Making of a Color Spy utility with WTL

//////////////////////////////////////////////////////////////////////
// ColorSpy Copyright 2003 Tom Furuya
//
// Readers of this article may copy the code for use in developing their own applications.
// If the code is used in a commercial application, however, an acknolegement must 
// be included in the following form: 
// "Segment of the code (c) 2003 Tom Furuya for CodeProject.com"
//////////////////////////////////////////////////////////////////////

// SysColors.h: interface for the CSysColors class.

#if !defined(AFX_SYSCOLORS_H__28A71688_1A1F_40FD_AD2A_D4009D229DBB__INCLUDED_)
#define AFX_SYSCOLORS_H__28A71688_1A1F_40FD_AD2A_D4009D229DBB__INCLUDED_

#pragma once

#include "Duo.h"

#define SCT_ENTRY(type) \
	{ type, _T(#type), 0, 0 }

#define theSystemColors CSysColors::GetSysColors()

//
// CSysColors - System Color utility class
//
class CSysColors  
{
public:
    typedef struct SysColor 
    {
        int type;  
        TCHAR* name;
        int nameLen;    // for performance
        COLORREF clr;
    };

    enum { INVALID_COLOR_TYPE = -1 };

	static bool s_bStaticInit;
    static int  s_nMaxPatternLen;

    static DuoT<bool, COLORREF> GetColorByName(const CString& name)
    {
        const DuoT<bool, COLORREF> InvalidColor = make_duo(false, 0);
        const CString strColor = _T("COLOR_");
        const int nMinLen = 6;
        const int len = name.GetLength();

        SysColor* pos = GetSysColors();

        if (len <= nMinLen || s_nMaxPatternLen < len) return InvalidColor;
        if (strColor != name.Left(nMinLen)) return InvalidColor;

        while (pos->type != INVALID_COLOR_TYPE)
        {
            if (len == pos->nameLen && pos->name[nMinLen] == name[nMinLen])
            {
                if (name == pos->name)
                    return make_duo(true, pos->clr);
            }
            pos++;
        }
        return InvalidColor;
    }

    inline COLORREF GetSystemColor(int nIndex)
    {
        ATLASSERT(COLOR_SCROLLBAR <= nIndex && nIndex <= COLOR_MENUBAR);
        ATLASSERT(nIndex != 25); // unused slot

        return GetSysColors()[nIndex].clr;
    }

    static SysColor* const GetSysColors() 
    {
        // There are about 30 different system color types as display aspects [WinUser.h].

        static SysColor SysColors[] = 
        {
            SCT_ENTRY(COLOR_SCROLLBAR),         // Scroll bar color
            SCT_ENTRY(COLOR_BACKGROUND),        // Desktop color (same as COLOR_DESKTOP which sounds more descriptive)
            SCT_ENTRY(COLOR_ACTIVECAPTION),     // Color of the title bar for the active window (Color1)
            SCT_ENTRY(COLOR_INACTIVECAPTION),   // Color of the title bar for the inactive window
            SCT_ENTRY(COLOR_MENU),              // Menu background color
            SCT_ENTRY(COLOR_WINDOW),            // Window background color
            SCT_ENTRY(COLOR_WINDOWFRAME),       // Window frame color
            SCT_ENTRY(COLOR_MENUTEXT),          // Color of text on menus
            SCT_ENTRY(COLOR_WINDOWTEXT),        // Color of text in windows
            SCT_ENTRY(COLOR_CAPTIONTEXT),       // Color of text in caption, size box, and
                                                // scroll arrow
            SCT_ENTRY(COLOR_ACTIVEBORDER),      // Border color of active window
            SCT_ENTRY(COLOR_INACTIVEBORDER),    // Border color of inactive window
            SCT_ENTRY(COLOR_APPWORKSPACE),      // Background color of multiple-document interface
                                                // (MDI) applications
            SCT_ENTRY(COLOR_HIGHLIGHT),         // Background color of items selected in a control
            SCT_ENTRY(COLOR_HIGHLIGHTTEXT),     // Text color of items selected in a control
            SCT_ENTRY(COLOR_BTNFACE),           // Color of shading on the face of command buttons
            SCT_ENTRY(COLOR_BTNSHADOW),         // Color of shading on the edge of command buttons
            SCT_ENTRY(COLOR_GRAYTEXT),          // Grayed (disabled) text
            SCT_ENTRY(COLOR_BTNTEXT),           // Text color on push buttons
            SCT_ENTRY(COLOR_INACTIVECAPTIONTEXT),// Color of text in an inactive caption
            SCT_ENTRY(COLOR_BTNHIGHLIGHT),      // Highlight color for 3-D display elements

#if(WINVER >= 0x0400)

            SCT_ENTRY(COLOR_3DDKSHADOW),        // Darkest shadow color for 3-D display elements
            SCT_ENTRY(COLOR_3DLIGHT),           // Second lightest 3-D color after 3DHighlight
            SCT_ENTRY(COLOR_INFOTEXT),          // Color of text in ToolTips
            SCT_ENTRY(COLOR_INFOBK),            // Background color of ToolTips

#endif /* WINVER >= 0x0400 */

            { 0, NULL, 0, 0 },                  // 25 - no entry...

#if(WINVER >= 0x0500)

            SCT_ENTRY(COLOR_HOTLIGHT),
            SCT_ENTRY(COLOR_GRADIENTACTIVECAPTION),  //Active Titlebar background color (color for Color2)
            SCT_ENTRY(COLOR_GRADIENTINACTIVECAPTION),//Inactive Titlebar background color 

#endif /* WINVER >= 0x0500 */

#if(WINVER >= 0x0501)

            SCT_ENTRY(COLOR_MENUHILIGHT),
            SCT_ENTRY(COLOR_MENUBAR),

#endif /* WINVER >= 0x0501 */

            { INVALID_COLOR_TYPE, NULL, 0, 0 }
        };

        if (s_bStaticInit) return SysColors;
        // one time initialization
        SysColor* pos = SysColors;
        while (pos->type != INVALID_COLOR_TYPE)
        {
            pos->nameLen = lstrlen(pos->name);
            if (s_nMaxPatternLen < pos->nameLen)
                s_nMaxPatternLen = pos->nameLen;
            pos->clr = GetSysColor(pos->type);
            pos++;
        }
        // done
        s_bStaticInit = true;
        return SysColors;
    }

};

__declspec(selectany) bool CSysColors::s_bStaticInit = false;
__declspec(selectany) int CSysColors::s_nMaxPatternLen = 0;

#endif // !defined(AFX_SYSCOLORS_H__28A71688_1A1F_40FD_AD2A_D4009D229DBB__INCLUDED_)