text: /* (c) Magnus Auvinen. See licence.txt in the root of the distribution for more information. */
  /* If you are missing that file, acquire a complete release at teeworlds.com.                */
  #include <stdlib.h>
  #include <base/system.h>
  #include <engine/external/pnglite/pnglite.h>
  
  typedef struct
  {
  	unsigned char r, g, b, a;
  } CPixel;
  
  static CPixel Sample(int x, int y, int w, int h, CPixel *pData, int Pitch, float u, float v)
  {
  	x = x + (int)(w*u);
  	y = y + (int)(h*v);
  	return pData[y*Pitch+x];
  }
  
  static void TilesetBorderfix(int w, int h, CPixel *pSrc, CPixel *pDest)
  {
  	int TileW = w/16;
  	int TileH = h/16;
  	
  	mem_zero(pDest, sizeof(CPixel)*w*h);
  	
  	for(int ty = 0; ty < 16; ty++)
  	{
  		for(int tx = 0; tx < 16; tx++)
  		{
  			for(int y = 0; y < TileH-2; y++)
  			{
  				for(int x = 0; x < TileW-2; x++)
  				{
  					float u = 0.5f/TileW + x/(float)(TileW-2);
  					float v = 0.5f/TileH + y/(float)(TileH-2);
  					int k = (ty*TileH+1+y)*w + tx*TileW+x+1;
  					pDest[k] = Sample(tx*TileW, ty*TileH, TileW, TileH, pSrc, w, u, v);
  					
  					if(x == 0) pDest[k-1] = pDest[k];
  					if(x == TileW-2-1) pDest[k+1] = pDest[k];
  					if(y == 0) pDest[k-w] = pDest[k];
  					if(y == TileH-2-1) pDest[k+w] = pDest[k];
  					
  					if(x == 0 && y == 0) pDest[k-w-1] = pDest[k];
  					if(x == TileW-2-1 && y == 0) pDest[k-w+1] = pDest[k];
  					if(x == 0 && y == TileH-2-1) pDest[k+w-1] = pDest[k];
  					if(x == TileW-2-1 && y == TileH-2-1) pDest[k+w+1] = pDest[k];
  				}
  			}
  		}
  	}
  }
  
  
  int main(int argc, char **argv)
  {
  	png_t Png;
  	CPixel *pBuffer[2] = {0,0};
  	
  	png_init(0, 0);
  	png_open_file(&Png, argv[1]);
  	
  	if(Png.color_type != PNG_TRUECOLOR_ALPHA)
  	{
  		dbg_msg("dilate", "not an RGBA image");
  		return -1;
  	}
  	
  	int w = Png.width;
  	int h = Png.height;
  	
  	pBuffer[0] = (CPixel*)mem_alloc(w*h*sizeof(CPixel), 1);
  	pBuffer[1] = (CPixel*)mem_alloc(w*h*sizeof(CPixel), 1);
  	png_get_data(&Png, (unsigned char *)pBuffer[0]);
  	png_close_file(&Png);
  	
  	TilesetBorderfix(w, h, pBuffer[0], pBuffer[1]);
  	
  	// save here
  	png_open_file_write(&Png, argv[1]);
  	png_set_data(&Png, w, h, 8, PNG_TRUECOLOR_ALPHA, (unsigned char *)pBuffer[1]);
  	png_close_file(&Png);
  		
  	return 0;
  }
  