path: root/win/tkWinSysTray.c

/*
 * 	tkWinSysTray.c implements a "systray" Tcl command which permits to
 * 	change the system tray/taskbar icon of a Tk toplevel window and
 * 	a "sysnotify" command to post system notifications.
 *
 * Copyright (c) 1995-1996 Microsoft Corp.
 * Copyright (c) 1998 Brueckner & Jarosch Ing.GmbH, Erfurt, Germany
 * Copyright (c) 2020 Kevin Walzer/WordTech Communications LLC.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
*/

#include "tkInt.h"
#include <windows.h>
#include <shellapi.h>
#include "tkWin.h"
#include "tkWinIco.h"
#include "tkWinInt.h"

/*
 * Based extensively on the winico extension and sample code from Microsoft.
 * Some of the code was adapted into tkWinWM.c to implement the "wm iconphoto"
 * command (TIP 159), and here we are borrowing that code to use Tk images
 * to create system tray icons instead of ico files. Additionally, we are
 * removing obsolete parts of the winico extension, and implementing
 * more of the Shell_Notification API to add balloon/system notifications.
 */

#define GETHINSTANCE Tk_GetHINSTANCE()

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif

#ifdef _MSC_VER
/*
 * Earlier versions of MSVC don't know snprintf, but _snprintf is compatible.
 * Note that sprintf is deprecated.
 */
# define snprintf _snprintf
#endif

static BlockOfIconImagesPtr CreateIcoFromTkImage(Tcl_Interp *interp, const char *image);

typedef struct IcoInfo {
    HICON hIcon;                /* icon handle returned by LoadIcon. */
    int itype;
    int id;                     /* Integer identifier for command;  used to
                                 * cancel it. */
    BlockOfIconImagesPtr lpIR;  /* IconresourcePtr */
    int iconpos;                /* hIcon is the nth Icon*/
    Tcl_Obj *taskbar_txt;       /* text to display in the taskbar */
    Tcl_Interp *interp;         /* interp which created the icon */
    Tcl_Obj *taskbar_command;   /* command to eval if events in the taskbar
                                 * arrive */
    int taskbar_flags;          /* taskbar related flags*/
    HWND hwndFocus;
    struct IcoInfo *nextPtr;
} IcoInfo;

/* Per-interp struture */
typedef struct IcoInterpInfo {
    int counter;                /* Counter for IcoInfo id generation */
    IcoInfo *firstIcoPtr;       /* List of created IcoInfo */
    struct IcoInterpInfo *nextPtr;
} IcoInterpInfo;

#define ICO_LOAD 1
#define ICO_FILE 2

#define TASKBAR_ICON 1
#define ICON_MESSAGE WM_USER + 1234

#define HANDLER_CLASS "Wtk_TaskbarHandler"
static HWND CreateTaskbarHandlerWindow(void);

static HWND handlerWindow = NULL;
static BlockOfIconImagesPtr iconBits = NULL;

static IcoInterpInfo *firstIcoInterpPtr = NULL;
static Tcl_ExitProc WinIcoDestroy;

/*
 *----------------------------------------------------------------------
 *
 * FreeIconResource --
 *
 * 	Frees memory from icon.
 *
 * Results:
 *	Memory released.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
FreeIconResource(
    BlockOfIconImagesPtr lpIR)
{
    int i;
    if (lpIR == NULL)
        return;
    /* Free all the bits */
    for (i = 0; i < lpIR->nNumImages; i++) {
        if (lpIR->IconImages[i].lpBits != NULL)
            ckfree(lpIR->IconImages[i].lpBits);
        if (lpIR->IconImages[i].hIcon != NULL)
            DestroyIcon(lpIR->IconImages[i].hIcon);
    }
    ckfree(lpIR);
}

/*
 * If someone wants to see the several masks somewhere on the screen...
 * set the ICO_DRAW define and feel free to make some Tcl commands
 * for accessing it.  The normal drawing of an Icon to a DC is really easy:
 * DrawIcon(hdc,x,y,hIcon) or , more complicated
 * DrawIconEx32PlusMoreParameters ...
 */

/* #define ICO_DRAW */
#ifdef ICO_DRAW
#define RectWidth(r)((r).right - (r).left + 1)
#define RectHeight(r)((r).bottom - (r).top + 1)

/*
 *----------------------------------------------------------------------
 *
 * DrawXORMask --
 *
 * 	Using DIB functions, draw XOR mask on hDC in Rect.
 *
 * Results:
 *	Icon is rendered.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static BOOL
DrawXORMask(
    HDC hDC,
    RECT Rect,
    LPLPICONIMAGE lpIcon)
{
    int x, y;

    /* Sanity checks */
    if (lpIcon == NULL)
        return FALSE;
    if (lpIcon->lpBits == NULL)
        return FALSE;

    /* Account for height*2 thing */
    lpIcon->lpbi->bmiHeader.biHeight /= 2;

    /* Locate it */
    x = Rect.left + ((RectWidth(Rect) - lpIcon->lpbi->bmiHeader.biWidth) / 2);
    y = Rect.top + ((RectHeight(Rect) - lpIcon->lpbi->bmiHeader.biHeight) / 2);

    /* Blast it to the screen */
    SetDIBitsToDevice(hDC, x, y,
            lpIcon->lpbi->bmiHeader.biWidth,
            lpIcon->lpbi->bmiHeader.biHeight,
            0, 0, 0, lpIcon->lpbi->bmiHeader.biHeight,
            lpIcon->lpXOR, lpIcon->lpbi, DIB_RGB_COLORS);

    /* UnAccount for height*2 thing */
    lpIcon->lpbi->bmiHeader.biHeight *= 2;

    return TRUE;
}

/*
 *----------------------------------------------------------------------
 *
 * DrawANDMask --
 *
 * 	Using DIB functions, draw AND mask on hDC in Rect.
 *
 * Results:
 *	Icon is rendered.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

BOOL
DrawANDMask(
    HDC hDC,
    RECT Rect,
    LPLPICONIMAGE lpIcon)
{
    LPBITMAPINFO lpbi;
    int x, y;

    /* Sanity checks */
    if (lpIcon == NULL)
        return FALSE;
    if (lpIcon->lpBits == NULL)
        return FALSE;

    /* Need a bitmap header for the mono mask */
    lpbi = ckalloc(sizeof(BITMAPINFO) + (2 * sizeof(RGBQUAD)));
    lpbi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    lpbi->bmiHeader.biWidth = lpIcon->lpbi->bmiHeader.biWidth;
    lpbi->bmiHeader.biHeight = lpIcon->lpbi->bmiHeader.biHeight / 2;
    lpbi->bmiHeader.biPlanes = 1;
    lpbi->bmiHeader.biBitCount = 1;
    lpbi->bmiHeader.biCompression = BI_RGB;
    lpbi->miHeader.biSizeImage = 0;
    lpbi->bmiHeader.biXPelsPerMeter = 0;
    lpbi->bmiHeader.biYPelsPerMeter = 0;
    lpbi->bmiHeader.biClrUsed = 0;
    lpbi->bmiHeader.biClrImportant = 0;
    lpbi->bmiColors[0].rgbRed = 0;
    lpbi->bmiColors[0].rgbGreen = 0;
    lpbi->bmiColors[0].rgbBlue = 0;
    lpbi->bmiColors[0].rgbReserved = 0;
    lpbi->bmiColors[1].rgbRed = 255;
    lpbi->bmiColors[1].rgbGreen = 255;
    lpbi->bmiColors[1].rgbBlue = 255;
    lpbi->bmiColors[1].rgbReserved = 0;

    /* Locate it */
    x = Rect.left + ((RectWidth(Rect) - lpbi->bmiHeader.biWidth) / 2);
    y = Rect.top + ((RectHeight(Rect) - lpbi->bmiHeader.biHeight) / 2);

    /* Blast it to the screen */
    SetDIBitsToDevice(hDC, x, y,
            lpbi->bmiHeader.biWidth,
            lpbi->bmiHeader.biHeight,
            0, 0, 0, lpbi->bmiHeader.biHeight,
            lpIcon->lpAND, lpbi, DIB_RGB_COLORS);

    /* clean up */
    ckfree((char *) lpbi);

    return TRUE;
}
#endif /* ICO_DRAW */

/*
 *----------------------------------------------------------------------
 *
 * TaskbarOperation --
 *
 * 	Management of icon display.
 *
 * Results:
 *	Icon is displayed or deleted.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
TaskbarOperation(
    IcoInfo *icoPtr,
    int oper)
{
    NOTIFYICONDATAW ni;
    WCHAR *str;

    ni.cbSize = sizeof(NOTIFYICONDATAW);
    ni.hWnd = CreateTaskbarHandlerWindow();
    ni.uID = (unsigned int) icoPtr;
    ni.uFlags = NIF_ICON | NIF_TIP | NIF_MESSAGE;
    ni.uCallbackMessage = ICON_MESSAGE;
    ni.hIcon = icoPtr->hIcon;

    if (icoPtr->taskbar_txt != NULL) {
        Tcl_DString dst;
        Tcl_DStringInit(&dst);
        str = (WCHAR *)Tcl_UtfToWCharDString(Tcl_GetString(icoPtr->taskbar_txt), -1, &dst);
        wcsncpy(ni.szTip, str, (Tcl_DStringLength(&dst) + 2) / 2);
        Tcl_DStringFree(&dst);
    } else {
        ni.szTip[0] = 0;
    }

    if (Shell_NotifyIconW(oper, &ni) == 1) {
        if (oper == NIM_ADD || oper == NIM_MODIFY) {
            icoPtr->taskbar_flags |= TASKBAR_ICON;
        }
        if (oper == NIM_DELETE) {
            icoPtr->taskbar_flags &= ~TASKBAR_ICON;
        }
    }
    /* Silently ignore error? */
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * NewIcon --
 *
 * 	Create icon for display in system tray.
 *
 * Results:
 *	Icon is created for display.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static IcoInfo *
NewIcon(
    Tcl_Interp *interp,
    IcoInterpInfo *icoInterpPtr,
    HICON hIcon,
    int itype, BlockOfIconImagesPtr lpIR, int iconpos)
{
    IcoInfo *icoPtr;

    icoPtr = (IcoInfo *)ckalloc(sizeof(IcoInfo));
    memset(icoPtr, 0, sizeof(IcoInfo));
    icoPtr->id = ++icoInterpPtr->counter;
    icoPtr->hIcon = hIcon;
    icoPtr->itype = itype;
    icoPtr->lpIR = lpIR;
    icoPtr->iconpos = iconpos;
    icoPtr->taskbar_txt = NULL;
    icoPtr->interp = interp;
    icoPtr->taskbar_command = NULL;
    icoPtr->taskbar_flags = 0;
    icoPtr->hwndFocus = NULL;
    if (itype == ICO_LOAD) {
        icoPtr->lpIR = (BlockOfIconImagesPtr) NULL;
        icoPtr->iconpos = 0;
    }
    icoPtr->nextPtr = icoInterpPtr->firstIcoPtr;
    icoInterpPtr->firstIcoPtr = icoPtr;
    return icoPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * FreeIcoPtr --
 *
 * 	Delete icon and free memory.
 *
 * Results:
 *	Icon is removed from display.
 *
 * Side effects:
 *	Memory/resources freed.
 *
 *----------------------------------------------------------------------
 */

static void
FreeIcoPtr(
    IcoInterpInfo *icoInterpPtr,
    IcoInfo *icoPtr)
{
    IcoInfo *prevPtr;
    if (icoInterpPtr->firstIcoPtr == icoPtr) {
        icoInterpPtr->firstIcoPtr = icoPtr->nextPtr;
    } else {
        for (prevPtr = icoInterpPtr->firstIcoPtr; prevPtr->nextPtr != icoPtr; prevPtr = prevPtr->nextPtr) {
            /* Empty loop body. */
        }
        prevPtr->nextPtr = icoPtr->nextPtr;
    }
    if (icoPtr->taskbar_flags & TASKBAR_ICON) {
        TaskbarOperation(icoPtr, NIM_DELETE);
    }
    if (icoPtr->itype != ICO_FILE) {
        FreeIconResource(icoPtr->lpIR);
        ckfree(icoPtr->lpIR);
    }
    if (icoPtr->taskbar_txt != NULL) {
        Tcl_DecrRefCount(icoPtr->taskbar_txt);
    }
    if (icoPtr->taskbar_command != NULL) {
        Tcl_DecrRefCount(icoPtr->taskbar_command);
    }
    ckfree(icoPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * GetIcoPtr --
 *
 * 	Get pointer to icon for display.
 *
 * Results:
 *	Icon is obtained for display.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static IcoInfo *
GetIcoPtr(
    Tcl_Interp *interp,
    IcoInterpInfo *icoInterpPtr,
    const char *string)
{
    IcoInfo *icoPtr;
    int id;
    const char *start;
    char *end;

    if (strncmp(string, "ico#", 4) != 0) {
        goto notfound;
    }
    start = string + 4;
    id = strtoul(start, &end, 10);
    if ((end == start) || (*end != 0)) {
        goto notfound;
    }
    for (icoPtr = icoInterpPtr->firstIcoPtr; icoPtr != NULL; icoPtr = icoPtr->nextPtr) {
        if (icoPtr->id == id) {
            return icoPtr;
        }
    }

notfound:
    Tcl_AppendResult(interp, "icon \"", string,
        "\" doesn't exist", (char *) NULL);
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * GetInt --
 *
 * Utility function for calculating buffer length.
 *
 * Results:
 *	Length.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
GetInt(
    long theint,
    char *buffer,
    size_t len)
{
    snprintf(buffer, len, "0x%lx", theint);
    buffer[len - 1] = 0;
    return (int) strlen(buffer);
}

/*
 *----------------------------------------------------------------------
 *
 * GetIntDec --
 *
 * Utility function for calculating buffer length.
 *
 * Results:
 *	Length.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
GetIntDec(
    long theint,
    char *buffer,
    size_t len)
{
    snprintf(buffer, len - 1, "%ld", theint);
    buffer[len - 1] = 0;
    return (int) strlen(buffer);
}

/*
 *----------------------------------------------------------------------
 *
 * TaskbarExpandPercents --
 *
 * Parse strings in taskbar display.
 *
 * Results:
 *	Strings.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static char*
TaskbarExpandPercents(
    IcoInfo *icoPtr,
    const char *msgstring,
    WPARAM wParam,
    LPARAM lParam,
    char *before,
    char *after,
    int *aftersize)
{
#define SPACELEFT (*aftersize-(dst-after)-1)
#define AFTERLEN ((*aftersize>0)?(*aftersize*2):1024)
#define ALLOCLEN ((len>AFTERLEN)?(len*2):AFTERLEN)
    char buffer[TCL_INTEGER_SPACE + 5];
    char* dst;
    dst = after;
    while (*before) {
        const char *ptr=before;
        int len=1;
        if(*before=='%') {
            switch(before[1]){
                case 'M':
                case 'm': {
                    before++;
                    len = strlen(msgstring);
                    ptr = msgstring;
                    break;
                }
                /* case 'W': {
                   before++;
                   len=(int)strlen(winstring);
                   ptr=winstring;
                   break;
                   }
                */
                case 'i': {
                    before++;
                    snprintf(buffer, sizeof(buffer) - 1, "ico#%d", icoPtr->id);
                    len = strlen(buffer);
                    ptr = buffer;
                    break;
                }
                case 'w': {
                    before++;
                    len = GetInt((long)wParam,buffer, sizeof(buffer));
                    ptr = buffer;
                    break;
                }
                case 'l': {
                    before++;
                    len = GetInt((long)lParam,buffer, sizeof(buffer));
                    ptr = buffer;
                    break;
                }
                case 't': {
                    before++;
                    len = GetInt((long)GetTickCount(), buffer, sizeof(buffer));
                    ptr = buffer;
                    break;
                }
                case 'x': {
                    POINT pt;
                    GetCursorPos(&pt);
                    before++;
                    len = GetIntDec((long)pt.x, buffer, sizeof(buffer));
                    ptr = buffer;
                    break;
                }
                case 'y': {
                    POINT pt;
                    GetCursorPos(&pt);
                    before++;
                    len = GetIntDec((long)pt.y,buffer, sizeof(buffer));
                    ptr = buffer;
                    break;
                }
                case 'X': {
                    DWORD dw;
                    dw=GetMessagePos();
                    before++;
                    len = GetIntDec((long)LOWORD(dw),buffer, sizeof(buffer));
                    ptr = buffer;
                    break;
                }
                case 'Y': {
                    DWORD dw;
                    dw = GetMessagePos();
                    before++;
                    len = GetIntDec((long)HIWORD(dw),buffer, sizeof(buffer));
                    ptr = buffer;
                    break;
                }
                case 'H': {
                    before++;
                    len = GetInt(PTR2INT(icoPtr->hwndFocus), buffer, sizeof(buffer));
                    ptr = buffer;
                    break;
                }
                case '%': {
                    before++;
                    len = 1;
                    ptr = "%";
                    break;
                }
            }
        }
        if (SPACELEFT < len) {
            char *newspace;
            ptrdiff_t dist = dst - after;
            int alloclen = ALLOCLEN;
            newspace = (char *)ckalloc(alloclen);
            if (dist>0)
                memcpy(newspace, after, dist);
            if (after && *aftersize) {
                ckfree(after);
            }
            *aftersize =alloclen;
            after = newspace;
            dst = after + dist;
        }
        if (len > 0) {
            memcpy(dst, ptr, len);
        }
        dst += len;
        if ((dst-after)>(*aftersize-1)) {
            printf("oops\n");
        }
        before++;
    }
    *dst = 0;
    return after;
}

/*
 *----------------------------------------------------------------------
 *
 * TaskbarEval --
 *
 * Parse mouse and keyboard events over taskbar.
 *
 * Results:
 *	Event processing.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
TaskbarEval(
    IcoInfo *icoPtr,
    WPARAM wParam,
    LPARAM lParam)
{
    const char *msgstring = "none";
    char evalspace[200];
    int evalsize = 200;
    char *expanded;
    int fixup = 0;

    switch (lParam) {
    case WM_MOUSEMOVE:
        msgstring = "WM_MOUSEMOVE";
        icoPtr->hwndFocus = GetFocus();
        break;
    case WM_LBUTTONDOWN:
        msgstring = "WM_LBUTTONDOWN";
        fixup = 1;
        break;
    case WM_LBUTTONUP:
        msgstring = "WM_LBUTTONUP";
        fixup = 1;
        break;
    case WM_LBUTTONDBLCLK:
        msgstring = "WM_LBUTTONDBLCLK";
        fixup = 1;
        break;
    case WM_RBUTTONDOWN:
        msgstring = "WM_RBUTTONDOWN";
        fixup = 1;
        break;
    case WM_RBUTTONUP:
        msgstring = "WM_RBUTTONUP";
        fixup = 1;
        break;
    case WM_RBUTTONDBLCLK:
        msgstring = "WM_RBUTTONDBLCLK";
        fixup = 1;
        break;
    case WM_MBUTTONDOWN:
        msgstring = "WM_MBUTTONDOWN";
        fixup = 1;
        break;
    case WM_MBUTTONUP:
        msgstring = "WM_MBUTTONUP";
        fixup = 1;
        break;
    case WM_MBUTTONDBLCLK:
        msgstring = "WM_MBUTTONDBLCLK";
        fixup = 1;
        break;
    default:
        msgstring = "WM_NULL";
        fixup = 0;
    }
    expanded = TaskbarExpandPercents(icoPtr, msgstring, wParam, lParam,
        Tcl_GetString(icoPtr->taskbar_command), evalspace, &evalsize);
    if (icoPtr->interp != NULL) {
        int result;
        HWND hwnd = NULL;

        /* See http//:support.microsoft.com/kb/q135788 */
        if (fixup) {
            if (icoPtr->hwndFocus != NULL && IsWindow(icoPtr->hwndFocus)) {
                hwnd = icoPtr->hwndFocus;
            } else {
                Tk_Window tkwin = Tk_MainWindow(icoPtr->interp);
                hwnd = Tk_GetHWND(Tk_WindowId(tkwin));
            }
            SetForegroundWindow(hwnd);
        }

        result = Tcl_GlobalEval(icoPtr->interp, expanded);

        if (hwnd != NULL) {
            /* See http:/ /support.microsoft.com/kb/q135788/ */
            PostMessageW(hwnd, WM_NULL, 0, 0);
        }
        if (result != TCL_OK) {
            char buffer[100];
            sprintf(buffer, "\n  (command bound to taskbar-icon ico#%d)", icoPtr->id);
            Tcl_AddErrorInfo(icoPtr->interp, buffer);
            Tcl_BackgroundError(icoPtr->interp);
        }
    }
    if (expanded != evalspace) {
        ckfree(expanded);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TaskbarHandlerProc --
 *
 * 	Windows callback procedure, if ICON_MESSAGE arrives, try to execute
 * 	the taskbar_command.
 *
 * Results:
 *	Command execution.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static LRESULT CALLBACK
TaskbarHandlerProc(
    HWND hwnd,
    UINT message,
    WPARAM wParam,
    LPARAM lParam)
{
    static UINT msgTaskbarCreated = 0;
    IcoInterpInfo *icoInterpPtr;
    IcoInfo *icoPtr;

    switch (message) {
    case WM_CREATE:
        msgTaskbarCreated = RegisterWindowMessage(TEXT("TaskbarCreated"));
        break;

    case ICON_MESSAGE:
        icoPtr = (IcoInfo*) wParam;
        if (icoPtr->taskbar_command != NULL) {
            TaskbarEval(icoPtr, wParam, lParam);
        }
        break;

    default:
        /*
         * Check to see if explorer has been restarted and we need to
         * re-add our icons.
         */
        if (message == msgTaskbarCreated) {
            for (icoInterpPtr = firstIcoInterpPtr; icoInterpPtr != NULL; icoInterpPtr = icoInterpPtr->nextPtr) {
                for (icoPtr = icoInterpPtr->firstIcoPtr; icoPtr != NULL; icoPtr = icoPtr->nextPtr) {
                    if (icoPtr->taskbar_flags & TASKBAR_ICON) {
                        TaskbarOperation(icoPtr, NIM_ADD);
                    }
                }
            }
        }
        return DefWindowProc(hwnd, message, wParam, lParam);
    }
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * RegisterHandlerClass --
 *
 * 	Registers the handler window class.
 *
 * Results:
 *	Handler class registered.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
RegisterHandlerClass(
    HINSTANCE hInstance)
{
    WNDCLASS wndclass;
    memset(&wndclass, 0, sizeof(WNDCLASS));
    wndclass.style = 0;
    wndclass.lpfnWndProc = TaskbarHandlerProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = HANDLER_CLASS;
    return RegisterClass(&wndclass);
}

/*
 *----------------------------------------------------------------------
 *
 * CreateTaskbarHandlerWindow --
 *
 * 	Creates a hidden window to handle taskbar messages.
 *
 * Results:
 *	Hidden window created.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static HWND
CreateTaskbarHandlerWindow(void) {
    static int registered = 0;
    HINSTANCE hInstance = GETHINSTANCE;
    if (handlerWindow)
        return handlerWindow;
    if (!registered) {
        if (!RegisterHandlerClass(hInstance))
            return 0;
        registered = 1;
    }
    return (handlerWindow = CreateWindow(HANDLER_CLASS, "", WS_OVERLAPPED, 0, 0,
            CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL));
}

/*
 *----------------------------------------------------------------------
 *
 * DestroyHandlerWindow --
 *
 * 	Destroys hidden window.
 *
 * Results:
 *	Hidden window deleted.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
DestroyHandlerWindow(void) {
    if (handlerWindow)
        DestroyWindow(handlerWindow);
}

/*
 *----------------------------------------------------------------------
 *
 * WinIcoDestroy --
 *
 * 	Deletes icon and hidden window from display.
 *
 * Results:
 *	Icon/window removed and memory freed.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
WinIcoDestroy(
    ClientData clientData)
{
    IcoInterpInfo *icoInterpPtr = (IcoInterpInfo*) clientData;
    IcoInterpInfo *prevIcoInterpPtr;
    IcoInfo *icoPtr;
    IcoInfo *nextPtr;

    Tcl_DeleteThreadExitHandler(WinIcoDestroy, clientData);
    
    if (firstIcoInterpPtr == icoInterpPtr) {
        firstIcoInterpPtr = icoInterpPtr->nextPtr;
    } else {
        for (prevIcoInterpPtr = firstIcoInterpPtr; prevIcoInterpPtr->nextPtr != icoInterpPtr;
             prevIcoInterpPtr = prevIcoInterpPtr->nextPtr) {
            /* Empty loop body. */
        }
        prevIcoInterpPtr->nextPtr = icoInterpPtr->nextPtr;
    }

    for (icoPtr = icoInterpPtr->firstIcoPtr; icoPtr != NULL; icoPtr = nextPtr) {
        nextPtr = icoPtr->nextPtr;
        FreeIcoPtr(icoInterpPtr, icoPtr);
    }
    ckfree((char *) icoInterpPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * CreateIcoFromTkImage --
 *
 *	Create ico pointer from Tk image for display in system tray. Adapted
 *      from "wm iconphoto" code in tkWinWm.c.
 *
 * Results:
 *	Icon image is created from a valid Tk photo image.
 *
 * Side effects:
 *	Icon is created.
 *
 *----------------------------------------------------------------------
 */

static BlockOfIconImagesPtr
CreateIcoFromTkImage(
    Tcl_Interp *interp,         /* Current interpreter. */
    const char *image)          /* Image to convert. */
{
    Tk_PhotoHandle photo;
    Tk_PhotoImageBlock block;
    int width, height, idx, bufferSize;
    union {unsigned char *ptr; void *voidPtr;} bgraPixel;
    union {unsigned char *ptr; void *voidPtr;} bgraMask;
    HICON hIcon;
    unsigned size;
    BITMAPINFO bmInfo;
    ICONINFO iconInfo;
    Tk_Image tk_image;
    Tk_Window tkwin = Tk_MainWindow(interp);

    tk_image = Tk_GetImage(interp, tkwin, image, NULL, NULL);
    if (tk_image == NULL) {
        return NULL;
    }

    /*
     * The image exists. Try to allocate the needed memory space.
     */

    size = sizeof(BlockOfIconImages) + (sizeof(ICONIMAGE));
    iconBits = (BlockOfIconImagesPtr)attemptckalloc(size);
    if (iconBits == NULL) {
        return NULL;
    }
    ZeroMemory(iconBits, size);

    iconBits->nNumImages = 1;

    photo = Tk_FindPhoto(interp, image);
    Tk_PhotoGetSize(photo, &width, &height);
    Tk_PhotoGetImage(photo, &block);

    /*
     * Don't use CreateIcon to create the icon, as it requires color
     * bitmap data in device-dependent format. Instead we use
     * CreateIconIndirect which takes device-independent bitmaps and
     * converts them as required. Initialise icon info structure.
     */

    ZeroMemory(&iconInfo, sizeof(iconInfo));
    iconInfo.fIcon = TRUE;

    /*
     * Create device-independent color bitmap.
     */

    ZeroMemory(&bmInfo, sizeof bmInfo);
    bmInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    bmInfo.bmiHeader.biWidth = width;
    bmInfo.bmiHeader.biHeight = -height;
    bmInfo.bmiHeader.biPlanes = 1;
    bmInfo.bmiHeader.biBitCount = 32;
    bmInfo.bmiHeader.biCompression = BI_RGB;

    iconInfo.hbmColor = CreateDIBSection(NULL, &bmInfo, DIB_RGB_COLORS,
            &bgraPixel.voidPtr, NULL, 0);
    if (!iconInfo.hbmColor) {
        FreeIconResource(iconBits);
        Tcl_SetObjResult(interp, Tcl_ObjPrintf(
                "failed to create an iconphoto with image \"%s\"", image));
        return NULL;
    }

    /*
     * Convert the photo image data into BGRA format (RGBQUAD).
     */

    bufferSize = height * width * 4;
    for (idx = 0 ; idx < bufferSize ; idx += 4) {
        bgraPixel.ptr[idx] = block.pixelPtr[idx+2];
        bgraPixel.ptr[idx+1] = block.pixelPtr[idx+1];
        bgraPixel.ptr[idx+2] = block.pixelPtr[idx+0];
        bgraPixel.ptr[idx+3] = block.pixelPtr[idx+3];
    }

    /*
     * Create a dummy mask bitmap. The contents of this don't appear to
     * matter, as CreateIconIndirect will setup the icon mask based on the
     * alpha channel in our color bitmap.
     */

    bmInfo.bmiHeader.biBitCount = 1;

    iconInfo.hbmMask = CreateDIBSection(NULL, &bmInfo, DIB_RGB_COLORS,
            &bgraMask.voidPtr, NULL, 0);
    if (!iconInfo.hbmMask) {
        DeleteObject(iconInfo.hbmColor);
        FreeIconResource(iconBits);
        Tcl_SetObjResult(interp, Tcl_ObjPrintf(
                "failed to create mask bitmap for \"%s\"", image));
        return NULL;
    }

    ZeroMemory(bgraMask.ptr, width*height/8);

    /*
     * Create an icon from the bitmaps.
     */

    hIcon = CreateIconIndirect(&iconInfo);
    DeleteObject(iconInfo.hbmColor);
    DeleteObject(iconInfo.hbmMask);
    if (hIcon == NULL) {
        /*
         * XXX should free up created icons.
         */

        FreeIconResource(iconBits);
        Tcl_SetObjResult(interp, Tcl_ObjPrintf(
	        "failed to create icon for \"%s\"",
	        image));
        return NULL;
    }
    iconBits->IconImages[0].Width = width;
    iconBits->IconImages[0].Height = height;
    iconBits->IconImages[0].Colors = 4;
    iconBits->IconImages[0].hIcon = hIcon;

    return iconBits;
}

/*
 *----------------------------------------------------------------------
 *
 * WinSystrayCmd --
 *
 * 	Main command for creating, displaying, and removing icons from taskbar.
 *
 * Results:
 *	Management of icon display in taskbar/system tray.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
WinSystrayCmd(
    ClientData clientData,
    Tcl_Interp *interp,
    int objc,
    Tcl_Obj *const objv[])
{
    static const char *cmdStrings[] = {
        "add", "delete", "modify", NULL
    };
    enum { CMD_ADD, CMD_DELETE, CMD_MODIFY };
    static const char *optStrings[] = {
        "-image", "-text", "-callback", NULL
    };
    enum { OPT_IMAGE, OPT_TEXT, OPT_CALLBACK };
    int cmd, opt;

    HICON hIcon;
    int i;
    IcoInterpInfo *icoInterpPtr = (IcoInterpInfo*) clientData;
    IcoInfo *icoPtr;
    BlockOfIconImagesPtr lpIR = NULL;

    if (objc < 2) {
        Tcl_WrongNumArgs(interp, 1, objv, "command ...");
        return TCL_ERROR;
    }
    if (Tcl_GetIndexFromObj(interp, objv[1], cmdStrings, "command",
            0, &cmd) == TCL_ERROR) {
        return TCL_ERROR;
    }
    switch (cmd) {
        case CMD_ADD:
        case CMD_MODIFY: {
            Tcl_Obj *imageObj = NULL, *textObj = NULL, *callbackObj = NULL;
            int optStart;
            int oper;
            if (cmd == CMD_ADD) {
                optStart = 2;
                oper = NIM_ADD;
            } else {
                optStart = 3;
                oper = NIM_MODIFY;
                if (objc != 5) {
                    Tcl_WrongNumArgs(interp, 2, objv, "id option value");
                    return TCL_ERROR;
                }
                icoPtr = GetIcoPtr(interp, icoInterpPtr, Tcl_GetString(objv[2]));
                if (icoPtr == NULL) {
                    return TCL_ERROR;
                }
            }
            for (i=optStart; i<objc; i+=2) {
                if (Tcl_GetIndexFromObj(interp, objv[i], optStrings, "option",
                        0, &opt) == TCL_ERROR) {
                    return TCL_ERROR;
                }
                if (i+1 >= objc) {
                    Tcl_AppendResult(interp,
                        "missing value for option \"", Tcl_GetString(objv[i]), "\"", NULL);
                    return TCL_ERROR;
                }
                switch (opt) {
                    case OPT_IMAGE:
                        imageObj = objv[i+1];
                        break;
                    case OPT_TEXT:
                        textObj = objv[i+1];
                        break;
                    case OPT_CALLBACK:
                        callbackObj = objv[i+1];
                        break;
                }
            }
            if (cmd == CMD_ADD && imageObj == NULL) {
                Tcl_SetResult(interp, "missing required option \"-image\"", TCL_STATIC);
                return TCL_ERROR;
            }
            if (imageObj != NULL) {
                lpIR = CreateIcoFromTkImage(interp, Tcl_GetString(imageObj));
                if (lpIR == NULL) {
                    return TCL_ERROR;
                }
            }
            if (cmd == CMD_ADD) {
                hIcon = lpIR->IconImages[0].hIcon;
                icoPtr = NewIcon(interp, icoInterpPtr, hIcon, ICO_FILE, lpIR, 0);
            } else {
                if (imageObj != NULL) {
                    DestroyIcon(icoPtr->hIcon);
                    icoPtr->hIcon = lpIR->IconImages[0].hIcon;
                }
            }
            if (callbackObj != NULL) {
                if (icoPtr->taskbar_command != NULL) {
                    Tcl_DecrRefCount(icoPtr->taskbar_command);
                }
                icoPtr->taskbar_command = callbackObj;
                Tcl_IncrRefCount(icoPtr->taskbar_command);
            }
            if (textObj != NULL) {
                if (icoPtr->taskbar_txt != NULL) {
                    Tcl_DecrRefCount(icoPtr->taskbar_txt);
                }
                icoPtr->taskbar_txt = textObj;
                Tcl_IncrRefCount(icoPtr->taskbar_txt);
            }
            TaskbarOperation(icoPtr, oper);
            if (cmd == CMD_ADD) {
                char buffer[5 + TCL_INTEGER_SPACE];
                int n;
                n = _snprintf(buffer, sizeof(buffer) - 1, "ico#%d", icoPtr->id);
                buffer[n] = 0;
                Tcl_SetObjResult(interp, Tcl_NewStringObj(buffer, n));
            }
            return TCL_OK;
        }
        case CMD_DELETE:
            if (objc != 3) {
                Tcl_WrongNumArgs(interp, 2, objv, "id");
                return TCL_ERROR;
            }
            icoPtr = GetIcoPtr(interp, icoInterpPtr, Tcl_GetString(objv[2]));
            if (icoPtr == NULL) {
                return TCL_ERROR;
            }
            FreeIcoPtr(icoInterpPtr, icoPtr);
            return TCL_OK;
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * WinSysNotifyCmd --
 *
 * 	Main command for creating and displaying notifications/balloons from system tray.
 *
 * Results:
 *	Display of notifications.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
WinSysNotifyCmd(
    ClientData clientData,
    Tcl_Interp *interp,
    int objc,
    Tcl_Obj *const objv[])
{
    IcoInterpInfo *icoInterpPtr = (IcoInterpInfo*) clientData;
    IcoInfo *icoPtr;
    Tcl_DString infodst;
    Tcl_DString titledst;
    NOTIFYICONDATAW ni;
    char *msgtitle;
    char *msginfo;

    if (objc < 2) {
        Tcl_WrongNumArgs(interp, 1, objv, "command ...");
        return TCL_ERROR;
    }
    if (strcmp(Tcl_GetString(objv[1]), "notify") != 0) {
        Tcl_AppendResult(interp, "unknown subcommand \"", Tcl_GetString(objv[1]),
            "\": must be notify", NULL);
        return TCL_ERROR;
    }
    if (objc != 5) {
        Tcl_WrongNumArgs(interp, 2, objv, "id title detail");
        return TCL_ERROR;
    }

    icoPtr = GetIcoPtr(interp, icoInterpPtr, Tcl_GetString(objv[2]));
    if (icoPtr == NULL) {
        return TCL_ERROR;
    }

    ni.cbSize = sizeof(NOTIFYICONDATAW);
    ni.hWnd = CreateTaskbarHandlerWindow();
    ni.uID = (unsigned int) icoPtr;
    ni.uFlags = NIF_INFO;
    ni.uCallbackMessage = ICON_MESSAGE;
    ni.hIcon = icoPtr->hIcon;
    ni.dwInfoFlags = NIIF_INFO; /*Use a sane platform-specific icon here.*/

    msgtitle = Tcl_GetString(objv[3]);
    msginfo = Tcl_GetString(objv[4]);

    /* Balloon notification for system tray icon. */
    if (msgtitle != NULL) {
        WCHAR *title;
        Tcl_DStringInit(&titledst);
        title = Tcl_UtfToWCharDString(msgtitle, -1, &titledst);
        wcsncpy(ni.szInfoTitle, title, (Tcl_DStringLength(&titledst) + 2) / 2);
        Tcl_DStringFree(&titledst);
    }
    if (msginfo != NULL) {
        WCHAR *info;
        Tcl_DStringInit(&infodst);
        info = Tcl_UtfToWCharDString(msginfo, -1, &infodst);
        wcsncpy(ni.szInfo, info, (Tcl_DStringLength(&infodst) + 2) / 2);
        Tcl_DStringFree(&infodst);
    }

    Shell_NotifyIconW(NIM_MODIFY, &ni);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * WinIcoInit --
 *
 * 	Initialize this package and create script-level commands.
 *
 * Results:
 *	Initialization of code.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
WinIcoInit(
    Tcl_Interp *interp)
{
    IcoInterpInfo *icoInterpPtr;

#ifdef USE_TCL_STUBS
    if (Tcl_InitStubs(interp, TCL_VERSION, 0) == NULL) {
        return TCL_ERROR;
    }
#endif
#ifdef USE_TK_STUBS
    if (Tk_InitStubs(interp, TK_VERSION, 0) == NULL) {
        return TCL_ERROR;
    }
#endif

    icoInterpPtr = (IcoInterpInfo*) ckalloc(sizeof(IcoInterpInfo));
    icoInterpPtr->counter = 0;
    icoInterpPtr->firstIcoPtr = NULL;
    icoInterpPtr->nextPtr = firstIcoInterpPtr;
    firstIcoInterpPtr = icoInterpPtr;
    Tcl_CreateObjCommand(interp, "::tk::systray::_systray", WinSystrayCmd,
        (ClientData) icoInterpPtr, NULL);
    Tcl_CreateObjCommand(interp, "::tk::sysnotify::_sysnotify", WinSysNotifyCmd,
        (ClientData) icoInterpPtr, NULL);

    Tcl_CallWhenDeleted(interp, (Tcl_InterpDeleteProc*) WinIcoDestroy, (ClientData) icoInterpPtr);
    Tcl_CreateThreadExitHandler(WinIcoDestroy, (ClientData) icoInterpPtr);
    
    return TCL_OK;
}

/*
 * Local variables:
 * mode: c
 * indent-tabs-mode: nil
 * End:
 */