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233 lines (191 loc) · 8.51 KB
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#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>
#include "_image_resample.h"
#include "py_converters_11.h"
/**********************************************************************
* Free functions
* */
const char* image_resample__doc__ =
"Resample input_array, blending it in-place into output_array, using an\n"
"affine transformation.\n\n"
"Parameters\n"
"----------\n"
"input_array : 2-d or 3-d NumPy array of float, double or `numpy.uint8`\n"
" If 2-d, the image is grayscale. If 3-d, the image must be of size\n"
" 4 in the last dimension and represents RGBA data.\n\n"
"output_array : 2-d or 3-d NumPy array of float, double or `numpy.uint8`\n"
" The dtype and number of dimensions must match `input_array`.\n\n"
"transform : matplotlib.transforms.Transform instance\n"
" The transformation from the input array to the output array.\n\n"
"interpolation : int, default: NEAREST\n"
" The interpolation method. Must be one of the following constants\n"
" defined in this module:\n\n"
" NEAREST, BILINEAR, BICUBIC, SPLINE16, SPLINE36,\n"
" HANNING, HAMMING, HERMITE, KAISER, QUADRIC, CATROM, GAUSSIAN,\n"
" BESSEL, MITCHELL, SINC, LANCZOS, BLACKMAN\n\n"
"resample : bool, optional\n"
" When `True`, use a full resampling method. When `False`, only\n"
" resample when the output image is larger than the input image.\n\n"
"alpha : float, default: 1\n"
" The transparency level, from 0 (transparent) to 1 (opaque).\n\n"
"norm : bool, default: False\n"
" Whether to norm the interpolation function.\n\n"
"radius: float, default: 1\n"
" The radius of the kernel, if method is SINC, LANCZOS or BLACKMAN.\n";
static pybind11::array_t<double>
_get_transform_mesh(const pybind11::object& transform, const pybind11::ssize_t *dims)
{
/* TODO: Could we get away with float, rather than double, arrays here? */
/* Given a non-affine transform object, create a mesh that maps
every pixel in the output image to the input image. This is used
as a lookup table during the actual resampling. */
// If attribute doesn't exist, raises Python AttributeError
auto inverse = transform.attr("inverted")();
pybind11::ssize_t mesh_dims[2] = {dims[0]*dims[1], 2};
pybind11::array_t<double> input_mesh(mesh_dims);
auto p = input_mesh.mutable_data();
for (auto y = 0; y < dims[0]; ++y) {
for (auto x = 0; x < dims[1]; ++x) {
*p++ = (double)x;
*p++ = (double)y;
}
}
auto output_mesh = inverse.attr("transform")(input_mesh);
auto output_mesh_array =
pybind11::array_t<double, pybind11::array::c_style | pybind11::array::forcecast>(output_mesh);
if (output_mesh_array.ndim() != 2) {
throw std::runtime_error(
"Inverse transformed mesh array should be 2D not " +
std::to_string(output_mesh_array.ndim()) + "D");
}
return output_mesh_array;
}
// Using generic pybind::array for input and output arrays rather than the more usual
// pybind::array_t<type> as function supports multiple array dtypes.
static void
image_resample(pybind11::array input_array,
pybind11::array& output_array,
const pybind11::object& transform,
interpolation_e interpolation,
bool resample_, // Avoid name clash with resample() function
float alpha,
bool norm,
float radius)
{
// Validate input_array
auto dtype = input_array.dtype(); // Validated when determine resampler below
auto ndim = input_array.ndim();
if (ndim != 2 && ndim != 3) {
throw std::invalid_argument("Input array must be a 2D or 3D array");
}
if (ndim == 3 && input_array.shape(2) != 4) {
throw std::invalid_argument(
"3D input array must be RGBA with shape (M, N, 4), has trailing dimension of " +
std::to_string(input_array.shape(2)));
}
// Ensure input array is contiguous, regardless of dtype
input_array = pybind11::array::ensure(input_array, pybind11::array::c_style);
// Validate output array
auto out_ndim = output_array.ndim();
if (out_ndim != ndim) {
throw std::invalid_argument(
"Input (" + std::to_string(ndim) + "D) and output (" + std::to_string(out_ndim) +
"D) arrays have different dimensionalities");
}
if (out_ndim == 3 && output_array.shape(2) != 4) {
throw std::invalid_argument(
"3D output array must be RGBA with shape (M, N, 4), has trailing dimension of " +
std::to_string(output_array.shape(2)));
}
if (!output_array.dtype().is(dtype)) {
throw std::invalid_argument("Input and output arrays have mismatched types");
}
if ((output_array.flags() & pybind11::array::c_style) == 0) {
throw std::invalid_argument("Output array must be C-contiguous");
}
if (!output_array.writeable()) {
throw std::invalid_argument("Output array must be writeable");
}
resample_params_t params;
params.interpolation = interpolation;
params.transform_mesh = nullptr;
params.resample = resample_;
params.norm = norm;
params.radius = radius;
params.alpha = alpha;
// Only used if transform is not affine.
// Need to keep it in scope for the duration of this function.
pybind11::array_t<double> transform_mesh;
// Validate transform
if (transform.is_none()) {
params.is_affine = true;
} else {
// Raises Python AttributeError if no such attribute or TypeError if cast fails
bool is_affine = pybind11::cast<bool>(transform.attr("is_affine"));
if (is_affine) {
convert_trans_affine(transform, params.affine);
params.is_affine = true;
} else {
transform_mesh = _get_transform_mesh(transform, output_array.shape());
params.transform_mesh = transform_mesh.data();
params.is_affine = false;
}
}
if (auto resampler =
(ndim == 2) ? (
(dtype.is(pybind11::dtype::of<std::uint8_t>())) ? resample<agg::gray8> :
(dtype.is(pybind11::dtype::of<std::int8_t>())) ? resample<agg::gray8> :
(dtype.is(pybind11::dtype::of<std::uint16_t>())) ? resample<agg::gray16> :
(dtype.is(pybind11::dtype::of<std::int16_t>())) ? resample<agg::gray16> :
(dtype.is(pybind11::dtype::of<float>())) ? resample<agg::gray32> :
(dtype.is(pybind11::dtype::of<double>())) ? resample<agg::gray64> :
nullptr) : (
// ndim == 3
(dtype.is(pybind11::dtype::of<std::uint8_t>())) ? resample<agg::rgba8> :
(dtype.is(pybind11::dtype::of<std::int8_t>())) ? resample<agg::rgba8> :
(dtype.is(pybind11::dtype::of<std::uint16_t>())) ? resample<agg::rgba16> :
(dtype.is(pybind11::dtype::of<std::int16_t>())) ? resample<agg::rgba16> :
(dtype.is(pybind11::dtype::of<float>())) ? resample<agg::rgba32> :
(dtype.is(pybind11::dtype::of<double>())) ? resample<agg::rgba64> :
nullptr)) {
Py_BEGIN_ALLOW_THREADS
resampler(
input_array.data(), input_array.shape(1), input_array.shape(0),
output_array.mutable_data(), output_array.shape(1), output_array.shape(0),
params);
Py_END_ALLOW_THREADS
} else {
throw std::invalid_argument("arrays must be of dtype byte, short, float32 or float64");
}
}
PYBIND11_MODULE(_image, m) {
pybind11::enum_<interpolation_e>(m, "_InterpolationType")
.value("NEAREST", NEAREST)
.value("BILINEAR", BILINEAR)
.value("BICUBIC", BICUBIC)
.value("SPLINE16", SPLINE16)
.value("SPLINE36", SPLINE36)
.value("HANNING", HANNING)
.value("HAMMING", HAMMING)
.value("HERMITE", HERMITE)
.value("KAISER", KAISER)
.value("QUADRIC", QUADRIC)
.value("CATROM", CATROM)
.value("GAUSSIAN", GAUSSIAN)
.value("BESSEL", BESSEL)
.value("MITCHELL", MITCHELL)
.value("SINC", SINC)
.value("LANCZOS", LANCZOS)
.value("BLACKMAN", BLACKMAN)
.export_values();
m.def("resample", &image_resample,
pybind11::arg("input_array"),
pybind11::arg("output_array"),
pybind11::arg("transform"),
pybind11::arg("interpolation") = interpolation_e::NEAREST,
pybind11::arg("resample") = false,
pybind11::arg("alpha") = 1,
pybind11::arg("norm") = false,
pybind11::arg("radius") = 1,
image_resample__doc__);
}
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