Adds png support
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Joshua Moerman
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0853249e2d
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2 changed files with 306 additions and 0 deletions
115
include/basics.hpp
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115
include/basics.hpp
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//
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// basics.hpp
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// ImageStreams
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//
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// Created by Joshua Moerman on 9/7/12.
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// Copyright (c) 2012 Vadovas. All rights reserved.
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//
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#ifndef ImageStreams_basics_hpp
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#define ImageStreams_basics_hpp
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/*
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A PixelFormat p should have the following constructors (depending on number
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of colors):
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p(int r, int g, int b, int a)
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p(double r, double g, double b, double a)
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p(int v)
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p(double v)
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The order in the ctor is rgb even though the internal structure may be
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different
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It should be trivially copyable (for memcpy).
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Furthermore it should have a static const size_t num_colors indicating the
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number of colors and a static const size_t bit_per_color indicating the
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number of bits per color (TODO: what to do with encodings like 565 ?)
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*/
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#include <cstdint>
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#include <algorithm>
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namespace pixel_formats {
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inline uint8_t clamp(int n){
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return std::min(255, std::max(0, n));
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}
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struct gray {
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static const size_t num_colors = 1;
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static const size_t bits_per_color = 8;
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gray() : value(0) {}
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gray(double intensity) : value(clamp(255*intensity)) {}
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gray(int intensity) : value(clamp(intensity)) {}
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private:
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uint8_t value;
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};
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struct rgb {
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static const size_t num_colors = 3;
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static const size_t bits_per_color = 8;
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rgb()
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: red(0)
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, green(0)
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, blue(0)
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{}
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rgb(double red, double green, double blue)
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: red(clamp(255*red))
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, green(clamp(255*green))
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, blue(clamp(255*blue))
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{}
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rgb(int red, int green, int blue)
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: red(clamp(red))
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, green(clamp(green))
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, blue(clamp(blue))
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{}
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private:
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uint8_t red;
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uint8_t green;
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uint8_t blue;
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};
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struct bgr{
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static const size_t num_colors = 3;
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static const size_t bits_per_color = 8;
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bgr()
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: blue(0)
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, green(0)
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, red(0)
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{}
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bgr(double red, double green, double blue)
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: blue(clamp(255*blue))
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, green(clamp(255*green))
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, red(clamp(255*red))
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{}
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bgr(int red, int green, int blue)
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: blue(clamp(blue))
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, green(clamp(green))
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, red(clamp(red))
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{}
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private:
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uint8_t blue;
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uint8_t green;
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uint8_t red;
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};
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template <typename PixelType>
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struct traits {
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static const size_t num_colors = PixelType::num_colors;
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static const size_t bits_per_color = PixelType::bits_per_color;
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static const size_t bits_per_pixel = num_colors * bits_per_color;
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};
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}
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#endif
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191
include/png.hpp
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include/png.hpp
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//
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// png.hpp
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// ImageStreams
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//
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// Created by Joshua Moerman on 9/7/12.
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// Copyright (c) 2012 Vadovas. All rights reserved.
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//
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#ifndef ImageStreams_png_hpp
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#define ImageStreams_png_hpp
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#include <cstdio>
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#include <stdexcept>
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#include <vector>
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#include <png.h>
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#include "basics.hpp"
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namespace png{
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template <typename P>
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int color_type(){
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int num_colors = pixel_formats::traits<P>::num_colors;
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switch (num_colors) {
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case 1: return PNG_COLOR_TYPE_GRAY;
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case 2: return PNG_COLOR_TYPE_GRAY_ALPHA;
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case 3: return PNG_COLOR_TYPE_RGB;
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case 4: return PNG_COLOR_TYPE_RGB_ALPHA;
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default: return PNG_COLOR_TYPE_RGB;
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}
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}
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template <typename P = pixel_formats::rgb>
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struct ostream{
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typedef P pixel;
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ostream() = delete;
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ostream(ostream const &) = delete;
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ostream & operator=(ostream const &) = delete;
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ostream(uint32_t width, uint32_t height, std::string filename)
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: fp(0)
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, png_ptr(0)
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, info_ptr(0)
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, row(width)
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, x(0)
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{
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fp = fopen(filename.c_str(), "wb");
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if(!fp) throw std::runtime_error("Could not open file");
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png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
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if(!png_ptr) throw std::runtime_error("PNG structure could not be allocated");
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info_ptr = png_create_info_struct(png_ptr);
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if(!info_ptr) throw std::runtime_error("PNG information structure could not be allocated");
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png_init_io(png_ptr, fp);
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png_set_IHDR(png_ptr, info_ptr, width, height, pixel_formats::traits<pixel>::bits_per_color, color_type<pixel>(), PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
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png_set_compression_level(png_ptr, 9);
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png_write_info(png_ptr, info_ptr);
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}
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~ostream(){
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// NOTE: the pnglib already checks for us whether all pixels are written
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png_write_end(png_ptr, info_ptr);
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png_destroy_info_struct(png_ptr, &info_ptr);
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fclose(fp);
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}
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ostream& operator<<(pixel const & p){
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row[x] = p;
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++x;
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if(x >= row.size()){
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png_write_row(png_ptr, reinterpret_cast<unsigned char const*>(row.data()));
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x = 0;
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}
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return *this;
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}
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private:
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FILE* fp;
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png_structp png_ptr;
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png_infop info_ptr;
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std::vector<pixel> row;
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uint32_t x;
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};
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typedef ostream<> colored_ostream;
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typedef ostream<pixel_formats::gray> gray_ostream;
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struct istream{
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//typedef pixel pixel;
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istream(std::string filename)
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: fp(0)
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, png_ptr(0)
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, info_ptr(0)
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, valid(true)
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, row()
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, stride(0)
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, x(0)
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, y(0)
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, height(0)
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{
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fp = fopen(filename.c_str(), "rb");
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if(!fp) throw std::runtime_error(filename + " could not be opened");
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png_byte header[8];
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fread(header, 1, 8, fp);
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if(png_sig_cmp(header, 0, 8) != 0) throw std::runtime_error("File is not a PNG file.");
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png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
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if(!png_ptr) throw std::runtime_error("PNG structure could not be allocated");
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info_ptr = png_create_info_struct(png_ptr);
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if(!info_ptr) throw std::runtime_error("PNG information structure could not be allocated");
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png_init_io(png_ptr, fp);
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png_set_sig_bytes(png_ptr, 8);
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png_read_info(png_ptr, info_ptr);
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if(png_get_interlace_type(png_ptr, info_ptr) != PNG_INTERLACE_NONE)
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throw std::runtime_error("Interalced PNG's are not supported");
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height = png_get_image_height(png_ptr, info_ptr);
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auto width = png_get_image_width(png_ptr, info_ptr);
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auto bit_depth = png_get_bit_depth(png_ptr, info_ptr);
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auto channels = png_get_channels(png_ptr, info_ptr);
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// number of bytes in one row
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stride = bit_depth * channels / 8;
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size_t row_size = width * stride;
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if(bit_depth < 8) throw std::runtime_error("Bitdepths lower than 8 are not supported (yet)");
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row.resize(row_size);
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png_read_row(png_ptr, (png_bytep)row.data(), 0);
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}
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~istream(){
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png_read_end(png_ptr, 0);
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png_destroy_read_struct(&png_ptr, &info_ptr, 0);
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fclose(fp);
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}
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template <typename Pixel>
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istream& operator>>(Pixel & p){
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if( y >= height){
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valid = false;
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return *this;
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}
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p = row[x];
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if(++x >= get_width()){
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x = 0;
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++y;
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if(y < height)
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png_read_row(png_ptr, (png_bytep)row.data(), 0);
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}
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return *this;
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}
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operator bool() const {
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return valid;
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}
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uint32_t get_width() const { return row.size(); }
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uint32_t get_height() const { return height; }
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private:
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FILE* fp;
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png_structp png_ptr;
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png_infop info_ptr;
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bool valid;
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std::vector<char> row;
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uint32_t stride;
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uint32_t x;
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uint32_t y;
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uint32_t height;
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};
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}
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#endif
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