From: Tomas Musil <tomik.musil@gmail.com>
Date: Fri, 19 Oct 2012 19:05:12 +0000 (+0200)
Subject: edge_detection in C
X-Git-Url: http://git.tomasm.cz/imago.git/commitdiff_plain/ad06aed1192f4b21ae009c593e8bf2ca5ed14fad?hp=6e16bbc7797b679d6681eee08d9103984728b98f

edge_detection in C
---

diff --git a/pcf.c b/pcf.c
index eccb991..4a14681 100644
--- a/pcf.c
+++ b/pcf.c
@@ -1,23 +1,63 @@
 #include <Python.h>
 
-static PyObject* py_test(PyObject* self, PyObject* args)
+static PyObject* py_edge(PyObject* self, PyObject* args)
 {
-	unsigned char *image;
+	const unsigned char *image;
 	int x;
 	int y;
 	int size;
 
-	if (!PyArg_ParseTuple(args, "(ii)s#", &x, &y, &image, &size)) return NULL;
-	
 	int i;
-	for (i=0; i < size; i++) {
-		image[i] = i % 256;
+	int j;
+	int sum;
+
+	unsigned char *n_image;
+	PyObject *result;
+
+	if (!PyArg_ParseTuple(args, "(ii)s#", &x, &y, &image, &size)) return NULL;
+
+	n_image = (char*) malloc(size);
+	for (i=0; i < 2 * x; i++) {
+		n_image[i] = 0;
+		n_image[(y - 2) * x + i] = 0;
+	}
+	for (i=0; i < y; i++) {
+		n_image[x * i] = 0;
+		n_image[x * i + 1] = 0;
+		n_image[x * i + x - 2] = 0;
+		n_image[x * i + x - 1] = 0;
+	}
+
+
+
+	for (i=2; i < x - 2; i++) {
+		for (j=2; j < y - 2; j++) {
+			sum = image[x * j + i - 2] + image[x * j + i - 1] + image[x * j + i + 1] + image[x * j + i + 2] + 
+				image[x * (j - 2) + i - 2] + image[x * (j - 2) + i - 1] + image[x * (j - 2) + i] + 
+				image[x * (j - 2) + i + 1] + image[x * (j - 2) + i + 2] + 
+				image[x * (j - 1) + i - 2] + image[x * (j - 1) + i - 1] + image[x * (j - 1) + i] + 
+				image[x * (j - 1) + i + 1] + image[x * (j - 1) + i + 2] +
+				image[x * (j + 2) + i - 2] + image[x * (j + 2) + i - 1] + image[x * (j + 2) + i] + 
+				image[x * (j + 2) + i + 1] + image[x * (j + 2) + i + 2] +
+				image[x * (j + 1) + i - 2] + image[x * (j + 1) + i - 1] + image[x * (j + 1) + i] + 
+				image[x * (j + 1) + i + 1] + image[x * (j + 1) + i + 2] 
+				- (25 * image[x * j + i]);
+			if (sum < 0) sum = 0;
+			if (sum > 255) sum = 255;
+			n_image[x * j + i] = sum;
+		}
 	}
 
-	return Py_BuildValue("s#", image, size);
+
+
+	result = Py_BuildValue("s#", n_image, size);
+	free(n_image);
+	return result;
 }
+
+
 static PyMethodDef myModule_methods[] = {
-	{"test", py_test, METH_VARARGS},
+	{"edge", py_edge, METH_VARARGS},
 	{NULL, NULL}
 };