// if the global clip region has a new age,// this function empty effective clip region first,// and then intersect local clip region and global clip region.BOOL dc_GenerateECRgn(PDC pdc, BOOL fForce){    RECT rc, rcInter;    PCLIPRECT pcr, pgcr;    PCONTROL pCtrl;    // is global clip region is empty?    if ((!fForce) && (!dc_IsVisible (pdc)))            return FALSE;#if defined(_LITE_VERSION) && !defined(_STAND_ALONE)    if (!mgIsServer) lock_scr_sem ();#endif    // need regenerate?#if defined(_LITE_VERSION) && !defined(_STAND_ALONE)    if (fForce || (pdc->oldage != pdc->pGCRInfo->age)               || (!mgIsServer && pdc->scr_sig != SHAREDRES_SCRINFO.signature)) {#else    if (fForce || (pdc->oldage != pdc->pGCRInfo->age)) {#endif        EmptyClipRgn (&pdc->ecrgn);        pcr = pdc->lcrgn.head;        while (pcr) {            rc = pcr->rc;            coor_LP2SP (pdc, &rc.left, &rc.top);            coor_LP2SP (pdc, &rc.right, &rc.bottom);                        pgcr = pdc->pGCRInfo->crgn.head;            while (pgcr) {                if (IntersectRect (&rcInter, &rc, &pgcr->rc))                    AddClipRect (&pdc->ecrgn, &rcInter);                pgcr = pgcr->next;            }                        pcr = pcr->next;        }                if (pdc->lcrgn.head == NULL)            ClipRgnCopy (&pdc->ecrgn, &pdc->pGCRInfo->crgn);        // update the DevRC;        if (pdc->bIsClient)            WndClientRect (pdc->hwnd, &pdc->DevRC);        else            WndRect (pdc->hwnd, &pdc->DevRC);                    IntersectClipRect (&pdc->ecrgn, &pdc->DevRC);        pCtrl = Control (pdc->hwnd);        if (pCtrl && !(pCtrl->dwExStyle & WS_EX_CTRLASMAINWIN))            RestrictControlECRGN (&pdc->ecrgn, pCtrl);        pdc->oldage = pdc->pGCRInfo->age;#if defined(_LITE_VERSION) && !defined(_STAND_ALONE)        /*         * Subtract the server clipping rects.         */        if (!mgIsServer) {            int i;            RECT* crcs = SHAREDRES_SCRINFO.clip_rects;            for (i = 0; i < MAX_SRV_CLIP_RECTS; i++) {                if (!IsRectEmpty (crcs + i))                    SubtractClipRect (&pdc->ecrgn, crcs + i);            }            pdc->scr_sig = SHAREDRES_SCRINFO.signature;        }#endif    }    return TRUE;}// This function init DC.// set the default parameters.static void dc_InitDC(PDC pdc, HWND hWnd, BOOL bIsClient){    PCONTROL pCtrl;    pdc->hwnd = hWnd;    pdc->gc = PHYSICALGC;    pdc->bkcolor = PIXEL_lightwhite;    pdc->bkmode = 0;    pdc->brushcolor = PIXEL_lightwhite;    pdc->pencolor = PIXEL_black;    pdc->CurPenPos.x = pdc->CurPenPos.y = 0;    pdc->textcolor = PIXEL_black;    if (!(pdc->pLogFont = GetWindowFont (hWnd)))        pdc->pLogFont = GetSystemFont (SYSLOGFONT_WCHAR_DEF);    pdc->tabstop = 8;    pdc->CurTextPos.x = pdc->CurTextPos.y = 0;    pdc->cExtra = pdc->alExtra = pdc->blExtra = 0;    pdc->mapmode = MM_TEXT;    pdc->ViewOrig.x = pdc->ViewOrig.y = 0;    pdc->ViewExtent.x = pdc->ViewExtent.y = 1;    pdc->WindowOrig.x = pdc->WindowOrig.y = 0;    pdc->WindowExtent.x = pdc->WindowExtent.y = 1;    // assume that the local clip region is empty.      // Get global clip region info and generate effective clip region.    pdc->pGCRInfo = GetGCRgnInfo (hWnd);#ifndef _LITE_VERSION    pthread_mutex_lock (&pdc->pGCRInfo->lock);#endif    pdc->oldage = pdc->pGCRInfo->age;    ClipRgnCopy (&pdc->ecrgn, &pdc->pGCRInfo->crgn);    if (bIsClient)        WndClientRect (pdc->hwnd, &pdc->DevRC);    else        WndRect (pdc->hwnd, &pdc->DevRC);    pdc->bIsClient = bIsClient;    if (bIsClient)        IntersectClipRect (&pdc->ecrgn, &pdc->DevRC);    pCtrl = Control (pdc->hwnd);    if (pCtrl && !(pCtrl->dwExStyle & WS_EX_CTRLASMAINWIN))        RestrictControlECRGN (&pdc->ecrgn, pCtrl);#ifndef _LITE_VERSION    pthread_mutex_unlock (&pdc->pGCRInfo->lock);#endif#if defined(_LITE_VERSION) && !defined(_STAND_ALONE)    /*     * Subtract the server clipping rects.     */    if (!mgIsServer) {        int i;        RECT* crcs = SHAREDRES_SCRINFO.clip_rects;        lock_scr_sem ();        for (i = 0; i < MAX_SRV_CLIP_RECTS; i++) {            if (!IsRectEmpty (crcs + i))                SubtractClipRect (&pdc->ecrgn, crcs + i);        }        pdc->scr_sig = SHAREDRES_SCRINFO.signature;        unlock_scr_sem ();    }#endif}static void dc_Init_ScreenDC (void){    __mg_screen_dc.DataType = TYPE_HDC;    __mg_screen_dc.DCType   = TYPE_SCRDC;    __mg_screen_dc.hwnd = 0;    __mg_screen_dc.gc = PHYSICALGC;    __mg_screen_dc.bkcolor = PIXEL_lightwhite;    __mg_screen_dc.bkmode = 0;    __mg_screen_dc.brushcolor = PIXEL_lightwhite;    __mg_screen_dc.pencolor = PIXEL_black;    __mg_screen_dc.CurPenPos.x = __mg_screen_dc.CurPenPos.y = 0;    __mg_screen_dc.textcolor = PIXEL_black;    __mg_screen_dc.pLogFont = GetSystemFont (SYSLOGFONT_WCHAR_DEF);    __mg_screen_dc.tabstop = 8;    __mg_screen_dc.CurTextPos.x = __mg_screen_dc.CurTextPos.y = 0;    __mg_screen_dc.cExtra = __mg_screen_dc.alExtra = __mg_screen_dc.blExtra = 0;    __mg_screen_dc.ViewOrig.x = __mg_screen_dc.ViewOrig.y = 0;    __mg_screen_dc.ViewExtent.x = __mg_screen_dc.ViewExtent.y = 1;    __mg_screen_dc.WindowOrig.x = __mg_screen_dc.WindowOrig.y = 0;    __mg_screen_dc.WindowExtent.x = __mg_screen_dc.WindowExtent.y = 1;    __mg_screen_dc.bIsClient = FALSE;    // init local clip region    InitClipRgn (&__mg_screen_dc.lcrgn, &sg_FreeClipRectList);    // init effective clip region    InitClipRgn (&__mg_screen_dc.ecrgn, &sg_FreeClipRectList);    // init global clip region information    __mg_screen_dc.pGCRInfo = NULL;    __mg_screen_dc.oldage = 0;    __mg_screen_dc.DevRC.left = 0;    __mg_screen_dc.DevRC.top  = 0;    __mg_screen_dc.DevRC.right = WIDTHOFPHYGC - 1;    __mg_screen_dc.DevRC.bottom = HEIGHTOFPHYGC - 1;    // Set local clip region and effetive clip region to the screen.    SetClipRgn (&__mg_screen_dc.lcrgn, &__mg_screen_dc.DevRC);    SetClipRgn (&__mg_screen_dc.ecrgn, &__mg_screen_dc.DevRC);}        /* * Function: HDC GUIAPI GetClientDC(HWND hWnd) *     This function get the specified window client's DC. * Parameter: *     HWND hWnd: The window, 0 for screen. * Return: *     The handle of wanted DC. */HDC GUIAPI GetClientDC(HWND hWnd){    int i;#ifndef _LITE_VERSION    pthread_mutex_lock (&dcslot);#endif    for (i = 0; i < DCSLOTNUMBER; i++) {        if (!DCSlot[i].inuse) {            DCSlot[i].inuse = TRUE;            DCSlot[i].DataType = TYPE_HDC;            DCSlot[i].DCType   = TYPE_GENDC;            break;        }    }#ifndef _LITE_VERSION    pthread_mutex_unlock (&dcslot);#endif    if (i >= DCSLOTNUMBER)        return HDC_SCREEN;    dc_InitDC (DCSlot + i, hWnd, TRUE);    return (HDC) (DCSlot + i);}/* * Function: HDC GUIAPI GetDC(HWND hWnd) *     This function get the specified window's DC. * Parameter: *     HWND hWnd: The window, 0 for screen. * Return: *     The handle of wanted DC. */HDC GUIAPI GetDC(HWND hWnd){    int i;#ifndef _LITE_VERSION    // allocate an empty dc slot exclusively       pthread_mutex_lock (&dcslot);#endif    for(i = 0; i < DCSLOTNUMBER; i++) {        if(!DCSlot[i].inuse) {            DCSlot[i].inuse = TRUE;            DCSlot[i].DataType = TYPE_HDC;            DCSlot[i].DCType   = TYPE_GENDC;            break;        }    }#ifndef _LITE_VERSION    pthread_mutex_unlock(&dcslot);#endif    if (i >= DCSLOTNUMBER)        return HDC_SCREEN;    dc_InitDC(DCSlot + i, hWnd, FALSE);    return (HDC)(DCSlot + i);}/* * Function: void GUIAPI ReleaseDC(HDC hDC) *     This function release the specified DC. * Parameter: *     HDC hDC: The DC handle want to release. * Return: *     None.  */void GUIAPI ReleaseDC (HDC hDC){    PMAINWIN pWin;    PDC pdc;    PCONTROL pCtrl;    pdc = dc_HDC2PDC(hDC);    EmptyClipRgn (&pdc->lcrgn);    pWin = (PMAINWIN)(pdc->hwnd);    if (pWin && pWin->privCDC == hDC) {#ifndef _LITE_VERSION        /* for private DC, we reset the clip region info. */        pthread_mutex_lock (&pdc->pGCRInfo->lock);#endif        pdc->oldage = pdc->pGCRInfo->age;        ClipRgnCopy (&pdc->ecrgn, &pdc->pGCRInfo->crgn);        if (pdc->bIsClient)            WndClientRect (pdc->hwnd, &pdc->DevRC);        else            WndRect (pdc->hwnd, &pdc->DevRC);        IntersectClipRect (&pdc->ecrgn, &pdc->DevRC);        pCtrl = Control (pdc->hwnd);        if (pCtrl && !(pCtrl->dwExStyle & WS_EX_CTRLASMAINWIN))            RestrictControlECRGN (&pdc->ecrgn, pCtrl);#ifndef _LITE_VERSION        pthread_mutex_unlock (&pdc->pGCRInfo->lock);#endif    }    else {        EmptyClipRgn (&pdc->ecrgn);        pdc->pGCRInfo = NULL;        pdc->oldage = 0;#ifndef _LITE_VERSION        pthread_mutex_lock (&dcslot);#endif        pdc->inuse = FALSE;#ifndef _LITE_VERSION        pthread_mutex_unlock(&dcslot);#endif    }}/* * Function: HDC GUIAPI CreateCompatibleDC (HDC hdc) *     This function create a memory dc, which is compatible  *     with specified hdc. * Parameters: *     HDC hdc: the specified DC handle. * Return: *     None. */HDC GUIAPI CreateCompatibleDC(HDC hdc){    GAL_GC gc;    PDC pdc;    PDC pMemDC = NULL;    pdc = dc_HDC2PDC(hdc);    if (!(pMemDC = malloc (sizeof(DC)))) return HDC_INVALID;#ifndef _LITE_VERSION    pthread_mutex_lock (&__mg_gdilock);#endif    if (GAL_AllocateGC (pdc->gc, RECTW (pdc->DevRC), RECTH (pdc->DevRC),             GAL_BytesPerPixel (pdc->gc), &gc) != 0) {#ifndef _LITE_VERSION        pthread_mutex_unlock (&__mg_gdilock);#endif        return HDC_INVALID;    }#ifndef _LITE_VERSION    pthread_mutex_unlock (&__mg_gdilock);#endif    memcpy (pMemDC, pdc, sizeof(DC));    pMemDC->DataType = TYPE_HDC;    pMemDC->DCType   = TYPE_MEMDC;    pMemDC->inuse = TRUE;    pMemDC->gc = gc;    // clip region info    InitClipRgn (&pMemDC->lcrgn, &sg_FreeClipRectList);    InitClipRgn (&pMemDC->ecrgn, &sg_FreeClipRectList);    pMemDC->pGCRInfo = NULL;    pMemDC->oldage = 0;    pMemDC->DevRC.left = 0;    pMemDC->DevRC.top  = 0;    pMemDC->DevRC.right = RECTW(pdc->DevRC);    pMemDC->DevRC.bottom = RECTH(pdc->DevRC);    SetClipRgn (&pMemDC->ecrgn, &pMemDC->DevRC);        return (HDC)pMemDC;}/* *  Function: DeleteCompatibleDC (HDC hdc) *      This function delete the memory DC, and free the associated memory. *  Parameters: *      HDC hdc: the DC handle want to delete. *  Return: *      FALSE: the specified HDC is not a valid memory DC. *      TRUE:  deleted. */void GUIAPI DeleteCompatibleDC(HDC hdc){    PDC pMemDC;        pMemDC = dc_HDC2PDC(hdc);    // free gl resource    GAL_FreeGC (pMemDC->gc);    // free clip region info    EmptyClipRgn (&pMemDC->lcrgn);    EmptyClipRgn (&pMemDC->ecrgn);    // free DC slot    free (pMemDC);}HDC GUIAPI CreatePrivateDC(HWND hwnd){    PDC pdc;    if (!(pdc = malloc (sizeof(DC)))) return HDC_INVALID;    InitClipRgn (&pdc->lcrgn, &sg_FreeClipRectList);    InitClipRgn (&pdc->ecrgn, &sg_FreeClipRectList);        pdc->inuse = TRUE;    pdc->DataType = TYPE_HDC;    pdc->DCType   = TYPE_GENDC;    dc_InitDC(pdc, hwnd, FALSE);    return (HDC)(pdc);}HDC GUIAPI CreatePrivateClientDC(HWND hwnd){    PDC pdc;    if (!(pdc = malloc (sizeof(DC)))) return HDC_INVALID;    InitClipRgn (&pdc->lcrgn, &sg_FreeClipRectList);    InitClipRgn (&pdc->ecrgn, &sg_FreeClipRectList);        pdc->inuse = TRUE;    pdc->DataType = TYPE_HDC;    pdc->DCType   = TYPE_GENDC;    dc_InitDC(pdc, hwnd, TRUE);    return (HDC)(pdc);}void GUIAPI DeletePrivateDC(HDC hdc){    PDC pdc;    pdc = (PDC)hdc;        EmptyClipRgn (&pdc->lcrgn);    EmptyClipRgn (&pdc->ecrgn);    free (pdc);}HDC GUIAPI GetPrivateClientDC (HWND hwnd){    PMAINWIN pWin = (PMAINWIN)hwnd;    return pWin->privCDC;}