1 files changed, 113 insertions, 0 deletions
diff --git a/test/pdiff/lpyramid.c b/test/pdiff/lpyramid.c
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+/*
+  Laplacian Pyramid
+  Copyright (C) 2006 Yangli Hector Yee
+
+  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.
+
+  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
+*/
+
+#include "lpyramid.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct _lpyramid {
+    /* Succesively blurred versions of the original image */
+    float *levels[MAX_PYR_LEVELS];
+
+    int width;
+    int height;
+};
+
+static void
+convolve (lpyramid_t *pyramid, float *a, float *b)
+/* convolves image b with the filter kernel and stores it in a */
+{
+    int y,x,i,j,nx,ny;
+    const float Kernel[] = {0.05f, 0.25f, 0.4f, 0.25f, 0.05f};
+    int width = pyramid->width;
+    int height = pyramid->height;
+
+    for (y=0; y<height; y++) {
+	for (x=0; x<width; x++) {
+	    int index = y * width + x;
+	    a[index] = 0.0f;
+	    for (i=-2; i<=2; i++) {
+		for (j=-2; j<=2; j++) {
+		    nx=x+i;
+		    ny=y+j;
+		    if (nx<0) nx=-nx;
+		    if (ny<0) ny=-ny;
+		    if (nx>=width) nx=2*(width-1)-nx;
+		    if (ny>=height) ny=2*(height-1)-ny;
+		    a[index] += Kernel[i+2] * Kernel[j+2] * b[ny * width + nx];
+		}
+	    }
+	}
+    }
+}
+
+/*
+ * Construction/Destruction
+ */
+
+lpyramid_t *
+lpyramid_create (float *image, int width, int height)
+{
+    lpyramid_t *pyramid;
+    int i;
+
+    /* XXX: Remove stupid cast after finishing port to C */
+    pyramid = (lpyramid_t *) malloc (sizeof (lpyramid_t));
+    if (pyramid == NULL) {
+	fprintf (stderr, "Out of memory.\n");
+	exit (1);
+    }
+    pyramid->width = width;
+    pyramid->height = height;
+
+    /* Make the Laplacian pyramid by successively
+     * copying the earlier levels and blurring them */
+    for (i=0; i<MAX_PYR_LEVELS; i++) {
+	/* XXX: Remove stupid cast after finishing port to C */
+	pyramid->levels[i] = (float *) malloc (width * height * sizeof (float));
+	if (pyramid->levels[i] == NULL) {
+	    fprintf (stderr, "Out of memory.\n");
+	    exit (1);
+	}
+	if (i == 0) {
+	    memcpy (pyramid->levels[i], image, width * height * sizeof (float));
+	} else {
+	    convolve(pyramid, pyramid->levels[i], pyramid->levels[i - 1]);
+	}
+    }
+
+    return pyramid;
+}
+
+void
+lpyramid_destroy (lpyramid_t *pyramid)
+{
+    int i;
+
+    for (i=0; i<MAX_PYR_LEVELS; i++)
+	free (pyramid->levels[i]);
+}
+
+float
+lpyramid_get_value (lpyramid_t *pyramid, int x, int y, int level)
+{
+    int index = x + y * pyramid->width;
+    int l = level;
+    if (l > MAX_PYR_LEVELS)
+	l = MAX_PYR_LEVELS;
+    return pyramid->levels[level][index];
+}