reactos操作系统实现(167)

co_UserRedrawWindow函数是用来实现窗口重画的功能，实现代码如下：

#001 BOOL FASTCALL

#002 co_UserRedrawWindow(PWINDOW_OBJECT Window,const RECT* UpdateRect,HRGN UpdateRgn,

#003 ULONG Flags)

#004 {

#005 HRGN hRgn = NULL;

#006

#007 /*

#008 * Step 1.

#009 * Validation of passed parameters.

#010 */

#011

检验是否合适的参数。

#012 if (!IntIsWindowDrawable(Window) ||

#013 (Flags & (RDW_VALIDATE | RDW_INVALIDATE)) ==

#014 (RDW_VALIDATE | RDW_INVALIDATE))

#015 {

#016 return FALSE;

#017 }

#018

#019 /*

#020 * Step 2.

#021 * Transform the parameters UpdateRgn and UpdateRect into

#022 * a region hRgn specified in screen coordinates.

#023 */

#024

创建更新的区域。

#025 if (Flags & (RDW_INVALIDATE | RDW_VALIDATE))

#026 {

根据用户指定的区域进行更新。

#027 if (UpdateRgn != NULL)

#028 {

#029 hRgn = NtGdiCreateRectRgn(0,0);

#030 if (NtGdiCombineRgn(hRgn,UpdateRgn,NULL,RGN_COPY) == NULLREGION)

#031 {

#032 NtGdiDeleteObject(hRgn);

#033 hRgn = NULL;

#034 }

否则更新整个窗口。

#035 else

#036 NtGdiOffsetRgn(hRgn,Window->Wnd->ClientRect.left,Window->Wnd->ClientRect.top);

#037 }

#038 else if (UpdateRect != NULL)

#039 {

#040 if (!IntGdiIsEmptyRect(UpdateRect))

#041 {

#042 hRgn = UnsafeIntCreateRectRgnIndirect((RECT *)UpdateRect);

#043 NtGdiOffsetRgn(hRgn,Window->Wnd->ClientRect.top);

#044 }

#045 }

#046 else if ((Flags & (RDW_INVALIDATE | RDW_FRAME)) == (RDW_INVALIDATE | RDW_FRAME) ||

#047 (Flags & (RDW_VALIDATE | RDW_NOFRAME)) == (RDW_VALIDATE | RDW_NOFRAME))

#048 {

#049 if (!IntGdiIsEmptyRect(&Window->Wnd->WindowRect))

#050 hRgn = UnsafeIntCreateRectRgnIndirect(&Window->Wnd->WindowRect);

#051 }

#052 else

#053 {

创建客户区窗口区域更新。

#054 if (!IntGdiIsEmptyRect(&Window->Wnd->ClientRect))

#055 hRgn = UnsafeIntCreateRectRgnIndirect(&Window->Wnd->ClientRect);

#056 }

#057 }

#058

#059 /*

#060 * Step 3.

#061 * Adjust the window update region depending on hRgn and flags.

#062 */

#063

根据指定的区域进行更新。

#064 if (Flags & (RDW_INVALIDATE | RDW_VALIDATE | RDW_INTERNALPAINT | RDW_NOINTERNALPAINT) &&

#065 hRgn != NULL)

#066 {

#067 IntInvalidateWindows(Window,hRgn,Flags);

#068 }

#069

#070 /*

#071 * Step 4.

#072 * Repaint and erase windows if needed.

#073 */

#074

重新画窗口。

#075 if (Flags & (RDW_ERASENOW | RDW_UPDATENOW))

#076 {

#077 co_IntPaintWindows(Window,Flags,FALSE);

#078 }

#079

#080 /*

#081 * Step 5.

#082 * Cleanup ;-)

#083 */

#084

#085 if (hRgn != NULL)

#086 {

#087 NtGdiDeleteObject(hRgn);

#088 }

#089

#090 return TRUE;

#091}

（编辑：李大同）

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