#include <stdio.h>
// Use the main header file of Foxit Reader SDK
#include "fpdfview.h"

// Write a Foxit Device Independant Bitmap to a PPM file
void WritePPM(FPDF_BITMAP pBitmap, char* filename)
{
  FILE* file = fopen(filename, "wb");
  if (file == NULL) return;

  // Write a simple file header
  int width = FPDFBitmap_GetWidth(pBitmap);
  int height = FPDFBitmap_GetHeight(pBitmap);
  fprintf(file, "P6 %d %d 255\n", width, height);

  // Write pixel color values one by one.
  for (int row = 0; row < height; row ++) {
    char* scan_line = (char*)FPDFBitmap_GetBuffer(pBitmap) + row * width * 4;
    for (int col = 0; col < width; col ++)
	// NOTE: Foxit DIB uses BGRA byte order, PPM uses RGB, 
	// so we need to swap here.
	fprintf(file, "%c%c%c", scan_line[col*4+2], scan_line[col*4+1], 
		scan_line[col*4]);
  }

  // Finished
  fclose(file);
}

int main(int argc, char** argv)
{
  if (argc == 1) {
    printf("Please specify a file name.\n");
    return 0;
  }

  // Load the PDF document
  FPDF_DOCUMENT doc = FPDF_LoadDocument(argv[1], NULL);
  if (doc == NULL) {
    printf("error opening file\n");
    return 0;
  }

  // Load first page
  FPDF_PAGE page = FPDF_LoadPage(doc, 0);

  // Create a bitmap device for displaying the page
  int width = 480, height = 640;		// width and height of the bitmap device
  FPDF_BITMAP bitmap = FPDFBitmap_Create(width, height, 0);		// we don't use alpha channel here

  // Fill the whole bitmap with white background
  FPDFBitmap_FillRect(bitmap, 0, 0, width, height, 255, 255, 255, 255);

  // Now we can display the page into the bitmap
  FPDF_RenderPageBitmap(bitmap, page, 0, 0, width, height, 0, 0);

  // Write the result bitmap to a simple PPM bitmap file
  WritePPM(bitmap, "test.ppm");

  // Clean up
  FPDFBitmap_Destroy(bitmap);
  FPDF_ClosePage(page);
  FPDF_CloseDocument(doc);

  return 0;
}