reactos/base/applications/taskmgr/proclist.c

   1 /*
   2  *  ReactOS Task Manager
   3  *
   4  *  proclist.c
   5  *
   6  *  Copyright (C) 1999 - 2001  Brian Palmer  <brianp@reactos.org>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <precomp.h>
  24
  25
  26 INT_PTR CALLBACK    ProcessListWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
  27
  28 WNDPROC             OldProcessListWndProc;
  29
  30
  31 INT_PTR CALLBACK
  32 ProcessListWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
  33 {
  34     HBRUSH    hbrBackground;
  35     RECT    rcItem;
  36     RECT    rcClip;
  37     HDC        hDC;
  38     int        DcSave;
  39
  40     switch (message)
  41     {
  42     case WM_ERASEBKGND:
  43
  44         /*
  45          * The list control produces a nasty flicker
  46          * when the user is resizing the window because
  47          * it erases the background to white, then
  48          * paints the list items over it.
  49          *
  50          * We will clip the drawing so that it only
  51          * erases the parts of the list control that
  52          * show only the background.
  53          */
  54
  55         /*
  56          * Get the device context and save it's state
  57          * to be restored after we're done
  58          */
  59         hDC = (HDC) wParam;
  60         DcSave = SaveDC(hDC);
  61
  62         /*
  63          * Get the background brush
  64          */
  65         hbrBackground = (HBRUSH)(LONG_PTR) GetClassLongPtr(hWnd, GCL_HBRBACKGROUND);
  66
  67         /*
  68          * Calculate the clip rect by getting the RECT
  69          * of the first and last items and adding them up.
  70          *
  71          * We also have to get the item's icon RECT and
  72          * subtract it from our clip rect because we don't
  73          * use icons in this list control.
  74          */
  75         (void)ListView_GetItemRect(hWnd, 0, &rcClip, LVIR_BOUNDS);
  76         (void)ListView_GetItemRect(hWnd, ListView_GetItemCount(hWnd) - 1, &rcItem, LVIR_BOUNDS);
  77         rcClip.bottom = rcItem.bottom;
  78         (void)ListView_GetItemRect(hWnd, 0, &rcItem, LVIR_ICON);
  79         rcClip.left = rcItem.right;
  80
  81         /*
  82          * Now exclude the clip rect
  83          */
  84         ExcludeClipRect(hDC, rcClip.left, rcClip.top, rcClip.right, rcClip.bottom);
  85
  86         /*
  87          * Now erase the background
  88          *
  89          *
  90          * FIXME: Should I erase it myself or
  91          * pass down the updated HDC and let
  92          * the default handler do it?
  93          */
  94         GetClientRect(hWnd, &rcItem);
  95         FillRect(hDC, &rcItem, hbrBackground);
  96
  97         /*
  98          * Now restore the DC state that we
  99          * saved earlier
 100          */
 101         RestoreDC(hDC, DcSave);
 102
 103         return TRUE;
 104     }
 105
 106     /*
 107      * We pass on all messages except WM_ERASEBKGND
 108      */
 109     return CallWindowProc(OldProcessListWndProc, hWnd, message, wParam, lParam);
 110 }