From: Jason Rumney <jasonr@gnu.org>
Date: Thu, 24 Jan 2002 20:29:39 +0000 (+0000)
Subject: (x_scroll_run): Use ScrollWindowEx in place of BitBlt.
X-Git-Tag: emacs-21.2~155
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=1f24706df4ed814a0e2f614172b229e810005edb;p=emacs.git

(x_scroll_run): Use ScrollWindowEx in place of BitBlt.
If region left to draw is not what was expected, mark the frame as
garbaged.
---

diff --git a/src/ChangeLog b/src/ChangeLog
index 8af6cb3adec..147ee0c8fee 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2002-01-24  Jason Rumney  <jasonr@gnu.org>
+
+	* w32term.c (x_scroll_run): Use ScrollWindowEx in place of BitBlt.
+	If region left to draw is not what was expected, mark the frame as
+	garbaged.
+
+	* w32fns.c (w32_wnd_proc) <WM_PAINT>: Initialize update_rect.
+	Combine the regions returned by BeginPaint and GetUpdateRect.
+
 2002-01-20  Eli Zaretskii  <eliz@is.elta.co.il>
 
 	* unexelf.c (unexec) [__sgi]: Support the .got sections.
diff --git a/src/w32term.c b/src/w32term.c
index 19c1d07853e..88cbd325401 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -5479,7 +5479,8 @@ x_scroll_run (w, run)
 {
   struct frame *f = XFRAME (w->frame);
   int x, y, width, height, from_y, to_y, bottom_y;
-  HDC hdc = get_frame_dc (f);
+  HWND hwnd = FRAME_W32_WINDOW (f);
+  HRGN expect_dirty;
 
   /* Get frame-relative bounding box of the text display area of W,
      without mode lines.  Include in this box the flags areas to the
@@ -5500,6 +5501,7 @@ x_scroll_run (w, run)
 	height = bottom_y - from_y;
       else
 	height = run->height;
+      expect_dirty = CreateRectRgn (x, y + height, x + width, bottom_y);
     }
   else
     {
@@ -5509,6 +5511,7 @@ x_scroll_run (w, run)
 	height = bottom_y - to_y;
       else
 	height = run->height;
+      expect_dirty = CreateRectRgn (x, y, x + width, to_y);
     }
 
   BLOCK_INPUT;
@@ -5517,10 +5520,32 @@ x_scroll_run (w, run)
   updated_window = w;
   x_clear_cursor (w);
 
-  BitBlt (hdc, x, to_y, width, height, hdc, x, from_y, SRCCOPY);
-  
+  {
+    RECT from;
+    RECT to;
+    HRGN dirty = CreateRectRgn (0, 0, 0, 0);
+    HRGN combined = CreateRectRgn (0, 0, 0, 0);
+
+    from.left = to.left = x;
+    from.right = to.right = x + width;
+    from.top = from_y;
+    from.bottom = from_y + height;
+    to.top = y;
+    to.bottom = bottom_y;
+
+    ScrollWindowEx (hwnd, 0, to_y - from_y, &from, &to, dirty,
+		    NULL, SW_INVALIDATE);
+
+    /* Combine this with what we expect to be dirty. This covers the
+       case where not all of the region we expect is actually dirty.  */
+    CombineRgn (combined, dirty, expect_dirty, RGN_OR);
+
+    /* If the dirty region is not what we expected, redraw the entire frame.  */
+    if (!EqualRgn (combined, expect_dirty))
+      SET_FRAME_GARBAGED (f);
+  }
+
   UNBLOCK_INPUT;
-  release_frame_dc (f, hdc);
 }