF   * lpCustColors;    16:4
*|   DWORD        Flags;           20:4
*|   LPARAM       lCustData;       24:4
*|   LPCCHOOKPROC lpfnHook;        28:4
*|   LPCTSTR      lpTemplateName;  32:4
*| } CHOOSECOLOR, *LPCHOOSECOLOR; total=36 bytes
 
#DEFINE CHOOSECOLOR_SIZE     36
 
*| typedef DWORD COLORREF;
*| typedef DWORD *LPCOLORREF;
*| 0x00bbggrr
#DEFINE COLORREF_ARRAY_SIZE  64
 
LOCAL hWindow, lcBuffer, lnInitColor, lnFlags,;
    lnCustColors, lcCustColors, ii
 
hWindow = GetActiveWindow()
 
* the color initially selected when the dialog box is created
lnInitColor = Rgb(128,0,0)
 
* allocating memory block for 16 COLORREF values (DWORD)
* for the custom color boxes in the dialog box
* and filling this memory with zeroes
 
#DEFINE GMEM_FIXED 0
lnCustColors = GlobalAlloc(GMEM_FIXED, COLORREF_ARRAY_SIZE)
= ZeroMemory(lnCustColors, COLORREF_ARRAY_SIZE)
 
* initialization flags
lnFlags = CC_FULLOPEN + CC_RGBINIT
 
* compiling the CHOOSECOLOR structure
lcBuffer = num2dword(CHOOSECOLOR_SIZE) +;
    num2dword(hWindow) +;
    num2dword(0) +;
    num2dword(lnInitColor) +;
    num2dword(lnCustColors) +;
    num2dword(lnFlags) +;
    num2dword(0) +;
    num2dword(0) +;
    num2dword(0)
 
IF ChooseColor(@lcBuffer) <> 0
* the OK button of the dialog box has been selected
    ? "Color selected:", buf2dword(SUBSTR(lcBuffer, 13,4))
 
    ? "Custom colors stored:"
 
    * copying the memory block content to a VFP string
    * just to have an opportunity to work with its substring;
    * quite weird way, though not much choice available
    * considering the VFP specifics
 
    lcCustColors = Repli(Chr(0), COLORREF_ARRAY_SIZE)
    = Heap2Str(@lcCustColors, lnCustColors, COLORREF_ARRAY_SIZE)
 
    FOR ii=1 TO 16
        ? ii, buf2dword(SUBSTR(lcCustColors, (ii-1)*4+1, 4))
    ENDFOR
ENDIF
 
* free the memory block if you do not use it for the
* following calls to this function
= GlobalFree(lnCustColors)
 
* end of main
 
FUNCTION num2dword (lnValue)
#DEFINE m0 0x100
#DEFINE m1 0x10000
#DEFINE m2 0x1000000
    LOCAL b0, b1, b2, b3
    b3 = Int(lnValue/m2)
    b2 = Int((lnValue - b3*m2)/m1)
    b1 = Int((lnValue - b3*m2 - b2*m1)/m0)
    b0 = Mod(lnValue, m0)
RETURN Chr(b0)+Chr(b1)+Chr(b2)+Chr(b3)
 
FUNCTION buf2dword (lcBuffer)
#DEFINE MAX_DWORD 0xffffffff
#DEFINE MAX_LONG 0x7FFFFFFF
    LOCAL lnResult
    lnResult = Asc(SUBSTR(lcBuffer, 1,1)) + ;
        Asc(SUBSTR(lcBuffer, 2,1)) * 256 +;
        Asc(SUBSTR(lcBuffer, 3,1)) * 65536 +;
        Asc(SUBSTR(lcBuffer, 4,1)) * 16777216
RETURN IIF(lnResult>MAX_LONG, lnResult-MAX_DWORD, lnResult)
 
PROCEDURE declare
    DECLARE INTEGER ChooseColor IN comdlg32 STRING @lpcc
    DECLARE INTEGER GetActiveWindow IN user32
    DECLARE INTEGER GlobalFree IN kernel32 INTEGER hMem
    DECLARE RtlZeroMemory IN kernel32 As ZeroMemory;
        INTEGER dest, INTEGER numBytes
 
    DECLARE INTEGER GlobalAlloc IN kernel32;
        INTEGER wFlags, INTEGER dwBytes
 
    DECLARE RtlMoveMemory IN kernel32 As Heap2Str;
            STRING @, INTEGER, INTEGER