Pillow/src/_imagingmorph.c
2023-03-22 18:56:52 +11:00

274 lines
7.7 KiB
C

/*
* 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 "libImaging/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;
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
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 (ret == NULL) {
return NULL;
}
if (!PyArg_ParseTuple(args, "On", &py_lut, &i0)) {
Py_DECREF(ret);
PyErr_SetString(PyExc_RuntimeError, "Argument parsing problem");
return NULL;
}
if (!PyBytes_Check(py_lut)) {
Py_DECREF(ret);
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) {
Py_DECREF(ret);
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) {
Py_DECREF(ret);
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;
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);
Py_XDECREF(coordObj);
}
}
}
return ret;
}
/* Return a list of the coordinates of all turned on pixels in an image.
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);
if (ret == NULL) {
return NULL;
}
if (!PyArg_ParseTuple(args, "n", &i0)) {
Py_DECREF(ret);
PyErr_SetString(PyExc_RuntimeError, "Argument parsing problem");
return NULL;
}
img = (Imaging)i0;
rows = img->image8;
width = img->xsize;
height = img->ysize;
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);
Py_XDECREF(coordObj);
}
}
}
return ret;
}
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);
return m;
}