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/*
Copyright (C) 2021 Carl Hetherington <cth@carlh.net>
This file is part of DCP-o-matic.
DCP-o-matic is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
DCP-o-matic is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with DCP-o-matic. If not, see <http://www.gnu.org/licenses/>.
*/
#include "dcpomatic_assert.h"
#include "exceptions.h"
#include "image.h"
#include <png.h>
#include "i18n.h"
using std::shared_ptr;
class Memory
{
public:
Memory () {}
Memory (Memory const&) = delete;
Memory& operator= (Memory const&) = delete;
~Memory ()
{
free (data);
}
uint8_t* data = nullptr;
size_t size = 0;
};
static void
png_write_data (png_structp png_ptr, png_bytep data, png_size_t length)
{
auto mem = reinterpret_cast<Memory*>(png_get_io_ptr(png_ptr));
size_t size = mem->size + length;
if (mem->data) {
mem->data = reinterpret_cast<uint8_t*>(realloc(mem->data, size));
} else {
mem->data = reinterpret_cast<uint8_t*>(malloc(size));
}
if (!mem->data) {
throw EncodeError (N_("could not allocate memory for PNG"));
}
memcpy (mem->data + mem->size, data, length);
mem->size += length;
}
static void
png_flush (png_structp)
{
}
static void
png_error_fn (png_structp, char const * message)
{
throw EncodeError (fmt::format("Error during PNG write: {}", message));
}
dcp::ArrayData
image_as_png (shared_ptr<const Image> image)
{
png_byte color_type;
switch (image->pixel_format()) {
case AV_PIX_FMT_RGBA:
color_type = PNG_COLOR_TYPE_RGBA;
break;
case AV_PIX_FMT_RGB24:
color_type = PNG_COLOR_TYPE_RGB;
break;
default:
return image_as_png(image->convert_pixel_format(dcp::YUVToRGB::REC709, AV_PIX_FMT_RGBA, Image::Alignment::PADDED, false));
}
/* error handling? */
auto png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, reinterpret_cast<void*>(const_cast<Image*>(image.get())), png_error_fn, 0);
if (!png_ptr) {
throw EncodeError (N_("could not create PNG write struct"));
}
Memory state;
png_set_write_fn (png_ptr, &state, png_write_data, png_flush);
auto info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_write_struct (&png_ptr, &info_ptr);
throw EncodeError (N_("could not create PNG info struct"));
}
int const width = image->size().width;
int const height = image->size().height;
png_set_IHDR(png_ptr, info_ptr, width, height, 8, color_type, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
auto row_pointers = reinterpret_cast<png_byte **>(png_malloc(png_ptr, image->size().height * sizeof(png_byte *)));
auto const data = image->data()[0];
auto const stride = image->stride()[0];
for (int i = 0; i < height; ++i) {
row_pointers[i] = reinterpret_cast<png_byte *>(data + i * stride);
}
png_write_info (png_ptr, info_ptr);
png_write_image (png_ptr, row_pointers);
png_write_end (png_ptr, info_ptr);
png_destroy_write_struct (&png_ptr, &info_ptr);
png_free (png_ptr, row_pointers);
return dcp::ArrayData (state.data, state.size);
}
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