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Diffstat (limited to 'src/base/pngwriter.cc')
| -rw-r--r-- | src/base/pngwriter.cc | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/base/pngwriter.cc b/src/base/pngwriter.cc new file mode 100644 index 000000000..3b49d479d --- /dev/null +++ b/src/base/pngwriter.cc @@ -0,0 +1,175 @@ +/* + * Copyright (c) 2017 ARM Limited + * All rights reserved + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Giacomo Travaglini + */ + +/** + * @file Definition of a class that writes a frame buffer to a png + */ + +#include "base/pngwriter.hh" + +extern "C" +{ +#include <png.h> +} + +#include <cstdio> +#include <cstdlib> + +#include "base/misc.hh" + +const char* PngWriter::_imgExtension = "png"; + +/** + * Write callback to use with libpng APIs + * + * @param pngPtr pointer to the png_struct structure + * @param data pointer to the data being written + * @param length number of bytes being written + */ +static void +writePng(png_structp pngPtr, png_bytep data, png_size_t length) +{ + // Here we get our IO pointer back from the write struct + // and we cast it into a ostream* type. + std::ostream* strmPtr = reinterpret_cast<std::ostream*>( + png_get_io_ptr(pngPtr) + ); + + // Write length bytes to data + strmPtr->write(reinterpret_cast<const char *>(data), length); +} + +struct PngWriter::PngStructHandle { + private: + // Make PngStructHandle uncopyable + PngStructHandle(const PngStructHandle&) = delete; + PngStructHandle& operator=(const PngStructHandle&) = delete; + public: + + PngStructHandle() : + pngWriteP(NULL), pngInfoP(NULL) + { + // Creating write structure + pngWriteP = png_create_write_struct( + PNG_LIBPNG_VER_STRING, NULL, NULL, NULL + ); + + if (pngWriteP) { + // Creating info structure + pngInfoP = png_create_info_struct(pngWriteP); + } + } + + ~PngStructHandle() + { + if (pngWriteP) { + png_destroy_write_struct(&pngWriteP, &pngInfoP); + } + } + + /** Pointer to PNG Write struct */ + png_structp pngWriteP; + + /** Pointer to PNG Info struct */ + png_infop pngInfoP; +}; + +void +PngWriter::write(std::ostream &png) const +{ + + // Height of the frame buffer + unsigned height = fb.height(); + unsigned width = fb.width(); + + // Do not write if frame buffer is empty + if (!fb.area()) { + png.flush(); + return; + } + + // Initialize Png structures + PngStructHandle handle; + + // Png info/write pointers. + png_structp pngPtr = handle.pngWriteP; + png_infop infoPtr = handle.pngInfoP; + + if (!pngPtr) { + warn("Frame buffer dump aborted: Unable to create" + "Png Write Struct\n"); + return; + } + + if (!infoPtr) { + warn("Frame buffer dump aborted: Unable to create" + "Png Info Struct\n"); + return; + } + + // We cannot use default libpng write function since it requires + // a file pointer (FILE*), whereas we want to use the ostream. + // The following function replaces the write function with a custom + // one provided by us (writePng) + png_set_write_fn(pngPtr, (png_voidp)&png, writePng, NULL); + + png_set_IHDR(pngPtr, infoPtr, width, height, 8, + PNG_COLOR_TYPE_RGB, + PNG_INTERLACE_NONE, + PNG_COMPRESSION_TYPE_DEFAULT, + PNG_FILTER_TYPE_DEFAULT); + + png_write_info(pngPtr, infoPtr); + + // libpng requires an array of pointers to the frame buffer's rows. + std::vector<PixelType> rowPacked(width); + for (unsigned y=0; y < height; ++y) { + for (unsigned x=0; x < height; ++x) { + rowPacked[x] = fb.pixel(x, y); + } + + png_write_row(pngPtr, + reinterpret_cast<png_bytep>(rowPacked.data()) + ); + } + + // End of write + png_write_end(pngPtr, NULL); +} + |