PyObject*
_png_module::_read_png(const Py::Object& py_fileobj, const bool float_result,
int result_bit_depth)
{
png_byte header[8]; // 8 is the maximum size that can be checked
FILE* fp = NULL;
bool close_file = false;
bool close_dup_file = false;
PyObject *py_file = NULL;
if (py_fileobj.isString())
{
if ((py_file = npy_PyFile_OpenFile(py_fileobj.ptr(), (char *)"rb")) == NULL) {
throw Py::Exception();
}
close_file = true;
} else {
py_file = py_fileobj.ptr();
}
if ((fp = npy_PyFile_Dup(py_file, "rb")))
{
close_dup_file = true;
}
else
{
PyErr_Clear();
PyObject* read_method = PyObject_GetAttrString(py_file, "read");
if (!(read_method && PyCallable_Check(read_method)))
{
Py_XDECREF(read_method);
throw Py::TypeError(
"Object does not appear to be a 8-bit string path or a Python "
"file-like object");
}
Py_XDECREF(read_method);
}
if (fp)
{
if (fread(header, 1, 8, fp) != 8)
{
throw Py::RuntimeError(
"_image_module::readpng: error reading PNG header");
}
}
else
{
_read_png_data(py_file, header, 8);
}
if (png_sig_cmp(header, 0, 8))
{
throw Py::RuntimeError(
"_image_module::readpng: file not recognized as a PNG file");
}
/* initialize stuff */
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
{
throw Py::RuntimeError(
"_image_module::readpng: png_create_read_struct failed");
}
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
{
throw Py::RuntimeError(
"_image_module::readpng: png_create_info_struct failed");
}
if (setjmp(png_jmpbuf(png_ptr)))
{
throw Py::RuntimeError(
"_image_module::readpng: error during init_io");
}
if (fp)
{
png_init_io(png_ptr, fp);
}
else
{
png_set_read_fn(png_ptr, (void*)py_file, &read_png_data);
}
png_set_sig_bytes(png_ptr, 8);
png_read_info(png_ptr, info_ptr);
png_uint_32 width = png_get_image_width(png_ptr, info_ptr);
png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
// Unpack 1, 2, and 4-bit images
if (bit_depth < 8)
png_set_packing(png_ptr);
// If sig bits are set, shift data
png_color_8p sig_bit;
if ((png_get_color_type(png_ptr, info_ptr) != PNG_COLOR_TYPE_PALETTE) &&
png_get_sBIT(png_ptr, info_ptr, &sig_bit))
{
png_set_shift(png_ptr, sig_bit);
}
// Convert big endian to little
if (bit_depth == 16)
{
png_set_swap(png_ptr);
}
// Convert palletes to full RGB
if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_PALETTE)
{
png_set_palette_to_rgb(png_ptr);
bit_depth = 8;
}
// If there's an alpha channel convert gray to RGB
if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_GRAY_ALPHA)
{
png_set_gray_to_rgb(png_ptr);
}
png_set_interlace_handling(png_ptr);
png_read_update_info(png_ptr, info_ptr);
/* read file */
if (setjmp(png_jmpbuf(png_ptr)))
{
throw Py::RuntimeError(
"_image_module::readpng: error during read_image");
}
png_bytep *row_pointers = new png_bytep[height];
png_uint_32 row;
for (row = 0; row < height; row++)
{
row_pointers[row] = new png_byte[png_get_rowbytes(png_ptr,info_ptr)];
}
png_read_image(png_ptr, row_pointers);
npy_intp dimensions[3];
dimensions[0] = height; //numrows
dimensions[1] = width; //numcols
if (png_get_color_type(png_ptr, info_ptr) & PNG_COLOR_MASK_ALPHA)
{
dimensions[2] = 4; //RGBA images
}
else if (png_get_color_type(png_ptr, info_ptr) & PNG_COLOR_MASK_COLOR)
{
dimensions[2] = 3; //RGB images
}
else
{
dimensions[2] = 1; //Greyscale images
}
//For gray, return an x by y array, not an x by y by 1
int num_dims = (png_get_color_type(png_ptr, info_ptr)
& PNG_COLOR_MASK_COLOR) ? 3 : 2;
PyArrayObject *A = NULL;
if (float_result) {
double max_value = (1 << bit_depth) - 1;
A = (PyArrayObject *) PyArray_SimpleNew(num_dims, dimensions, NPY_FLOAT);
if (A == NULL)
{
throw Py::MemoryError("Could not allocate image array");
}
for (png_uint_32 y = 0; y < height; y++)
{
png_byte* row = row_pointers[y];
for (png_uint_32 x = 0; x < width; x++)
{
size_t offset = y * A->strides[0] + x * A->strides[1];
if (bit_depth == 16)
{
png_uint_16* ptr = &reinterpret_cast<png_uint_16*>(row)[x * dimensions[2]];
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++)
{
*(float*)(A->data + offset + p*A->strides[2]) = (float)(ptr[p]) / max_value;
}
}
else
{
png_byte* ptr = &(row[x * dimensions[2]]);
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++)
{
*(float*)(A->data + offset + p*A->strides[2]) = (float)(ptr[p]) / max_value;
}
}
}
}
} else {
if (result_bit_depth < 0) {
result_bit_depth = bit_depth;
}
if (result_bit_depth == 8) {
A = (PyArrayObject *) PyArray_SimpleNew(num_dims, dimensions, NPY_UBYTE);
} else if (result_bit_depth == 16) {
A = (PyArrayObject *) PyArray_SimpleNew(num_dims, dimensions, NPY_UINT16);
} else {
throw Py::RuntimeError(
"_image_module::readpng: image has unknown bit depth");
}
if (A == NULL)
{
throw Py::MemoryError("Could not allocate image array");
}
for (png_uint_32 y = 0; y < height; y++)
{
png_byte* row = row_pointers[y];
for (png_uint_32 x = 0; x < width; x++)
{
size_t offset = y * A->strides[0] + x * A->strides[1];
if (bit_depth == 16)
{
png_uint_16* ptr = &reinterpret_cast<png_uint_16*>(row)[x * dimensions[2]];
if (result_bit_depth == 16) {
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++)
{
*(png_uint_16*)(A->data + offset + p*A->strides[2]) = ptr[p];
}
} else {
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++)
{
*(png_byte*)(A->data + offset + p*A->strides[2]) = ptr[p] >> 8;
}
}
}
else
{
png_byte* ptr = &(row[x * dimensions[2]]);
if (result_bit_depth == 16) {
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++)
{
*(png_uint_16*)(A->data + offset + p*A->strides[2]) = ptr[p];
}
} else {
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++)
{
*(png_byte*)(A->data + offset + p*A->strides[2]) = ptr[p];
}
}
}
}
}
Py::Object
_png_module::read_png(const Py::Tuple& args)
{
args.verify_length(1);
png_byte header[8]; // 8 is the maximum size that can be checked
FILE* fp = NULL;
bool close_file = false;
Py::Object py_fileobj = Py::Object(args[0]);
#if PY_MAJOR_VERSION >= 3
int fd = PyObject_AsFileDescriptor(py_fileobj.ptr());
PyErr_Clear();
#endif
if (py_fileobj.isString())
{
std::string fileName = Py::String(py_fileobj);
const char *file_name = fileName.c_str();
if ((fp = fopen(file_name, "rb")) == NULL)
{
throw Py::RuntimeError(
Printf("Could not open file %s for reading", file_name).str());
}
close_file = true;
}
#if PY_MAJOR_VERSION >= 3
else if (fd != -1) {
fp = fdopen(fd, "r");
}
#else
else if (PyFile_CheckExact(py_fileobj.ptr()))
{
fp = PyFile_AsFile(py_fileobj.ptr());
}
#endif
else
{
PyObject* read_method = PyObject_GetAttrString(py_fileobj.ptr(), "read");
if (!(read_method && PyCallable_Check(read_method)))
{
Py_XDECREF(read_method);
throw Py::TypeError("Object does not appear to be a 8-bit string path or a Python file-like object");
}
Py_XDECREF(read_method);
}
if (fp)
{
if (fread(header, 1, 8, fp) != 8)
{
throw Py::RuntimeError(
"_image_module::readpng: error reading PNG header");
}
}
else
{
_read_png_data(py_fileobj.ptr(), header, 8);
}
if (png_sig_cmp(header, 0, 8))
{
throw Py::RuntimeError(
"_image_module::readpng: file not recognized as a PNG file");
}
/* initialize stuff */
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
{
throw Py::RuntimeError(
"_image_module::readpng: png_create_read_struct failed");
}
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
{
throw Py::RuntimeError(
"_image_module::readpng: png_create_info_struct failed");
}
if (setjmp(png_jmpbuf(png_ptr)))
{
throw Py::RuntimeError(
"_image_module::readpng: error during init_io");
}
if (fp)
{
png_init_io(png_ptr, fp);
}
else
{
png_set_read_fn(png_ptr, (void*)py_fileobj.ptr(), &read_png_data);
}
png_set_sig_bytes(png_ptr, 8);
png_read_info(png_ptr, info_ptr);
png_uint_32 width = info_ptr->width;
png_uint_32 height = info_ptr->height;
int bit_depth = info_ptr->bit_depth;
// Unpack 1, 2, and 4-bit images
if (bit_depth < 8)
png_set_packing(png_ptr);
// If sig bits are set, shift data
png_color_8p sig_bit;
if ((info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) &&
png_get_sBIT(png_ptr, info_ptr, &sig_bit))
{
png_set_shift(png_ptr, sig_bit);
}
// Convert big endian to little
if (bit_depth == 16)
{
png_set_swap(png_ptr);
}
// Convert palletes to full RGB
if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
png_set_palette_to_rgb(png_ptr);
}
// If there's an alpha channel convert gray to RGB
if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
{
png_set_gray_to_rgb(png_ptr);
}
png_set_interlace_handling(png_ptr);
png_read_update_info(png_ptr, info_ptr);
/* read file */
if (setjmp(png_jmpbuf(png_ptr)))
{
throw Py::RuntimeError(
"_image_module::readpng: error during read_image");
}
png_bytep *row_pointers = new png_bytep[height];
png_uint_32 row;
for (row = 0; row < height; row++)
{
row_pointers[row] = new png_byte[png_get_rowbytes(png_ptr,info_ptr)];
}
png_read_image(png_ptr, row_pointers);
npy_intp dimensions[3];
dimensions[0] = height; //numrows
dimensions[1] = width; //numcols
if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
{
dimensions[2] = 4; //RGBA images
}
else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
{
dimensions[2] = 3; //RGB images
}
else
{
dimensions[2] = 1; //Greyscale images
}
//For gray, return an x by y array, not an x by y by 1
int num_dims = (info_ptr->color_type & PNG_COLOR_MASK_COLOR) ? 3 : 2;
double max_value = (1 << ((bit_depth < 8) ? 8 : bit_depth)) - 1;
PyArrayObject *A = (PyArrayObject *) PyArray_SimpleNew(
num_dims, dimensions, PyArray_FLOAT);
if (A == NULL)
{
throw Py::MemoryError("Could not allocate image array");
}
for (png_uint_32 y = 0; y < height; y++)
{
png_byte* row = row_pointers[y];
for (png_uint_32 x = 0; x < width; x++)
{
size_t offset = y * A->strides[0] + x * A->strides[1];
if (bit_depth == 16)
{
png_uint_16* ptr = &reinterpret_cast<png_uint_16*>(row)[x * dimensions[2]];
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++)
{
*(float*)(A->data + offset + p*A->strides[2]) = (float)(ptr[p]) / max_value;
}
}
else
{
png_byte* ptr = &(row[x * dimensions[2]]);
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++)
{
*(float*)(A->data + offset + p*A->strides[2]) = (float)(ptr[p]) / max_value;
}
}
}
}
//free the png memory
png_read_end(png_ptr, info_ptr);
#ifndef png_infopp_NULL
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
#else
png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);
#endif
if (close_file)
{
fclose(fp);
}
for (row = 0; row < height; row++)
{
delete [] row_pointers[row];
}
delete [] row_pointers;
return Py::asObject((PyObject*)A);
}
static void read_png_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
PyObject* py_file_obj = (PyObject*)png_get_io_ptr(png_ptr);
_read_png_data(py_file_obj, data, length);
}
static PyObject *_read_png(PyObject *filein, bool float_result)
{
png_byte header[8]; // 8 is the maximum size that can be checked
FILE *fp = NULL;
mpl_off_t offset = 0;
bool close_file = false;
bool close_dup_file = false;
PyObject *py_file = NULL;
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
int num_dims;
std::vector<png_bytep> row_pointers;
png_uint_32 width = 0;
png_uint_32 height = 0;
int bit_depth;
PyObject *result = NULL;
// TODO: Remove direct calls to Numpy API here
if (PyBytes_Check(filein) || PyUnicode_Check(filein)) {
if ((py_file = mpl_PyFile_OpenFile(filein, (char *)"rb")) == NULL) {
goto exit;
}
close_file = true;
} else {
py_file = filein;
}
if ((fp = mpl_PyFile_Dup(py_file, (char *)"rb", &offset))) {
close_dup_file = true;
} else {
PyErr_Clear();
PyObject *read_method = PyObject_GetAttrString(py_file, "read");
if (!(read_method && PyCallable_Check(read_method))) {
Py_XDECREF(read_method);
PyErr_SetString(PyExc_TypeError,
"Object does not appear to be a 8-bit string path or "
"a Python file-like object");
goto exit;
}
Py_XDECREF(read_method);
}
if (fp) {
if (fread(header, 1, 8, fp) != 8) {
PyErr_SetString(PyExc_IOError, "error reading PNG header");
goto exit;
}
} else {
_read_png_data(py_file, header, 8);
}
if (png_sig_cmp(header, 0, 8)) {
PyErr_SetString(PyExc_ValueError, "invalid PNG header");
goto exit;
}
/* initialize stuff */
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr) {
PyErr_SetString(PyExc_RuntimeError, "png_create_read_struct failed");
goto exit;
}
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
PyErr_SetString(PyExc_RuntimeError, "png_create_info_struct failed");
goto exit;
}
if (setjmp(png_jmpbuf(png_ptr))) {
PyErr_SetString(PyExc_RuntimeError, "Error setting jump");
goto exit;
}
if (fp) {
png_init_io(png_ptr, fp);
} else {
png_set_read_fn(png_ptr, (void *)py_file, &read_png_data);
}
png_set_sig_bytes(png_ptr, 8);
png_read_info(png_ptr, info_ptr);
width = png_get_image_width(png_ptr, info_ptr);
height = png_get_image_height(png_ptr, info_ptr);
bit_depth = png_get_bit_depth(png_ptr, info_ptr);
// Unpack 1, 2, and 4-bit images
if (bit_depth < 8) {
png_set_packing(png_ptr);
}
// If sig bits are set, shift data
png_color_8p sig_bit;
if ((png_get_color_type(png_ptr, info_ptr) != PNG_COLOR_TYPE_PALETTE) &&
png_get_sBIT(png_ptr, info_ptr, &sig_bit)) {
png_set_shift(png_ptr, sig_bit);
}
// Convert big endian to little
if (bit_depth == 16) {
png_set_swap(png_ptr);
}
// Convert palletes to full RGB
if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_PALETTE) {
png_set_palette_to_rgb(png_ptr);
bit_depth = 8;
}
// If there's an alpha channel convert gray to RGB
if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_GRAY_ALPHA) {
png_set_gray_to_rgb(png_ptr);
}
png_set_interlace_handling(png_ptr);
png_read_update_info(png_ptr, info_ptr);
row_pointers.resize(height);
for (png_uint_32 row = 0; row < height; row++) {
row_pointers[row] = new png_byte[png_get_rowbytes(png_ptr, info_ptr)];
}
png_read_image(png_ptr, &row_pointers[0]);
npy_intp dimensions[3];
dimensions[0] = height; // numrows
dimensions[1] = width; // numcols
if (png_get_color_type(png_ptr, info_ptr) & PNG_COLOR_MASK_ALPHA) {
dimensions[2] = 4; // RGBA images
} else if (png_get_color_type(png_ptr, info_ptr) & PNG_COLOR_MASK_COLOR) {
dimensions[2] = 3; // RGB images
} else {
dimensions[2] = 1; // Greyscale images
}
if (float_result) {
double max_value = (1 << bit_depth) - 1;
numpy::array_view<float, 3> A(dimensions);
for (png_uint_32 y = 0; y < height; y++) {
png_byte *row = row_pointers[y];
for (png_uint_32 x = 0; x < width; x++) {
if (bit_depth == 16) {
png_uint_16 *ptr = &reinterpret_cast<png_uint_16 *>(row)[x * dimensions[2]];
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++) {
A(y, x, p) = (float)(ptr[p]) / max_value;
}
} else {
png_byte *ptr = &(row[x * dimensions[2]]);
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++) {
A(y, x, p) = (float)(ptr[p]) / max_value;
}
}
}
}
result = A.pyobj();
} else if (bit_depth == 16) {
numpy::array_view<png_uint_16, 3> A(dimensions);
for (png_uint_32 y = 0; y < height; y++) {
png_byte *row = row_pointers[y];
for (png_uint_32 x = 0; x < width; x++) {
png_uint_16 *ptr = &reinterpret_cast<png_uint_16 *>(row)[x * dimensions[2]];
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++) {
A(y, x, p) = ptr[p];
}
}
}
result = A.pyobj();
} else if (bit_depth == 8) {
numpy::array_view<png_byte, 3> A(dimensions);
for (png_uint_32 y = 0; y < height; y++) {
png_byte *row = row_pointers[y];
for (png_uint_32 x = 0; x < width; x++) {
png_byte *ptr = &(row[x * dimensions[2]]);
for (png_uint_32 p = 0; p < (png_uint_32)dimensions[2]; p++) {
A(y, x, p) = ptr[p];
}
}
}
result = A.pyobj();
} else {
PyErr_SetString(PyExc_RuntimeError, "image has unknown bit depth");
goto exit;
}
// free the png memory
png_read_end(png_ptr, info_ptr);
// For gray, return an x by y array, not an x by y by 1
num_dims = (png_get_color_type(png_ptr, info_ptr) & PNG_COLOR_MASK_COLOR) ? 3 : 2;
if (num_dims == 2) {
PyArray_Dims dims = {dimensions, 2};
PyObject *reshaped = PyArray_Newshape((PyArrayObject *)result, &dims, NPY_CORDER);
Py_DECREF(result);
result = reshaped;
}
exit:
if (png_ptr && info_ptr) {
#ifndef png_infopp_NULL
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
#else
png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);
#endif
}
if (close_dup_file) {
mpl_PyFile_DupClose(py_file, fp, offset);
}
if (close_file) {
mpl_PyFile_CloseFile(py_file);
Py_DECREF(py_file);
}
for (png_uint_32 row = 0; row < height; row++) {
delete[] row_pointers[row];
}
if (PyErr_Occurred()) {
Py_XDECREF(result);
return NULL;
} else {
return result;
}
}
