bitmap.c

#include <stdio.h>
#include <stdlib.h>

#include "bitmap.h"

Bitmap *BitmapNewImage(uint16_t width, uint16_t height) {
  Bitmap *bitmap;

  bitmap = (Bitmap *)calloc(1, sizeof(*bitmap));

  uint32_t headerSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPCOREHEADER);
  uint32_t rowSize = sizeof(RGBTRIPLE) * width;
  // NOTE: Each row in the Pixel array is padded to a multiple of 4 bytes in size.
  if (rowSize % 4) {
    rowSize += 4 - rowSize % 4;
  }
  uint32_t size = rowSize * height;

  bitmap->fileHeader = (BITMAPFILEHEADER){BMP_MAGIC, headerSize + size, 0, 0, headerSize};
  bitmap->dibHeader = (BITMAPCOREHEADER){12, width, height, 1, 24};
  bitmap->pixels = (RGBTRIPLE *)calloc(1, size);

  return bitmap;
}

bool BitmapDestroy(Bitmap *bitmap) {
  if (bitmap == NULL) {
#ifndef NDEBUG
    fprintf(stderr, "%s: trying to free null pointer, ignored.\n", __FUNCTION_NAME__);
#endif
    return false;
  }
  free(bitmap->pixels);
  free(bitmap);
  return true; // TODO: implement error handler
}

bool BitmapWriteFile(const Bitmap *bitmap, const char *filename) {
  FILE *fp = fopen(filename, "w+");
  fwrite(&bitmap->fileHeader, sizeof(BITMAPFILEHEADER), 1, fp);
  fwrite(&bitmap->dibHeader, sizeof(BITMAPCOREHEADER), 1, fp);
  fwrite(bitmap->pixels, bitmap->fileHeader.bfSize - bitmap->fileHeader.bfOffBits, 1, fp);
  fclose(fp);
  return true; // TODO: implement error handler
}

bool BitmapSetPixelColor(Bitmap *bitmap, uint16_t x, uint16_t y, const RGBTRIPLE *color) {
  if (bitmap->dibHeader.bcWidth <= x || bitmap->dibHeader.bcHeight <= y) {
#ifndef NDEBUG
    fprintf(stderr, "%s: Invalid pixel indices (x:%d<%d, y:%d<%d)\n", __FUNCTION_NAME__, x, bitmap->dibHeader.bcWidth, y, bitmap->dibHeader.bcHeight);
#endif
    return false;
  }
  bitmap->pixels[x + bitmap->dibHeader.bcWidth * (bitmap->dibHeader.bcHeight - y - 1)] = *color;
  return true;
}