/* Copyright (c) 2013 Frank Ham and Phuc Quang */
#include <iostream>
#include <string>
#include <png.h>using namespace std;#ifndef PNG_WRITER_HPP
#define PNG_WRITER_HPP// Sample usage:
//    PngWriter png(nx,ny);
//    // then one or more calls to...
//    png.set(i, j, red, green, blue); // 0 <= red,green,blue <= 255
//    png.write("myfile.png");
//      at this point you can change the image and write again...
//    png.set(i, j, red, green, blue);
//    png.write("myfile2.png");
class PngWriter {
private:unsigned char (*buffer)[3]; // 0 <= r,g,b < 255 int nx,ny;
public:PngWriter(const int width,const int height) {nx = width;ny = height;buffer = new unsigned char[nx*ny][3];for (int i = 0; i < nx*ny; ++i) {//cyanbuffer[i][0] = 73;buffer[i][1] = 175;buffer[i][2] = 205;}}~PngWriter() {delete[] buffer;}/*给某一点的像素赋值*/void set(const int i,const int j,const unsigned char r,const unsigned char g,         const unsigned char b) {buffer[(ny-j-1)*nx+i][0] = r;buffer[(ny-j-1)*nx+i][1] = g;buffer[(ny-j-1)*nx+i][2] = b;}/*修复原作者的char **/void write(string filename) {FILE * fp = fopen(filename.c_str(),"wb");if (!fp) {std::cout << "Warning: could not open png file: " << filename << std::endl;return;}png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,(png_voidp)NULL,NULL,NULL);if (!png_ptr) {fclose(fp);std::cout << "Warning: could not create png_ptr" << std::endl;return;}png_infop info_ptr = png_create_info_struct(png_ptr);if (!info_ptr) {png_destroy_write_struct(&png_ptr,(png_infopp)NULL);std::cout << "Warning: could not create info_ptr" << std::endl;return;}png_init_io(png_ptr, fp);png_set_IHDR(png_ptr, info_ptr,nx, ny,             // width, height8,                  // bits per pixel -- 16 does not work with blockbusterPNG_COLOR_TYPE_RGB, // non-alpha options are PNG_COLOR_TYPE_RGB,PNG_COLOR_TYPE_GRAY,PNG_INTERLACE_NONE,PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);/* Some bits per pixel notes: 16 does not work with blockbuster, and there are also
         issues with PNG_COLOR_TYPE_GRAY interpretation, so stick to 8 and PNG_COLOR_TYPE_RGB
         for now. Note that if you do use 16, pay attention to MSB/LSB order. Endian is
         flipped on my linux workstation... */png_write_info(png_ptr, info_ptr);// set up row pointers to point into the raw image data in buffer...png_byte * row_pointers[ny];for (int i = 0; i < ny; ++i)row_pointers[i] = (png_byte*)(buffer + i*nx);png_write_image(png_ptr, row_pointers);png_write_end(png_ptr, NULL);png_destroy_write_struct(&png_ptr, &info_ptr);fclose(fp);}
};
#endif// g++ main.cpp -lpng
int main(int argc,char * argv[])
{PngWriter png(800,600);// set some pixels....for (int i = 0; i < 800; ++i)for (int j = 0; j < 600; ++j)png.set(i,j,i+j,i-j,j-i); // then write...png.write("sample1.png");for (int i = 400; i < 500; ++i)for (int j = 200; j < 300; ++j)png.set(i,j,10,10,10);png.write("sample2.png");
}

$ g++ main.cpp -lpng$ ./a.exe