winhlp32: Use EM_SCROLL to scroll richedit control.

[Dylan Smith]

Previously the richedit control contents were scrolled directly using
ScrollWindow.  This caused the richedit control to not actually scroll,
but only look like it scrolled, therefore causing plenty of glitches.
---
 programs/winhlp32/winhelp.c |   40 ++++++++++------------------------------
 1 files changed, 10 insertions(+), 30 deletions(-)
-------------- next part --------------
diff --git a/programs/winhlp32/winhelp.c b/programs/winhlp32/winhelp.c
index 02529ee..d62649f 100644
--- a/programs/winhlp32/winhelp.c
+++ b/programs/winhlp32/winhelp.c
@@ -1263,8 +1263,7 @@ static LRESULT CALLBACK WINHELP_MainWndProc(HWND hWnd, UINT msg, WPARAM wParam,
 {
     WINHELP_WINDOW *win;
     WINHELP_BUTTON *button;
-    RECT rect;
-    INT  curPos, min, max, dy, keyDelta;
+    INT  keyDelta;
     HWND hTextWnd;
     LRESULT ret;
 
@@ -1379,42 +1378,23 @@ static LRESULT CALLBACK WINHELP_MainWndProc(HWND hWnd, UINT msg, WPARAM wParam,
 
     case WM_KEYDOWN:
         keyDelta = 0;
+        win = (WINHELP_WINDOW*) GetWindowLongPtr(hWnd, 0);
+        hTextWnd = GetDlgItem(win->hMainWnd, CTL_ID_TEXT);
 
         switch (wParam)
         {
         case VK_UP:
+            SendMessage(hTextWnd, EM_SCROLL, SB_LINEUP, 0);
+            return 0;
         case VK_DOWN:
-            keyDelta = GetSystemMetrics(SM_CXVSCROLL);
-            if (wParam == VK_UP)
-                keyDelta = -keyDelta;
-
+            SendMessage(hTextWnd, EM_SCROLL, SB_LINEDOWN, 0);
+            return 0;
         case VK_PRIOR:
+            SendMessage(hTextWnd, EM_SCROLL, SB_PAGEUP, 0);
+            return 0;
         case VK_NEXT:
-            win = (WINHELP_WINDOW*) GetWindowLongPtr(hWnd, 0);
-            hTextWnd = GetDlgItem(win->hMainWnd, CTL_ID_TEXT);
-            curPos = GetScrollPos(hTextWnd, SB_VERT);
-            GetScrollRange(hTextWnd, SB_VERT, &min, &max);
-
-            if (keyDelta == 0)
-            {
-                GetClientRect(hTextWnd, &rect);
-                keyDelta = (rect.bottom - rect.top) / 2;
-                if (wParam == VK_PRIOR)
-                    keyDelta = -keyDelta;
-            }
-
-            curPos += keyDelta;
-            if (curPos > max)
-                 curPos = max;
-            else if (curPos < min)
-                 curPos = min;
-
-            dy = GetScrollPos(hTextWnd, SB_VERT) - curPos;
-            SetScrollPos(hTextWnd, SB_VERT, curPos, TRUE);
-            ScrollWindow(hTextWnd, 0, dy, NULL, NULL);
-            UpdateWindow(hTextWnd);
+            SendMessage(hTextWnd, EM_SCROLL, SB_PAGEDOWN, 0);
             return 0;
-
         case VK_ESCAPE:
             MACRO_Exit();
             return 0;