wrlib: add image flip functions

This patch adds RVerticalFlipImage and RHorizontalFlipImage functions.

wrlib/flip.c

@@ -0,0 +1,133 @@
+/* flip.c - image flip
+ *
+ * Raster graphics library
+ *
+ * Copyright (c) 2014 Window Maker Team
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 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
+ *  Library General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Library General Public
+ *  License along with this library; if not, write to the Free
+ *  Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ *  MA 02110-1301, USA.
+ */
+
+#include <config.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <X11/Xlib.h>
+#include "wraster.h"
+
+RImage *RVerticalFlipImage(RImage *image)
+{
+	RImage *img;
+	int nwidth, nheight;
+	int x, y;
+	int bpp = image->format == RRGBAFormat ? 4 : 3;
+
+	nwidth = image->width;
+	nheight = image->height;
+
+	img = RCreateImage(nwidth, nheight, True);
+	if (!img)
+		return NULL;
+
+	if (bpp == 3) {
+			unsigned char *optr, *nptr;
+
+			optr = image->data;
+			nptr = img->data + 4 * (nwidth * nheight - nwidth - 1);
+
+			for (y = 0; y < nheight; y++) {
+				for (x = 0; x < nwidth; x++) {
+					nptr[0] = optr[0];
+					nptr[1] = optr[1];
+					nptr[2] = optr[2];
+					nptr[3] = 255;
+
+					optr += 3;
+					nptr += 4;
+				}
+				nptr -= nwidth*8;
+			}
+		} else {
+			unsigned char *optr, *nptr;
+
+			optr = image->data;
+			nptr = img->data + 4 * (nwidth * nheight - nwidth - 1);
+
+			for (y = 0; y < nheight; y++) {
+				for (x = 0; x < nwidth; x++) {
+					nptr[0] = optr[0];
+					nptr[1] = optr[1];
+					nptr[2] = optr[2];
+					nptr[3] = optr[3];
+
+					optr += 4;
+					nptr += 4;
+				}
+				nptr -= nwidth*8;
+			}
+		}
+	return img;
+}
+
+RImage *RHorizontalFlipImage(RImage *image)
+{
+	RImage *img;
+	int nwidth, nheight;
+	int x, y;
+	int bpp = image->format == RRGBAFormat ? 4 : 3;
+
+	nwidth = image->width;
+	nheight = image->height;
+
+	img = RCreateImage(nwidth, nheight, True);
+	if (!img)
+		return NULL;
+
+	if (bpp == 3) {
+			unsigned char *optr, *nptr;
+
+			nptr = img->data + nwidth * nheight * 4 - 4;
+			for (y = nheight; y; y--) {
+				for (x = 0; x < nwidth; x++) {
+					optr = image->data + (y*nwidth + x) * 3;
+
+					nptr[0] = optr[0];
+					nptr[1] = optr[1];
+					nptr[2] = optr[2];
+					nptr[3] = 255;
+
+					nptr -= 4;
+				}
+			}
+		} else {
+			unsigned char *optr, *nptr;
+
+			nptr = img->data + nwidth * nheight * 4 - 4;
+			for (y = nheight; y; y--) {
+				for (x = 0; x < nwidth; x++) {
+					optr = image->data + (y*nwidth + x) * 4;
+
+					nptr[0] = optr[0];
+					nptr[1] = optr[1];
+					nptr[2] = optr[2];
+					nptr[3] = optr[3];
+
+					nptr -= 4;
+				}
+			}
+		}
+	return img;
+}