1 files changed, 133 insertions, 0 deletions
diff --git a/source/blender/imbuf/intern/dither.c b/source/blender/imbuf/intern/dither.c
new file mode 100644
index 00000000000..608332af244
--- /dev/null
+++ b/source/blender/imbuf/intern/dither.c
@@ -0,0 +1,133 @@
+/**
+ *
+ * ***** BEGIN GPL/BL DUAL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version. The Blender
+ * Foundation also sells licenses for use in proprietary software under
+ * the Blender License.  See http://www.blender.org/BL/ for information
+ * about this.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): none yet.
+ *
+ * ***** END GPL/BL DUAL LICENSE BLOCK *****
+ * dither.c
+ *
+ * $Id$
+ */
+
+#include "BLI_blenlib.h"
+
+#include "imbuf.h"
+#include "imbuf_patch.h"
+#include "IMB_imbuf_types.h"
+#include "IMB_imbuf.h"
+
+void IMB_dit0(struct ImBuf * ibuf, short ofs, short bits)
+{
+	int x, y, and, add, pix;
+	uchar *rect;
+
+	rect= (uchar *)ibuf->rect;
+	rect +=ofs;
+
+	bits = 8 - bits;
+	and = ~((1 << bits)-1);
+	add = 1 << (bits - 1);
+	
+	for (y = ibuf->y; y > 0; y--){
+		for (x = ibuf->x; x > 0; x--) {
+			pix = *rect + add;
+			if (pix > 255) pix = 255; 
+			*rect = pix & and;
+			rect += 4;
+		}
+	}
+}
+
+void IMB_dit2(struct ImBuf * ibuf, short ofs, short bits)
+{
+	short x,y,pix,and,add1,add2;
+	uchar *rect;
+	uchar dit[4];
+
+	rect= (uchar *)ibuf->rect;
+	rect +=ofs;
+
+	bits = 8 - bits;
+	and = ~((1<<bits)-1);
+	bits -= 2;
+
+	ofs = 0;
+	
+	switch(ofs){
+	case 3:
+		break;
+	case 2:
+		dit[0]=0;
+		dit[1]=1;
+		dit[2]=2;
+		dit[3]=3;
+		break;
+	case 1:
+		dit[0]=3;
+		dit[1]=1;
+		dit[2]=0;
+		dit[3]=2;
+		break;
+	case 0:
+		dit[0]=0;
+		dit[1]=2;
+		dit[2]=3;
+		dit[3]=1;
+		break;
+	}
+	
+	if (bits < 0){
+		dit[0] >>= -bits;
+		dit[1] >>= -bits;
+		dit[2] >>= -bits;
+		dit[3] >>= -bits;
+	} else{
+		dit[0] <<= bits;
+		dit[1] <<= bits;
+		dit[2] <<= bits;
+		dit[3] <<= bits;
+	}
+
+	for(y=ibuf->y;y>0;y--){
+		if(y & 1){
+			add1=dit[0];
+			add2=dit[1];
+		}
+		else{
+			add1=dit[2];
+			add2=dit[3];
+		}
+		for(x=ibuf->x;x>0;x--){
+			pix = *rect;
+			if (x & 1) pix += add1;
+			else pix += add2;
+
+			if (pix>255) pix=255;
+			*rect = pix & and;
+			rect += 4;
+		}
+	}
+}