pytorch

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// example6.c - Demonstrates how to miniz's PNG writer func
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// Public domain, April 11 2012, Rich Geldreich, richgel99@gmail.com. See "unlicense" statement at the end of tinfl.c.
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// Mandlebrot set code from http://rosettacode.org/wiki/Mandelbrot_set#C
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// Must link this example against libm on Linux.
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// Purposely disable a whole bunch of stuff this low-level example doesn't use.
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#define MINIZ_NO_STDIO
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#define MINIZ_NO_TIME
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#define MINIZ_NO_ZLIB_APIS
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#include "miniz.h"
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// Now include stdio.h because this test uses fopen(), etc. (but we still don't want miniz.c's stdio stuff, for testing).
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#include <stdio.h>
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#include <limits.h>
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#include <math.h>
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typedef unsigned char uint8;
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typedef unsigned short uint16;
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typedef unsigned int uint;
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typedef struct
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{
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  uint8 r, g, b;
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} rgb_t;
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static void hsv_to_rgb(int hue, int min, int max, rgb_t *p)
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{
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  const int invert = 0;
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  const int saturation = 1;
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  const int color_rotate = 0;
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  if (min == max) max = min + 1;
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  if (invert) hue = max - (hue - min);
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  if (!saturation) {
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    p->r = p->g = p->b = 255 * (max - hue) / (max - min);
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    return;
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  }
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  double h = fmod(color_rotate + 1e-4 + 4.0 * (hue - min) / (max - min), 6);
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  double c = 255.0f * saturation;
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  double X = c * (1 - fabs(fmod(h, 2) - 1));
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  p->r = p->g = p->b = 0;
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  switch((int)h) {
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  case 0: p->r = c; p->g = X; return;
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  case 1:	p->r = X; p->g = c; return;
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  case 2: p->g = c; p->b = X; return;
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  case 3: p->g = X; p->b = c; return;
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  case 4: p->r = X; p->b = c; return;
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  default:p->r = c; p->b = X;
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  }
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}
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int main(int argc, char *argv[])
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{
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  (void)argc, (void)argv;
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  // Image resolution
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  const int iXmax = 4096;
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  const int iYmax = 4096;
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  // Output filename
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  static const char *pFilename = "mandelbrot.png";
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  int iX, iY;
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  const double CxMin = -2.5;
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  const double CxMax = 1.5;
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  const double CyMin = -2.0;
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  const double CyMax = 2.0;
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  double PixelWidth = (CxMax - CxMin) / iXmax;
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  double PixelHeight = (CyMax - CyMin) / iYmax;
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  // Z=Zx+Zy*i  ;   Z0 = 0
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  double Zx, Zy;
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  double Zx2, Zy2; // Zx2=Zx*Zx;  Zy2=Zy*Zy
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  int Iteration;
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  const int IterationMax = 200;
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  // bail-out value , radius of circle
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  const double EscapeRadius = 2;
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  double ER2=EscapeRadius * EscapeRadius;
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  uint8 *pImage = (uint8 *)malloc(iXmax * 3 * iYmax);
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  // world ( double) coordinate = parameter plane
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  double Cx,Cy;
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  int MinIter = 9999, MaxIter = 0;
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  for(iY = 0; iY < iYmax; iY++)
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  {
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    Cy = CyMin + iY * PixelHeight;
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    if (fabs(Cy) < PixelHeight/2)
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      Cy = 0.0; // Main antenna
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    for(iX = 0; iX < iXmax; iX++)
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    {
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      uint8 *color = pImage + (iX * 3) + (iY * iXmax * 3);
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      Cx = CxMin + iX * PixelWidth;
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      // initial value of orbit = critical point Z= 0
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      Zx = 0.0;
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      Zy = 0.0;
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      Zx2 = Zx * Zx;
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      Zy2 = Zy * Zy;
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      for (Iteration=0;Iteration<IterationMax && ((Zx2+Zy2)<ER2);Iteration++)
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      {
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        Zy = 2 * Zx * Zy + Cy;
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        Zx =Zx2 - Zy2 + Cx;
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        Zx2 = Zx * Zx;
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        Zy2 = Zy * Zy;
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      };
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      color[0] = (uint8)Iteration;
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      color[1] = (uint8)Iteration >> 8;
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      color[2] = 0;
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      if (Iteration < MinIter)
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        MinIter = Iteration;
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      if (Iteration > MaxIter)
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        MaxIter = Iteration;
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    }
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  }
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  for(iY = 0; iY < iYmax; iY++)
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  {
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    for(iX = 0; iX < iXmax; iX++)
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    {
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      uint8 *color = (uint8 *)(pImage + (iX * 3) + (iY * iXmax * 3));
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      uint Iterations = color[0] | (color[1] << 8U);
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      hsv_to_rgb(Iterations, MinIter, MaxIter, (rgb_t *)color);
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    }
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  }
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  // Now write the PNG image.
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  {
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    size_t png_data_size = 0;
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    void *pPNG_data = tdefl_write_image_to_png_file_in_memory_ex(pImage, iXmax, iYmax, 3, &png_data_size, 6, MZ_FALSE);
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    if (!pPNG_data)
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      fprintf(stderr, "tdefl_write_image_to_png_file_in_memory_ex() failed!\n");
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    else
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    {
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      FILE *pFile = fopen(pFilename, "wb");
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      fwrite(pPNG_data, 1, png_data_size, pFile);
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      fclose(pFile);
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      printf("Wrote %s\n", pFilename);
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    }
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    // mz_free() is by default just an alias to free() internally, but if you've overridden miniz's allocation funcs you'll probably need to call mz_free().
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    mz_free(pPNG_data);
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  }
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  free(pImage);
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  return EXIT_SUCCESS;
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}
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