Pillow/src/_imagingmorph.c

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/*
* The Python Imaging Library
*
* A binary morphology add-on for the Python Imaging Library
*
* History:
* 2014-06-04 Initial version.
*
* Copyright (c) 2014 Dov Grobgeld <dov.grobgeld@gmail.com>
*
* See the README file for information on usage and redistribution.
*/
#include "Python.h"
#include "Imaging.h"
#define LUT_SIZE (1<<9)
/* Apply a morphologic LUT to a binary image. Outputs a
a new binary image.
Expected parameters:
1. a LUT - a 512 byte size lookup table.
2. an input Imaging image id.
3. an output Imaging image id
Returns number of changed pixels.
*/
static PyObject*
apply(PyObject *self, PyObject* args)
{
const char *lut;
PyObject *py_lut;
Py_ssize_t lut_len, i0, i1;
Imaging imgin, imgout;
int width, height;
int row_idx, col_idx;
UINT8 **inrows, **outrows;
int num_changed_pixels = 0;
if (!PyArg_ParseTuple(args, "Onn", &py_lut, &i0, &i1)) {
PyErr_SetString(PyExc_RuntimeError, "Argument parsing problem");
return NULL;
}
if (!PyBytes_Check(py_lut)) {
PyErr_SetString(PyExc_RuntimeError, "The morphology LUT is not a bytes object");
return NULL;
}
lut_len = PyBytes_Size(py_lut);
if (lut_len < LUT_SIZE) {
PyErr_SetString(PyExc_RuntimeError, "The morphology LUT has the wrong size");
return NULL;
}
lut = PyBytes_AsString(py_lut);
imgin = (Imaging) i0;
imgout = (Imaging) i1;
width = imgin->xsize;
height = imgin->ysize;
if (imgin->type != IMAGING_TYPE_UINT8 ||
imgin->bands != 1) {
PyErr_SetString(PyExc_RuntimeError, "Unsupported image type");
return NULL;
}
if (imgout->type != IMAGING_TYPE_UINT8 ||
imgout->bands != 1) {
PyErr_SetString(PyExc_RuntimeError, "Unsupported image type");
return NULL;
}
inrows = imgin->image8;
outrows = imgout->image8;
for (row_idx=0; row_idx < height; row_idx++) {
UINT8 *outrow = outrows[row_idx];
UINT8 *inrow = inrows[row_idx];
UINT8 *prow, *nrow; /* Previous and next row */
/* zero boundary conditions. TBD support other modes */
outrow[0] = outrow[width-1] = 0;
if (row_idx==0 || row_idx == height-1) {
for(col_idx=0; col_idx<width; col_idx++)
outrow[col_idx] = 0;
continue;
}
prow = inrows[row_idx-1];
nrow = inrows[row_idx+1];
for (col_idx=1; col_idx<width-1; col_idx++) {
int cim = col_idx-1;
int cip = col_idx+1;
unsigned char b0 = prow[cim] &1;
unsigned char b1 = prow[col_idx]&1;
unsigned char b2 = prow[cip]&1;
unsigned char b3 = inrow[cim]&1;
unsigned char b4 = inrow[col_idx]&1;
unsigned char b5 = inrow[cip]&1;
unsigned char b6 = nrow[cim]&1;
unsigned char b7 = nrow[col_idx]&1;
unsigned char b8 = nrow[cip]&1;
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int lut_idx = (b0
|(b1 << 1)
|(b2 << 2)
|(b3 << 3)
|(b4 << 4)
|(b5 << 5)
|(b6 << 6)
|(b7 << 7)
|(b8 << 8));
outrow[col_idx] = 255*(lut[lut_idx]&1);
num_changed_pixels += ((b4&1)!=(outrow[col_idx]&1));
}
}
return Py_BuildValue("i",num_changed_pixels);
}
/* Match a morphologic LUT to a binary image and return a list
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of the coordinates of all matching pixels.
Expected parameters:
1. a LUT - a 512 byte size lookup table.
2. an input Imaging image id.
Returns list of matching pixels.
*/
static PyObject*
match(PyObject *self, PyObject* args)
{
const char *lut;
PyObject *py_lut;
Py_ssize_t lut_len, i0;
Imaging imgin;
int width, height;
int row_idx, col_idx;
UINT8 **inrows;
PyObject *ret = PyList_New(0);
if (!PyArg_ParseTuple(args, "On", &py_lut, &i0)) {
PyErr_SetString(PyExc_RuntimeError, "Argument parsing problem");
return NULL;
}
if (!PyBytes_Check(py_lut)) {
PyErr_SetString(PyExc_RuntimeError, "The morphology LUT is not a bytes object");
return NULL;
}
lut_len = PyBytes_Size(py_lut);
if (lut_len < LUT_SIZE) {
PyErr_SetString(PyExc_RuntimeError, "The morphology LUT has the wrong size");
return NULL;
}
lut = PyBytes_AsString(py_lut);
imgin = (Imaging) i0;
if (imgin->type != IMAGING_TYPE_UINT8 ||
imgin->bands != 1) {
PyErr_SetString(PyExc_RuntimeError, "Unsupported image type");
return NULL;
}
inrows = imgin->image8;
width = imgin->xsize;
height = imgin->ysize;
for (row_idx=1; row_idx < height-1; row_idx++) {
UINT8 *inrow = inrows[row_idx];
UINT8 *prow, *nrow;
prow = inrows[row_idx-1];
nrow = inrows[row_idx+1];
for (col_idx=1; col_idx<width-1; col_idx++) {
int cim = col_idx-1;
int cip = col_idx+1;
unsigned char b0 = prow[cim] &1;
unsigned char b1 = prow[col_idx]&1;
unsigned char b2 = prow[cip]&1;
unsigned char b3 = inrow[cim]&1;
unsigned char b4 = inrow[col_idx]&1;
unsigned char b5 = inrow[cip]&1;
unsigned char b6 = nrow[cim]&1;
unsigned char b7 = nrow[col_idx]&1;
unsigned char b8 = nrow[cip]&1;
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int lut_idx = (b0
|(b1 << 1)
|(b2 << 2)
|(b3 << 3)
|(b4 << 4)
|(b5 << 5)
|(b6 << 6)
|(b7 << 7)
|(b8 << 8));
if (lut[lut_idx]) {
PyObject *coordObj = Py_BuildValue("(nn)",col_idx,row_idx);
PyList_Append(ret, coordObj);
}
}
}
return ret;
}
/* Return a list of the coordinates of all turned on pixels in an image.
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May be used to extract features after a sequence of MorphOps were applied.
This is faster than match as only 1x1 lookup is made.
*/
static PyObject*
get_on_pixels(PyObject *self, PyObject* args)
{
Py_ssize_t i0;
Imaging img;
UINT8 **rows;
int row_idx, col_idx;
int width, height;
PyObject *ret = PyList_New(0);
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if (!PyArg_ParseTuple(args, "n", &i0)) {
PyErr_SetString(PyExc_RuntimeError, "Argument parsing problem");
return NULL;
}
img = (Imaging) i0;
rows = img->image8;
width = img->xsize;
height = img->ysize;
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for (row_idx=0; row_idx < height; row_idx++) {
UINT8 *row = rows[row_idx];
for (col_idx=0; col_idx<width; col_idx++) {
if (row[col_idx]) {
PyObject *coordObj = Py_BuildValue("(nn)",col_idx,row_idx);
PyList_Append(ret, coordObj);
}
}
}
return ret;
}
static int
setup_module(PyObject* m)
{
PyObject* d = PyModule_GetDict(m);
PyDict_SetItemString(d, "__version", PyUnicode_FromString("0.1"));
return 0;
}
static PyMethodDef functions[] = {
/* Functions */
{"apply", (PyCFunction)apply, METH_VARARGS, NULL},
{"get_on_pixels", (PyCFunction)get_on_pixels, METH_VARARGS, NULL},
{"match", (PyCFunction)match, METH_VARARGS, NULL},
{NULL, NULL, 0, NULL}
};
PyMODINIT_FUNC
PyInit__imagingmorph(void) {
PyObject* m;
static PyModuleDef module_def = {
PyModuleDef_HEAD_INIT,
"_imagingmorph", /* m_name */
"A module for doing image morphology", /* m_doc */
-1, /* m_size */
functions, /* m_methods */
};
m = PyModule_Create(&module_def);
if (setup_module(m) < 0)
return NULL;
return m;
}