src/base/pngwriter.cc

   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
  46 extern "C"
  47 {
  48 #include <png.h>
  49 }
  50
  51 #include <cstdio>
  52 #include <cstdlib>
  53
  54 #include "base/misc.hh"
  55
  56 const 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  */
  65 static void
  66 writePng(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
  78 struct 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
 113 void
 114 PngWriter::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