Using FreeImage in Ubuntu

In my last post I mentioned I wanted to output a visualization of the time it takes to render various parts of my fractal generator. To do this I used FreeImage, so here is a little tutorial on how to use the library in Ubuntu.

To install, just install the libfreeimage-dev package, either through Synaptic or using:

sudo apt-get install libfreeimage-dev

Once you've got that installed, you can link to it from your C/C++ programs.

Here's some simple code to output a blue background to a bitmap:

#include <FreeImage.h>
#include <stdlib.h>

int main(){
  FreeImage_Initialise();
  atexit(FreeImage_DeInitialise);

  // create the bitmap object
  FIBITMAP * bitmap = FreeImage_Allocate(200, 200, 32);  // allocate a 200x200 pixel image, with 32-bit colour

  // create the blue colour
  RGBQUAD blue;
  blue.rgbBlue = 255;

  for (int i = 0; i < 200; i++){
    for (int j = 0; j < 200; j++){
      // draw a blue pixel at (i, j)
      FreeImage_SetPixelColor(bitmap, i, j, &blue);
    }
  }

  // save it as output.bmp
  FreeImage_Save(FIF_BMP, bitmap, "output.bmp");

  // deallocate memory
  FreeImage_Unload(bitmap);
}

Then to compile:

g++ image.cpp -o image -lfreeimage