347 lines
11 KiB
C++
347 lines
11 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
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/*
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* Copyright the Collabora Online contributors.
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*
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* SPDX-License-Identifier: MPL-2.0
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#pragma once
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/* cairo - a vector graphics library with display and print output
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*
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* Copyright © 2003 University of Southern California
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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 either under the terms of the GNU Lesser General Public
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* License version 2.1 as published by the Free Software Foundation
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* (the "LGPL") or, at your option, under the terms of the Mozilla
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* Public License Version 1.1 (the "MPL"). If you do not alter this
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* notice, a recipient may use your version of this file under either
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* the MPL or the LGPL.
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*
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* You should have received a copy of the LGPL along with this library
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* in the file COPYING-LGPL-2.1; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
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* You should have received a copy of the MPL along with this library
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* in the file COPYING-MPL-1.1
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.1 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
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* OF ANY KIND, either express or implied. See the LGPL or the MPL for
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* the specific language governing rights and limitations.
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*
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* The Original Code is the cairo graphics library.
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*
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* The Initial Developer of the Original Code is University of Southern
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* California.
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*
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* Contributor(s):
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* Carl D. Worth <cworth@cworth.org>
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* Kristian Høgsberg <krh@redhat.com>
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* Chris Wilson <chris@chris-wilson.co.uk>
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*/
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#define PNG_SKIP_SETJMP_CHECK
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#include <png.h>
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#include <zlib.h>
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#include <cassert>
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#include <chrono>
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#include <iomanip>
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#include "Log.hpp"
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#include "TraceEvent.hpp"
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namespace Png
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{
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// Callback functions for libpng
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extern "C"
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{
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static void user_write_status_fn(png_structp, png_uint_32, int)
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{
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}
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static void user_write_fn(png_structp png_ptr, png_bytep data, png_size_t length)
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{
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std::vector<char>* outputp = static_cast<std::vector<char>*>(png_get_io_ptr(png_ptr));
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const size_t oldsize = outputp->size();
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outputp->resize(oldsize + length);
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std::memcpy(outputp->data() + oldsize, data, length);
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}
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static void user_flush_fn(png_structp)
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{
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}
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}
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/* Unpremultiplies data and converts native endian BGRA => RGBA bytes */
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static void
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unpremultiply_bgra_data (png_structp /*png*/, png_row_infop row_info, png_bytep data)
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{
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unsigned int i;
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for (i = 0; i < row_info->rowbytes; i += 4)
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{
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uint8_t *b = &data[i];
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uint32_t pix;
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uint8_t alpha;
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std::memcpy (&pix, b, sizeof (uint32_t));
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alpha = (pix & 0xff000000) >> 24;
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if (alpha == 255)
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{
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b[0] = ((pix & 0xff0000) >> 16);
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b[1] = ((pix & 0x00ff00) >> 8);
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b[2] = ((pix & 0x0000ff) >> 0);
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b[3] = 255;
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}
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else if (alpha == 0)
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{
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b[0] = b[1] = b[2] = b[3] = 0;
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}
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else
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{
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b[0] = (((pix & 0xff0000) >> 16) * 255 + alpha / 2) / alpha;
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b[1] = (((pix & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha;
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b[2] = (((pix & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha;
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b[3] = alpha;
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}
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}
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}
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/* Unpremultiplies data already in RGBA order*/
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static void
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unpremultiply_rgba_data (png_structp /*png*/, png_row_infop row_info, png_bytep data)
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{
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unsigned int i;
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for (i = 0; i < row_info->rowbytes; i += 4)
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{
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uint8_t *b = &data[i];
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uint32_t pix;
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uint8_t alpha;
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std::memcpy (&pix, b, sizeof (uint32_t));
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alpha = (pix & 0xff000000) >> 24;
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if (alpha == 255)
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{
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std::memcpy(b, &pix, sizeof (uint32_t));
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}
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else if (alpha == 0)
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{
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b[0] = b[1] = b[2] = b[3] = 0;
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}
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else
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{
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b[0] = (((pix & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha;
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b[1] = (((pix & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha;
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b[2] = (((pix & 0xff0000) >> 16) * 255 + alpha / 2) / alpha;
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b[3] = alpha;
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}
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}
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}
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/// This function uses setjmp which may clobbers non-trivial objects.
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/// So we can't use logging or create complex C++ objects in this frame.
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/// Specifically, logging uses std::string objects, and GCC gives the following:
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/// error: variable ‘__capacity’ might be clobbered by ‘longjmp’ or ‘vfork’ [-Werror=clobbered]
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/// In practice, this is bogus, since __capacity is has a trivial type, but this error
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/// shows up with the sanitizers. But technically we shouldn't mix C++ objects with setjmp.
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/// Sadly, older libpng headers don't use const for the pixmap pointer parameter to
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/// png_write_row(), so can't use const here for pixmap.
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inline bool impl_encodeSubBufferToPNG(unsigned char* pixmap, size_t startX, size_t startY,
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int width, int height, int bufferWidth, int bufferHeight,
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std::vector<char>& output, LibreOfficeKitTileMode mode)
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{
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if (bufferWidth < width || bufferHeight < height)
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{
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return false;
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}
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png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
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png_infop info_ptr = png_create_info_struct(png_ptr);
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if (setjmp(png_jmpbuf(png_ptr)))
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{
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png_destroy_write_struct(&png_ptr, nullptr);
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return false;
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}
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#if MOBILEAPP
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png_set_compression_level(png_ptr, Z_BEST_SPEED);
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#else
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// Level 4 gives virtually identical compression
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// ratio to level 6, but is between 5-10% faster.
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// Level 3 runs almost twice as fast, but the
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// output is typically 2-3x larger.
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png_set_compression_level(png_ptr, 4);
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#endif
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png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
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PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
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png_set_write_fn(png_ptr, &output, user_write_fn, user_flush_fn);
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png_set_write_status_fn(png_ptr, user_write_status_fn);
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png_write_info(png_ptr, info_ptr);
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switch (mode)
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{
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case LOK_TILEMODE_BGRA:
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png_set_write_user_transform_fn (png_ptr, unpremultiply_bgra_data);
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break;
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case LOK_TILEMODE_RGBA:
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png_set_write_user_transform_fn (png_ptr, unpremultiply_rgba_data);
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break;
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}
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for (int y = 0; y < height; ++y)
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{
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size_t position = ((startY + y) * bufferWidth * 4) + (startX * 4);
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png_write_row(png_ptr, pixmap + position);
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}
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png_write_end(png_ptr, info_ptr);
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png_destroy_write_struct(&png_ptr, &info_ptr);
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return true;
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}
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/// Sadly, older libpng headers don't use const for the pixmap pointer parameter to
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/// png_write_row(), so can't use const here for pixmap.
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inline bool encodeSubBufferToPNG(unsigned char* pixmap, size_t startX, size_t startY, int width,
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int height, int bufferWidth, int bufferHeight,
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std::vector<char>& output, LibreOfficeKitTileMode mode)
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{
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ProfileZone pz("encodeSubBufferToPNG");
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const auto start = std::chrono::steady_clock::now();
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const bool res = impl_encodeSubBufferToPNG(pixmap, startX, startY, width, height, bufferWidth,
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bufferHeight, output, mode);
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if (Log::traceEnabled())
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{
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const auto end = std::chrono::steady_clock::now();
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std::chrono::milliseconds duration
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= std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
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static std::chrono::milliseconds totalDuration;
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static int nCalls = 0;
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totalDuration += duration;
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++nCalls;
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static uint64_t totalPixelBytes = 0;
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static uint64_t totalOutputBytes = 0;
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totalPixelBytes += (static_cast<uint64_t>(width) * height * 4);
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totalOutputBytes += output.size();
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LOG_TRC("PNG compression took "
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<< duration << " (" << output.size() << " bytes from " << (width * height * 4) << "). Average after " << nCalls
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<< " calls: " << (totalDuration.count() / static_cast<double>(nCalls)) << "ms, "
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<< (totalOutputBytes / static_cast<double>(nCalls)) << " bytes, "
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<< std::setprecision(2) << (100. * totalOutputBytes / totalPixelBytes) << "% compression.");
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}
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return res;
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}
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inline
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bool encodeBufferToPNG(unsigned char* pixmap, int width, int height,
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std::vector<char>& output, LibreOfficeKitTileMode mode)
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{
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return encodeSubBufferToPNG(pixmap, 0, 0, width, height, width, height, output, mode);
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}
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static
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void readTileData(png_structp png_ptr, png_bytep data, png_size_t length)
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{
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png_voidp io_ptr = png_get_io_ptr(png_ptr);
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assert(io_ptr);
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std::stringstream& streamTile = *static_cast<std::stringstream*>(io_ptr);
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streamTile.read(reinterpret_cast<char*>(data), length);
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}
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inline
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std::vector<png_bytep> decodePNG(std::stringstream& stream, png_uint_32& height, png_uint_32& width, png_uint_32& rowBytes)
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{
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png_byte signature[0x08];
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stream.read(reinterpret_cast<char *>(signature), 0x08);
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if (png_sig_cmp(signature, 0x00, 0x08))
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{
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throw std::runtime_error("Invalid PNG signature.");
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}
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png_structp ptrPNG = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
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if (ptrPNG == nullptr)
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{
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throw std::runtime_error("png_create_read_struct failed.");
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}
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png_infop ptrInfo = png_create_info_struct(ptrPNG);
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if (ptrInfo == nullptr)
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{
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throw std::runtime_error("png_create_info_struct failed.");
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}
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png_infop ptrEnd = png_create_info_struct(ptrPNG);
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if (ptrEnd == nullptr)
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{
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throw std::runtime_error("png_create_info_struct failed.");
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}
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png_set_read_fn(ptrPNG, &stream, readTileData);
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png_set_sig_bytes(ptrPNG, 0x08);
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png_read_info(ptrPNG, ptrInfo);
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width = png_get_image_width(ptrPNG, ptrInfo);
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height = png_get_image_height(ptrPNG, ptrInfo);
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png_set_interlace_handling(ptrPNG);
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png_read_update_info(ptrPNG, ptrInfo);
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rowBytes = png_get_rowbytes(ptrPNG, ptrInfo);
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assert(width == rowBytes / 4);
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const size_t dataSize = (rowBytes + sizeof(png_bytep)) * height / sizeof(png_bytep);
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const size_t size = dataSize + height + sizeof(png_bytep);
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std::vector<png_bytep> rows;
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rows.resize(size);
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// rows
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for (png_uint_32 itRow = 0; itRow < height; itRow++)
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{
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const size_t index = height + (itRow * rowBytes + sizeof(png_bytep) - 1) / sizeof(png_bytep);
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rows[itRow] = reinterpret_cast<png_bytep>(&rows[index]);
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}
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png_read_image(ptrPNG, rows.data());
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png_read_end(ptrPNG, ptrEnd);
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png_destroy_read_struct(&ptrPNG, &ptrInfo, &ptrEnd);
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return rows;
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}
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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