pngwriter.cc revision 12230:48021d6b51eb
1/* 2 * Copyright (c) 2017 ARM Limited 3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions are 16 * met: redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer; 18 * redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution; 21 * neither the name of the copyright holders nor the names of its 22 * contributors may be used to endorse or promote products derived from 23 * this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * Authors: Giacomo Travaglini 38 */ 39 40/** 41 * @file Definition of a class that writes a frame buffer to a png 42 */ 43 44#include "base/pngwriter.hh" 45 46extern "C" 47{ 48#include <png.h> 49} 50 51#include <cstdio> 52#include <cstdlib> 53 54#include "base/misc.hh" 55 56const char* PngWriter::_imgExtension = "png"; 57 58/** 59 * Write callback to use with libpng APIs 60 * 61 * @param pngPtr pointer to the png_struct structure 62 * @param data pointer to the data being written 63 * @param length number of bytes being written 64 */ 65static void 66writePng(png_structp pngPtr, png_bytep data, png_size_t length) 67{ 68 // Here we get our IO pointer back from the write struct 69 // and we cast it into a ostream* type. 70 std::ostream* strmPtr = reinterpret_cast<std::ostream*>( 71 png_get_io_ptr(pngPtr) 72 ); 73 74 // Write length bytes to data 75 strmPtr->write(reinterpret_cast<const char *>(data), length); 76} 77 78struct PngWriter::PngStructHandle { 79 private: 80 // Make PngStructHandle uncopyable 81 PngStructHandle(const PngStructHandle&) = delete; 82 PngStructHandle& operator=(const PngStructHandle&) = delete; 83 public: 84 85 PngStructHandle() : 86 pngWriteP(NULL), pngInfoP(NULL) 87 { 88 // Creating write structure 89 pngWriteP = png_create_write_struct( 90 PNG_LIBPNG_VER_STRING, NULL, NULL, NULL 91 ); 92 93 if (pngWriteP) { 94 // Creating info structure 95 pngInfoP = png_create_info_struct(pngWriteP); 96 } 97 } 98 99 ~PngStructHandle() 100 { 101 if (pngWriteP) { 102 png_destroy_write_struct(&pngWriteP, &pngInfoP); 103 } 104 } 105 106 /** Pointer to PNG Write struct */ 107 png_structp pngWriteP; 108 109 /** Pointer to PNG Info struct */ 110 png_infop pngInfoP; 111}; 112 113void 114PngWriter::write(std::ostream &png) const 115{ 116 117 // Height of the frame buffer 118 unsigned height = fb.height(); 119 unsigned width = fb.width(); 120 121 // Do not write if frame buffer is empty 122 if (!fb.area()) { 123 png.flush(); 124 return; 125 } 126 127 // Initialize Png structures 128 PngStructHandle handle; 129 130 // Png info/write pointers. 131 png_structp pngPtr = handle.pngWriteP; 132 png_infop infoPtr = handle.pngInfoP; 133 134 if (!pngPtr) { 135 warn("Frame buffer dump aborted: Unable to create" 136 "Png Write Struct\n"); 137 return; 138 } 139 140 if (!infoPtr) { 141 warn("Frame buffer dump aborted: Unable to create" 142 "Png Info Struct\n"); 143 return; 144 } 145 146 // We cannot use default libpng write function since it requires 147 // a file pointer (FILE*), whereas we want to use the ostream. 148 // The following function replaces the write function with a custom 149 // one provided by us (writePng) 150 png_set_write_fn(pngPtr, (png_voidp)&png, writePng, NULL); 151 152 png_set_IHDR(pngPtr, infoPtr, width, height, 8, 153 PNG_COLOR_TYPE_RGB, 154 PNG_INTERLACE_NONE, 155 PNG_COMPRESSION_TYPE_DEFAULT, 156 PNG_FILTER_TYPE_DEFAULT); 157 158 png_write_info(pngPtr, infoPtr); 159 160 // libpng requires an array of pointers to the frame buffer's rows. 161 std::vector<PixelType> rowPacked(width); 162 for (unsigned y=0; y < height; ++y) { 163 for (unsigned x=0; x < height; ++x) { 164 rowPacked[x] = fb.pixel(x, y); 165 } 166 167 png_write_row(pngPtr, 168 reinterpret_cast<png_bytep>(rowPacked.data()) 169 ); 170 } 171 172 // End of write 173 png_write_end(pngPtr, NULL); 174} 175 176