From 8da4aa27122b9a0a5befdc86f8d391278a0211f3 Mon Sep 17 00:00:00 2001
From: Steven Edwards <winehacker@gmail.com>
Date: Sun, 16 Nov 2003 22:44:39 +0000
Subject: [PATCH] Added port of LineDDA function from WINE.

svn path=/trunk/; revision=6671
---
 reactos/lib/gdi32/makefile          |  3 +-
 reactos/lib/gdi32/misc/stubs.c      | 22 +-------
 reactos/lib/gdi32/objects/linedda.c | 80 +++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 22 deletions(-)
 create mode 100644 reactos/lib/gdi32/objects/linedda.c

diff --git a/reactos/lib/gdi32/makefile b/reactos/lib/gdi32/makefile
index db2bee3b387..e944af61166 100644
--- a/reactos/lib/gdi32/makefile
+++ b/reactos/lib/gdi32/makefile
@@ -1,4 +1,4 @@
-# $Id: makefile,v 1.34 2003/11/15 15:18:05 weiden Exp $
+# $Id: makefile,v 1.35 2003/11/16 22:44:39 sedwards Exp $
 
 PATH_TO_TOP = ../..
 
@@ -39,6 +39,7 @@ OBJECTS_OBJECTS = \
  objects/dc.o \
  objects/fillshap.o \
  objects/line.o \
+ objects/linedda.o \
  objects/metafile.o \
  objects/pen.o \
  objects/region.o \
diff --git a/reactos/lib/gdi32/misc/stubs.c b/reactos/lib/gdi32/misc/stubs.c
index b08e3d2b069..11a491ec800 100644
--- a/reactos/lib/gdi32/misc/stubs.c
+++ b/reactos/lib/gdi32/misc/stubs.c
@@ -1,4 +1,4 @@
-/* $Id: stubs.c,v 1.39 2003/11/08 22:54:26 navaraf Exp $
+/* $Id: stubs.c,v 1.40 2003/11/16 22:44:39 sedwards Exp $
  *
  * reactos/lib/gdi32/misc/stubs.c
  *
@@ -513,26 +513,6 @@ InvertRgn(
 	return FALSE;
 }
 
-
-/*
- * @unimplemented
- */
-BOOL
-STDCALL
-LineDDA(
-	int		a0,
-	int		a1,
-	int		a2,
-	int		a3,
-	LINEDDAPROC	a4,
-	LPARAM		a5
-	)
-{
-	SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
-	return FALSE;
-}
-
-
 /*
  * @unimplemented
  */
diff --git a/reactos/lib/gdi32/objects/linedda.c b/reactos/lib/gdi32/objects/linedda.c
new file mode 100644
index 00000000000..d0cc5237264
--- /dev/null
+++ b/reactos/lib/gdi32/objects/linedda.c
@@ -0,0 +1,80 @@
+/*
+ * LineDDA
+ *
+ * Copyright 1993 Bob Amstadt
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+/* 
+ * COPYRIGHT:        See COPYING in the top level directory
+ * PROJECT:          ReactOS GDI32
+ * PURPOSE:          LineDDA Function
+ * FILE:             lib/gdi32/objects/linedda.c
+ * PROGRAMER:        Steven Edwards
+ * REVISION HISTORY: 2003/11/15 sedwards Created
+ * NOTES:            Adapted from Wine
+ */
+
+#include <windows.h>
+#include <ddk/ntddk.h>
+#include <win32k/kapi.h>
+#include <debug.h>
+
+/**********************************************************************
+ *           LineDDA   (GDI32.@)
+ * @implemented
+ */
+BOOL STDCALL LineDDA(INT nXStart, INT nYStart, INT nXEnd, INT nYEnd,
+                        LINEDDAPROC callback, LPARAM lParam )
+{
+    INT xadd = 1, yadd = 1;
+    INT err,erradd;
+    INT cnt;
+    INT dx = nXEnd - nXStart;
+    INT dy = nYEnd - nYStart;
+
+    if (dx < 0)  {
+      dx = -dx; xadd = -1;
+    }
+    if (dy < 0)  {
+      dy = -dy; yadd = -1;
+    }
+    if (dx > dy) { /* line is "more horizontal" */
+      err = 2*dy - dx; erradd = 2*dy - 2*dx;
+      for(cnt = 0;cnt <= dx; cnt++) {
+        callback(nXStart,nYStart,lParam);
+	if (err > 0) {
+	  nYStart += yadd;
+	  err += erradd;
+	} else  {
+	  err += 2*dy;
+	}
+	nXStart += xadd;
+      }
+    } else  { /* line is "more vertical" */
+      err = 2*dx - dy; erradd = 2*dx - 2*dy;
+      for(cnt = 0;cnt <= dy; cnt++) {
+	callback(nXStart,nYStart,lParam);
+	if (err > 0) {
+	  nXStart += xadd;
+	  err += erradd;
+	} else  {
+	  err += 2*dx;
+	}
+	nYStart += yadd;
+      }
+    }
+    return TRUE;
+}