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
  38 /**
  39  * @file Definition of a class that writes a frame buffer to a png
  40  */
  41
  42 #include "base/pngwriter.hh"
  43
  44 extern "C"
  45 {
  46 #include <png.h>
  47 }
  48
  49 #include <cstdio>
  50 #include <cstdlib>
  51
  52 #include "base/logging.hh"
  53
  54 const char* PngWriter::_imgExtension = "png";
  55
  56 /**
  57  * Write callback to use with libpng APIs
  58  *
  59  * @param pngPtr  pointer to the png_struct structure
  60  * @param data    pointer to the data being written
  61  * @param length  number of bytes being written
  62  */
  63 static void
  64 writePng(png_structp pngPtr, png_bytep data, png_size_t length)
  65 {
  66     // Here we get our IO pointer back from the write struct
  67     // and we cast it into a ostream* type.
  68     std::ostream* strmPtr = reinterpret_cast<std::ostream*>(
  69         png_get_io_ptr(pngPtr)
  70     );
  71
  72     // Write length bytes to data
  73     strmPtr->write(reinterpret_cast<const char *>(data), length);
  74 }
  75
  76 struct PngWriter::PngStructHandle {
  77   private:
  78     // Make PngStructHandle uncopyable
  79     PngStructHandle(const PngStructHandle&) = delete;
  80     PngStructHandle& operator=(const PngStructHandle&) = delete;
  81   public:
  82
  83     PngStructHandle() :
  84         pngWriteP(NULL), pngInfoP(NULL)
  85     {
  86         // Creating write structure
  87         pngWriteP = png_create_write_struct(
  88             PNG_LIBPNG_VER_STRING, NULL, NULL, NULL
  89         );
  90
  91         if (pngWriteP) {
  92             // Creating info structure
  93             pngInfoP = png_create_info_struct(pngWriteP);
  94         }
  95     }
  96
  97     ~PngStructHandle()
  98     {
  99         if (pngWriteP) {
 100             png_destroy_write_struct(&pngWriteP, &pngInfoP);
 101         }
 102     }
 103
 104     /** Pointer to PNG Write struct */
 105     png_structp pngWriteP;
 106
 107     /** Pointer to PNG Info struct */
 108     png_infop pngInfoP;
 109 };
 110
 111 void
 112 PngWriter::write(std::ostream &png) const
 113 {
 114
 115     // Height of the frame buffer
 116     unsigned height = fb.height();
 117     unsigned width  = fb.width();
 118
 119     // Do not write if frame buffer is empty
 120     if (!fb.area()) {
 121         png.flush();
 122         return;
 123     }
 124
 125     // Initialize Png structures
 126     PngStructHandle handle;
 127
 128     // Png info/write pointers.
 129     png_structp pngPtr  = handle.pngWriteP;
 130     png_infop   infoPtr = handle.pngInfoP;
 131
 132     if (!pngPtr) {
 133         warn("Frame buffer dump aborted: Unable to create"
 134              "Png Write Struct\n");
 135         return;
 136     }
 137
 138     if (!infoPtr) {
 139         warn("Frame buffer dump aborted: Unable to create"
 140              "Png Info Struct\n");
 141         return;
 142     }
 143
 144     // We cannot use default libpng write function since it requires
 145     // a file pointer (FILE*), whereas we want to use the ostream.
 146     // The following function replaces the write function with a custom
 147     // one provided by us (writePng)
 148     png_set_write_fn(pngPtr, (png_voidp)&png, writePng, NULL);
 149
 150     png_set_IHDR(pngPtr, infoPtr, width, height, 8,
 151                  PNG_COLOR_TYPE_RGB,
 152                  PNG_INTERLACE_NONE,
 153                  PNG_COMPRESSION_TYPE_DEFAULT,
 154                  PNG_FILTER_TYPE_DEFAULT);
 155
 156     png_write_info(pngPtr, infoPtr);
 157
 158     // libpng requires an array of pointers to the frame buffer's rows.
 159     std::vector<PixelType> rowPacked(width);
 160     for (unsigned y=0; y < height; ++y) {
 161         for (unsigned x=0; x < width; ++x) {
 162             rowPacked[x] = fb.pixel(x, y);
 163         }
 164
 165         png_write_row(pngPtr,
 166             reinterpret_cast<png_bytep>(rowPacked.data())
 167         );
 168     }
 169
 170     // End of write
 171     png_write_end(pngPtr, NULL);
 172 }
 173