134 lines
4.2 KiB
C++
134 lines
4.2 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2021 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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#ifndef MAPNIK_JPEG_IO_HPP
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#define MAPNIK_JPEG_IO_HPP
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#if defined(HAVE_JPEG)
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#include <new>
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#include <ostream>
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#include <cstdio>
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extern "C" {
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#include <jpeglib.h>
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}
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#define BUFFER_SIZE 4096
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namespace jpeg_detail {
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typedef struct
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{
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struct jpeg_destination_mgr pub;
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std::ostream* out;
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JOCTET* buffer;
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} dest_mgr;
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inline void init_destination(j_compress_ptr cinfo)
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{
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dest_mgr* dest = reinterpret_cast<dest_mgr*>(cinfo->dest);
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dest->buffer = (JOCTET*)(*cinfo->mem->alloc_small)((j_common_ptr)cinfo, JPOOL_IMAGE, BUFFER_SIZE * sizeof(JOCTET));
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dest->pub.next_output_byte = dest->buffer;
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dest->pub.free_in_buffer = BUFFER_SIZE;
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}
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inline boolean empty_output_buffer(j_compress_ptr cinfo)
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{
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dest_mgr* dest = reinterpret_cast<dest_mgr*>(cinfo->dest);
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dest->out->write((char*)dest->buffer, BUFFER_SIZE);
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if (!*(dest->out))
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return boolean(0);
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dest->pub.next_output_byte = dest->buffer;
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dest->pub.free_in_buffer = BUFFER_SIZE;
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return boolean(1);
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}
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inline void term_destination(j_compress_ptr cinfo)
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{
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dest_mgr* dest = reinterpret_cast<dest_mgr*>(cinfo->dest);
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size_t size = BUFFER_SIZE - dest->pub.free_in_buffer;
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if (size > 0)
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{
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dest->out->write((char*)dest->buffer, size);
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}
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dest->out->flush();
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}
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} // namespace jpeg_detail
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namespace mapnik {
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template<typename T1, typename T2>
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void save_as_jpeg(T1& file, int quality, T2 const& image)
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{
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struct jpeg_compress_struct cinfo;
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struct jpeg_error_mgr jerr;
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int width = static_cast<int>(image.width());
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int height = static_cast<int>(image.height());
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cinfo.err = jpeg_std_error(&jerr);
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jpeg_create_compress(&cinfo);
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cinfo.dest = (struct jpeg_destination_mgr*)(*cinfo.mem->alloc_small)((j_common_ptr)&cinfo,
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JPOOL_PERMANENT,
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sizeof(jpeg_detail::dest_mgr));
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jpeg_detail::dest_mgr* dest = reinterpret_cast<jpeg_detail::dest_mgr*>(cinfo.dest);
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dest->pub.init_destination = jpeg_detail::init_destination;
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dest->pub.empty_output_buffer = jpeg_detail::empty_output_buffer;
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dest->pub.term_destination = jpeg_detail::term_destination;
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dest->out = &file;
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// jpeg_stdio_dest(&cinfo, fp);
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cinfo.image_width = width;
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cinfo.image_height = height;
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cinfo.input_components = 3;
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cinfo.in_color_space = JCS_RGB;
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jpeg_set_defaults(&cinfo);
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jpeg_set_quality(&cinfo, quality, boolean(1));
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jpeg_start_compress(&cinfo, boolean(1));
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JSAMPROW row_pointer[1];
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JSAMPLE* row = reinterpret_cast<JSAMPLE*>(::operator new(sizeof(JSAMPLE) * width * 3));
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while (cinfo.next_scanline < cinfo.image_height)
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{
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const unsigned* imageRow = image.get_row(cinfo.next_scanline);
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int index = 0;
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for (int i = 0; i < width; ++i)
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{
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row[index++] = (imageRow[i]) & 0xff;
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row[index++] = (imageRow[i] >> 8) & 0xff;
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row[index++] = (imageRow[i] >> 16) & 0xff;
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}
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row_pointer[0] = &row[0];
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(void)jpeg_write_scanlines(&cinfo, row_pointer, 1);
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}
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::operator delete(row);
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jpeg_finish_compress(&cinfo);
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jpeg_destroy_compress(&cinfo);
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}
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} // namespace mapnik
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#endif
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#endif // MAPNIK_JPEG_IO_HPP
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