programs/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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  21  */
  22
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25
  26 #include <windows.h>
  27 #include <commctrl.h>
  28 #include <winnt.h>
  29
  30 #include "taskmgr.h"
  31 #include "perfdata.h"
  32
  33
  34 WNDPROC                OldProcessListWndProc;
  35
  36
  37 LRESULT CALLBACK ProcessListWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
  38 {
  39     HBRUSH    hbrBackground;
  40     int     count;
  41     RECT    rcItem;
  42     RECT    rcClip;
  43     HDC        hDC;
  44     int        DcSave;
  45
  46     switch (message)
  47     {
  48     case WM_ERASEBKGND:
  49
  50         /*
  51          * The list control produces a nasty flicker
  52          * when the user is resizing the window because
  53          * it erases the background to white, then
  54          * paints the list items over it.
  55          *
  56          * We will clip the drawing so that it only
  57          * erases the parts of the list control that
  58          * show only the background.
  59          */
  60
  61         /*
  62          * Get the device context and save its state
  63          * to be restored after we're done
  64          */
  65         hDC = (HDC) wParam;
  66         DcSave = SaveDC(hDC);
  67
  68         /*
  69          * Get the background brush
  70          */
  71         hbrBackground = (HBRUSH) GetClassLongPtrW(hWnd, GCLP_HBRBACKGROUND);
  72
  73         /*
  74          * Calculate the clip rect by getting the RECT
  75          * of the first and last items and adding them up.
  76          *
  77          * We also have to get the item's icon RECT and
  78          * subtract it from our clip rect because we don't
  79          * use icons in this list control.
  80          */
  81         rcClip.left = LVIR_BOUNDS;
  82         SendMessageW(hWnd, LVM_GETITEMRECT, 0, (LPARAM) &rcClip);
  83         rcItem.left = LVIR_BOUNDS;
  84         count = SendMessageW(hWnd, LVM_GETITEMCOUNT, 0, 0);
  85         SendMessageW(hWnd, LVM_GETITEMRECT, count - 1, (LPARAM) &rcItem);
  86
  87         rcClip.bottom = rcItem.bottom;
  88         rcItem.left = LVIR_ICON;
  89         SendMessageW(hWnd, LVM_GETITEMRECT, 0, (LPARAM) &rcItem);
  90         rcClip.left = rcItem.right;
  91
  92         /*
  93          * Now exclude the clip rect
  94          */
  95         ExcludeClipRect(hDC, rcClip.left, rcClip.top, rcClip.right, rcClip.bottom);
  96
  97         /*
  98          * Now erase the background
  99          *
 100          *
 101          * FIXME: Should I erase it myself or
 102          * pass down the updated HDC and let
 103          * the default handler do it?
 104          */
 105         GetClientRect(hWnd, &rcItem);
 106         FillRect(hDC, &rcItem, hbrBackground);
 107
 108         /*
 109          * Now restore the DC state that we
 110          * saved earlier
 111          */
 112         RestoreDC(hDC, DcSave);
 113
 114         return TRUE;
 115     }
 116
 117     /*
 118      * We pass on all messages except WM_ERASEBKGND
 119      */
 120     return CallWindowProcW(OldProcessListWndProc, hWnd, message, wParam, lParam);
 121 }