windows/scroll.c

   1 /*
   2  * Scroll windows and DCs
   3  *
   4  * Copyright  David W. Metcalfe, 1993
   5  *
   6  */
   7
   8 static char Copyright[] = "Copyright  David W. Metcalfe, 1993";
   9
  10 #include <stdlib.h>
  11 #include "windows.h"
  12 #include "gdi.h"
  13
  14 static int RgnType;
  15
  16
  17 /*************************************************************************
  18  *             ScrollWindow         (USER.61)
  19  */
  20
  21 void ScrollWindow(HWND hwnd, short dx, short dy, LPRECT rect, LPRECT clipRect)
  22 {
  23     HDC hdc;
  24     HRGN hrgnUpdate;
  25     RECT rc, cliprc;
  26
  27 #ifdef DEBUG_SCROLL
  28     printf("ScrollWindow: dx=%d, dy=%d, rect=%d,%d,%d,%d\n", dx, dy,
  29            rect->left, rect->top, rect->right, rect->bottom);
  30 #endif
  31
  32     hdc = GetDC(hwnd);
  33
  34     if (rect == NULL)
  35         GetWindowRect(hwnd, &rc);
  36     else
  37         CopyRect(&rc, rect);
  38     if (clipRect == NULL)
  39         GetWindowRect(hwnd, &cliprc);
  40     else
  41         CopyRect(&cliprc, clipRect);
  42
  43     hrgnUpdate = CreateRectRgn(0, 0, 0, 0);
  44     ScrollDC(hdc, dx, dy, &rc, &cliprc, hrgnUpdate, NULL);
  45     InvalidateRgn(hwnd, hrgnUpdate, TRUE);
  46     ReleaseDC(hwnd, hdc);
  47 }
  48
  49
  50 /*************************************************************************
  51  *             ScrollDC         (USER.221)
  52  */
  53
  54 BOOL ScrollDC(HDC hdc, short dx, short dy, LPRECT rc, LPRECT cliprc,
  55               HRGN hrgnUpdate, LPRECT rcUpdate)
  56 {
  57     HRGN hrgnClip, hrgn1, hrgn2;
  58     POINT src, dest;
  59     short width, height;
  60     DC *dc = (DC *)GDI_GetObjPtr(hdc, DC_MAGIC);
  61
  62 #ifdef DEBUG_SCROLL
  63     printf("ScrollDC: dx=%d, dy=%d, rc=%d,%d,%d,%d\n", dx, dy,
  64            rc->left, rc->top, rc->right, rc->bottom);
  65 #endif
  66
  67     if (rc == NULL)
  68         return;
  69
  70     if (cliprc)
  71     {
  72         hrgnClip = CreateRectRgnIndirect(cliprc);
  73         SelectClipRgn(hdc, hrgnClip);
  74     }
  75
  76     if (dx > 0)
  77     {
  78         src.x = XDPTOLP(dc, rc->left);
  79         dest.x = XDPTOLP(dc, rc->left + abs(dx));
  80     }
  81     else
  82     {
  83         src.x = XDPTOLP(dc, rc->left + abs(dx));
  84         dest.x = XDPTOLP(dc, rc->left);
  85     }
  86     if (dy > 0)
  87     {
  88         src.y = YDPTOLP(dc, rc->top);
  89         dest.y = YDPTOLP(dc, rc->top + abs(dy));
  90     }
  91     else
  92     {
  93         src.y = YDPTOLP(dc, rc->top + abs(dy));
  94         dest.y = YDPTOLP(dc, rc->top);
  95     }
  96
  97     width = rc->right - rc->left - abs(dx);
  98     height = rc->bottom - rc->top - abs(dy);
  99
 100     if (!BitBlt(hdc, dest.x, dest.y, width, height, hdc, src.x, src.y,
 101                 SRCCOPY))
 102         return;
 103
 104     if (hrgnUpdate)
 105     {
 106         if (dx > 0)
 107             hrgn1 = CreateRectRgn(rc->left, rc->top, rc->left+dx, rc->bottom);
 108         else if (dx < 0)
 109             hrgn1 = CreateRectRgn(rc->right+dx, rc->top, rc->right,
 110                                   rc->bottom);
 111         else
 112             hrgn1 = CreateRectRgn(0, 0, 0, 0);
 113
 114         if (dy > 0)
 115             hrgn2 = CreateRectRgn(rc->left, rc->top, rc->right, rc->top+dy);
 116         else if (dy < 0)
 117             hrgn2 = CreateRectRgn(rc->left, rc->bottom+dy, rc->right,
 118                                   rc->bottom);
 119         else
 120             hrgn2 = CreateRectRgn(0, 0, 0, 0);
 121
 122         RgnType = CombineRgn(hrgnUpdate, hrgn1, hrgn2, RGN_OR);
 123     }
 124
 125     if (rcUpdate)
 126     {
 127         SelectClipRgn(hdc, hrgnUpdate);
 128         GetClipBox(hdc, rcUpdate);
 129     }
 130 }
 131
 132
 133 /*************************************************************************
 134  *             ScrollWindowEx       (USER.319)
 135  */
 136
 137 int ScrollWindowEx(HWND hwnd, short dx, short dy, LPRECT rect, LPRECT clipRect,
 138                    HRGN hrgnUpdate, LPRECT rcUpdate, WORD flags)
 139 {
 140     HDC hdc;
 141     RECT rc, cliprc;
 142
 143 #ifdef DEBUG_SCROLL
 144     printf("ScrollWindowEx: dx=%d, dy=%d, rect=%d,%d,%d,%d\n", dx, dy,
 145            rect->left, rect->top, rect->right, rect->bottom);
 146 #endif
 147
 148     hdc = GetDC(hwnd);
 149
 150     if (rect == NULL)
 151         GetWindowRect(hwnd, &rc);
 152     else
 153         CopyRect(&rc, rect);
 154     if (clipRect == NULL)
 155         GetWindowRect(hwnd, &cliprc);
 156     else
 157         CopyRect(&cliprc, clipRect);
 158
 159     ScrollDC(hdc, dx, dy, &rc, &cliprc, hrgnUpdate, rcUpdate);
 160
 161     if (flags | SW_INVALIDATE)
 162     {
 163         InvalidateRgn(hwnd, hrgnUpdate, FALSE);
 164
 165         if (flags | SW_ERASE)
 166             SendMessage(hwnd, WM_ERASEBKGND, (WORD)hdc, (LONG)NULL);
 167     }
 168
 169     ReleaseDC(hwnd, hdc);
 170     return RgnType;
 171 }