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Pillow/path.c

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/*
* The Python Imaging Library.
*
* 2D path utilities
*
* history:
* 1996-11-04 fl Added to PIL (incomplete)
* 1996-11-05 fl Added sequence semantics
* 1997-02-28 fl Fixed getbbox
* 1997-06-12 fl Added id attribute
* 1997-06-14 fl Added slicing and setitem
* 1998-12-29 fl Improved sequence handling (from Richard Jones)
* 1999-01-10 fl Fixed IndexError test for 1.5 (from Fred Drake)
* 2000-10-12 fl Added special cases for tuples and lists
* 2002-10-27 fl Added clipping boilerplate
* 2004-09-19 fl Added tolist(flat) variant
* 2005-05-06 fl Added buffer interface support to path constructor
*
* notes:
* FIXME: fill in remaining slots in the sequence api
*
* Copyright (c) 1997-2005 by Secret Labs AB
* Copyright (c) 1997-2005 by Fredrik Lundh
*
* See the README file for information on usage and redistribution.
*/
#include "Python.h"
#include <math.h>
#include "py3.h"
/* compatibility wrappers (defined in _imaging.c) */
extern int PyImaging_CheckBuffer(PyObject* buffer);
extern int PyImaging_GetBuffer(PyObject* buffer, Py_buffer *view);
/* -------------------------------------------------------------------- */
/* Class */
/* -------------------------------------------------------------------- */
typedef struct {
PyObject_HEAD
Py_ssize_t count;
double *xy;
int index; /* temporary use, e.g. in decimate */
} PyPathObject;
static PyTypeObject PyPathType;
static double*
alloc_array(Py_ssize_t count)
{
double* xy;
if (count < 0) {
PyErr_NoMemory();
return NULL;
}
xy = malloc(2 * count * sizeof(double) + 1);
if (!xy)
PyErr_NoMemory();
return xy;
}
static PyPathObject*
path_new(Py_ssize_t count, double* xy, int duplicate)
{
PyPathObject *path;
if (duplicate) {
/* duplicate path */
double* p = alloc_array(count);
if (!p)
return NULL;
memcpy(p, xy, count * 2 * sizeof(double));
xy = p;
}
if (PyType_Ready(&PyPathType) < 0)
return NULL;
path = PyObject_New(PyPathObject, &PyPathType);
if (path == NULL)
return NULL;
path->count = count;
path->xy = xy;
return path;
}
static void
path_dealloc(PyPathObject* path)
{
free(path->xy);
PyObject_Del(path);
}
/* -------------------------------------------------------------------- */
/* Helpers */
/* -------------------------------------------------------------------- */
#define PyPath_Check(op) (Py_TYPE(op) == &PyPathType)
int
PyPath_Flatten(PyObject* data, double **pxy)
{
int i, j, n;
double *xy;
if (PyPath_Check(data)) {
/* This was another path object. */
PyPathObject *path = (PyPathObject*) data;
xy = alloc_array(path->count);
if (!xy)
return -1;
memcpy(xy, path->xy, 2 * path->count * sizeof(double));
*pxy = xy;
return path->count;
}
if (PyImaging_CheckBuffer(data)) {
/* Assume the buffer contains floats */
Py_buffer buffer;
if (PyImaging_GetBuffer(data, &buffer) == 0) {
int n = buffer.len / (2 * sizeof(float));
float *ptr = (float*) buffer.buf;
xy = alloc_array(n);
if (!xy)
return -1;
for (i = 0; i < n+n; i++)
xy[i] = ptr[i];
*pxy = xy;
PyBuffer_Release(&buffer);
return n;
}
PyErr_Clear();
}
if (!PySequence_Check(data)) {
PyErr_SetString(PyExc_TypeError, "argument must be sequence");
return -1;
}
j = 0;
n = PyObject_Length(data);
/* Just in case __len__ breaks (or doesn't exist) */
if (PyErr_Occurred())
return -1;
/* Allocate for worst case */
xy = alloc_array(n);
if (!xy)
return -1;
/* Copy table to path array */
if (PyList_Check(data)) {
for (i = 0; i < n; i++) {
double x, y;
PyObject *op = PyList_GET_ITEM(data, i);
if (PyFloat_Check(op))
xy[j++] = PyFloat_AS_DOUBLE(op);
else if (PyInt_Check(op))
xy[j++] = (float) PyInt_AS_LONG(op);
else if (PyNumber_Check(op))
xy[j++] = PyFloat_AsDouble(op);
else if (PyArg_ParseTuple(op, "dd", &x, &y)) {
xy[j++] = x;
xy[j++] = y;
} else {
free(xy);
return -1;
}
}
} else if (PyTuple_Check(data)) {
for (i = 0; i < n; i++) {
double x, y;
PyObject *op = PyTuple_GET_ITEM(data, i);
if (PyFloat_Check(op))
xy[j++] = PyFloat_AS_DOUBLE(op);
else if (PyInt_Check(op))
xy[j++] = (float) PyInt_AS_LONG(op);
else if (PyNumber_Check(op))
xy[j++] = PyFloat_AsDouble(op);
else if (PyArg_ParseTuple(op, "dd", &x, &y)) {
xy[j++] = x;
xy[j++] = y;
} else {
free(xy);
return -1;
}
}
} else {
for (i = 0; i < n; i++) {
double x, y;
PyObject *op = PySequence_GetItem(data, i);
if (!op) {
/* treat IndexError as end of sequence */
if (PyErr_Occurred() &&
PyErr_ExceptionMatches(PyExc_IndexError)) {
PyErr_Clear();
break;
} else {
free(xy);
return -1;
}
}
if (PyFloat_Check(op))
xy[j++] = PyFloat_AS_DOUBLE(op);
else if (PyInt_Check(op))
xy[j++] = (float) PyInt_AS_LONG(op);
else if (PyNumber_Check(op))
xy[j++] = PyFloat_AsDouble(op);
else if (PyArg_ParseTuple(op, "dd", &x, &y)) {
xy[j++] = x;
xy[j++] = y;
} else {
Py_DECREF(op);
free(xy);
return -1;
}
Py_DECREF(op);
}
}
if (j & 1) {
PyErr_SetString(PyExc_ValueError, "wrong number of coordinates");
free(xy);
return -1;
}
*pxy = xy;
return j/2;
}
/* -------------------------------------------------------------------- */
/* Factories */
/* -------------------------------------------------------------------- */
PyObject*
PyPath_Create(PyObject* self, PyObject* args)
{
PyObject* data;
Py_ssize_t count;
double *xy;
if (PyArg_ParseTuple(args, "n:Path", &count)) {
/* number of vertices */
xy = alloc_array(count);
if (!xy)
return NULL;
} else {
/* sequence or other path */
PyErr_Clear();
if (!PyArg_ParseTuple(args, "O", &data))
return NULL;
count = PyPath_Flatten(data, &xy);
if (count < 0)
return NULL;
}
return (PyObject*) path_new(count, xy, 0);
}
/* -------------------------------------------------------------------- */
/* Methods */
/* -------------------------------------------------------------------- */
static PyObject*
path_compact(PyPathObject* self, PyObject* args)
{
/* Simple-minded method to shorten path. A point is removed if
the city block distance to the previous point is less than the
given distance */
int i, j;
double *xy;
double cityblock = 2.0;
if (!PyArg_ParseTuple(args, "|d:compact", &cityblock))
return NULL;
xy = self->xy;
/* remove bogus vertices */
for (i = j = 1; i < self->count; i++) {
if (fabs(xy[j+j-2]-xy[i+i]) + fabs(xy[j+j-1]-xy[i+i+1]) >= cityblock) {
xy[j+j] = xy[i+i];
xy[j+j+1] = xy[i+i+1];
j++;
}
}
i = self->count - j;
self->count = j;
/* shrink coordinate array */
self->xy = realloc(self->xy, 2 * self->count * sizeof(double));
return Py_BuildValue("i", i); /* number of removed vertices */
}
static PyObject*
path_clip_polygon(PyPathObject* self, PyObject* args)
{
/* Clip path representing a single polygon */
PyErr_SetString(PyExc_RuntimeError, "not yet implemented");
return NULL;
}
static PyObject*
path_clip_polyline(PyPathObject* self, PyObject* args)
{
/* Clip path representing a single polyline (outline) */
PyErr_SetString(PyExc_RuntimeError, "not yet implemented");
return NULL;
}
static PyObject*
path_getbbox(PyPathObject* self, PyObject* args)
{
/* Find bounding box */
int i;
double *xy;
double x0, y0, x1, y1;
if (!PyArg_ParseTuple(args, ":getbbox"))
return NULL;
xy = self->xy;
x0 = x1 = xy[0];
y0 = y1 = xy[1];
for (i = 1; i < self->count; i++) {
if (xy[i+i] < x0)
x0 = xy[i+i];
if (xy[i+i] > x1)
x1 = xy[i+i];
if (xy[i+i+1] < y0)
y0 = xy[i+i+1];
if (xy[i+i+1] > y1)
y1 = xy[i+i+1];
}
return Py_BuildValue("dddd", x0, y0, x1, y1);
}
static PyObject*
path_getitem(PyPathObject* self, int i)
{
if (i < 0)
i = self->count + i;
if (i < 0 || i >= self->count) {
PyErr_SetString(PyExc_IndexError, "path index out of range");
return NULL;
}
return Py_BuildValue("dd", self->xy[i+i], self->xy[i+i+1]);
}
static PyObject*
path_getslice(PyPathObject* self, Py_ssize_t ilow, Py_ssize_t ihigh)
{
/* adjust arguments */
if (ilow < 0)
ilow = 0;
else if (ilow >= self->count)
ilow = self->count;
if (ihigh < 0)
ihigh = 0;
if (ihigh < ilow)
ihigh = ilow;
else if (ihigh > self->count)
ihigh = self->count;
return (PyObject*) path_new(ihigh - ilow, self->xy + ilow * 2, 1);
}
static Py_ssize_t
path_len(PyPathObject* self)
{
return self->count;
}
static PyObject*
path_map(PyPathObject* self, PyObject* args)
{
/* Map coordinate set through function */
int i;
double *xy;
PyObject* function;
if (!PyArg_ParseTuple(args, "O:map", &function))
return NULL;
xy = self->xy;
/* apply function to coordinate set */
for (i = 0; i < self->count; i++) {
double x = xy[i+i];
double y = xy[i+i+1];
PyObject* item = PyObject_CallFunction(function, "dd", x, y);
if (!item || !PyArg_ParseTuple(item, "dd", &x, &y)) {
Py_XDECREF(item);
return NULL;
}
xy[i+i] = x;
xy[i+i+1] = y;
Py_DECREF(item);
}
Py_INCREF(Py_None);
return Py_None;
}
static int
path_setitem(PyPathObject* self, int i, PyObject* op)
{
double* xy;
if (i < 0 || i >= self->count) {
PyErr_SetString(PyExc_IndexError,
"path assignment index out of range");
return -1;
}
if (op == NULL) {
PyErr_SetString(PyExc_TypeError,
"cannot delete from path");
return -1;
}
xy = &self->xy[i+i];
if (!PyArg_ParseTuple(op, "dd", &xy[0], &xy[1]))
return -1;
return 0;
}
static PyObject*
path_tolist(PyPathObject* self, PyObject* args)
{
PyObject *list;
int i;
int flat = 0;
if (!PyArg_ParseTuple(args, "|i:tolist", &flat))
return NULL;
if (flat) {
list = PyList_New(self->count*2);
for (i = 0; i < self->count*2; i++) {
PyObject* item;
item = PyFloat_FromDouble(self->xy[i]);
if (!item)
goto error;
PyList_SetItem(list, i, item);
}
} else {
list = PyList_New(self->count);
for (i = 0; i < self->count; i++) {
PyObject* item;
item = Py_BuildValue("dd", self->xy[i+i], self->xy[i+i+1]);
if (!item)
goto error;
PyList_SetItem(list, i, item);
}
}
return list;
error:
Py_DECREF(list);
return NULL;
}
static PyObject*
path_transform(PyPathObject* self, PyObject* args)
{
/* Apply affine transform to coordinate set */
int i;
double *xy;
double a, b, c, d, e, f;
double wrap = 0.0;
if (!PyArg_ParseTuple(args, "(dddddd)|d:transform",
&a, &b, &c, &d, &e, &f,
&wrap))
return NULL;
xy = self->xy;
/* transform the coordinate set */
if (b == 0.0 && d == 0.0)
/* scaling */
for (i = 0; i < self->count; i++) {
xy[i+i] = a*xy[i+i]+c;
xy[i+i+1] = e*xy[i+i+1]+f;
}
else
/* affine transform */
for (i = 0; i < self->count; i++) {
double x = xy[i+i];
double y = xy[i+i+1];
xy[i+i] = a*x+b*y+c;
xy[i+i+1] = d*x+e*y+f;
}
/* special treatment of geographical map data */
if (wrap != 0.0)
for (i = 0; i < self->count; i++)
xy[i+i] = fmod(xy[i+i], wrap);
Py_INCREF(Py_None);
return Py_None;
}
static struct PyMethodDef methods[] = {
{"getbbox", (PyCFunction)path_getbbox, 1},
{"tolist", (PyCFunction)path_tolist, 1},
{"clip_polygon", (PyCFunction)path_clip_polygon, 1},
{"clip_polyline", (PyCFunction)path_clip_polyline, 1},
{"compact", (PyCFunction)path_compact, 1},
{"map", (PyCFunction)path_map, 1},
{"transform", (PyCFunction)path_transform, 1},
{NULL, NULL} /* sentinel */
};
static PyObject*
path_getattr_id(PyPathObject* self, void* closure)
{
return Py_BuildValue("n", (Py_ssize_t) self->xy);
}
static struct PyGetSetDef getsetters[] = {
{ "id", (getter) path_getattr_id },
{ NULL }
};
static PyObject*
path_subscript(PyPathObject* self, PyObject* item) {
if (PyIndex_Check(item)) {
Py_ssize_t i;
i = PyNumber_AsSsize_t(item, PyExc_IndexError);
if (i == -1 && PyErr_Occurred())
return NULL;
return path_getitem(self, i);
}
if (PySlice_Check(item)) {
int len = 4;
Py_ssize_t start, stop, step, slicelength;
#if PY_VERSION_HEX >= 0x03020000
if (PySlice_GetIndicesEx(item, len, &start, &stop, &step, &slicelength) < 0)
return NULL;
#else
if (PySlice_GetIndicesEx((PySliceObject*)item, len, &start, &stop, &step, &slicelength) < 0)
return NULL;
#endif
if (slicelength <= 0) {
double *xy = alloc_array(0);
return (PyObject*) path_new(0, xy, 0);
}
else if (step == 1) {
return path_getslice(self, start, stop);
}
else {
PyErr_SetString(PyExc_TypeError, "slice steps not supported");
return NULL;
}
}
else {
PyErr_Format(PyExc_TypeError,
"Path indices must be integers, not %.200s",
Py_TYPE(&item)->tp_name);
return NULL;
}
}
static PySequenceMethods path_as_sequence = {
(lenfunc)path_len, /*sq_length*/
(binaryfunc)0, /*sq_concat*/
(ssizeargfunc)0, /*sq_repeat*/
(ssizeargfunc)path_getitem, /*sq_item*/
(ssizessizeargfunc)path_getslice, /*sq_slice*/
(ssizeobjargproc)path_setitem, /*sq_ass_item*/
(ssizessizeobjargproc)0, /*sq_ass_slice*/
};
static PyMappingMethods path_as_mapping = {
(lenfunc)path_len,
(binaryfunc)path_subscript,
NULL
};
static PyTypeObject PyPathType = {
PyVarObject_HEAD_INIT(NULL, 0)
"Path", /*tp_name*/
sizeof(PyPathObject), /*tp_size*/
0, /*tp_itemsize*/
/* methods */
(destructor)path_dealloc, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
0, /*tp_repr*/
0, /*tp_as_number */
&path_as_sequence, /*tp_as_sequence */
&path_as_mapping, /*tp_as_mapping */
0, /*tp_hash*/
0, /*tp_call*/
0, /*tp_str*/
0, /*tp_getattro*/
0, /*tp_setattro*/
0, /*tp_as_buffer*/
Py_TPFLAGS_DEFAULT, /*tp_flags*/
0, /*tp_doc*/
0, /*tp_traverse*/
0, /*tp_clear*/
0, /*tp_richcompare*/
0, /*tp_weaklistoffset*/
0, /*tp_iter*/
0, /*tp_iternext*/
methods, /*tp_methods*/
0, /*tp_members*/
getsetters, /*tp_getset*/
};
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